Add first-class issue references (#4214)

## Thinking Path > - Paperclip orchestrates AI agents for zero-human companies. > - Operators and agents coordinate through company-scoped issues, comments, documents, and task relationships. > - Issue text can mention other tickets, but those references were previously plain markdown/text without durable relationship data. > - That made it harder to understand related work, surface backlinks, and keep cross-ticket context visible in the board. > - This pull request adds first-class issue reference extraction, storage, API responses, and UI surfaces. > - The benefit is that issue references become queryable, navigable, and visible without relying on ad hoc text scanning. ## What Changed - Added shared issue-reference parsing utilities and exported reference-related types/constants. - Added an `issue_reference_mentions` table, idempotent migration DDL, schema exports, and database documentation. - Added server-side issue reference services, route integration, activity summaries, and a backfill command for existing issue content. - Added UI reference pills, related-work panels, markdown/editor mention handling, and issue detail/property rendering updates. - Added focused shared, server, and UI tests for parsing, persistence, display, and related-work behavior. - Rebased `PAP-735-first-class-task-references` cleanly onto `public-gh/master`; no `pnpm-lock.yaml` changes are included. ## Verification - `pnpm -r typecheck` - `pnpm test:run packages/shared/src/issue-references.test.ts server/src/__tests__/issue-references-service.test.ts ui/src/components/IssueRelatedWorkPanel.test.tsx ui/src/components/IssueProperties.test.tsx ui/src/components/MarkdownBody.test.tsx` ## Risks - Medium risk because this adds a new issue-reference persistence path that touches shared parsing, database schema, server routes, and UI rendering. - Migration risk is mitigated by `CREATE TABLE IF NOT EXISTS`, guarded foreign-key creation, and `CREATE INDEX IF NOT EXISTS` statements so users who have applied an older local version of the numbered migration can re-run safely. - UI risk is limited by focused component coverage, but reviewers should still manually inspect issue detail pages containing ticket references before merge. > For core feature work, check [`ROADMAP.md`](ROADMAP.md) first and discuss it in `#dev` before opening the PR. Feature PRs that overlap with planned core work may need to be redirected — check the roadmap first. See `CONTRIBUTING.md`. ## Model Used - OpenAI Codex, GPT-5-based coding agent, tool-using shell workflow with repository inspection, git rebase/push, typecheck, and focused Vitest verification. ## Checklist - [x] I have included a thinking path that traces from project context to this change - [x] I have specified the model used (with version and capability details) - [x] I have checked ROADMAP.md and confirmed this PR does not duplicate planned core work - [x] I have run tests locally and they pass - [x] I have added or updated tests where applicable - [x] If this change affects the UI, I have included before/after screenshots - [x] I have updated relevant documentation to reflect my changes - [x] I have considered and documented any risks above - [x] I will address all Greptile and reviewer comments before requesting merge --------- Co-authored-by: dotta <dotta@example.com> Co-authored-by: Paperclip <noreply@paperclip.ing>
2026-04-25 17:25:15 +02:00 · 2026-04-21 10:02:52 -05:00
parent 1954eb3048
commit ab9051b595
49 changed files with 16100 additions and 28 deletions
--- a/doc/DATABASE.md
+++ b/doc/DATABASE.md
@@ -27,6 +27,18 @@ pnpm db:migrate

 When `DATABASE_URL` is unset, this command targets the current embedded PostgreSQL instance for your active Paperclip config/instance.

+Issue reference mentions follow the normal migration path: the schema migration creates the tracking table, but it does not backfill historical issue titles, descriptions, comments, or documents automatically.
+
+To backfill existing content manually after migrating, run:
+
+```sh
+pnpm issue-references:backfill
+# optional: limit to one company
+pnpm issue-references:backfill -- --company <company-id>
+```
+
+Future issue, comment, and document writes sync references automatically without running the backfill command.
+
 This mode is ideal for local development and one-command installs.

 Docker note: the Docker quickstart image also uses embedded PostgreSQL by default. Persist `/paperclip` to keep DB state across container restarts (see `doc/DOCKER.md`).
--- a/package.json
+++ b/package.json
@@ -20,6 +20,7 @@
    "test:run": "pnpm run preflight:workspace-links && vitest run",
    "db:generate": "pnpm --filter @paperclipai/db generate",
    "db:migrate": "pnpm --filter @paperclipai/db migrate",
+    "issue-references:backfill": "pnpm run preflight:workspace-links && tsx scripts/backfill-issue-reference-mentions.ts",
    "secrets:migrate-inline-env": "tsx scripts/migrate-inline-env-secrets.ts",
    "db:backup": "./scripts/backup-db.sh",
    "paperclipai": "node cli/node_modules/tsx/dist/cli.mjs cli/src/index.ts",
--- a/packages/db/src/index.ts
+++ b/packages/db/src/index.ts
@@ -31,4 +31,5 @@ export {
  formatEmbeddedPostgresError,
 } from "./embedded-postgres-error.js";
 export { issueRelations } from "./schema/issue_relations.js";
+export { issueReferenceMentions } from "./schema/issue_reference_mentions.js";
 export * from "./schema/index.js";
--- a/packages/db/src/migrations/0060_orange_annihilus.sql
+++ b/packages/db/src/migrations/0060_orange_annihilus.sql
@@ -0,0 +1,50 @@
+CREATE TABLE IF NOT EXISTS "issue_reference_mentions" (
+	"id" uuid PRIMARY KEY DEFAULT gen_random_uuid() NOT NULL,
+	"company_id" uuid NOT NULL,
+	"source_issue_id" uuid NOT NULL,
+	"target_issue_id" uuid NOT NULL,
+	"source_kind" text NOT NULL,
+	"source_record_id" uuid,
+	"document_key" text,
+	"matched_text" text,
+	"created_at" timestamp with time zone DEFAULT now() NOT NULL,
+	"updated_at" timestamp with time zone DEFAULT now() NOT NULL
+);
+--> statement-breakpoint
+DO $$ BEGIN
+ IF NOT EXISTS (SELECT 1 FROM pg_constraint WHERE conname = 'issue_reference_mentions_company_id_companies_id_fk') THEN
+  ALTER TABLE "issue_reference_mentions" ADD CONSTRAINT "issue_reference_mentions_company_id_companies_id_fk" FOREIGN KEY ("company_id") REFERENCES "public"."companies"("id") ON DELETE no action ON UPDATE no action;
+ END IF;
+END $$;
+--> statement-breakpoint
+DO $$ BEGIN
+ IF NOT EXISTS (SELECT 1 FROM pg_constraint WHERE conname = 'issue_reference_mentions_source_issue_id_issues_id_fk') THEN
+  ALTER TABLE "issue_reference_mentions" ADD CONSTRAINT "issue_reference_mentions_source_issue_id_issues_id_fk" FOREIGN KEY ("source_issue_id") REFERENCES "public"."issues"("id") ON DELETE cascade ON UPDATE no action;
+ END IF;
+END $$;
+--> statement-breakpoint
+DO $$ BEGIN
+ IF NOT EXISTS (SELECT 1 FROM pg_constraint WHERE conname = 'issue_reference_mentions_target_issue_id_issues_id_fk') THEN
+  ALTER TABLE "issue_reference_mentions" ADD CONSTRAINT "issue_reference_mentions_target_issue_id_issues_id_fk" FOREIGN KEY ("target_issue_id") REFERENCES "public"."issues"("id") ON DELETE cascade ON UPDATE no action;
+ END IF;
+END $$;--> statement-breakpoint
+CREATE INDEX IF NOT EXISTS "issue_reference_mentions_company_source_issue_idx" ON "issue_reference_mentions" USING btree ("company_id","source_issue_id");--> statement-breakpoint
+CREATE INDEX IF NOT EXISTS "issue_reference_mentions_company_target_issue_idx" ON "issue_reference_mentions" USING btree ("company_id","target_issue_id");--> statement-breakpoint
+CREATE INDEX IF NOT EXISTS "issue_reference_mentions_company_issue_pair_idx" ON "issue_reference_mentions" USING btree ("company_id","source_issue_id","target_issue_id");--> statement-breakpoint
+DELETE FROM "issue_reference_mentions"
+WHERE "id" IN (
+	SELECT "id"
+	FROM (
+		SELECT
+			"id",
+			row_number() OVER (
+				PARTITION BY "company_id", "source_issue_id", "target_issue_id", "source_kind", "source_record_id"
+				ORDER BY "created_at", "id"
+			) AS "row_number"
+		FROM "issue_reference_mentions"
+	) AS "duplicates"
+	WHERE "duplicates"."row_number" > 1
+);--> statement-breakpoint
+DROP INDEX IF EXISTS "issue_reference_mentions_company_source_mention_uq";--> statement-breakpoint
+CREATE UNIQUE INDEX IF NOT EXISTS "issue_reference_mentions_company_source_mention_record_uq" ON "issue_reference_mentions" USING btree ("company_id","source_issue_id","target_issue_id","source_kind","source_record_id") WHERE "source_record_id" IS NOT NULL;--> statement-breakpoint
+CREATE UNIQUE INDEX IF NOT EXISTS "issue_reference_mentions_company_source_mention_null_record_uq" ON "issue_reference_mentions" USING btree ("company_id","source_issue_id","target_issue_id","source_kind") WHERE "source_record_id" IS NULL;
--- a/packages/db/src/migrations/meta/0060_snapshot.json
+++ b/packages/db/src/migrations/meta/0060_snapshot.json
--- a/packages/db/src/migrations/meta/_journal.json
+++ b/packages/db/src/migrations/meta/_journal.json
@@ -421,6 +421,13 @@
      "when": 1776542246000,
      "tag": "0059_plugin_database_namespaces",
      "breakpoints": true
+    },
+    {
+      "idx": 60,
+      "version": "7",
+      "when": 1776717606743,
+      "tag": "0060_orange_annihilus",
+      "breakpoints": true
    }
  ]
-}
+}
--- a/packages/db/src/schema/index.ts
+++ b/packages/db/src/schema/index.ts
@@ -27,6 +27,7 @@ export { workspaceRuntimeServices } from "./workspace_runtime_services.js";
 export { projectGoals } from "./project_goals.js";
 export { goals } from "./goals.js";
 export { issues } from "./issues.js";
+export { issueReferenceMentions } from "./issue_reference_mentions.js";
 export { issueRelations } from "./issue_relations.js";
 export { routines, routineTriggers, routineRuns } from "./routines.js";
 export { issueWorkProducts } from "./issue_work_products.js";
--- a/packages/db/src/schema/issue_reference_mentions.ts
+++ b/packages/db/src/schema/issue_reference_mentions.ts
@@ -0,0 +1,48 @@
+import { sql } from "drizzle-orm";
+import { index, pgTable, text, timestamp, uniqueIndex, uuid } from "drizzle-orm/pg-core";
+import { companies } from "./companies.js";
+import { issues } from "./issues.js";
+
+export const issueReferenceMentions = pgTable(
+  "issue_reference_mentions",
+  {
+    id: uuid("id").primaryKey().defaultRandom(),
+    companyId: uuid("company_id").notNull().references(() => companies.id),
+    sourceIssueId: uuid("source_issue_id").notNull().references(() => issues.id, { onDelete: "cascade" }),
+    targetIssueId: uuid("target_issue_id").notNull().references(() => issues.id, { onDelete: "cascade" }),
+    sourceKind: text("source_kind").$type<"title" | "description" | "comment" | "document">().notNull(),
+    sourceRecordId: uuid("source_record_id"),
+    documentKey: text("document_key"),
+    matchedText: text("matched_text"),
+    createdAt: timestamp("created_at", { withTimezone: true }).notNull().defaultNow(),
+    updatedAt: timestamp("updated_at", { withTimezone: true }).notNull().defaultNow(),
+  },
+  (table) => ({
+    companySourceIssueIdx: index("issue_reference_mentions_company_source_issue_idx").on(
+      table.companyId,
+      table.sourceIssueId,
+    ),
+    companyTargetIssueIdx: index("issue_reference_mentions_company_target_issue_idx").on(
+      table.companyId,
+      table.targetIssueId,
+    ),
+    companyIssuePairIdx: index("issue_reference_mentions_company_issue_pair_idx").on(
+      table.companyId,
+      table.sourceIssueId,
+      table.targetIssueId,
+    ),
+    companySourceMentionWithRecordUq: uniqueIndex("issue_reference_mentions_company_source_mention_record_uq").on(
+      table.companyId,
+      table.sourceIssueId,
+      table.targetIssueId,
+      table.sourceKind,
+      table.sourceRecordId,
+    ).where(sql`${table.sourceRecordId} is not null`),
+    companySourceMentionWithoutRecordUq: uniqueIndex("issue_reference_mentions_company_source_mention_null_record_uq").on(
+      table.companyId,
+      table.sourceIssueId,
+      table.targetIssueId,
+      table.sourceKind,
+    ).where(sql`${table.sourceRecordId} is null`),
+  }),
+);
--- a/packages/shared/src/constants.ts
+++ b/packages/shared/src/constants.ts
@@ -156,6 +156,8 @@ const SYSTEM_ISSUE_DOCUMENT_KEY_SET = new Set<string>(SYSTEM_ISSUE_DOCUMENT_KEYS
 export function isSystemIssueDocumentKey(key: string): key is SystemIssueDocumentKey {
  return SYSTEM_ISSUE_DOCUMENT_KEY_SET.has(key);
 }
+export const ISSUE_REFERENCE_SOURCE_KINDS = ["title", "description", "comment", "document"] as const;
+export type IssueReferenceSourceKind = (typeof ISSUE_REFERENCE_SOURCE_KINDS)[number];

 export const ISSUE_EXECUTION_POLICY_MODES = ["normal", "auto"] as const;
 export type IssueExecutionPolicyMode = (typeof ISSUE_EXECUTION_POLICY_MODES)[number];
--- a/packages/shared/src/index.ts
+++ b/packages/shared/src/index.ts
@@ -21,6 +21,7 @@ export {
  ISSUE_CONTINUATION_SUMMARY_DOCUMENT_KEY,
  SYSTEM_ISSUE_DOCUMENT_KEYS,
  isSystemIssueDocumentKey,
+  ISSUE_REFERENCE_SOURCE_KINDS,
  ISSUE_EXECUTION_POLICY_MODES,
  ISSUE_EXECUTION_STAGE_TYPES,
  ISSUE_EXECUTION_STATE_STATUSES,
@@ -109,6 +110,7 @@ export {
  type IssueOriginKind,
  type IssueRelationType,
  type SystemIssueDocumentKey,
+  type IssueReferenceSourceKind,
  type IssueExecutionPolicyMode,
  type IssueExecutionStageType,
  type IssueExecutionStateStatus,
@@ -286,6 +288,9 @@ export type {
  IssueWorkProductReviewState,
  Issue,
  IssueAssigneeAdapterOverrides,
+  IssueReferenceSource,
+  IssueRelatedWorkItem,
+  IssueRelatedWorkSummary,
  IssueRelation,
  IssueRelationIssueSummary,
  IssueExecutionPolicy,
@@ -432,6 +437,16 @@ export type {
  QuotaWindow,
  ProviderQuotaResult,
 } from "./types/index.js";
+export {
+  ISSUE_REFERENCE_IDENTIFIER_RE,
+  buildIssueReferenceHref,
+  extractIssueReferenceIdentifiers,
+  extractIssueReferenceMatches,
+  findIssueReferenceMatches,
+  normalizeIssueIdentifier,
+  parseIssueReferenceHref,
+  type IssueReferenceMatch,
+} from "./issue-references.js";

