diff --git a/commands/gsd/from-gsd2.md b/commands/gsd/from-gsd2.md
new file mode 100644
index 00000000..5bfc4e48
--- /dev/null
+++ b/commands/gsd/from-gsd2.md
@@ -0,0 +1,45 @@
+---
+name: gsd:from-gsd2
+description: Import a GSD-2 (.gsd/) project back to GSD v1 (.planning/) format
+argument-hint: "[--path <dir>] [--force]"
+allowed-tools:
+  - Read
+  - Write
+  - Bash
+type: prompt
+---
+
+<objective>
+Reverse-migrate a GSD-2 project (`.gsd/` directory) back to GSD v1 (`.planning/`) format.
+
+Maps the GSD-2 hierarchy (Milestone → Slice → Task) to the GSD v1 hierarchy (Milestone sections in ROADMAP.md → Phase → Plan), preserving completion state, research files, and summaries.
+</objective>
+
+<process>
+
+1. **Locate the .gsd/ directory** — check the current working directory (or `--path` argument):
+   ```bash
+   node "$HOME/.claude/get-shit-done/bin/gsd-tools.cjs" from-gsd2 --dry-run
+   ```
+   If no `.gsd/` is found, report the error and stop.
+
+2. **Show the dry-run preview** — present the full file list and migration statistics to the user. Ask for confirmation before writing anything.
+
+3. **Run the migration** after confirmation:
+   ```bash
+   node "$HOME/.claude/get-shit-done/bin/gsd-tools.cjs" from-gsd2
+   ```
+   Use `--force` if `.planning/` already exists and the user has confirmed overwrite.
+
+4. **Report the result** — show the `filesWritten` count, `planningDir` path, and the preview summary.
+
+</process>
+
+<notes>
+- The migration is non-destructive: `.gsd/` is never modified or removed.
+- Pass `--path <dir>` to migrate a project at a different path than the current directory.
+- Slices are numbered sequentially across all milestones (M001/S01 → phase 01, M001/S02 → phase 02, M002/S01 → phase 03, etc.).
+- Tasks within each slice become plans (T01 → plan 01, T02 → plan 02, etc.).
+- Completed slices and tasks carry their done state into ROADMAP.md checkboxes and SUMMARY.md files.
+- GSD-2 cost/token ledger, database state, and VS Code extension state cannot be migrated.
+</notes>
diff --git a/get-shit-done/bin/gsd-tools.cjs b/get-shit-done/bin/gsd-tools.cjs
index d0bfb19f..540905ff 100755
--- a/get-shit-done/bin/gsd-tools.cjs
+++ b/get-shit-done/bin/gsd-tools.cjs
@@ -154,6 +154,10 @@
  *   learnings copy                       Copy from current project's LEARNINGS.md
  *   learnings prune --older-than <dur>   Remove entries older than duration (e.g. 90d)
  *   learnings delete <id>                Delete a learning by ID
+ *
+ * GSD-2 Migration:
+ *   from-gsd2 [--path <dir>] [--force] [--dry-run]
+ *             Import a GSD-2 (.gsd/) project back to GSD v1 (.planning/) format
  */
 
 const fs = require('fs');
@@ -1070,6 +1074,14 @@ async function runCommand(command, args, cwd, raw, defaultValue) {
       break;
     }
 
+    // ─── GSD-2 Reverse Migration ───────────────────────────────────────────
+
+    case 'from-gsd2': {
+      const gsd2Import = require('./lib/gsd2-import.cjs');
+      gsd2Import.cmdFromGsd2(args.slice(1), cwd, raw);
+      break;
+    }
+
     default:
       error(`Unknown command: ${command}`);
   }
diff --git a/get-shit-done/bin/lib/gsd2-import.cjs b/get-shit-done/bin/lib/gsd2-import.cjs
new file mode 100644
index 00000000..26dea66f
--- /dev/null
+++ b/get-shit-done/bin/lib/gsd2-import.cjs
@@ -0,0 +1,511 @@
+'use strict';
+
+/**
+ * gsd2-import — Reverse migration from GSD-2 (.gsd/) to GSD v1 (.planning/)
+ *
+ * Reads a GSD-2 project directory structure and produces a complete
+ * .planning/ artifact tree in GSD v1 format.
