feat(agents): enforce size budget + extract duplicated boilerplate (#2361) (#2362)

Adds tiered agent-size-budget test to prevent unbounded growth in agent
definitions, which are loaded verbatim into context on every subagent
dispatch. Extracts two duplicated blocks (mandatory-initial-read,
project-skills-discovery) to shared references under
get-shit-done/references/ and migrates the 5 top agents (planner,
executor, debugger, verifier, phase-researcher) to @file includes.

Also fixes two broken relative @planner-source-audit.md references in
gsd-planner.md that silently disabled the planner's source audit
discipline.

Closes #2361

Co-authored-by: Claude Opus 4.7 <noreply@anthropic.com>

CHANGELOG.md

@@ -6,10 +6,17 @@ Format follows [Keep a Changelog](https://keepachangelog.com/en/1.1.0/).
 
 ## [Unreleased]
 
+### Added
+- **Agent size-budget enforcement** — New `tests/agent-size-budget.test.cjs` enforces tiered line-count limits on every `gsd-*.md` agent (XL=1600, LARGE=1000, DEFAULT=500). Unbounded agent growth is paid in context on every subagent dispatch; the test prevents regressions and requires a deliberate PR rationale to raise a budget (#2361)
+- **Shared `references/mandatory-initial-read.md`** — Extracts the `<required_reading>` enforcement block that was duplicated across 5 top agents. Agents now include it via a single `@~/.claude/get-shit-done/references/mandatory-initial-read.md` line, using Claude Code's progressive-disclosure `@file` reference mechanism (#2361)
+- **Shared `references/project-skills-discovery.md`** — Extracts the 5-step project skills discovery checklist that was copy-pasted across 5 top agents with slight divergence. Single source of truth with a per-agent "Application" paragraph documenting how planners, executors, researchers, verifiers, and debuggers each apply the rules (#2361)
+
 ### Changed
 - **`gsd-debugger` philosophy extracted to shared reference** — The 76-line `<philosophy>` block containing evergreen debugging disciplines (user-as-reporter framing, meta-debugging, foundation principles, cognitive-bias table, systematic investigation, when-to-restart protocol) is now in `get-shit-done/references/debugger-philosophy.md` and pulled into the agent via a single `@file` include. Same content, lighter per-dispatch context footprint (#2363)
+- **`gsd-planner`, `gsd-executor`, `gsd-debugger`, `gsd-verifier`, `gsd-phase-researcher`** — Migrated to `@file` includes for the mandatory-initial-read and project-skills-discovery boilerplate. Reduces per-dispatch context load without changing behavior (#2361)
 
 ### Fixed
+- **Broken `@planner-source-audit.md` relative references in `gsd-planner.md`** — Two locations referenced `@planner-source-audit.md` (resolves relative to working directory, almost always missing) instead of the correct absolute `@~/.claude/get-shit-done/references/planner-source-audit.md`. The planner's source audit discipline was silently unenforced (#2361)
 - **Shell hooks falsely flagged as stale on every session** — `gsd-phase-boundary.sh`, `gsd-session-state.sh`, and `gsd-validate-commit.sh` now ship with a `# gsd-hook-version: {{GSD_VERSION}}` header; the installer substitutes `{{GSD_VERSION}}` in `.sh` hooks the same way it does for `.js` hooks; and the stale-hook detector in `gsd-check-update.js` now matches bash `#` comment syntax in addition to JS `//` syntax. All three changes are required together — neither the regex fix alone nor the install fix alone is sufficient to resolve the false positive (#2136, #2206, #2209, #2210, #2212)
 
 ## [1.36.0] - 2026-04-14

agents/gsd-debugger.md

@@ -21,8 +21,7 @@ You are spawned by:
 
 Your job: Find the root cause through hypothesis testing, maintain debug file state, optionally fix and verify (depending on mode).
 
-**CRITICAL: Mandatory Initial Read**
-If the prompt contains a `<required_reading>` block, you MUST use the `Read` tool to load every file listed there before performing any other actions. This is your primary context.
+@~/.claude/get-shit-done/references/mandatory-initial-read.md
 
 **Core responsibilities:**
 - Investigate autonomously (user reports symptoms, you find cause)
@@ -37,14 +36,9 @@ If the prompt contains a `<required_reading>` block, you MUST use the `Read` too
 @~/.claude/get-shit-done/references/common-bug-patterns.md
 </required_reading>
 
-**Project skills:** Check `.claude/skills/` or `.agents/skills/` directory if either exists:
-1. List available skills (subdirectories)
-2. Read `SKILL.md` for each skill (lightweight index ~130 lines)
-3. Load specific `rules/*.md` files as needed during implementation
-4. Do NOT load full `AGENTS.md` files (100KB+ context cost)
-5. Follow skill rules relevant to the bug being investigated and the fix being applied.
-
-This ensures project-specific patterns, conventions, and best practices are applied during execution.
+**Project skills:** @~/.claude/get-shit-done/references/project-skills-discovery.md
+- Load `rules/*.md` as needed during **investigation and fix**.
+- Follow skill rules relevant to the bug being investigated and the fix being applied.
 