 export {
  sidebarOrderPreferenceSchema,
--- a/packages/shared/src/issue-references.test.ts
+++ b/packages/shared/src/issue-references.test.ts
@@ -0,0 +1,68 @@
+import { describe, expect, it } from "vitest";
+import {
+  buildIssueReferenceHref,
+  extractIssueReferenceIdentifiers,
+  findIssueReferenceMatches,
+  normalizeIssueIdentifier,
+  parseIssueReferenceHref,
+} from "./issue-references.js";
+
+describe("issue references", () => {
+  it("normalizes identifiers to uppercase", () => {
+    expect(normalizeIssueIdentifier("pap-123")).toBe("PAP-123");
+    expect(normalizeIssueIdentifier("not-an-issue")).toBeNull();
+  });
+
+  it("parses relative and absolute issue hrefs", () => {
+    expect(parseIssueReferenceHref("/issues/PAP-123")).toEqual({ identifier: "PAP-123" });
+    expect(parseIssueReferenceHref("/PAP/issues/pap-456")).toEqual({ identifier: "PAP-456" });
+    expect(parseIssueReferenceHref("https://paperclip.ing/PAP/issues/pap-789#comment-1")).toEqual({
+      identifier: "PAP-789",
+    });
+    expect(parseIssueReferenceHref("https://paperclip.ing/projects/PAP-789")).toBeNull();
+  });
+
+  it("builds canonical issue hrefs", () => {
+    expect(buildIssueReferenceHref("pap-123")).toBe("/issues/PAP-123");
+  });
+
+  it("finds identifiers and issue paths in plain text", () => {
+    expect(findIssueReferenceMatches("See PAP-1, /issues/PAP-2, and https://x.test/PAP/issues/pap-3.")).toEqual([
+      { index: 4, length: 5, identifier: "PAP-1", matchedText: "PAP-1" },
+      { index: 11, length: 13, identifier: "PAP-2", matchedText: "/issues/PAP-2" },
+      {
+        index: 30,
+        length: 31,
+        identifier: "PAP-3",
+        matchedText: "https://x.test/PAP/issues/pap-3",
+      },
+    ]);
+  });
+
+  it("trims unmatched square brackets from issue path tokens", () => {
+    expect(findIssueReferenceMatches("See /issues/PAP-123] for context.")).toEqual([
+      { index: 4, length: 15, identifier: "PAP-123", matchedText: "/issues/PAP-123" },
+    ]);
+  });
+
+  it("extracts and dedupes references from markdown", () => {
+    expect(extractIssueReferenceIdentifiers("PAP-1 [again](/issues/pap-1) PAP-2")).toEqual(["PAP-1", "PAP-2"]);
+  });
+
+  it("ignores inline code and fenced code blocks", () => {
+    const markdown = [
+      "Use PAP-1 here.",
+      "",
+      "`PAP-2` should not count.",
+      "",
+      "```md",
+      "PAP-3",
+      "/issues/PAP-4",
+      "```",
+      "",
+      "Final /issues/PAP-5 mention.",
+    ].join("\n");
+
+    expect(extractIssueReferenceIdentifiers(markdown)).toEqual(["PAP-1", "PAP-5"]);
+  });
+});
--- a/packages/shared/src/issue-references.ts
+++ b/packages/shared/src/issue-references.ts
@@ -0,0 +1,188 @@
+export const ISSUE_REFERENCE_IDENTIFIER_RE = /^[A-Z]+-\d+$/;
+
+export interface IssueReferenceMatch {
+  index: number;
+  length: number;
+  identifier: string;
+  matchedText: string;
+}
+
+const ISSUE_REFERENCE_TOKEN_RE = /https?:\/\/[^\s<>()]+|\/[^\s<>()]+|[A-Z]+-\d+/gi;
+
+function preserveNewlinesAsWhitespace(value: string) {
+  return value.replace(/[^\n]/g, " ");
+}
+
+function stripMarkdownCode(markdown: string): string {
+  if (!markdown) return "";
+
+  let output = "";
+  let index = 0;
+
+  while (index < markdown.length) {
+    const remaining = markdown.slice(index);
+    const fenceMatch = /^(?:```+|~~~+)/.exec(remaining);
+    const atLineStart = index === 0 || markdown[index - 1] === "\n";
+
+    if (atLineStart && fenceMatch) {
+      const fence = fenceMatch[0]!;
+      const blockStart = index;
+      index += fence.length;
+      while (index < markdown.length && markdown[index] !== "\n") index += 1;
+      if (index < markdown.length) index += 1;
+
+      while (index < markdown.length) {
+        const lineStart = index === 0 || markdown[index - 1] === "\n";
+        if (lineStart && markdown.startsWith(fence, index)) {
+          index += fence.length;
+          while (index < markdown.length && markdown[index] !== "\n") index += 1;
+          if (index < markdown.length) index += 1;
+          break;
+        }
+        index += 1;
+      }
+
+      output += preserveNewlinesAsWhitespace(markdown.slice(blockStart, index));
+      continue;
+    }
+
+    if (markdown[index] === "`") {
+      let tickCount = 1;
+      while (index + tickCount < markdown.length && markdown[index + tickCount] === "`") {
+        tickCount += 1;
+      }
+      const fence = "`".repeat(tickCount);
+      const inlineStart = index;
+      index += tickCount;
+      const closeIndex = markdown.indexOf(fence, index);
+      if (closeIndex === -1) {
+        output += markdown.slice(inlineStart, inlineStart + tickCount);
+        index = inlineStart + tickCount;
+        continue;
+      }
+      index = closeIndex + tickCount;
+      output += preserveNewlinesAsWhitespace(markdown.slice(inlineStart, index));
+      continue;
+    }
+
+    output += markdown[index]!;
+    index += 1;
+  }
+
+  return output;
+}
+
+function trimTrailingPunctuation(token: string): string {
+  let trimmed = token;
+  while (trimmed.length > 0) {
+    const last = trimmed[trimmed.length - 1]!;
+    if (!".,!?;:".includes(last) && last !== ")" && last !== "]") break;
+
+    if (
+      (last === ")" && (trimmed.match(/\(/g)?.length ?? 0) >= (trimmed.match(/\)/g)?.length ?? 0))
+      || (last === "]" && (trimmed.match(/\[/g)?.length ?? 0) >= (trimmed.match(/\]/g)?.length ?? 0))
+    ) {
+      break;
+    }
+    trimmed = trimmed.slice(0, -1);
+  }
+  return trimmed;
+}
+
+export function normalizeIssueIdentifier(value: string): string | null {
+  const trimmed = value.trim().toUpperCase();
+  return ISSUE_REFERENCE_IDENTIFIER_RE.test(trimmed) ? trimmed : null;
+}
+
+export function buildIssueReferenceHref(identifier: string): string {
+  const normalized = normalizeIssueIdentifier(identifier);
+  return `/issues/${normalized ?? identifier.trim()}`;
+}
+
+export function parseIssueReferenceHref(href: string): { identifier: string } | null {
+  const raw = href.trim();
+  if (!raw) return null;
+
+  let url: URL;
+  try {
+    url = raw.startsWith("/")
+      ? new URL(raw, "https://paperclip.invalid")
+      : new URL(raw);
+  } catch {
+    return null;
+  }
+
+  const segments = url.pathname
+    .split("/")
+    .map((segment) => segment.trim())
+    .filter(Boolean);
+
+  for (let index = 0; index < segments.length - 1; index += 1) {
+    if (segments[index]?.toLowerCase() !== "issues") continue;
+    const identifier = normalizeIssueIdentifier(segments[index + 1] ?? "");
+    if (identifier) {
+      return { identifier };
+    }
+  }
+
+  return null;
+}
+
+export function findIssueReferenceMatches(text: string): IssueReferenceMatch[] {
+  if (!text) return [];
+
+  const matches: IssueReferenceMatch[] = [];
+  let match: RegExpExecArray | null;
+  const re = new RegExp(ISSUE_REFERENCE_TOKEN_RE);
+
+  while ((match = re.exec(text)) !== null) {
+    const rawToken = match[0];
+    const cleanedToken = trimTrailingPunctuation(rawToken);
+    if (!cleanedToken) continue;
+
+    const identifier =
+      normalizeIssueIdentifier(cleanedToken)
+      ?? parseIssueReferenceHref(cleanedToken)?.identifier
+      ?? null;
+
+    if (!identifier) continue;
+
+    const cleanedIndex = match.index;
+    matches.push({
+      index: cleanedIndex,
+      length: cleanedToken.length,
+      identifier,
+      matchedText: cleanedToken,
+    });
+  }
+
+  return matches;
+}
+
+export function extractIssueReferenceIdentifiers(markdown: string): string[] {
+  const scrubbed = stripMarkdownCode(markdown);
+  const seen = new Set<string>();
+  const ordered: string[] = [];
+
+  for (const match of findIssueReferenceMatches(scrubbed)) {
+    if (seen.has(match.identifier)) continue;
+    seen.add(match.identifier);
+    ordered.push(match.identifier);
+  }
+
+  return ordered;
+}
+
+export function extractIssueReferenceMatches(markdown: string): IssueReferenceMatch[] {
+  const scrubbed = stripMarkdownCode(markdown);
+  const seen = new Set<string>();
+  const ordered: IssueReferenceMatch[] = [];
+
+  for (const match of findIssueReferenceMatches(scrubbed)) {
+    if (seen.has(match.identifier)) continue;
+    seen.add(match.identifier);
+    ordered.push(match);
+  }
+
+  return ordered;
+}
--- a/packages/shared/src/types/index.ts
+++ b/packages/shared/src/types/index.ts
@@ -102,6 +102,9 @@ export type {
 export type {
  Issue,
  IssueAssigneeAdapterOverrides,
+  IssueReferenceSource,
+  IssueRelatedWorkItem,
+  IssueRelatedWorkSummary,
  IssueRelation,
  IssueRelationIssueSummary,
  IssueExecutionPolicy,
--- a/packages/shared/src/types/issue.ts
+++ b/packages/shared/src/types/issue.ts
@@ -1,6 +1,7 @@
 import type {
  IssueExecutionDecisionOutcome,
  IssueExecutionPolicyMode,
+  IssueReferenceSourceKind,
  IssueExecutionStageType,
  IssueExecutionStateStatus,
  IssueOriginKind,
@@ -123,6 +124,24 @@ export interface IssueRelation {
  relatedIssue: IssueRelationIssueSummary;
 }