+ *
+ * GSD-2 hierarchy:  Milestone → Slice → Task
+ * GSD v1 hierarchy: Milestone (in ROADMAP.md) → Phase → Plan
+ *
+ * Mapping rules:
+ *   - Slices are numbered sequentially across all milestones (01, 02, …)
+ *   - Tasks within a slice become plans (01-01, 01-02, …)
+ *   - Completed slices ([x] in ROADMAP) → [x] phases in ROADMAP.md
+ *   - Tasks with a SUMMARY file → SUMMARY.md written
+ *   - Slice RESEARCH.md → phase XX-RESEARCH.md
+ */
+
+const fs = require('node:fs');
+const path = require('node:path');
+
+// ─── Utilities ──────────────────────────────────────────────────────────────
+
+function readOptional(filePath) {
+  try { return fs.readFileSync(filePath, 'utf8'); } catch { return null; }
+}
+
+function zeroPad(n, width = 2) {
+  return String(n).padStart(width, '0');
+}
+
+function slugify(title) {
+  return title.toLowerCase().replace(/[^a-z0-9]+/g, '-').replace(/^-|-$/g, '');
+}
+
+// ─── GSD-2 Parser ───────────────────────────────────────────────────────────
+
+/**
+ * Find the .gsd/ directory starting from a project root.
+ * Returns the absolute path or null if not found.
+ */
+function findGsd2Root(startPath) {
+  if (path.basename(startPath) === '.gsd' && fs.existsSync(startPath)) {
+    return startPath;
+  }
+  const candidate = path.join(startPath, '.gsd');
+  if (fs.existsSync(candidate) && fs.statSync(candidate).isDirectory()) {
+    return candidate;
+  }
+  return null;
+}
+
+/**
+ * Parse the ## Slices section from a GSD-2 milestone ROADMAP.md.
+ * Each slice entry looks like:
+ *   - [x] **S01: Title** `risk:medium` `depends:[S00]`
+ */
+function parseSlicesFromRoadmap(content) {
+  const slices = [];
+  const sectionMatch = content.match(/## Slices\n([\s\S]*?)(?:\n## |\n# |$)/);
+  if (!sectionMatch) return slices;
+
+  for (const line of sectionMatch[1].split('\n')) {
+    const m = line.match(/^- \[([x ])\]\s+\*\*(\w+):\s*([^*]+)\*\*/);
+    if (!m) continue;
+    slices.push({ done: m[1] === 'x', id: m[2].trim(), title: m[3].trim() });
+  }
+  return slices;
+}
+
+/**
+ * Parse the milestone title from the first heading in a GSD-2 ROADMAP.md.
+ * Format: # M001: Title
+ */
+function parseMilestoneTitle(content) {
+  const m = content.match(/^# \w+:\s*(.+)/m);
+  return m ? m[1].trim() : null;
+}
+
+/**
+ * Parse a task title from a GSD-2 T##-PLAN.md.
+ * Format: # T01: Title
+ */
+function parseTaskTitle(content, fallback) {
+  const m = content.match(/^# \w+:\s*(.+)/m);
+  return m ? m[1].trim() : fallback;
+}
+
+/**
+ * Parse the ## Description body from a GSD-2 task plan.
+ */
+function parseTaskDescription(content) {
+  const m = content.match(/## Description\n+([\s\S]+?)(?:\n## |\n# |$)/);
+  return m ? m[1].trim() : '';
+}
+
+/**
+ * Parse ## Must-Haves items from a GSD-2 task plan.
+ */
+function parseTaskMustHaves(content) {
+  const m = content.match(/## Must-Haves\n+([\s\S]+?)(?:\n## |\n# |$)/);
+  if (!m) return [];
+  return m[1].split('\n')
+    .map(l => l.match(/^- \[[ x]\]\s*(.+)/))
+    .filter(Boolean)
+    .map(match => match[1].trim());
+}
+
+/**
+ * Read all task plan files from a GSD-2 tasks/ directory.