 <philosophy>
 

agents/gsd-executor.md

@@ -18,8 +18,7 @@ Spawned by `/gsd-execute-phase` orchestrator.
 
 Your job: Execute the plan completely, commit each task, create SUMMARY.md, update STATE.md.
 
-**CRITICAL: Mandatory Initial Read**
-If the prompt contains a `<required_reading>` block, you MUST use the `Read` tool to load every file listed there before performing any other actions. This is your primary context.
+@~/.claude/get-shit-done/references/mandatory-initial-read.md
 </role>
 
 <documentation_lookup>
@@ -54,14 +53,9 @@ Before executing, discover project context:
 
 **Project instructions:** Read `./CLAUDE.md` if it exists in the working directory. Follow all project-specific guidelines, security requirements, and coding conventions.
 
-**Project skills:** Check `.claude/skills/` or `.agents/skills/` directory if either exists:
-1. List available skills (subdirectories)
-2. Read `SKILL.md` for each skill (lightweight index ~130 lines)
-3. Load specific `rules/*.md` files as needed during implementation
-4. Do NOT load full `AGENTS.md` files (100KB+ context cost)
-5. Follow skill rules relevant to your current task
-
-This ensures project-specific patterns, conventions, and best practices are applied during execution.
+**Project skills:** @~/.claude/get-shit-done/references/project-skills-discovery.md
+- Load `rules/*.md` as needed during **implementation**.
+- Follow skill rules relevant to the task you are about to commit.
 
 **CLAUDE.md enforcement:** If `./CLAUDE.md` exists, treat its directives as hard constraints during execution. Before committing each task, verify that code changes do not violate CLAUDE.md rules (forbidden patterns, required conventions, mandated tools). If a task action would contradict a CLAUDE.md directive, apply the CLAUDE.md rule — it takes precedence over plan instructions. Document any CLAUDE.md-driven adjustments as deviations (Rule 2: auto-add missing critical functionality).
 </project_context>

agents/gsd-phase-researcher.md

@@ -16,8 +16,7 @@ You are a GSD phase researcher. You answer "What do I need to know to PLAN this
 
 Spawned by `/gsd-plan-phase` (integrated) or `/gsd-research-phase` (standalone).
 
-**CRITICAL: Mandatory Initial Read**
-If the prompt contains a `<required_reading>` block, you MUST use the `Read` tool to load every file listed there before performing any other actions. This is your primary context.
+@~/.claude/get-shit-done/references/mandatory-initial-read.md
 
 **Core responsibilities:**
 - Investigate the phase's technical domain
@@ -62,14 +61,9 @@ Before researching, discover project context:
 
 **Project instructions:** Read `./CLAUDE.md` if it exists in the working directory. Follow all project-specific guidelines, security requirements, and coding conventions.
 
-**Project skills:** Check `.claude/skills/` or `.agents/skills/` directory if either exists:
-1. List available skills (subdirectories)
-2. Read `SKILL.md` for each skill (lightweight index ~130 lines)
-3. Load specific `rules/*.md` files as needed during research
-4. Do NOT load full `AGENTS.md` files (100KB+ context cost)
-5. Research should account for project skill patterns
-
-This ensures research aligns with project-specific conventions and libraries.
+**Project skills:** @~/.claude/get-shit-done/references/project-skills-discovery.md
+- Load `rules/*.md` as needed during **research**.
+- Research output should account for project skill patterns and conventions.
 
 **CLAUDE.md enforcement:** If `./CLAUDE.md` exists, extract all actionable directives (required tools, forbidden patterns, coding conventions, testing rules, security requirements). Include a `## Project Constraints (from CLAUDE.md)` section in RESEARCH.md listing these directives so the planner can verify compliance. Treat CLAUDE.md directives with the same authority as locked decisions from CONTEXT.md — research should not recommend approaches that contradict them.
 </project_context>

agents/gsd-planner.md

@@ -22,8 +22,7 @@ Spawned by:
 
 Your job: Produce PLAN.md files that Claude executors can implement without interpretation. Plans are prompts, not documents that become prompts.
 