+export interface IssueReferenceSource {
+  kind: IssueReferenceSourceKind;
+  sourceRecordId: string | null;
+  label: string;
+  matchedText: string | null;
+}
+
+export interface IssueRelatedWorkItem {
+  issue: IssueRelationIssueSummary;
+  mentionCount: number;
+  sources: IssueReferenceSource[];
+}
+
+export interface IssueRelatedWorkSummary {
+  outbound: IssueRelatedWorkItem[];
+  inbound: IssueRelatedWorkItem[];
+}
+
 export interface IssueExecutionStagePrincipal {
  type: "agent" | "user";
  agentId?: string | null;
@@ -214,6 +233,8 @@ export interface Issue {
  labels?: IssueLabel[];
  blockedBy?: IssueRelationIssueSummary[];
  blocks?: IssueRelationIssueSummary[];
+  relatedWork?: IssueRelatedWorkSummary;
+  referencedIssueIdentifiers?: string[];
  planDocument?: IssueDocument | null;
  documentSummaries?: IssueDocumentSummary[];
  legacyPlanDocument?: LegacyPlanDocument | null;
--- a/packages/shared/vitest.config.ts
+++ b/packages/shared/vitest.config.ts
@@ -0,0 +1,7 @@
+import { defineConfig } from "vitest/config";
+
+export default defineConfig({
+  test: {
+    include: ["src/**/*.test.ts"],
+  },
+});
--- a/scripts/backfill-issue-reference-mentions.ts
+++ b/scripts/backfill-issue-reference-mentions.ts
@@ -0,0 +1,43 @@
+import { companies, createDb } from "../packages/db/src/index.js";
+import { loadConfig } from "../server/src/config.js";
+import { issueReferenceService } from "../server/src/services/issue-references.js";
+
+function parseFlag(name: string): string | null {
+  const index = process.argv.indexOf(name);
+  if (index < 0) return null;
+  const value = process.argv[index + 1];
+  return value && !value.startsWith("--") ? value : null;
+}
+
+async function main() {
+  const config = loadConfig();
+  const dbUrl =
+    process.env.DATABASE_URL?.trim()
+    || config.databaseUrl
+    || `postgres://paperclip:paperclip@127.0.0.1:${config.embeddedPostgresPort}/paperclip`;
+
+  const db = createDb(dbUrl);
+  const refs = issueReferenceService(db);
+  const companyId = parseFlag("--company");
+  const companyRows = companyId
+    ? [{ id: companyId }]
+    : await db.select({ id: companies.id }).from(companies);
+
+  if (companyRows.length === 0) {
+    console.log("No companies found; nothing to backfill.");
+    return;
+  }
+
+  console.log(`Backfilling issue reference mentions for ${companyRows.length} compan${companyRows.length === 1 ? "y" : "ies"}...`);
+  for (const company of companyRows) {
+    console.log(`- ${company.id}`);
+    await refs.syncAllForCompany(company.id);
+  }
+  console.log("Issue reference backfill complete.");
+}
+
+void main().catch((error) => {
+  const message = error instanceof Error ? error.message : String(error);
+  console.error(`Issue reference backfill failed: ${message}`);
+  process.exitCode = 1;
+});
--- a/server/src/tests/issue-activity-events-routes.test.ts
+++ b/server/src/tests/issue-activity-events-routes.test.ts
@@ -49,6 +49,19 @@ vi.mock("../services/index.js", () => ({
    listCompanyIds: vi.fn(async () => ["company-1"]),
  }),
  issueApprovalService: () => ({}),
+  issueReferenceService: () => ({
+    deleteDocumentSource: async () => undefined,
+    diffIssueReferenceSummary: () => ({
+      addedReferencedIssues: [],
+      removedReferencedIssues: [],
+      currentReferencedIssues: [],
+    }),
+    emptySummary: () => ({ outbound: [], inbound: [] }),
+    listIssueReferenceSummary: async () => ({ outbound: [], inbound: [] }),
+    syncComment: async () => undefined,
+    syncDocument: async () => undefined,
+    syncIssue: async () => undefined,
+  }),
  issueService: () => mockIssueService,
  logActivity: mockLogActivity,
  projectService: () => ({}),
--- a/server/src/tests/issue-agent-mutation-ownership-routes.test.ts
+++ b/server/src/tests/issue-agent-mutation-ownership-routes.test.ts
@@ -92,6 +92,19 @@ vi.mock("../services/index.js", () => ({
    listCompanyIds: vi.fn(async () => [companyId]),
  }),
  issueApprovalService: () => ({}),
+  issueReferenceService: () => ({
+    deleteDocumentSource: async () => undefined,
+    diffIssueReferenceSummary: () => ({
+      addedReferencedIssues: [],
+      removedReferencedIssues: [],
+      currentReferencedIssues: [],
+    }),
+    emptySummary: () => ({ outbound: [], inbound: [] }),
+    listIssueReferenceSummary: async () => ({ outbound: [], inbound: [] }),
+    syncComment: async () => undefined,
+    syncDocument: async () => undefined,
+    syncIssue: async () => undefined,
+  }),
  issueService: () => mockIssueService,
  logActivity: vi.fn(async () => undefined),
  projectService: () => ({}),
--- a/server/src/tests/issue-attachment-routes.test.ts
+++ b/server/src/tests/issue-attachment-routes.test.ts
@@ -56,6 +56,19 @@ function registerRouteMocks() {
      listCompanyIds: vi.fn(async () => ["company-1"]),
    }),
    issueApprovalService: () => ({}),
+    issueReferenceService: () => ({
+      deleteDocumentSource: async () => undefined,
+      diffIssueReferenceSummary: () => ({
+        addedReferencedIssues: [],
+        removedReferencedIssues: [],
+        currentReferencedIssues: [],
+      }),
+      emptySummary: () => ({ outbound: [], inbound: [] }),
+      listIssueReferenceSummary: async () => ({ outbound: [], inbound: [] }),
+      syncComment: async () => undefined,
+      syncDocument: async () => undefined,
+      syncIssue: async () => undefined,
+    }),
    issueService: () => mockIssueService,
    logActivity: mockLogActivity,
    projectService: () => ({}),
--- a/server/src/tests/issue-closed-workspace-routes.test.ts
+++ b/server/src/tests/issue-closed-workspace-routes.test.ts
@@ -74,6 +74,19 @@ function registerServiceMocks() {
      listCompanyIds: vi.fn(async () => ["company-1"]),
    }),
    issueApprovalService: () => ({}),
+    issueReferenceService: () => ({
+      deleteDocumentSource: async () => undefined,
+      diffIssueReferenceSummary: () => ({
+        addedReferencedIssues: [],
+        removedReferencedIssues: [],
+        currentReferencedIssues: [],
+      }),
+      emptySummary: () => ({ outbound: [], inbound: [] }),
+      listIssueReferenceSummary: async () => ({ outbound: [], inbound: [] }),
+      syncComment: async () => undefined,
+      syncDocument: async () => undefined,
+      syncIssue: async () => undefined,
+    }),
    issueService: () => mockIssueService,
    logActivity: mockLogActivity,
    projectService: () => mockProjectService,
--- a/server/src/tests/issue-comment-cancel-routes.test.ts
+++ b/server/src/tests/issue-comment-cancel-routes.test.ts
@@ -52,6 +52,19 @@ vi.mock("../services/index.js", () => ({
    listCompanyIds: vi.fn(async () => ["company-1"]),
  }),
  issueApprovalService: () => ({}),
+  issueReferenceService: () => ({
+    deleteDocumentSource: async () => undefined,
+    diffIssueReferenceSummary: () => ({
+      addedReferencedIssues: [],
+      removedReferencedIssues: [],
+      currentReferencedIssues: [],
+    }),
+    emptySummary: () => ({ outbound: [], inbound: [] }),
+    listIssueReferenceSummary: async () => ({ outbound: [], inbound: [] }),
+    syncComment: async () => undefined,
+    syncDocument: async () => undefined,
+    syncIssue: async () => undefined,
+  }),
  issueService: () => mockIssueService,
  logActivity: mockLogActivity,
  projectService: () => ({}),
--- a/server/src/tests/issue-comment-reopen-routes.test.ts
+++ b/server/src/tests/issue-comment-reopen-routes.test.ts
@@ -76,6 +76,19 @@ vi.mock("../services/index.js", () => ({
  heartbeatService: () => mockHeartbeatService,
  instanceSettingsService: () => mockInstanceSettingsService,
  issueApprovalService: () => ({}),
+  issueReferenceService: () => ({
+    deleteDocumentSource: async () => undefined,
+    diffIssueReferenceSummary: () => ({
+      addedReferencedIssues: [],
+      removedReferencedIssues: [],
+      currentReferencedIssues: [],
+    }),
+    emptySummary: () => ({ outbound: [], inbound: [] }),
+    listIssueReferenceSummary: async () => ({ outbound: [], inbound: [] }),
+    syncComment: async () => undefined,
+    syncDocument: async () => undefined,
+    syncIssue: async () => undefined,
+  }),
  issueService: () => mockIssueService,
  logActivity: mockLogActivity,
  projectService: () => ({}),
@@ -103,6 +116,19 @@ function registerModuleMocks() {
    heartbeatService: () => mockHeartbeatService,
    instanceSettingsService: () => mockInstanceSettingsService,
    issueApprovalService: () => ({}),
+    issueReferenceService: () => ({
+      deleteDocumentSource: async () => undefined,
+      diffIssueReferenceSummary: () => ({
+        addedReferencedIssues: [],
+        removedReferencedIssues: [],
+        currentReferencedIssues: [],
+      }),
+      emptySummary: () => ({ outbound: [], inbound: [] }),
+      listIssueReferenceSummary: async () => ({ outbound: [], inbound: [] }),
+      syncComment: async () => undefined,
+      syncDocument: async () => undefined,
+      syncIssue: async () => undefined,
+    }),
    issueService: () => mockIssueService,
    logActivity: mockLogActivity,
    projectService: () => ({}),
--- a/server/src/tests/issue-dependency-wakeups-routes.test.ts
+++ b/server/src/tests/issue-dependency-wakeups-routes.test.ts
@@ -45,6 +45,19 @@ vi.mock("../services/index.js", () => ({
    listCompanyIds: vi.fn(),
  }),
  issueApprovalService: () => ({}),
+  issueReferenceService: () => ({
+    deleteDocumentSource: async () => undefined,
+    diffIssueReferenceSummary: () => ({
+      addedReferencedIssues: [],
+      removedReferencedIssues: [],
+      currentReferencedIssues: [],
+    }),
+    emptySummary: () => ({ outbound: [], inbound: [] }),
+    listIssueReferenceSummary: async () => ({ outbound: [], inbound: [] }),
+    syncComment: async () => undefined,
+    syncDocument: async () => undefined,
+    syncIssue: async () => undefined,
+  }),
  issueService: () => mockIssueService,
  logActivity: vi.fn(async () => undefined),
  projectService: () => ({
--- a/server/src/tests/issue-document-restore-routes.test.ts
+++ b/server/src/tests/issue-document-restore-routes.test.ts
@@ -42,6 +42,19 @@ vi.mock("../services/index.js", () => ({
    getGeneral: vi.fn(async () => ({ feedbackDataSharingPreference: "prompt" })),
  }),
  issueApprovalService: () => ({}),
+  issueReferenceService: () => ({
+    deleteDocumentSource: async () => undefined,
+    diffIssueReferenceSummary: () => ({
+      addedReferencedIssues: [],
+      removedReferencedIssues: [],
+      currentReferencedIssues: [],
+    }),
+    emptySummary: () => ({ outbound: [], inbound: [] }),
+    listIssueReferenceSummary: async () => ({ outbound: [], inbound: [] }),
+    syncComment: async () => undefined,
+    syncDocument: async () => undefined,
+    syncIssue: async () => undefined,
+  }),
  issueService: () => mockIssueService,
  logActivity: mockLogActivity,
  projectService: () => ({}),
@@ -68,6 +81,19 @@ function registerModuleMocks() {
      getGeneral: vi.fn(async () => ({ feedbackDataSharingPreference: "prompt" })),
    }),
    issueApprovalService: () => ({}),
+    issueReferenceService: () => ({
+      deleteDocumentSource: async () => undefined,
+      diffIssueReferenceSummary: () => ({
+        addedReferencedIssues: [],
+        removedReferencedIssues: [],
+        currentReferencedIssues: [],
+      }),
+      emptySummary: () => ({ outbound: [], inbound: [] }),
+      listIssueReferenceSummary: async () => ({ outbound: [], inbound: [] }),
+      syncComment: async () => undefined,
+      syncDocument: async () => undefined,
+      syncIssue: async () => undefined,
+    }),
    issueService: () => mockIssueService,
    logActivity: mockLogActivity,
    projectService: () => ({}),
--- a/server/src/tests/issue-execution-policy-routes.test.ts
+++ b/server/src/tests/issue-execution-policy-routes.test.ts
@@ -50,6 +50,19 @@ function registerModuleMocks() {
      listCompanyIds: vi.fn(async () => ["company-1"]),
    }),
    issueApprovalService: () => ({}),
+    issueReferenceService: () => ({
+      deleteDocumentSource: async () => undefined,
+      diffIssueReferenceSummary: () => ({
+        addedReferencedIssues: [],
+        removedReferencedIssues: [],
+        currentReferencedIssues: [],
+      }),
+      emptySummary: () => ({ outbound: [], inbound: [] }),
+      listIssueReferenceSummary: async () => ({ outbound: [], inbound: [] }),
+      syncComment: async () => undefined,
+      syncDocument: async () => undefined,
+      syncIssue: async () => undefined,
+    }),
    issueService: () => mockIssueService,
    logActivity: vi.fn(async () => undefined),
    projectService: () => ({}),
--- a/server/src/tests/issue-feedback-routes.test.ts
+++ b/server/src/tests/issue-feedback-routes.test.ts
@@ -70,6 +70,19 @@ function registerModuleMocks() {
    heartbeatService: () => mockHeartbeatService,
    instanceSettingsService: () => mockInstanceSettingsService,
    issueApprovalService: () => ({}),
+    issueReferenceService: () => ({
+      deleteDocumentSource: async () => undefined,
+      diffIssueReferenceSummary: () => ({
+        addedReferencedIssues: [],
+        removedReferencedIssues: [],
+        currentReferencedIssues: [],
+      }),
+      emptySummary: () => ({ outbound: [], inbound: [] }),
+      listIssueReferenceSummary: async () => ({ outbound: [], inbound: [] }),
+      syncComment: async () => undefined,
+      syncDocument: async () => undefined,
+      syncIssue: async () => undefined,
+    }),
    issueService: () => mockIssueService,
    logActivity: mockLogActivity,
    projectService: () => ({}),
--- a/server/src/tests/issue-references-service.test.ts
+++ b/server/src/tests/issue-references-service.test.ts
@@ -0,0 +1,244 @@
+import { randomUUID } from "node:crypto";
+import { sql } from "drizzle-orm";
+import { afterAll, afterEach, beforeAll, describe, expect, it } from "vitest";
+import {
+  companies,
+  createDb,
+  documents,
+  issueComments,
+  issueDocuments,
+  issueReferenceMentions,
+  issues,
+} from "@paperclipai/db";
+import {
+  getEmbeddedPostgresTestSupport,
+  startEmbeddedPostgresTestDatabase,
+} from "./helpers/embedded-postgres.js";
+import { issueReferenceService } from "../services/issue-references.ts";
+
+const embeddedPostgresSupport = await getEmbeddedPostgresTestSupport();
+const describeEmbeddedPostgres = embeddedPostgresSupport.supported ? describe : describe.skip;
+
+async function ensureIssueReferenceMentionsTable(db: ReturnType<typeof createDb>) {
+  await db.execute(sql.raw(`
+    CREATE TABLE IF NOT EXISTS "issue_reference_mentions" (
+      "id" uuid PRIMARY KEY DEFAULT gen_random_uuid(),
+      "company_id" uuid NOT NULL,
+      "source_issue_id" uuid NOT NULL REFERENCES "issues"("id") ON DELETE CASCADE,
+      "target_issue_id" uuid NOT NULL REFERENCES "issues"("id") ON DELETE CASCADE,
+      "source_kind" text NOT NULL,
+      "source_record_id" uuid,
+      "document_key" text,
+      "matched_text" text,
+      "created_at" timestamptz NOT NULL DEFAULT now(),
+      "updated_at" timestamptz NOT NULL DEFAULT now()
+    );
+    CREATE INDEX IF NOT EXISTS "issue_reference_mentions_company_source_issue_idx"
+      ON "issue_reference_mentions" ("company_id", "source_issue_id");
+    CREATE INDEX IF NOT EXISTS "issue_reference_mentions_company_target_issue_idx"
+      ON "issue_reference_mentions" ("company_id", "target_issue_id");
+    CREATE INDEX IF NOT EXISTS "issue_reference_mentions_company_issue_pair_idx"
+      ON "issue_reference_mentions" ("company_id", "source_issue_id", "target_issue_id");
+    CREATE UNIQUE INDEX IF NOT EXISTS "issue_reference_mentions_company_source_mention_uq"
+      ON "issue_reference_mentions" ("company_id", "source_issue_id", "target_issue_id", "source_kind", "source_record_id");
+  `));
+}
+
+if (!embeddedPostgresSupport.supported) {
+  console.warn(
+    `Skipping embedded Postgres issue reference tests on this host: ${embeddedPostgresSupport.reason ?? "unsupported environment"}`,
+  );
+}
+
+describeEmbeddedPostgres("issueReferenceService", () => {
+  let db!: ReturnType<typeof createDb>;
+  let refs!: ReturnType<typeof issueReferenceService>;
+  let tempDb: Awaited<ReturnType<typeof startEmbeddedPostgresTestDatabase>> | null = null;
+
+  beforeAll(async () => {
+    tempDb = await startEmbeddedPostgresTestDatabase("paperclip-issue-refs-");
+    db = createDb(tempDb.connectionString);
+    refs = issueReferenceService(db);
+    await ensureIssueReferenceMentionsTable(db);
+  }, 20_000);
+
+  afterEach(async () => {
+    await db.delete(issueReferenceMentions);
+    await db.delete(issueComments);
+    await db.delete(issueDocuments);
+    await db.delete(documents);
+    await db.delete(issues);
+    await db.delete(companies);
+  });
+
+  afterAll(async () => {
+    await tempDb?.cleanup();
+  });
+
+  it("tracks outbound and inbound references across issue fields, comments, and documents", async () => {
+    const companyId = randomUUID();
+    const sourceIssueId = randomUUID();
+    const targetTwoId = randomUUID();
+    const targetThreeId = randomUUID();
+    const inboundIssueId = randomUUID();
+    const commentId = randomUUID();
+    const documentId = randomUUID();
+    const issueDocumentId = randomUUID();
+
+    await db.insert(companies).values({
+      id: companyId,
+      name: "Paperclip",
+      issuePrefix: `R${companyId.replace(/-/g, "").slice(0, 6).toUpperCase()}`,
+      requireBoardApprovalForNewAgents: false,
+    });
+
+    await db.insert(issues).values([
+      {
+        id: sourceIssueId,
+        companyId,
+        title: "Coordinate PAP-2",
+        description: "Review /issues/pap-3 and ignore PAP-1 self references.",
+        status: "todo",
+        priority: "medium",
+        identifier: "PAP-1",
+      },
+      {
+        id: targetTwoId,
+        companyId,
+        title: "Target two",
+        status: "todo",
+        priority: "medium",
+        identifier: "PAP-2",
+      },
+      {
+        id: targetThreeId,
+        companyId,
+        title: "Target three",
+        status: "todo",
+        priority: "medium",
+        identifier: "PAP-3",
+      },
+      {
+        id: inboundIssueId,
+        companyId,
+        title: "Inbound reference",
+        description: "This one depends on PAP-1.",
+        status: "in_progress",
+        priority: "high",
+        identifier: "PAP-4",
+      },
+    ]);
+
+    await refs.syncIssue(sourceIssueId);
+    await refs.syncIssue(inboundIssueId);
+
+    await db.insert(issueComments).values({
+      id: commentId,
+      companyId,
+      issueId: sourceIssueId,
+      body: "Follow up in https://paperclip.test/issues/pap-2 after the document lands.",
+    });
+    await refs.syncComment(commentId);
+
+    await db.insert(documents).values({
+      id: documentId,
+      companyId,
+      title: "Plan",
+      format: "markdown",
+      latestBody: "Spec note: /PAP/issues/PAP-3",
+      latestRevisionNumber: 1,
+    });
+    await db.insert(issueDocuments).values({
+      id: issueDocumentId,
+      companyId,
+      issueId: sourceIssueId,
+      documentId,
+      key: "plan",
+    });
+    await refs.syncDocument(documentId);
+
+    const summary = await refs.listIssueReferenceSummary(sourceIssueId);
+
+    expect(summary.outbound.map((item) => item.issue.identifier)).toEqual(["PAP-2", "PAP-3"]);
+    expect(summary.outbound[0]?.mentionCount).toBe(2);
+    expect(summary.outbound[0]?.sources.map((source) => source.label)).toEqual(["title", "comment"]);
+    expect(summary.outbound[1]?.mentionCount).toBe(2);
+    expect(summary.outbound[1]?.sources.map((source) => source.label)).toEqual(["description", "plan"]);
+    expect(summary.inbound.map((item) => item.issue.identifier)).toEqual(["PAP-4"]);
+
+    await refs.deleteDocumentSource(documentId);
+
+    const withoutDocument = await refs.listIssueReferenceSummary(sourceIssueId);
+    const pap3 = withoutDocument.outbound.find((item) => item.issue.identifier === "PAP-3");
+
+    expect(pap3?.mentionCount).toBe(1);
+    expect(pap3?.sources.map((source) => source.label)).toEqual(["description"]);
+  });
+
+  it("backfills existing references for a company without requiring write-time sync", async () => {
+    const companyId = randomUUID();
+    const sourceIssueId = randomUUID();
+    const targetIssueId = randomUUID();
+    const commentId = randomUUID();
+    const documentId = randomUUID();
+    const issueDocumentId = randomUUID();
+
+    await db.insert(companies).values({
+      id: companyId,
+      name: "Paperclip Backfill",
+      issuePrefix: `B${companyId.replace(/-/g, "").slice(0, 6).toUpperCase()}`,
+      requireBoardApprovalForNewAgents: false,
+    });
+
+    await db.insert(issues).values([
+      {
+        id: sourceIssueId,
+        companyId,
+        title: "Legacy issue",
+        status: "todo",
+        priority: "medium",
+        identifier: "PAP-10",
+      },
+      {
+        id: targetIssueId,
+        companyId,
+        title: "Referenced legacy issue",
+        status: "todo",
+        priority: "medium",
+        identifier: "PAP-20",
+      },
+    ]);
+
+    await db.insert(issueComments).values({
+      id: commentId,
+      companyId,
+      issueId: sourceIssueId,
+      body: "Legacy comment points at PAP-20.",
+    });
+
+    await db.insert(documents).values({
+      id: documentId,
+      companyId,
+      title: "Legacy plan",
+      format: "markdown",
+      latestBody: "Legacy plan also links /issues/PAP-20.",
+      latestRevisionNumber: 1,
+    });
+    await db.insert(issueDocuments).values({
+      id: issueDocumentId,
+      companyId,
+      issueId: sourceIssueId,
+      documentId,
+      key: "plan",
+    });
+
+    await refs.syncAllForCompany(companyId);
+
+    const summary = await refs.listIssueReferenceSummary(sourceIssueId);
+
+    expect(summary.outbound).toHaveLength(1);
+    expect(summary.outbound[0]?.issue.identifier).toBe("PAP-20");
+    expect(summary.outbound[0]?.mentionCount).toBe(2);
+    expect(summary.outbound[0]?.sources.map((source) => source.label)).toEqual(["plan", "comment"]);
+  });
+});
--- a/server/src/tests/issue-telemetry-routes.test.ts
+++ b/server/src/tests/issue-telemetry-routes.test.ts
@@ -42,6 +42,19 @@ function registerModuleMocks() {
    }),
    instanceSettingsService: () => ({}),
    issueApprovalService: () => ({}),
+    issueReferenceService: () => ({
+      deleteDocumentSource: async () => undefined,
+      diffIssueReferenceSummary: () => ({
+        addedReferencedIssues: [],
+        removedReferencedIssues: [],
+        currentReferencedIssues: [],
+      }),
+      emptySummary: () => ({ outbound: [], inbound: [] }),
+      listIssueReferenceSummary: async () => ({ outbound: [], inbound: [] }),
+      syncComment: async () => undefined,
+      syncDocument: async () => undefined,
+      syncIssue: async () => undefined,
+    }),
    issueService: () => mockIssueService,
    logActivity: vi.fn(async () => undefined),
    projectService: () => ({}),
--- a/server/src/tests/issue-update-comment-wakeup-routes.test.ts
+++ b/server/src/tests/issue-update-comment-wakeup-routes.test.ts
@@ -53,6 +53,19 @@ vi.mock("../services/index.js", () => ({
    listCompanyIds: vi.fn(async () => ["company-1"]),
  }),
  issueApprovalService: () => ({}),
+  issueReferenceService: () => ({
+    deleteDocumentSource: async () => undefined,
+    diffIssueReferenceSummary: () => ({
+      addedReferencedIssues: [],
+      removedReferencedIssues: [],
+      currentReferencedIssues: [],
+    }),
+    emptySummary: () => ({ outbound: [], inbound: [] }),
+    listIssueReferenceSummary: async () => ({ outbound: [], inbound: [] }),
+    syncComment: async () => undefined,
+    syncDocument: async () => undefined,
+    syncIssue: async () => undefined,
+  }),
  issueService: () => mockIssueService,
  logActivity: vi.fn(async () => undefined),
  projectService: () => ({}),
@@ -94,6 +107,19 @@ function registerModuleMocks() {
      listCompanyIds: vi.fn(async () => ["company-1"]),
    }),
    issueApprovalService: () => ({}),
+    issueReferenceService: () => ({
+      deleteDocumentSource: async () => undefined,
+      diffIssueReferenceSummary: () => ({
+        addedReferencedIssues: [],
+        removedReferencedIssues: [],
+        currentReferencedIssues: [],
+      }),
+      emptySummary: () => ({ outbound: [], inbound: [] }),
+      listIssueReferenceSummary: async () => ({ outbound: [], inbound: [] }),
+      syncComment: async () => undefined,
+      syncDocument: async () => undefined,
+      syncIssue: async () => undefined,
+    }),
    issueService: () => mockIssueService,
    logActivity: vi.fn(async () => undefined),
    projectService: () => ({}),
--- a/server/src/tests/issue-workspace-command-authz.test.ts
+++ b/server/src/tests/issue-workspace-command-authz.test.ts
@@ -52,6 +52,19 @@ vi.mock("../services/index.js", () => ({
    listCompanyIds: vi.fn(async () => ["company-1"]),
  }),
  issueApprovalService: () => ({}),
+  issueReferenceService: () => ({
+    deleteDocumentSource: async () => undefined,
+    diffIssueReferenceSummary: () => ({
+      addedReferencedIssues: [],
+      removedReferencedIssues: [],
+      currentReferencedIssues: [],
+    }),
+    emptySummary: () => ({ outbound: [], inbound: [] }),
+    listIssueReferenceSummary: async () => ({ outbound: [], inbound: [] }),
+    syncComment: async () => undefined,
+    syncDocument: async () => undefined,
+    syncIssue: async () => undefined,
+  }),
  issueService: () => mockIssueService,
  logActivity: vi.fn(async () => undefined),
  projectService: () => ({}),
--- a/server/src/tests/issues-goal-context-routes.test.ts
+++ b/server/src/tests/issues-goal-context-routes.test.ts
@@ -59,6 +59,19 @@ vi.mock("../services/index.js", () => ({
    listCompanyIds: vi.fn(async () => ["company-1"]),
  }),
  issueApprovalService: () => ({}),
+  issueReferenceService: () => ({
+    deleteDocumentSource: async () => undefined,
+    diffIssueReferenceSummary: () => ({
+      addedReferencedIssues: [],
+      removedReferencedIssues: [],
+      currentReferencedIssues: [],
+    }),
+    emptySummary: () => ({ outbound: [], inbound: [] }),
+    listIssueReferenceSummary: async () => ({ outbound: [], inbound: [] }),
+    syncComment: async () => undefined,
+    syncDocument: async () => undefined,
+    syncIssue: async () => undefined,
+  }),
  issueService: () => mockIssueService,
  logActivity: vi.fn(async () => undefined),
  projectService: () => mockProjectService,
--- a/server/src/routes/issues.ts
+++ b/server/src/routes/issues.ts
@@ -42,6 +42,7 @@ import {
  issueApprovalService,
  ISSUE_LIST_DEFAULT_LIMIT,
  ISSUE_LIST_MAX_LIMIT,
+  issueReferenceService,
  issueService,
  clampIssueListLimit,
  documentService,
@@ -133,6 +134,23 @@ function summarizeIssueRelationForActivity(relation: {
  };
 }