+ */
+function readTasksDir(tasksDir) {
+  if (!fs.existsSync(tasksDir)) return [];
+
+  return fs.readdirSync(tasksDir)
+    .filter(f => f.endsWith('-PLAN.md'))
+    .sort()
+    .map(tf => {
+      const tid = tf.replace('-PLAN.md', '');
+      const plan = readOptional(path.join(tasksDir, tf));
+      const summary = readOptional(path.join(tasksDir, `${tid}-SUMMARY.md`));
+      return {
+        id: tid,
+        title: plan ? parseTaskTitle(plan, tid) : tid,
+        description: plan ? parseTaskDescription(plan) : '',
+        mustHaves: plan ? parseTaskMustHaves(plan) : [],
+        plan,
+        summary,
+        done: !!summary,
+      };
+    });
+}
+
+/**
+ * Parse a complete GSD-2 .gsd/ directory into a structured representation.
+ */
+function parseGsd2(gsdDir) {
+  const data = {
+    projectContent: readOptional(path.join(gsdDir, 'PROJECT.md')),
+    requirements: readOptional(path.join(gsdDir, 'REQUIREMENTS.md')),
+    milestones: [],
+  };
+
+  const milestonesBase = path.join(gsdDir, 'milestones');
+  if (!fs.existsSync(milestonesBase)) return data;
+
+  const milestoneIds = fs.readdirSync(milestonesBase)
+    .filter(d => fs.statSync(path.join(milestonesBase, d)).isDirectory())
+    .sort();
+
+  for (const mid of milestoneIds) {
+    const mDir = path.join(milestonesBase, mid);
+    const roadmapContent = readOptional(path.join(mDir, `${mid}-ROADMAP.md`));
+    const slicesDir = path.join(mDir, 'slices');
+
+    const sliceInfos = roadmapContent ? parseSlicesFromRoadmap(roadmapContent) : [];
+
+    const slices = sliceInfos.map(info => {
+      const sDir = path.join(slicesDir, info.id);
+      const hasSDir = fs.existsSync(sDir);
+      return {
+        id: info.id,
+        title: info.title,
+        done: info.done,
+        plan: hasSDir ? readOptional(path.join(sDir, `${info.id}-PLAN.md`)) : null,
+        summary: hasSDir ? readOptional(path.join(sDir, `${info.id}-SUMMARY.md`)) : null,
+        research: hasSDir ? readOptional(path.join(sDir, `${info.id}-RESEARCH.md`)) : null,
+        context: hasSDir ? readOptional(path.join(sDir, `${info.id}-CONTEXT.md`)) : null,
+        tasks: hasSDir ? readTasksDir(path.join(sDir, 'tasks')) : [],
+      };
+    });
+
+    data.milestones.push({
+      id: mid,
+      title: roadmapContent ? (parseMilestoneTitle(roadmapContent) ?? mid) : mid,
+      research: readOptional(path.join(mDir, `${mid}-RESEARCH.md`)),
+      slices,
+    });
+  }
+
+  return data;
+}
+
+// ─── Artifact Builders ──────────────────────────────────────────────────────
+
+/**
+ * Build a GSD v1 PLAN.md from a GSD-2 task.
+ */
+function buildPlanMd(task, phasePrefix, planPrefix, phaseSlug, milestoneTitle) {
+  const lines = [
+    '---',
+    `phase: "${phasePrefix}"`,
+    `plan: "${planPrefix}"`,
+    'type: "implementation"',
+    '---',
+    '',
+    '<objective>',
+    task.title,
+    '</objective>',
+    '',
+    '<context>',
+    `Phase: ${phasePrefix} (${phaseSlug}) — Milestone: ${milestoneTitle}`,
+  ];
+
+  if (task.description) {
+    lines.push('', task.description);
+  }
+
+  lines.push('</context>');
+
+  if (task.mustHaves.length > 0) {
+    lines.push('', '<must_haves>');
+    for (const mh of task.mustHaves) {
+      lines.push(`- ${mh}`);
+    }
+    lines.push('</must_haves>');
+  }
+
+  return lines.join('\n') + '\n';
+}
+
+/**
+ * Build a GSD v1 SUMMARY.md from a GSD-2 task summary.