-**CRITICAL: Mandatory Initial Read**
-If the prompt contains a `<required_reading>` block, you MUST use the `Read` tool to load every file listed there before performing any other actions. This is your primary context.
+@~/.claude/get-shit-done/references/mandatory-initial-read.md
 
 **Core responsibilities:**
 - **FIRST: Parse and honor user decisions from CONTEXT.md** (locked decisions are NON-NEGOTIABLE)
@@ -44,7 +43,9 @@ Before planning, discover project context:
 
 **Project instructions:** Read `./CLAUDE.md` if it exists in the working directory. Follow all project-specific guidelines, security requirements, and coding conventions.
 
-**Project skills:** Check `.claude/skills/` or `.agents/skills/` if either exists. Read `SKILL.md` for each skill (lightweight index), load specific `rules/*.md` as needed. Do NOT load full `AGENTS.md` files. Ensure plans reflect project skill patterns.
+**Project skills:** @~/.claude/get-shit-done/references/project-skills-discovery.md
+- Load `rules/*.md` as needed during **planning**.
+- Ensure plans account for project skill patterns and conventions.
 </project_context>
 
 <context_fidelity>
@@ -95,7 +96,7 @@ Do NOT silently omit features. Instead:
 
 ## Multi-Source Coverage Audit (MANDATORY in every plan set)
 
-@planner-source-audit.md for full format, examples, and gap-handling rules.
+@~/.claude/get-shit-done/references/planner-source-audit.md for full format, examples, and gap-handling rules.
 
 Audit ALL four source types before finalizing: **GOAL** (ROADMAP phase goal), **REQ** (phase_req_ids from REQUIREMENTS.md), **RESEARCH** (RESEARCH.md features/constraints), **CONTEXT** (D-XX decisions from CONTEXT.md).
 
@@ -107,7 +108,7 @@ Exclusions (not gaps): Deferred Ideas in CONTEXT.md, items scoped to other phase
 <planner_authority_limits>
 ## The Planner Does Not Decide What Is Too Hard
 
-@planner-source-audit.md for constraint examples.
+@~/.claude/get-shit-done/references/planner-source-audit.md for constraint examples.
 
 The planner has no authority to judge a feature as too difficult, omit features because they seem challenging, or use "complex/difficult/non-trivial" to justify scope reduction.
 

agents/gsd-verifier.md

@@ -16,8 +16,7 @@ You are a GSD phase verifier. You verify that a phase achieved its GOAL, not jus
 
 Your job: Goal-backward verification. Start from what the phase SHOULD deliver, verify it actually exists and works in the codebase.
 
-**CRITICAL: Mandatory Initial Read**
-If the prompt contains a `<required_reading>` block, you MUST use the `Read` tool to load every file listed there before performing any other actions. This is your primary context.
+@~/.claude/get-shit-done/references/mandatory-initial-read.md
 
 **Critical mindset:** Do NOT trust SUMMARY.md claims. SUMMARYs document what Claude SAID it did. You verify what ACTUALLY exists in the code. These often differ.
 
@@ -34,14 +33,9 @@ Before verifying, discover project context:
 
 **Project instructions:** Read `./CLAUDE.md` if it exists in the working directory. Follow all project-specific guidelines, security requirements, and coding conventions.
 
-**Project skills:** Check `.claude/skills/` or `.agents/skills/` directory if either exists:
-1. List available skills (subdirectories)
-2. Read `SKILL.md` for each skill (lightweight index ~130 lines)
-3. Load specific `rules/*.md` files as needed during verification
-4. Do NOT load full `AGENTS.md` files (100KB+ context cost)
-5. Apply skill rules when scanning for anti-patterns and verifying quality
-
-This ensures project-specific patterns, conventions, and best practices are applied during verification.
+**Project skills:** @~/.claude/get-shit-done/references/project-skills-discovery.md
+- Load `rules/*.md` as needed during **verification**.
+- Apply skill rules when scanning for anti-patterns and verifying quality.
 </project_context>
 
 <core_principle>

get-shit-done/references/mandatory-initial-read.md

@@ -0,0 +1,2 @@
+**CRITICAL: Mandatory Initial Read**
+If the prompt contains a `<required_reading>` block, you MUST use the `Read` tool to load every file listed there before performing any other actions. This is your primary context.

get-shit-done/references/project-skills-discovery.md

@@ -0,0 +1,19 @@
+# Project Skills Discovery
+
+Before execution, check for project-defined skills and apply their rules.
+
+**Discovery steps (shared across all GSD agents):**
+1. Check `.claude/skills/` or `.agents/skills/` directory — if neither exists, skip.
+2. List available skills (subdirectories).
+3. Read `SKILL.md` for each skill (lightweight index, typically ~130 lines).
+4. Load specific `rules/*.md` files only as needed during the current task.
+5. Do NOT load full `AGENTS.md` files — they are large (100KB+) and cost significant context.
+
+**Application** — how to apply the loaded rules depends on the calling agent:
+- Planners account for project skill patterns and conventions in the plan.
+- Executors follow skill rules relevant to the task being implemented.
+- Researchers ensure research output accounts for project skill patterns.
+- Verifiers apply skill rules when scanning for anti-patterns and verifying quality.
+- Debuggers follow skill rules relevant to the bug being investigated and the fix being applied.
+
+The caller's agent file should specify which application applies.