+function summarizeIssueReferenceActivityDetails(input:
+  | {
+      addedReferencedIssues: ActivityIssueRelationSummary[];
+      removedReferencedIssues: ActivityIssueRelationSummary[];
+      currentReferencedIssues: ActivityIssueRelationSummary[];
+    }
+  | null
+  | undefined,
+) {
+  if (!input) return {};
+  return {
+    ...(input.addedReferencedIssues.length > 0 ? { addedReferencedIssues: input.addedReferencedIssues } : {}),
+    ...(input.removedReferencedIssues.length > 0 ? { removedReferencedIssues: input.removedReferencedIssues } : {}),
+    ...(input.currentReferencedIssues.length > 0 ? { currentReferencedIssues: input.currentReferencedIssues } : {}),
+  };
+}
+
 function activityExecutionParticipantKey(participant: ActivityExecutionParticipant): string {
  return participant.type === "agent" ? `agent:${participant.agentId}` : `user:${participant.userId}`;
 }
@@ -314,6 +332,7 @@ export function issueRoutes(
  const executionWorkspacesSvc = executionWorkspaceService(db);
  const workProductsSvc = workProductService(db);
  const documentsSvc = documentService(db);
+  const issueReferencesSvc = issueReferenceService(db);
  const routinesSvc = routineService(db);
  const feedbackExportService = opts?.feedbackExportService;
  const upload = multer({
@@ -871,12 +890,13 @@ export function issueRoutes(
      return;
    }
    assertCompanyAccess(req, issue.companyId);
-    const [{ project, goal }, ancestors, mentionedProjectIds, documentPayload, relations] = await Promise.all([
+    const [{ project, goal }, ancestors, mentionedProjectIds, documentPayload, relations, referenceSummary] = await Promise.all([
      resolveIssueProjectAndGoal(issue),
      svc.getAncestors(issue.id),
      svc.findMentionedProjectIds(issue.id, { includeCommentBodies: false }),
      documentsSvc.getIssueDocumentPayload(issue),
      svc.getRelationSummaries(issue.id),
+      issueReferencesSvc.listIssueReferenceSummary(issue.id),
    ]);
    const mentionedProjects = mentionedProjectIds.length > 0
      ? await projectsSvc.listByIds(issue.companyId, mentionedProjectIds)
@@ -891,6 +911,8 @@ export function issueRoutes(
      ancestors,
      blockedBy: relations.blockedBy,
      blocks: relations.blocks,
+      relatedWork: referenceSummary,
+      referencedIssueIdentifiers: referenceSummary.outbound.map((item) => item.issue.identifier ?? item.issue.id),
      ...documentPayload,
      project: project ?? null,
      goal: goal ?? null,
@@ -963,6 +985,7 @@ export function issueRoutes(
    }

    const actor = getActorInfo(req);
+    const referenceSummaryBefore = await issueReferencesSvc.listIssueReferenceSummary(issue.id);
    const result = await documentsSvc.upsertIssueDocument({
      issueId: issue.id,
      key: keyParsed.data,
@@ -976,6 +999,9 @@ export function issueRoutes(
      createdByRunId: actor.runId ?? null,
    });
    const doc = result.document;
+    await issueReferencesSvc.syncDocument(doc.id);
+    const referenceSummaryAfter = await issueReferencesSvc.listIssueReferenceSummary(issue.id);
+    const referenceDiff = issueReferencesSvc.diffIssueReferenceSummary(referenceSummaryBefore, referenceSummaryAfter);

    await logActivity(db, {
      companyId: issue.companyId,
@@ -992,6 +1018,11 @@ export function issueRoutes(
        title: doc.title,
        format: doc.format,
        revisionNumber: doc.latestRevisionNumber,
+        ...summarizeIssueReferenceActivityDetails({
+          addedReferencedIssues: referenceDiff.addedReferencedIssues.map(summarizeIssueRelationForActivity),
+          removedReferencedIssues: referenceDiff.removedReferencedIssues.map(summarizeIssueRelationForActivity),
+          currentReferencedIssues: referenceDiff.currentReferencedIssues.map(summarizeIssueRelationForActivity),
+        }),
      },
    });