+ * Strips the GSD-2 frontmatter and preserves the body.
+ */
+function buildSummaryMd(task, phasePrefix, planPrefix) {
+  const raw = task.summary || '';
+  // Strip GSD-2 frontmatter block (--- ... ---) if present
+  const bodyMatch = raw.match(/^---[\s\S]*?---\n+([\s\S]*)$/);
+  const body = bodyMatch ? bodyMatch[1].trim() : raw.trim();
+
+  return [
+    '---',
+    `phase: "${phasePrefix}"`,
+    `plan: "${planPrefix}"`,
+    '---',
+    '',
+    body || 'Task completed (migrated from GSD-2).',
+    '',
+  ].join('\n');
+}
+
+/**
+ * Build a GSD v1 XX-CONTEXT.md from a GSD-2 slice.
+ */
+function buildContextMd(slice, phasePrefix) {
+  const lines = [
+    `# Phase ${phasePrefix} Context`,
+    '',
+    `Migrated from GSD-2 slice ${slice.id}: ${slice.title}`,
+  ];
+
+  const extra = slice.context || '';
+  if (extra.trim()) {
+    lines.push('', extra.trim());
+  }
+
+  return lines.join('\n') + '\n';
+}
+
+/**
+ * Build the GSD v1 ROADMAP.md with milestone-sectioned format.
+ */
+function buildRoadmapMd(milestones, phaseMap) {
+  const lines = ['# Roadmap', ''];
+
+  for (const milestone of milestones) {
+    lines.push(`## ${milestone.id}: ${milestone.title}`, '');
+    const mPhases = phaseMap.filter(p => p.milestoneId === milestone.id);
+    for (const { slice, phaseNum } of mPhases) {
+      const prefix = zeroPad(phaseNum);
+      const slug = slugify(slice.title);
+      const check = slice.done ? 'x' : ' ';
+      lines.push(`- [${check}] **Phase ${prefix}: ${slug}** — ${slice.title}`);
+    }
+    lines.push('');
+  }
+
+  return lines.join('\n');
+}
+
+/**
+ * Build the GSD v1 STATE.md reflecting the current position in the project.
+ */
+function buildStateMd(phaseMap) {
+  const currentEntry = phaseMap.find(p => !p.slice.done);
+  const totalPhases = phaseMap.length;
+  const donePhases = phaseMap.filter(p => p.slice.done).length;
+  const pct = totalPhases > 0 ? Math.round((donePhases / totalPhases) * 100) : 0;
+
+  const currentPhaseNum = currentEntry ? zeroPad(currentEntry.phaseNum) : zeroPad(totalPhases);
+  const currentSlug = currentEntry ? slugify(currentEntry.slice.title) : 'complete';
+  const status = currentEntry ? 'Ready to plan' : 'All phases complete';
+
+  const filled = Math.round(pct / 10);
+  const bar = `[${'█'.repeat(filled)}${'░'.repeat(10 - filled)}]`;
+  const today = new Date().toISOString().split('T')[0];
+
+  return [
+    '# Project State',
+    '',
+    '## Project Reference',
+    '',
+    'See: .planning/PROJECT.md',
+    '',
+    `**Current focus:** Phase ${currentPhaseNum} (${currentSlug})`,
+    '',
+    '## Current Position',
+    '',
+    `Phase: ${currentPhaseNum} of ${zeroPad(totalPhases)} (${currentSlug})`,
+    `Status: ${status}`,
+    `Last activity: ${today} — Migrated from GSD-2`,
+    '',
+    `Progress: ${bar} ${pct}%`,
+    '',
+    '## Accumulated Context',
+    '',
+    '### Decisions',
+    '',
+    'Migrated from GSD-2. Review PROJECT.md for key decisions.',
+    '',
+    '### Blockers/Concerns',
+    '',
+    'None.',
+    '',
+    '## Session Continuity',
+    '',
+    `Last session: ${today}`,
+    'Stopped at: Migration from GSD-2 completed',
+    'Resume file: None',
+    '',
+  ].join('\n');
+}
+
+// ─── Transformer ─────────────────────────────────────────────────────────────
+
+/**
+ * Convert parsed GSD-2 data into a map of relative path → file content.