tests/agent-size-budget.test.cjs

@@ -0,0 +1,112 @@
+/**
+ * Agent size budget.
+ *
+ * Agent definitions in `agents/gsd-*.md` are loaded verbatim into Claude's
+ * context on every subagent dispatch. Unbounded growth is paid on every call
+ * across every workflow.
+ *
+ * Budgets are tiered to reflect the intent of each agent class:
+ *   - XL       : top-level orchestrators that own end-to-end rubrics
+ *   - LARGE    : multi-phase operators with branching workflows
+ *   - DEFAULT  : focused single-purpose agents
+ *
+ * Raising a budget is a deliberate choice — adjust the constant, write a
+ * rationale in the PR, and make sure the bloat is not duplicated content
+ * that belongs in `get-shit-done/references/`.
+ *
+ * See: https://github.com/gsd-build/get-shit-done/issues/2361
+ */
+
+const { test, describe } = require('node:test');
+const assert = require('node:assert/strict');
+const fs = require('fs');
+const path = require('path');
+
+const AGENTS_DIR = path.join(__dirname, '..', 'agents');
+
+const XL_BUDGET = 1600;
+const LARGE_BUDGET = 1000;
+const DEFAULT_BUDGET = 500;
+
+const XL_AGENTS = new Set([
+  'gsd-debugger',
+  'gsd-planner',
+]);
+
+const LARGE_AGENTS = new Set([
+  'gsd-phase-researcher',
+  'gsd-verifier',
+  'gsd-doc-writer',
+  'gsd-plan-checker',
+  'gsd-executor',
+  'gsd-code-fixer',
+  'gsd-codebase-mapper',
+  'gsd-project-researcher',
+  'gsd-roadmapper',
+]);
+
+const ALL_AGENTS = fs.readdirSync(AGENTS_DIR)
+  .filter(f => f.startsWith('gsd-') && f.endsWith('.md'))
+  .map(f => f.replace('.md', ''));
+
+function budgetFor(agent) {
+  if (XL_AGENTS.has(agent)) return { tier: 'XL', limit: XL_BUDGET };
+  if (LARGE_AGENTS.has(agent)) return { tier: 'LARGE', limit: LARGE_BUDGET };
+  return { tier: 'DEFAULT', limit: DEFAULT_BUDGET };
+}
+
+function lineCount(filePath) {
+  const content = fs.readFileSync(filePath, 'utf-8');
+  if (content.length === 0) return 0;
+  const trailingNewline = content.endsWith('\n') ? 1 : 0;
+  return content.split('\n').length - trailingNewline;
+}
+
+describe('SIZE: agent line-count budget', () => {
+  for (const agent of ALL_AGENTS) {
+    const { tier, limit } = budgetFor(agent);
+    test(`${agent} (${tier}) stays under ${limit} lines`, () => {
+      const filePath = path.join(AGENTS_DIR, agent + '.md');
+      const lines = lineCount(filePath);
+      assert.ok(
+        lines <= limit,
+        `${agent}.md has ${lines} lines — exceeds ${tier} budget of ${limit}. ` +
+        `Extract shared boilerplate to get-shit-done/references/ or raise the budget ` +
+        `in tests/agent-size-budget.test.cjs with a rationale.`
+      );
+    });
+  }
+});
+
+describe('SIZE: every agent is classified', () => {
+  test('every agent falls in exactly one tier', () => {
+    for (const agent of ALL_AGENTS) {
+      const inXL = XL_AGENTS.has(agent);
+      const inLarge = LARGE_AGENTS.has(agent);
+      assert.ok(
+        !(inXL && inLarge),
+        `${agent} is in both XL_AGENTS and LARGE_AGENTS — pick one`
+      );
+    }
+  });
+
+  test('every named XL agent exists', () => {
+    for (const agent of XL_AGENTS) {
+      const filePath = path.join(AGENTS_DIR, agent + '.md');
+      assert.ok(
+        fs.existsSync(filePath),
+        `XL_AGENTS references ${agent}.md which does not exist — clean up the set`
+      );
+    }
+  });
+
+  test('every named LARGE agent exists', () => {
+    for (const agent of LARGE_AGENTS) {
+      const filePath = path.join(AGENTS_DIR, agent + '.md');
+      assert.ok(
+        fs.existsSync(filePath),
+        `LARGE_AGENTS references ${agent}.md which does not exist — clean up the set`
+      );
+    }
+  });
+});