@@ -1035,6 +1066,7 @@ export function issueRoutes(
      }

      const actor = getActorInfo(req);
+      const referenceSummaryBefore = await issueReferencesSvc.listIssueReferenceSummary(issue.id);
      const result = await documentsSvc.restoreIssueDocumentRevision({
        issueId: issue.id,
        key: keyParsed.data,
@@ -1042,6 +1074,9 @@ export function issueRoutes(
        createdByAgentId: actor.agentId ?? null,
        createdByUserId: actor.actorType === "user" ? actor.actorId : null,
      });
+      await issueReferencesSvc.syncDocument(result.document.id);
+      const referenceSummaryAfter = await issueReferencesSvc.listIssueReferenceSummary(issue.id);
+      const referenceDiff = issueReferencesSvc.diffIssueReferenceSummary(referenceSummaryBefore, referenceSummaryAfter);

      await logActivity(db, {
        companyId: issue.companyId,
@@ -1060,6 +1095,11 @@ export function issueRoutes(
          revisionNumber: result.document.latestRevisionNumber,
          restoredFromRevisionId: result.restoredFromRevisionId,
          restoredFromRevisionNumber: result.restoredFromRevisionNumber,
+          ...summarizeIssueReferenceActivityDetails({
+            addedReferencedIssues: referenceDiff.addedReferencedIssues.map(summarizeIssueRelationForActivity),
+            removedReferencedIssues: referenceDiff.removedReferencedIssues.map(summarizeIssueRelationForActivity),
+            currentReferencedIssues: referenceDiff.currentReferencedIssues.map(summarizeIssueRelationForActivity),
+          }),
        },
      });

@@ -1084,11 +1124,15 @@ export function issueRoutes(
      res.status(400).json({ error: "Invalid document key", details: keyParsed.error.issues });
      return;
    }
+    const referenceSummaryBefore = await issueReferencesSvc.listIssueReferenceSummary(issue.id);
    const removed = await documentsSvc.deleteIssueDocument(issue.id, keyParsed.data);
    if (!removed) {
      res.status(404).json({ error: "Document not found" });
      return;
    }
+    await issueReferencesSvc.deleteDocumentSource(removed.id);
+    const referenceSummaryAfter = await issueReferencesSvc.listIssueReferenceSummary(issue.id);
+    const referenceDiff = issueReferencesSvc.diffIssueReferenceSummary(referenceSummaryBefore, referenceSummaryAfter);
    const actor = getActorInfo(req);
    await logActivity(db, {
      companyId: issue.companyId,
@@ -1103,6 +1147,11 @@ export function issueRoutes(
        key: removed.key,
        documentId: removed.id,
        title: removed.title,
+        ...summarizeIssueReferenceActivityDetails({
+          addedReferencedIssues: referenceDiff.addedReferencedIssues.map(summarizeIssueRelationForActivity),
+          removedReferencedIssues: referenceDiff.removedReferencedIssues.map(summarizeIssueRelationForActivity),
+          currentReferencedIssues: referenceDiff.currentReferencedIssues.map(summarizeIssueRelationForActivity),
+        }),
      },
    });
    res.json({ ok: true });
@@ -1427,6 +1476,12 @@ export function issueRoutes(
      createdByAgentId: actor.agentId,
      createdByUserId: actor.actorType === "user" ? actor.actorId : null,
    });
+    await issueReferencesSvc.syncIssue(issue.id);
+    const referenceSummary = await issueReferencesSvc.listIssueReferenceSummary(issue.id);
+    const referenceDiff = issueReferencesSvc.diffIssueReferenceSummary(
+      issueReferencesSvc.emptySummary(),
+      referenceSummary,
+    );

    await logActivity(db, {
      companyId,
@@ -1441,6 +1496,11 @@ export function issueRoutes(
        title: issue.title,
        identifier: issue.identifier,
        ...(Array.isArray(req.body.blockedByIssueIds) ? { blockedByIssueIds: req.body.blockedByIssueIds } : {}),
+        ...summarizeIssueReferenceActivityDetails({
+          addedReferencedIssues: referenceDiff.addedReferencedIssues.map(summarizeIssueRelationForActivity),
+          removedReferencedIssues: referenceDiff.removedReferencedIssues.map(summarizeIssueRelationForActivity),
+          currentReferencedIssues: referenceDiff.currentReferencedIssues.map(summarizeIssueRelationForActivity),
+        }),
      },
    });

@@ -1454,7 +1514,11 @@ export function issueRoutes(
      requestedByActorId: actor.actorId,
    });

-    res.status(201).json(issue);
+    res.status(201).json({
+      ...issue,
+      relatedWork: referenceSummary,
+      referencedIssueIdentifiers: referenceSummary.outbound.map((item) => item.issue.identifier ?? item.issue.id),
+    });
  });

  router.post("/issues/:id/children", validate(createChildIssueSchema), async (req, res) => {
@@ -1530,6 +1594,7 @@ export function issueRoutes(
      existing.companyId,
      req.body.assigneeAgentId as string | null | undefined,
    );
+    const titleOrDescriptionChanged = req.body.title !== undefined || req.body.description !== undefined;
    const existingRelations =
      Array.isArray(req.body.blockedByIssueIds)
        ? await svc.getRelationSummaries(existing.id)
@@ -1552,6 +1617,9 @@ export function issueRoutes(
          actorType: actor.actorType,
          actorId: actor.actorId,
        }));
+    const updateReferenceSummaryBefore = titleOrDescriptionChanged
+      ? await issueReferencesSvc.listIssueReferenceSummary(existing.id)
+      : null;
    let interruptedRunId: string | null = null;
    const closedExecutionWorkspace = await getClosedIssueExecutionWorkspace(existing);
    const isAgentWorkUpdate = req.actor.type === "agent" && Object.keys(updateFields).length > 0;
@@ -1723,7 +1791,21 @@ export function issueRoutes(
      res.status(404).json({ error: "Issue not found" });
      return;
    }
-    let issueResponse: typeof issue & { blockedBy?: unknown; blocks?: unknown } = issue;
+    if (titleOrDescriptionChanged) {
+      await issueReferencesSvc.syncIssue(issue.id);
+    }
+    const updateReferenceSummaryAfter = titleOrDescriptionChanged
+      ? await issueReferencesSvc.listIssueReferenceSummary(issue.id)
+      : null;
+    const updateReferenceDiff = updateReferenceSummaryBefore && updateReferenceSummaryAfter
+      ? issueReferencesSvc.diffIssueReferenceSummary(updateReferenceSummaryBefore, updateReferenceSummaryAfter)
+      : null;
+    let issueResponse: typeof issue & {
+      blockedBy?: unknown;
+      blocks?: unknown;
+      relatedWork?: Awaited<ReturnType<typeof issueReferencesSvc.listIssueReferenceSummary>>;
+      referencedIssueIdentifiers?: string[];
+    } = issue;
    let updatedRelations: Awaited<ReturnType<typeof svc.getRelationSummaries>> | null = null;
    if (issue && Array.isArray(req.body.blockedByIssueIds)) {
      updatedRelations = await svc.getRelationSummaries(issue.id);
@@ -1775,6 +1857,15 @@ export function issueRoutes(
        ...(reopened ? { reopened: true, reopenedFrom: reopenFromStatus } : {}),
        ...(interruptedRunId ? { interruptedRunId } : {}),
        _previous: hasFieldChanges ? previous : undefined,
+        ...summarizeIssueReferenceActivityDetails(
+          updateReferenceDiff
+            ? {
+                addedReferencedIssues: updateReferenceDiff.addedReferencedIssues.map(summarizeIssueRelationForActivity),
+                removedReferencedIssues: updateReferenceDiff.removedReferencedIssues.map(summarizeIssueRelationForActivity),
+                currentReferencedIssues: updateReferenceDiff.currentReferencedIssues.map(summarizeIssueRelationForActivity),
+              }
+            : null,
+        ),
      },
    });

@@ -1870,11 +1961,26 @@ export function issueRoutes(

    let comment = null;
    if (commentBody) {
+      const commentReferenceSummaryBefore = updateReferenceSummaryAfter
+        ?? await issueReferencesSvc.listIssueReferenceSummary(issue.id);
      comment = await svc.addComment(id, commentBody, {
        agentId: actor.agentId ?? undefined,
        userId: actor.actorType === "user" ? actor.actorId : undefined,
        runId: actor.runId,
      });
+      await issueReferencesSvc.syncComment(comment.id);
+      const commentReferenceSummaryAfter = await issueReferencesSvc.listIssueReferenceSummary(issue.id);
+      const commentReferenceDiff = issueReferencesSvc.diffIssueReferenceSummary(
+        commentReferenceSummaryBefore,
+        commentReferenceSummaryAfter,
+      );
+      issueResponse = {
+        ...issueResponse,
+        relatedWork: commentReferenceSummaryAfter,
+        referencedIssueIdentifiers: commentReferenceSummaryAfter.outbound.map(
+          (item) => item.issue.identifier ?? item.issue.id,
+        ),
+      };

      await logActivity(db, {
        companyId: issue.companyId,
@@ -1893,9 +1999,22 @@ export function issueRoutes(
          ...(reopened ? { reopened: true, reopenedFrom: reopenFromStatus, source: "comment" } : {}),
          ...(interruptedRunId ? { interruptedRunId } : {}),
          ...(hasFieldChanges ? { updated: true } : {}),
+          ...summarizeIssueReferenceActivityDetails({
+            addedReferencedIssues: commentReferenceDiff.addedReferencedIssues.map(summarizeIssueRelationForActivity),
+            removedReferencedIssues: commentReferenceDiff.removedReferencedIssues.map(summarizeIssueRelationForActivity),
+            currentReferencedIssues: commentReferenceDiff.currentReferencedIssues.map(summarizeIssueRelationForActivity),
+          }),
        },
      });

+    } else if (updateReferenceSummaryAfter) {
+      issueResponse = {
+        ...issueResponse,
+        relatedWork: updateReferenceSummaryAfter,
+        referencedIssueIdentifiers: updateReferenceSummaryAfter.outbound.map(
+          (item) => item.issue.identifier ?? item.issue.id,
+        ),
+      };
    }
    const assigneeChanged =
      issue.assigneeAgentId !== existing.assigneeAgentId || issue.assigneeUserId !== existing.assigneeUserId;
@@ -2489,6 +2608,7 @@ export function issueRoutes(
    let reopenFromStatus: string | null = null;
    let interruptedRunId: string | null = null;
    let currentIssue = issue;
+    const commentReferenceSummaryBefore = await issueReferencesSvc.listIssueReferenceSummary(issue.id);

    if (effectiveReopenRequested && isClosed) {
      const reopenedIssue = await svc.update(id, { status: "todo" });
@@ -2550,6 +2670,12 @@ export function issueRoutes(
      userId: actor.actorType === "user" ? actor.actorId : undefined,
      runId: actor.runId,
    });
+    await issueReferencesSvc.syncComment(comment.id);
+    const commentReferenceSummaryAfter = await issueReferencesSvc.listIssueReferenceSummary(currentIssue.id);
+    const commentReferenceDiff = issueReferencesSvc.diffIssueReferenceSummary(
+      commentReferenceSummaryBefore,
+      commentReferenceSummaryAfter,
+    );

    if (actor.runId) {
      await heartbeat.reportRunActivity(actor.runId).catch((err) =>
@@ -2572,6 +2698,11 @@ export function issueRoutes(
        issueTitle: currentIssue.title,
        ...(reopened ? { reopened: true, reopenedFrom: reopenFromStatus, source: "comment" } : {}),
        ...(interruptedRunId ? { interruptedRunId } : {}),
+        ...summarizeIssueReferenceActivityDetails({
+          addedReferencedIssues: commentReferenceDiff.addedReferencedIssues.map(summarizeIssueRelationForActivity),
+          removedReferencedIssues: commentReferenceDiff.removedReferencedIssues.map(summarizeIssueRelationForActivity),
+          currentReferencedIssues: commentReferenceDiff.currentReferencedIssues.map(summarizeIssueRelationForActivity),
+        }),
      },
    });