+ * All paths are relative to the .planning/ root.
+ */
+function buildPlanningArtifacts(gsd2Data) {
+  const artifacts = new Map();
+
+  // Passthrough files
+  artifacts.set('PROJECT.md', gsd2Data.projectContent || '# Project\n\n(Migrated from GSD-2)\n');
+  if (gsd2Data.requirements) {
+    artifacts.set('REQUIREMENTS.md', gsd2Data.requirements);
+  }
+
+  // Minimal valid v1 config
+  artifacts.set('config.json', JSON.stringify({ version: 1 }, null, 2) + '\n');
+
+  // Build sequential phase map: flatten Milestones → Slices into numbered phases
+  const phaseMap = [];
+  let phaseNum = 1;
+  for (const milestone of gsd2Data.milestones) {
+    for (const slice of milestone.slices) {
+      phaseMap.push({ milestoneId: milestone.id, milestoneTitle: milestone.title, slice, phaseNum });
+      phaseNum++;
+    }
+  }
+
+  artifacts.set('ROADMAP.md', buildRoadmapMd(gsd2Data.milestones, phaseMap));
+  artifacts.set('STATE.md', buildStateMd(phaseMap));
+
+  for (const { slice, phaseNum, milestoneTitle } of phaseMap) {
+    const prefix = zeroPad(phaseNum);
+    const slug = slugify(slice.title);
+    const dir = `phases/${prefix}-${slug}`;
+
+    artifacts.set(`${dir}/${prefix}-CONTEXT.md`, buildContextMd(slice, prefix));
+
+    if (slice.research) {
+      artifacts.set(`${dir}/${prefix}-RESEARCH.md`, slice.research);
+    }
+
+    for (let i = 0; i < slice.tasks.length; i++) {
+      const task = slice.tasks[i];
+      const planPrefix = zeroPad(i + 1);
+
+      artifacts.set(
+        `${dir}/${prefix}-${planPrefix}-PLAN.md`,
+        buildPlanMd(task, prefix, planPrefix, slug, milestoneTitle)
+      );
+
+      if (task.done && task.summary) {
+        artifacts.set(
+          `${dir}/${prefix}-${planPrefix}-SUMMARY.md`,
+          buildSummaryMd(task, prefix, planPrefix)
+        );
+      }
+    }
+  }
+
+  return artifacts;
+}
+
+// ─── Preview ─────────────────────────────────────────────────────────────────
+
+/**
+ * Format a dry-run preview string for display before writing.
+ */
+function buildPreview(gsd2Data, artifacts) {
+  const lines = ['Preview — files that will be created in .planning/:'];
+
+  for (const rel of artifacts.keys()) {
+    lines.push(`  ${rel}`);
+  }
+
+  const totalSlices = gsd2Data.milestones.reduce((s, m) => s + m.slices.length, 0);
+  const doneSlices = gsd2Data.milestones.reduce((s, m) => s + m.slices.filter(sl => sl.done).length, 0);
+  const allTasks = gsd2Data.milestones.flatMap(m => m.slices.flatMap(sl => sl.tasks));
+  const doneTasks = allTasks.filter(t => t.done).length;
+
+  lines.push('');
+  lines.push(`Milestones: ${gsd2Data.milestones.length}`);
+  lines.push(`Phases (slices): ${totalSlices} (${doneSlices} completed)`);
+  lines.push(`Plans (tasks): ${allTasks.length} (${doneTasks} completed)`);
+  lines.push('');
+  lines.push('Cannot migrate automatically:');
+  lines.push('  - GSD-2 cost/token ledger (no v1 equivalent)');
+  lines.push('  - GSD-2 database state (rebuilt from files on first /gsd-health)');
+  lines.push('  - VS Code extension state');
+
+  return lines.join('\n');
+}
+
+// ─── Writer ───────────────────────────────────────────────────────────────────
+
+/**
+ * Write all artifacts to the .planning/ directory.