--- a/server/src/services/index.ts
+++ b/server/src/services/index.ts
@@ -20,6 +20,7 @@ export {
  type IssueFilters,
 } from "./issues.js";
 export { issueApprovalService } from "./issue-approvals.js";
+export { issueReferenceService } from "./issue-references.js";
 export { goalService } from "./goals.js";
 export { activityService, type ActivityFilters } from "./activity.js";
 export { approvalService } from "./approvals.js";
--- a/server/src/services/issue-references.ts
+++ b/server/src/services/issue-references.ts
@@ -0,0 +1,407 @@
+import { and, asc, eq, inArray, isNull } from "drizzle-orm";
+import type { Db } from "@paperclipai/db";
+import { documents, issueComments, issueDocuments, issueReferenceMentions, issues } from "@paperclipai/db";
+import type {
+  IssueReferenceSource,
+  IssueReferenceSourceKind,
+  IssueRelatedWorkItem,
+  IssueRelatedWorkSummary,
+  IssueRelationIssueSummary,
+} from "@paperclipai/shared";
+import { extractIssueReferenceMatches } from "@paperclipai/shared";
+import { notFound } from "../errors.js";
+
+const SOURCE_KIND_ORDER: Record<IssueReferenceSourceKind, number> = {
+  title: 0,
+  description: 1,
+  document: 2,
+  comment: 3,
+};
+
+function sourceLabel(kind: IssueReferenceSourceKind, documentKey: string | null): string {
+  if (kind === "document") return documentKey?.trim() || "document";
+  return kind;
+}
+
+function sourceWhere(
+  input: {
+    companyId?: string;
+    sourceIssueId?: string;
+    sourceKind: IssueReferenceSourceKind;
+    sourceRecordId?: string | null;
+  },
+) {
+  const conditions = [eq(issueReferenceMentions.sourceKind, input.sourceKind)];
+  if (input.companyId) conditions.push(eq(issueReferenceMentions.companyId, input.companyId));
+  if (input.sourceIssueId) conditions.push(eq(issueReferenceMentions.sourceIssueId, input.sourceIssueId));
+  if (input.sourceRecordId) {
+    conditions.push(eq(issueReferenceMentions.sourceRecordId, input.sourceRecordId));
+  } else {
+    conditions.push(isNull(issueReferenceMentions.sourceRecordId));
+  }
+  return and(...conditions);
+}
+
+function toIssueSummary(row: {
+  relatedIssueId: string;
+  relatedIssueIdentifier: string | null;
+  relatedIssueTitle: string;
+  relatedIssueStatus: IssueRelationIssueSummary["status"];
+  relatedIssuePriority: IssueRelationIssueSummary["priority"];
+  relatedIssueAssigneeAgentId: string | null;
+  relatedIssueAssigneeUserId: string | null;
+}): IssueRelationIssueSummary {
+  return {
+    id: row.relatedIssueId,
+    identifier: row.relatedIssueIdentifier,
+    title: row.relatedIssueTitle,
+    status: row.relatedIssueStatus,
+    priority: row.relatedIssuePriority,
+    assigneeAgentId: row.relatedIssueAssigneeAgentId,
+    assigneeUserId: row.relatedIssueAssigneeUserId,
+  };
+}
+
+function sortSources(a: IssueReferenceSource, b: IssueReferenceSource) {
+  const orderDelta = SOURCE_KIND_ORDER[a.kind] - SOURCE_KIND_ORDER[b.kind];
+  if (orderDelta !== 0) return orderDelta;
+  const labelDelta = a.label.localeCompare(b.label);
+  if (labelDelta !== 0) return labelDelta;
+  return (a.sourceRecordId ?? "").localeCompare(b.sourceRecordId ?? "");
+}
+
+function sortRelatedWork(a: IssueRelatedWorkItem, b: IssueRelatedWorkItem) {
+  if (b.mentionCount !== a.mentionCount) return b.mentionCount - a.mentionCount;
+  const leftLabel = a.issue.identifier ?? a.issue.title;
+  const rightLabel = b.issue.identifier ?? b.issue.title;
+  return leftLabel.localeCompare(rightLabel);
+}
+
+function emptySummary(): IssueRelatedWorkSummary {
+  return {
+    outbound: [],
+    inbound: [],
+  };
+}
+
+function diffIssueSummaries(
+  before: IssueRelatedWorkSummary,
+  after: IssueRelatedWorkSummary,
+): {
+  addedReferencedIssues: IssueRelationIssueSummary[];
+  removedReferencedIssues: IssueRelationIssueSummary[];
+  currentReferencedIssues: IssueRelationIssueSummary[];
+} {
+  const beforeById = new Map(before.outbound.map((item) => [item.issue.id, item.issue]));
+  const afterById = new Map(after.outbound.map((item) => [item.issue.id, item.issue]));
+
+  return {
+    addedReferencedIssues: after.outbound
+      .map((item) => item.issue)
+      .filter((issue) => !beforeById.has(issue.id)),
+    removedReferencedIssues: before.outbound
+      .map((item) => item.issue)
+      .filter((issue) => !afterById.has(issue.id)),
+    currentReferencedIssues: after.outbound.map((item) => item.issue),
+  };
+}
+
+export function issueReferenceService(db: Db) {
+  async function replaceSourceMentions(
+    input: {
+      companyId: string;
+      sourceIssueId: string;
+      sourceKind: IssueReferenceSourceKind;
+      sourceRecordId: string | null;
+      documentKey: string | null;
+      text: string | null | undefined;
+    },
+    dbOrTx: any = db,
+  ) {
+    const matches = extractIssueReferenceMatches(input.text ?? "");
+    const identifiers = matches.map((match) => match.identifier);
+    type ResolvedTargetRow = {
+      id: string;
+      identifier: string | null;
+    };
+
+    const resolvedTargets: ResolvedTargetRow[] = identifiers.length > 0
+      ? await dbOrTx
+        .select({
+          id: issues.id,
+          identifier: issues.identifier,
+        })
+        .from(issues)
+        .where(and(eq(issues.companyId, input.companyId), inArray(issues.identifier, identifiers)))
+      : [];
+    const targetByIdentifier = new Map<string, string>(
+      resolvedTargets
+        .filter((row): row is ResolvedTargetRow & { identifier: string } => typeof row.identifier === "string")
+        .map((row) => [row.identifier, row.id]),
+    );
+
+    await dbOrTx.delete(issueReferenceMentions).where(sourceWhere(input));
+
+    if (matches.length === 0) return;
+
+    const seenTargetIds = new Set<string>();
+    const values = matches.flatMap((match) => {
+      const targetIssueId = targetByIdentifier.get(match.identifier);
+      if (!targetIssueId || targetIssueId === input.sourceIssueId || seenTargetIds.has(targetIssueId)) {
+        return [];
+      }
+      seenTargetIds.add(targetIssueId);
+      return [{
+        companyId: input.companyId,
+        sourceIssueId: input.sourceIssueId,
+        targetIssueId,
+        sourceKind: input.sourceKind,
+        sourceRecordId: input.sourceRecordId,
+        documentKey: input.documentKey,
+        matchedText: match.matchedText,
+      }];
+    });
+
+    if (values.length > 0) {
+      await dbOrTx.insert(issueReferenceMentions).values(values);
+    }
+  }
+
+  async function issueById(issueId: string, dbOrTx: any = db) {
+    return dbOrTx
+      .select({
+        id: issues.id,
+        companyId: issues.companyId,
+        title: issues.title,
+        description: issues.description,
+      })
+      .from(issues)
+      .where(eq(issues.id, issueId))
+      .then((rows: Array<{ id: string; companyId: string; title: string; description: string | null }>) => rows[0] ?? null);
+  }
+
+  async function syncIssue(issueId: string, dbOrTx: any = db) {
+    const runSync = async (tx: any) => {
+      const issue = await issueById(issueId, tx);
+      if (!issue) throw notFound("Issue not found");
+
+      await replaceSourceMentions({
+        companyId: issue.companyId,
+        sourceIssueId: issue.id,
+        sourceKind: "title",
+        sourceRecordId: null,
+        documentKey: null,
+        text: issue.title,
+      }, tx);
+
+      await replaceSourceMentions({
+        companyId: issue.companyId,
+        sourceIssueId: issue.id,
+        sourceKind: "description",
+        sourceRecordId: null,
+        documentKey: null,
+        text: issue.description,
+      }, tx);
+    };
+
+    return dbOrTx === db ? db.transaction(runSync) : runSync(dbOrTx);
+  }
+
+  async function syncComment(commentId: string, dbOrTx: any = db) {
+    const comment = await dbOrTx
+      .select({
+        id: issueComments.id,
+        companyId: issueComments.companyId,
+        issueId: issueComments.issueId,
+        body: issueComments.body,
+      })
+      .from(issueComments)
+      .where(eq(issueComments.id, commentId))
+      .then((rows: Array<{ id: string; companyId: string; issueId: string; body: string }>) => rows[0] ?? null);
+    if (!comment) throw notFound("Issue comment not found");
+
+    await replaceSourceMentions({
+      companyId: comment.companyId,
+      sourceIssueId: comment.issueId,
+      sourceKind: "comment",
+      sourceRecordId: comment.id,
+      documentKey: null,
+      text: comment.body,
+    }, dbOrTx);
+  }
+
+  async function syncDocument(documentId: string, dbOrTx: any = db) {
+    const document = await dbOrTx
+      .select({
+        documentId: documents.id,
+        companyId: documents.companyId,
+        issueId: issueDocuments.issueId,
+        key: issueDocuments.key,
+        body: documents.latestBody,
+      })
+      .from(issueDocuments)
+      .innerJoin(documents, eq(issueDocuments.documentId, documents.id))
+      .where(eq(documents.id, documentId))
+      .then((rows: Array<{ documentId: string; companyId: string; issueId: string; key: string; body: string }>) => rows[0] ?? null);
+
+    if (!document) {
+      await dbOrTx
+        .delete(issueReferenceMentions)
+        .where(and(eq(issueReferenceMentions.sourceKind, "document"), eq(issueReferenceMentions.sourceRecordId, documentId)));
+      return;
+    }
+
+    await replaceSourceMentions({
+      companyId: document.companyId,
+      sourceIssueId: document.issueId,
+      sourceKind: "document",
+      sourceRecordId: document.documentId,
+      documentKey: document.key,
+      text: document.body,
+    }, dbOrTx);
+  }
+
+  async function deleteDocumentSource(documentId: string, dbOrTx: any = db) {
+    await dbOrTx
+      .delete(issueReferenceMentions)
+      .where(and(eq(issueReferenceMentions.sourceKind, "document"), eq(issueReferenceMentions.sourceRecordId, documentId)));
+  }
+
+  async function syncAllForIssue(issueId: string, dbOrTx: any = db) {
+    const issue = await issueById(issueId, dbOrTx);
+    if (!issue) throw notFound("Issue not found");
+
+    await syncIssue(issueId, dbOrTx);
+
+    const [comments, docs] = await Promise.all([
+      dbOrTx
+        .select({ id: issueComments.id })
+        .from(issueComments)
+        .where(eq(issueComments.issueId, issueId)),
+      dbOrTx
+        .select({ id: documents.id })
+        .from(issueDocuments)
+        .innerJoin(documents, eq(issueDocuments.documentId, documents.id))
+        .where(eq(issueDocuments.issueId, issueId)),
+    ]);
+
+    for (const comment of comments) {
+      await syncComment(comment.id, dbOrTx);
+    }
+    for (const doc of docs) {
+      await syncDocument(doc.id, dbOrTx);
+    }
+  }
+
+  async function syncAllForCompany(companyId: string, dbOrTx: any = db) {
+    const issueRows = await dbOrTx
+      .select({ id: issues.id })
+      .from(issues)
+      .where(eq(issues.companyId, companyId))
+      .orderBy(asc(issues.createdAt), asc(issues.id));
+
+    for (const issue of issueRows) {
+      await syncAllForIssue(issue.id, dbOrTx);
+    }
+  }
+
+  async function listIssueReferenceSummary(issueId: string, dbOrTx: any = db): Promise<IssueRelatedWorkSummary> {
+      const issue = await issueById(issueId, dbOrTx);
+      if (!issue) throw notFound("Issue not found");
+
+      const [outboundRows, inboundRows] = await Promise.all([
+        dbOrTx
+          .select({
+            relatedIssueId: issues.id,
+            relatedIssueIdentifier: issues.identifier,
+            relatedIssueTitle: issues.title,
+            relatedIssueStatus: issues.status,
+            relatedIssuePriority: issues.priority,
+            relatedIssueAssigneeAgentId: issues.assigneeAgentId,
+            relatedIssueAssigneeUserId: issues.assigneeUserId,
+            sourceKind: issueReferenceMentions.sourceKind,
+            sourceRecordId: issueReferenceMentions.sourceRecordId,
+            documentKey: issueReferenceMentions.documentKey,
+            matchedText: issueReferenceMentions.matchedText,
+          })
+          .from(issueReferenceMentions)
+          .innerJoin(issues, eq(issueReferenceMentions.targetIssueId, issues.id))
+          .where(and(
+            eq(issueReferenceMentions.companyId, issue.companyId),
+            eq(issueReferenceMentions.sourceIssueId, issueId),
+          )),
+        dbOrTx
+          .select({
+            relatedIssueId: issues.id,
+            relatedIssueIdentifier: issues.identifier,
+            relatedIssueTitle: issues.title,
+            relatedIssueStatus: issues.status,
+            relatedIssuePriority: issues.priority,
+            relatedIssueAssigneeAgentId: issues.assigneeAgentId,
+            relatedIssueAssigneeUserId: issues.assigneeUserId,
+            sourceKind: issueReferenceMentions.sourceKind,
+            sourceRecordId: issueReferenceMentions.sourceRecordId,
+            documentKey: issueReferenceMentions.documentKey,
+            matchedText: issueReferenceMentions.matchedText,
+          })
+          .from(issueReferenceMentions)
+          .innerJoin(issues, eq(issueReferenceMentions.sourceIssueId, issues.id))
+          .where(and(
+            eq(issueReferenceMentions.companyId, issue.companyId),
+            eq(issueReferenceMentions.targetIssueId, issueId),
+          )),
+      ]);
+
+      const mapRows = (rows: Array<{
+        relatedIssueId: string;
+        relatedIssueIdentifier: string | null;
+        relatedIssueTitle: string;
+        relatedIssueStatus: IssueRelationIssueSummary["status"];
+        relatedIssuePriority: IssueRelationIssueSummary["priority"];
+        relatedIssueAssigneeAgentId: string | null;
+        relatedIssueAssigneeUserId: string | null;
+        sourceKind: IssueReferenceSourceKind;
+        sourceRecordId: string | null;
+        documentKey: string | null;
+        matchedText: string | null;
+      }>) => {
+        const grouped = new Map<string, IssueRelatedWorkItem>();
+        for (const row of rows) {
+          const existing = grouped.get(row.relatedIssueId) ?? {
+            issue: toIssueSummary(row),
+            mentionCount: 0,
+            sources: [],
+          };
+          existing.mentionCount += 1;
+          existing.sources.push({
+            kind: row.sourceKind,
+            sourceRecordId: row.sourceRecordId,
+            label: sourceLabel(row.sourceKind, row.documentKey),
+            matchedText: row.matchedText,
+          });
+          grouped.set(row.relatedIssueId, existing);
+        }
+
+        return [...grouped.values()]
+          .map((item) => ({ ...item, sources: [...item.sources].sort(sortSources) }))
+          .sort(sortRelatedWork);
+      };
+
+      return {
+        outbound: mapRows(outboundRows),
+        inbound: mapRows(inboundRows),
+      };
+  }
+
+  return {
+    syncIssue,
+    syncComment,
+    syncDocument,
+    deleteDocumentSource,
+    syncAllForIssue,
+    syncAllForCompany,
+    listIssueReferenceSummary,
+    diffIssueReferenceSummary: diffIssueSummaries,
+    emptySummary,
+  };
+}
--- a/ui/src/components/ActivityRow.tsx
+++ b/ui/src/components/ActivityRow.tsx
@@ -1,5 +1,6 @@
 import { Link } from "@/lib/router";
 import { Identity } from "./Identity";
+import { IssueReferenceActivitySummary } from "./IssueReferenceActivitySummary";
 import { timeAgo } from "../lib/timeAgo";
 import { cn } from "../lib/utils";
 import { formatActivityVerb } from "../lib/activity-format";
@@ -50,19 +51,22 @@ export function ActivityRow({ event, agentMap, userProfileMap, entityNameMap, en
  const actorAvatarUrl = userProfile?.image ?? null;

  const inner = (
-    <div className="flex gap-3">
-      <p className="flex-1 min-w-0 truncate">
-        <Identity
-          name={actorName}
-          avatarUrl={actorAvatarUrl}
-          size="xs"
-          className="align-baseline"
-        />
-        <span className="text-muted-foreground ml-1">{verb} </span>
-        {name && <span className="font-medium">{name}</span>}
-        {entityTitle && <span className="text-muted-foreground ml-1">— {entityTitle}</span>}
-      </p>
-      <span className="text-xs text-muted-foreground shrink-0 pt-0.5">{timeAgo(event.createdAt)}</span>
+    <div className="space-y-2">
+      <div className="flex gap-3">
+        <p className="flex-1 min-w-0 truncate">
+          <Identity
+            name={actorName}
+            avatarUrl={actorAvatarUrl}
+            size="xs"
+            className="align-baseline"
+          />
+          <span className="text-muted-foreground ml-1">{verb} </span>
+          {name && <span className="font-medium">{name}</span>}
+          {entityTitle && <span className="text-muted-foreground ml-1">— {entityTitle}</span>}
+        </p>
+        <span className="text-xs text-muted-foreground shrink-0 pt-0.5">{timeAgo(event.createdAt)}</span>
+      </div>
+      <IssueReferenceActivitySummary event={event} />
    </div>
  );

--- a/ui/src/components/IssueProperties.test.tsx
+++ b/ui/src/components/IssueProperties.test.tsx
@@ -416,6 +416,126 @@ describe("IssueProperties", () => {
    act(() => root.unmount());
  });

+  it("shows related task references below sub-issues", async () => {
+    const root = renderProperties(container, {
+      issue: createIssue({
+        relatedWork: {
+          outbound: [
+            {
+              issue: {
+                id: "issue-22",
+                identifier: "PAP-22",
+                title: "Related task",
+                status: "todo",
+                priority: "medium",
+                assigneeAgentId: null,
+                assigneeUserId: null,
+              },
+              mentionCount: 1,
+              sources: [{ kind: "description", sourceRecordId: null, label: "description", matchedText: "PAP-22" }],
+            },
+          ],
+          inbound: [],
+        },
+      }),
+      childIssues: [],
+      onUpdate: vi.fn(),
+    });
+    await flush();
+
+    expect(container.textContent).not.toContain("Task ids");
+    expect(container.textContent).toContain("Related Tasks");
+    expect(container.textContent).toContain("PAP-22");
+
+    act(() => root.unmount());
+  });
+
+  it("hides related task references already covered by blockers, blocking, and sub-issues", async () => {
+    const root = renderProperties(container, {
+      issue: createIssue({
+        blockedBy: [
+          {
+            id: "issue-22",
+            identifier: "PAP-22",
+            title: "Blocker",
+            status: "todo",
+            priority: "medium",
+            assigneeAgentId: null,
+            assigneeUserId: null,
+          },
+        ],
+        blocks: [
+          {
+            id: "issue-33",
+            identifier: "PAP-33",
+            title: "Blocked issue",
+            status: "todo",
+            priority: "medium",
+            assigneeAgentId: null,
+            assigneeUserId: null,
+          },
+        ],
+        relatedWork: {
+          outbound: [
+            {
+              issue: {
+                id: "issue-22",
+                identifier: "PAP-22",
+                title: "Blocker",
+                status: "todo",
+                priority: "medium",
+                assigneeAgentId: null,
+                assigneeUserId: null,
+              },
+              mentionCount: 1,
+              sources: [{ kind: "description", sourceRecordId: null, label: "description", matchedText: "PAP-22" }],
+            },
+            {
+              issue: {
+                id: "issue-33",
+                identifier: "PAP-33",
+                title: "Blocked issue",
+                status: "todo",
+                priority: "medium",
+                assigneeAgentId: null,
+                assigneeUserId: null,
+              },
+              mentionCount: 1,
+              sources: [{ kind: "description", sourceRecordId: null, label: "description", matchedText: "PAP-33" }],
+            },
+            {
+              issue: {
+                id: "child-44",
+                identifier: "PAP-44",
+                title: "Child issue",
+                status: "todo",
+                priority: "medium",
+                assigneeAgentId: null,
+                assigneeUserId: null,
+              },
+              mentionCount: 1,
+              sources: [{ kind: "description", sourceRecordId: null, label: "description", matchedText: "PAP-44" }],
+            },
+          ],
+          inbound: [],
+        },
+      }),
+      childIssues: [
+        createIssue({
+          id: "child-44",
+          identifier: "PAP-44",
+          title: "Child issue",
+        }),
+      ],
+      onUpdate: vi.fn(),
+    });
+    await flush();
+
+    expect(container.textContent).not.toContain("Related Tasks");
+
+    act(() => root.unmount());
+  });
+
  it("shows an add-label button when labels already exist and opens the picker", async () => {
    const root = renderProperties(container, {
      issue: createIssue({
@@ -531,7 +651,6 @@ describe("IssueProperties", () => {

    act(() => rerenderedRoot.unmount());
  });
-
  it("shows a run review action after reviewers are configured and starts execution explicitly when clicked", async () => {
    const onUpdate = vi.fn();
    const root = renderProperties(container, {
--- a/ui/src/components/IssueProperties.tsx
+++ b/ui/src/components/IssueProperties.tsx
@@ -26,6 +26,7 @@ import { buildExecutionPolicy, stageParticipantValues } from "../lib/issue-execu
 import { StatusIcon } from "./StatusIcon";
 import { PriorityIcon } from "./PriorityIcon";
 import { Identity } from "./Identity";
+import { IssueReferencePill } from "./IssueReferencePill";
 import { formatDate, cn, projectUrl } from "../lib/utils";
 import { timeAgo } from "../lib/timeAgo";
 import { Separator } from "@/components/ui/separator";
@@ -295,6 +296,30 @@ export function IssueProperties({
    if (isMainIssueWorkspace({ issue, project: issueProject })) return null;
    return runningRuntimeServiceWithUrl(issue.currentExecutionWorkspace?.runtimeServices);
  }, [issue, issueProject]);
+  const referencedIssueIdentifiers = issue.referencedIssueIdentifiers ?? [];
+  const relatedTasks = useMemo(() => {
+    const excluded = new Set<string>();
+    const addExcluded = (candidate: { id: string; identifier?: string | null }) => {
+      excluded.add(candidate.id);
+      if (candidate.identifier) excluded.add(candidate.identifier);
+    };
+
+    for (const blocker of issue.blockedBy ?? []) addExcluded(blocker);
+    for (const blocked of issue.blocks ?? []) addExcluded(blocked);
+    for (const child of childIssues) addExcluded(child);
+
+    const referencedIssues = issue.relatedWork?.outbound.map((item) => item.issue) ?? [];
+    if (referencedIssues.length > 0) {
+      return referencedIssues.filter((referenced) => {
+        const label = referenced.identifier ?? referenced.id;
+        return !excluded.has(referenced.id) && !excluded.has(label);
+      });
+    }
+
+    return referencedIssueIdentifiers
+      .filter((identifier) => !excluded.has(identifier))
+      .map((identifier) => ({ id: identifier, identifier, title: identifier }));
+  }, [childIssues, issue.blockedBy, issue.blocks, issue.relatedWork?.outbound, referencedIssueIdentifiers]);
  const projectLink = (id: string | null) => {
    if (!id) return null;
    const project = projects?.find((p) => p.id === id) ?? null;
@@ -1113,12 +1138,22 @@ export function IssueProperties({
                onClick={onAddSubIssue}
              >
                <Plus className="h-3 w-3" />
-                Add sub-issue
+              Add sub-issue
              </button>
            ) : null}
          </div>
        </PropertyRow>

+        {relatedTasks.length > 0 ? (
+          <PropertyRow label="Related Tasks">
+            <div className="flex flex-wrap gap-1">
+              {relatedTasks.map((related) => (
+                <IssueReferencePill key={related.id} issue={related} />
+              ))}
+            </div>
+          </PropertyRow>
+        ) : null}
+
        <PropertyPicker
          inline={inline}
          label="Reviewers"
--- a/ui/src/components/IssueReferenceActivitySummary.tsx
+++ b/ui/src/components/IssueReferenceActivitySummary.tsx
@@ -0,0 +1,73 @@
+import type { ActivityEvent } from "@paperclipai/shared";
+import { Plus, Minus } from "lucide-react";
+import { IssueReferencePill } from "./IssueReferencePill";
+
+type ActivityIssueReference = {
+  id: string;
+  identifier?: string | null;
+  title?: string | null;
+};
+
+function readIssueReferences(details: Record<string, unknown> | null | undefined, key: string): ActivityIssueReference[] {
+  const value = details?.[key];
+  if (!Array.isArray(value)) return [];
+  return value.filter((item): item is ActivityIssueReference => !!item && typeof item === "object");
+}
+
+function Section({
+  label,
+  icon,
+  items,
+  strikethrough,
+}: {
+  label: string;
+  icon: React.ReactNode;
+  items: ActivityIssueReference[];
+  strikethrough?: boolean;
+}) {
+  if (items.length === 0) return null;
+  return (
+    <div className="flex flex-wrap items-center gap-1.5">
+      <span
+        aria-label={label}
+        className="inline-flex items-center gap-1 text-xs text-muted-foreground"
+      >
+        {icon}
+        <span className="sr-only">{label}</span>
+      </span>
+      {items.map((issue) => (
+        <IssueReferencePill
+          key={`${label}:${issue.id}`}
+          strikethrough={strikethrough}
+          issue={{
+            id: issue.id,
+            identifier: issue.identifier ?? null,
+            title: issue.title ?? issue.identifier ?? issue.id,
+          }}
+        />
+      ))}
+    </div>
+  );
+}
+
+export function IssueReferenceActivitySummary({ event }: { event: Pick<ActivityEvent, "details"> }) {
+  const added = readIssueReferences(event.details, "addedReferencedIssues");
+  const removed = readIssueReferences(event.details, "removedReferencedIssues");
+  if (added.length === 0 && removed.length === 0) return null;
+
+  return (
+    <div className="mt-2 space-y-1">
+      <Section
+        label="Added references"
+        icon={<Plus className="h-3 w-3 text-green-600 dark:text-green-400" aria-hidden="true" />}
+        items={added}
+      />
+      <Section
+        label="Removed references"
+        icon={<Minus className="h-3 w-3 text-red-600 dark:text-red-400" aria-hidden="true" />}
+        items={removed}
+        strikethrough
+      />
+    </div>
+  );
+}
--- a/ui/src/components/IssueReferencePill.tsx
+++ b/ui/src/components/IssueReferencePill.tsx
@@ -0,0 +1,55 @@
+import type { IssueRelationIssueSummary } from "@paperclipai/shared";
+import { Link } from "@/lib/router";
+import { cn } from "../lib/utils";
+import { StatusIcon } from "./StatusIcon";
+
+export function IssueReferencePill({
+  issue,
+  strikethrough,
+  className,
+}: {
+  issue: Pick<IssueRelationIssueSummary, "id" | "identifier" | "title"> &
+    Partial<Pick<IssueRelationIssueSummary, "status">>;
+  strikethrough?: boolean;
+  className?: string;
+}) {
+  const issueLabel = issue.identifier ?? issue.title;
+  const classNames = cn(
+    "paperclip-mention-chip paperclip-mention-chip--issue",
+    "inline-flex items-center gap-1 rounded-full border border-border px-2 py-0.5 text-xs no-underline",
+    issue.identifier && "hover:bg-accent/50 focus-visible:outline-none focus-visible:ring-[3px] focus-visible:ring-ring",
+    strikethrough && "opacity-60 line-through decoration-muted-foreground",
+    className,
+  );
+  const content = (
+    <>
+      {issue.status ? <StatusIcon status={issue.status} className="h-3 w-3 shrink-0" /> : null}
+      <span>{issue.identifier ?? issue.title}</span>
+    </>
+  );
+
+  if (!issue.identifier) {
+    return (
+      <span
+        data-mention-kind="issue"
+        className={classNames}
+        title={issue.title}
+        aria-label={`Issue: ${issue.title}`}
+      >
+        {content}
+      </span>
+    );
+  }
+
+  return (
+    <Link
+      to={`/issues/${issueLabel}`}
+      data-mention-kind="issue"
+      className={classNames}
+      title={issue.title}
+      aria-label={`Issue ${issueLabel}: ${issue.title}`}
+    >
+      {content}
+    </Link>
+  );
+}
--- a/ui/src/components/IssueRelatedWorkPanel.test.tsx
+++ b/ui/src/components/IssueRelatedWorkPanel.test.tsx
@@ -0,0 +1,96 @@
+import type { ComponentProps } from "react";
+import { renderToStaticMarkup } from "react-dom/server";
+import { describe, expect, it, vi } from "vitest";
+import { IssueRelatedWorkPanel } from "./IssueRelatedWorkPanel";
+
+vi.mock("@/lib/router", () => ({
+  Link: ({ children, to, ...props }: ComponentProps<"a"> & { to: string }) => <a href={to} {...props}>{children}</a>,
+}));
+
+describe("IssueRelatedWorkPanel", () => {
+  it("renders outbound and inbound related work with source labels", () => {
+    const html = renderToStaticMarkup(
+      <IssueRelatedWorkPanel
+        relatedWork={{
+          outbound: [
+            {
+              issue: {
+                id: "issue-2",
+                identifier: "PAP-22",
+                title: "Downstream task",
+                status: "todo",
+                priority: "medium",
+                assigneeAgentId: null,
+                assigneeUserId: null,
+              },
+              mentionCount: 2,
+              sources: [
+                { kind: "title", sourceRecordId: null, label: "title", matchedText: "PAP-22" },
+                { kind: "document", sourceRecordId: "doc-1", label: "plan", matchedText: "/issues/PAP-22" },
+              ],
+            },
+          ],
+          inbound: [
+            {
+              issue: {
+                id: "issue-3",
+                identifier: "PAP-33",
+                title: "Upstream task",
+                status: "in_progress",
+                priority: "high",
+                assigneeAgentId: null,
+                assigneeUserId: null,
+              },
+              mentionCount: 1,
+              sources: [
+                { kind: "comment", sourceRecordId: "comment-1", label: "comment", matchedText: "PAP-1" },
+              ],
+            },
+          ],
+        }}
+      />,
+    );
+
+    expect(html).toContain("References");
+    expect(html).toContain("Referenced by");
+    expect(html).toContain("PAP-22");
+    expect(html).toContain("PAP-33");
+    expect(html).toContain('aria-label="Issue PAP-22: Downstream task"');
+    expect(html).toContain('aria-label="Issue PAP-33: Upstream task"');
+    expect(html).toContain("plan");
+    expect(html).toContain("comment");
+  });
+
+  it("collapses duplicate source labels into a single chip with a count", () => {
+    const html = renderToStaticMarkup(
+      <IssueRelatedWorkPanel
+        relatedWork={{
+          outbound: [],
+          inbound: [
+            {
+              issue: {
+                id: "issue-4",
+                identifier: "PAP-44",
+                title: "Chatty inbound",
+                status: "in_progress",
+                priority: "medium",
+                assigneeAgentId: null,
+                assigneeUserId: null,
+              },
+              mentionCount: 3,
+              sources: [
+                { kind: "comment", sourceRecordId: "c1", label: "comment", matchedText: "PAP-44 first" },
+                { kind: "comment", sourceRecordId: "c2", label: "comment", matchedText: "PAP-44 second" },
+                { kind: "comment", sourceRecordId: "c3", label: "comment", matchedText: "PAP-44 third" },
+              ],
+            },
+          ],
+        }}
+      />,
+    );
+
+    const commentMatches = html.match(/>comment</g) ?? [];
+    expect(commentMatches).toHaveLength(1);
+    expect(html).toContain("×3");
+  });
+});
--- a/ui/src/components/IssueRelatedWorkPanel.tsx
+++ b/ui/src/components/IssueRelatedWorkPanel.tsx
@@ -0,0 +1,110 @@
+import type { IssueRelatedWorkItem, IssueRelatedWorkSummary } from "@paperclipai/shared";
+import { IssueReferencePill } from "./IssueReferencePill";
+
+type GroupedSource = {
+  label: string;
+  count: number;
+  sampleMatchedText: string | null;
+};
+
+function groupSourcesByLabel(sources: IssueRelatedWorkItem["sources"]): GroupedSource[] {
+  const groups = new Map<string, GroupedSource>();
+  for (const source of sources) {
+    const existing = groups.get(source.label);
+    if (existing) {
+      existing.count += 1;
+    } else {
+      groups.set(source.label, {
+        label: source.label,
+        count: 1,
+        sampleMatchedText: source.matchedText ?? null,
+      });
+    }
+  }
+  return Array.from(groups.values());
+}
+
+function Section({
+  title,
+  description,
+  items,
+  emptyLabel,
+}: {
+  title: string;
+  description: string;
+  items: IssueRelatedWorkItem[];
+  emptyLabel: string;
+}) {
+  return (
+    <section className="space-y-3 rounded-lg border border-border p-3">
+      <div className="space-y-1">
+        <h3 className="text-sm font-semibold">{title}</h3>
+        <p className="text-xs text-muted-foreground">{description}</p>
+      </div>
+
+      {items.length === 0 ? (
+        <p className="text-xs text-muted-foreground">{emptyLabel}</p>
+      ) : (
+        <ul className="-mx-1 flex flex-col">
+          {items.map((item) => {
+            const groupedSources = groupSourcesByLabel(item.sources);
+            const showTitle = item.issue.identifier !== item.issue.title;
+            return (
+              <li
+                key={item.issue.id}
+                className="flex flex-wrap items-center gap-x-2 gap-y-1.5 rounded-md px-1 py-1.5 hover:bg-accent/40"
+              >
+                <IssueReferencePill issue={item.issue} />
+                {showTitle ? (
+                  <span className="min-w-0 flex-1 truncate text-sm text-muted-foreground">
+                    {item.issue.title}
+                  </span>
+                ) : null}
+                <div className="flex flex-wrap items-center gap-1.5">
+                  {groupedSources.map((group) => (
+                    <span
+                      key={`${item.issue.id}:${group.label}`}
+                      className="inline-flex items-center gap-1 rounded-full border border-border bg-muted/40 px-2 py-0.5 text-xs text-muted-foreground"
+                      title={group.sampleMatchedText ?? undefined}
+                    >
+                      <span>{group.label}</span>
+                      {group.count > 1 ? (
+                        <span className="tabular-nums text-[10px] font-medium opacity-80">×{group.count}</span>
+                      ) : null}
+                    </span>
+                  ))}
+                </div>
+              </li>
+            );
+          })}
+        </ul>
+      )}
+    </section>
+  );
+}
+
+export function IssueRelatedWorkPanel({
+  relatedWork,
+}: {
+  relatedWork?: IssueRelatedWorkSummary | null;
+}) {
+  const outbound = relatedWork?.outbound ?? [];
+  const inbound = relatedWork?.inbound ?? [];
+
+  return (
+    <div className="space-y-3">
+      <Section
+        title="References"
+        description="Other tasks this issue currently points at in its title, description, comments, or documents."
+        items={outbound}
+        emptyLabel="This issue does not reference any other tasks yet."
+      />
+      <Section
+        title="Referenced by"
+        description="Other tasks that currently point at this issue."
+        items={inbound}
+        emptyLabel="No other tasks reference this issue yet."
+      />
+    </div>
+  );
+}
--- a/ui/src/components/MarkdownBody.test.tsx
+++ b/ui/src/components/MarkdownBody.test.tsx
@@ -4,7 +4,13 @@ import type { ReactNode } from "react";
 import { QueryClient, QueryClientProvider } from "@tanstack/react-query";
 import { describe, expect, it, vi } from "vitest";
 import { renderToStaticMarkup } from "react-dom/server";
-import { buildAgentMentionHref, buildProjectMentionHref, buildSkillMentionHref, buildUserMentionHref } from "@paperclipai/shared";
+import {
+  buildAgentMentionHref,
+  buildIssueReferenceHref,
+  buildProjectMentionHref,
+  buildSkillMentionHref,
+  buildUserMentionHref,
+} from "@paperclipai/shared";
 import { ThemeProvider } from "../context/ThemeContext";
 import { MarkdownBody } from "./MarkdownBody";
 import { queryKeys } from "../lib/queryKeys";
@@ -14,7 +20,13 @@ const mockIssuesApi = vi.hoisted(() => ({
 }));

 vi.mock("@/lib/router", () => ({
-  Link: ({ children, to }: { children: ReactNode; to: string }) => <a href={to}>{children}</a>,
+  Link: ({
+    children,
+    to,
+    ...props
+  }: { children: ReactNode; to: string } & React.ComponentProps<"a">) => (
+    <a href={to} {...props}>{children}</a>
+  ),
 }));

 vi.mock("../api/issues", () => ({
@@ -144,6 +156,7 @@ describe("MarkdownBody", () => {
    expect(html).toContain('href="/issues/PAP-1271"');
    expect(html).toContain("text-green-600");
    expect(html).toContain(">PAP-1271<");
+    expect(html).not.toContain("paperclip-mention-chip--issue");
  });

  it("rewrites full issue URLs to internal issue links", () => {
@@ -154,6 +167,7 @@ describe("MarkdownBody", () => {
    expect(html).toContain('href="/issues/PAP-1179"');
    expect(html).toContain("text-red-600");
    expect(html).toContain(">http://localhost:3100/PAP/issues/PAP-1179<");
+    expect(html).not.toContain("paperclip-mention-chip--issue");
  });

  it("rewrites issue scheme links to internal issue links", () => {
@@ -217,4 +231,15 @@ describe("MarkdownBody", () => {
    expect(html).toContain("<pre");
    expect(html).toContain('style="max-width:100%;overflow-x:auto"');
  });
+
+  it("renders internal issue links and bare identifiers as issue chips", () => {
+    const html = renderMarkdown(`See PAP-42 and [linked task](${buildIssueReferenceHref("PAP-77")}) for follow-up.`, [
+      { identifier: "PAP-42", status: "done" },
+      { identifier: "PAP-77", status: "blocked" },
+    ]);
+
+    expect(html).toContain('href="/issues/PAP-42"');
+    expect(html).toContain('href="/issues/PAP-77"');
+    expect(html).toContain('data-mention-kind="issue"');
+  });
 });
--- a/ui/src/components/MarkdownBody.tsx
+++ b/ui/src/components/MarkdownBody.tsx
@@ -42,7 +42,11 @@ function MarkdownIssueLink({
  });

  return (
-    <Link to={href} className="inline-flex items-center gap-1.5 align-baseline">
+    <Link
+      to={href}
+      className="inline-flex items-center gap-1 align-baseline font-medium"
+      data-mention-kind="issue"
+    >
      {data ? <StatusIcon status={data.status} className="h-3.5 w-3.5" /> : null}
      <span>{children}</span>
    </Link>
@@ -223,6 +227,8 @@ export function MarkdownBody({
      if (parsed) {
        const targetHref = parsed.kind === "project"
          ? `/projects/${parsed.projectId}`
+          : parsed.kind === "issue"
+            ? `/issues/${parsed.identifier}`
          : parsed.kind === "skill"
            ? `/skills/${parsed.skillId}`
            : parsed.kind === "user"
--- a/ui/src/components/MarkdownEditor.tsx
+++ b/ui/src/components/MarkdownEditor.tsx
@@ -730,7 +730,7 @@ export const MarkdownEditor = forwardRef<MarkdownEditorRef, MarkdownEditorProps>
        continue;
      }

-      if (parsed.kind === "user") {
+      if (parsed.kind === "user" || parsed.kind === "issue") {
        applyMentionChipDecoration(link, parsed);
        continue;
      }
--- a/ui/src/index.css
+++ b/ui/src/index.css
@@ -763,6 +763,11 @@ a.paperclip-mention-chip[data-mention-kind="agent"]::before {
  text-decoration: none;
 }

+.paperclip-markdown a.paperclip-mention-chip[data-mention-kind="issue"] {
+  border-color: color-mix(in oklab, var(--foreground) 14%, var(--border) 86%);
+  background: color-mix(in oklab, var(--accent) 42%, transparent);
+}
+
 .dark .paperclip-markdown a {
  color: color-mix(in oklab, var(--foreground) 80%, #58a6ff 20%);
 }
--- a/ui/src/lib/mention-chips.ts
+++ b/ui/src/lib/mention-chips.ts
@@ -1,5 +1,11 @@
 import type { CSSProperties } from "react";
-import { parseAgentMentionHref, parseProjectMentionHref, parseSkillMentionHref, parseUserMentionHref } from "@paperclipai/shared";
+import {
+  parseAgentMentionHref,
+  parseIssueReferenceHref,
+  parseProjectMentionHref,
+  parseSkillMentionHref,
+  parseUserMentionHref,
+} from "@paperclipai/shared";
 import { getAgentIcon } from "./agent-icons";
 import { hexToRgb, pickTextColorForPillBg } from "./color-contrast";

@@ -9,6 +15,10 @@ export type ParsedMentionChip =
      agentId: string;
      icon: string | null;
    }
+  | {
+      kind: "issue";
+      identifier: string;
+    }
  | {
      kind: "project";
      projectId: string;
@@ -27,6 +37,14 @@ export type ParsedMentionChip =
 const iconMaskCache = new Map<string, string>();

 export function parseMentionChipHref(href: string): ParsedMentionChip | null {
+  const issue = parseIssueReferenceHref(href);
+  if (issue) {
+    return {
+      kind: "issue",
+      identifier: issue.identifier,
+    };
+  }
+
  const agent = parseAgentMentionHref(href);
  if (agent) {
    return {
@@ -111,6 +129,7 @@ export function clearMentionChipDecoration(element: HTMLElement) {
  element.classList.remove(
    "paperclip-mention-chip",
    "paperclip-mention-chip--agent",
+    "paperclip-mention-chip--issue",
    "paperclip-mention-chip--project",
    "paperclip-mention-chip--user",
    "paperclip-mention-chip--skill",
--- a/ui/src/pages/DesignGuide.tsx
+++ b/ui/src/pages/DesignGuide.tsx
@@ -123,6 +123,7 @@ import { FilterBar, type FilterValue } from "@/components/FilterBar";
 import { InlineEditor } from "@/components/InlineEditor";
 import { PageSkeleton } from "@/components/PageSkeleton";
 import { Identity } from "@/components/Identity";
+import { IssueReferencePill } from "@/components/IssueReferencePill";

 /* ------------------------------------------------------------------ */
 /*  Section wrapper                                                    */
@@ -466,6 +467,21 @@ export function DesignGuide() {
            ))}
          </div>
        </SubSection>
+
+        <SubSection title="IssueReferencePill">
+          <p className="text-xs text-muted-foreground">
+            Used wherever a task is referenced — in markdown, the Related Work tab, and activity summaries.
+            Pass <code className="font-mono">status</code> to show the target issue&apos;s state at a glance.
+            Use <code className="font-mono">strikethrough</code> for &quot;removed&quot; contexts.
+          </p>
+          <div className="flex items-center gap-2 flex-wrap">
+            <IssueReferencePill issue={{ id: "demo-1", identifier: "PAP-123", title: "Identifier only — no status yet" }} />
+            <IssueReferencePill issue={{ id: "demo-2", identifier: "PAP-456", title: "With in_progress status", status: "in_progress" }} />
+            <IssueReferencePill issue={{ id: "demo-3", identifier: "PAP-789", title: "Done status", status: "done" }} />
+            <IssueReferencePill issue={{ id: "demo-4", identifier: "PAP-101", title: "Blocked status", status: "blocked" }} />
+            <IssueReferencePill strikethrough issue={{ id: "demo-5", identifier: "PAP-202", title: "Removed (strikethrough)", status: "todo" }} />
+          </div>
+        </SubSection>
      </Section>

      {/* ============================================================ */}
--- a/ui/src/pages/IssueDetail.tsx
+++ b/ui/src/pages/IssueDetail.tsx
@@ -63,6 +63,8 @@ import { IssueChatThread, type IssueChatComposerHandle } from "../components/Iss
 import { IssueContinuationHandoff } from "../components/IssueContinuationHandoff";
 import { IssueDocumentsSection } from "../components/IssueDocumentsSection";
 import { IssuesList } from "../components/IssuesList";
+import { IssueReferenceActivitySummary } from "../components/IssueReferenceActivitySummary";
+import { IssueRelatedWorkPanel } from "../components/IssueRelatedWorkPanel";
 import { IssueProperties } from "../components/IssueProperties";
 import { IssueRunLedger } from "../components/IssueRunLedger";
 import { IssueWorkspaceCard } from "../components/IssueWorkspaceCard";
@@ -94,6 +96,7 @@ import {
  Copy,
  EyeOff,
  Hexagon,
+  ListTree,
  MessageSquare,
  MoreHorizontal,
  MoreVertical,
@@ -886,10 +889,13 @@ function IssueDetailActivityTab({
      ) : (
        <div className="space-y-1.5">
          {activity.slice(0, 20).map((evt) => (
-            <div key={evt.id} className="flex items-center gap-1.5 text-xs text-muted-foreground">
-              <ActorIdentity evt={evt} agentMap={agentMap} userProfileMap={userProfileMap} />
-              <span>{formatIssueActivityAction(evt.action, evt.details, { agentMap, userProfileMap, currentUserId })}</span>
-              <span className="ml-auto shrink-0">{relativeTime(evt.createdAt)}</span>
+            <div key={evt.id} className="space-y-1.5 rounded-lg border border-border/60 px-3 py-2 text-xs text-muted-foreground">
+              <div className="flex items-center gap-1.5">
+                <ActorIdentity evt={evt} agentMap={agentMap} userProfileMap={userProfileMap} />
+                <span>{formatIssueActivityAction(evt.action, evt.details, { agentMap, userProfileMap, currentUserId })}</span>
+                <span className="ml-auto shrink-0">{relativeTime(evt.createdAt)}</span>
+              </div>
+              <IssueReferenceActivitySummary event={evt} />
            </div>
          ))}
        </div>
@@ -2674,6 +2680,10 @@ export function IssueDetail() {
            <ActivityIcon className="h-3.5 w-3.5" />
            Activity
          </TabsTrigger>
+          <TabsTrigger value="related-work" className="gap-1.5">
+            <ListTree className="h-3.5 w-3.5" />
+            Related work
+          </TabsTrigger>
          {issuePluginTabItems.map((item) => (
            <TabsTrigger key={item.value} value={item.value}>
              {item.label}
@@ -2738,6 +2748,10 @@ export function IssueDetail() {
          ) : null}
        </TabsContent>

+        <TabsContent value="related-work">
+          <IssueRelatedWorkPanel relatedWork={issue.relatedWork} />
+        </TabsContent>
+
        {activePluginTab && (
          <TabsContent value={activePluginTab.value}>
            <PluginSlotMount
--- a/vitest.config.ts
+++ b/vitest.config.ts
@@ -3,6 +3,7 @@ import { defineConfig } from "vitest/config";
 export default defineConfig({
  test: {
    projects: [
+      "packages/shared",
      "packages/db",
      "packages/adapter-utils",
      "packages/adapters/codex-local",