+ */
+function writePlanningDir(artifacts, planningRoot) {
+  for (const [rel, content] of artifacts) {
+    const absPath = path.join(planningRoot, rel);
+    fs.mkdirSync(path.dirname(absPath), { recursive: true });
+    fs.writeFileSync(absPath, content, 'utf8');
+  }
+}
+
+// ─── Command Handler ──────────────────────────────────────────────────────────
+
+/**
+ * Entry point called from gsd-tools.cjs.
+ * Supports: --force, --dry-run, --path <dir>
+ */
+function cmdFromGsd2(args, cwd, raw) {
+  const { output, error } = require('./core.cjs');
+
+  const force = args.includes('--force');
+  const dryRun = args.includes('--dry-run');
+
+  const pathIdx = args.indexOf('--path');
+  const projectDir = pathIdx >= 0 && args[pathIdx + 1]
+    ? path.resolve(cwd, args[pathIdx + 1])
+    : cwd;
+
+  const gsdDir = findGsd2Root(projectDir);
+  if (!gsdDir) {
+    return output({ success: false, error: `No .gsd/ directory found in ${projectDir}` }, raw);
+  }
+
+  const planningRoot = path.join(path.dirname(gsdDir), '.planning');
+  if (fs.existsSync(planningRoot) && !force) {
+    return output({
+      success: false,
+      error: `.planning/ already exists at ${planningRoot}. Pass --force to overwrite.`,
+    }, raw);
+  }
+
+  const gsd2Data = parseGsd2(gsdDir);
+  const artifacts = buildPlanningArtifacts(gsd2Data);
+  const preview = buildPreview(gsd2Data, artifacts);
+
+  if (dryRun) {
+    return output({ success: true, dryRun: true, preview }, raw);
+  }
+
+  writePlanningDir(artifacts, planningRoot);
+
+  return output({
+    success: true,
+    planningDir: planningRoot,
+    filesWritten: artifacts.size,
+    milestones: gsd2Data.milestones.length,
+    preview,
+  }, raw);
+}
+
+module.exports = {
+  findGsd2Root,
+  parseGsd2,
+  buildPlanningArtifacts,
+  buildPreview,
+  writePlanningDir,
+  cmdFromGsd2,
+  // Exported for unit tests
+  parseSlicesFromRoadmap,
+  parseMilestoneTitle,
+  parseTaskTitle,
+  parseTaskDescription,
+  parseTaskMustHaves,
+  buildPlanMd,
+  buildSummaryMd,
+  buildContextMd,
+  buildRoadmapMd,
+  buildStateMd,
+  slugify,
+  zeroPad,
+};
diff --git a/tests/gsd2-import.test.cjs b/tests/gsd2-import.test.cjs
new file mode 100644
index 00000000..80becb4a
--- /dev/null
+++ b/tests/gsd2-import.test.cjs
@@ -0,0 +1,550 @@
+'use strict';
+
+const { describe, it, test, beforeEach, afterEach } = require('node:test');
+const assert = require('node:assert/strict');
+const fs = require('node:fs');
+const path = require('node:path');
+const { createTempDir, cleanup, runGsdTools } = require('./helpers.cjs');
+
+const {
+  findGsd2Root,
+  parseSlicesFromRoadmap,
+  parseMilestoneTitle,
+  parseTaskTitle,
+  parseTaskDescription,
+  parseTaskMustHaves,
+  parseGsd2,
+  buildPlanningArtifacts,
+  buildRoadmapMd,
+  buildStateMd,
+  slugify,
+  zeroPad,
+} = require('../get-shit-done/bin/lib/gsd2-import.cjs');
+
+// ─── Fixture Builders ──────────────────────────────────────────────────────
+
+/** Build a minimal but complete GSD-2 .gsd/ directory in tmpDir. */
+function makeGsd2Project(tmpDir, opts = {}) {
+  const gsdDir = path.join(tmpDir, '.gsd');
+  const m001Dir = path.join(gsdDir, 'milestones', 'M001');
+  const s01Dir = path.join(m001Dir, 'slices', 'S01');
+  const s02Dir = path.join(m001Dir, 'slices', 'S02');
+  const s01TasksDir = path.join(s01Dir, 'tasks');
+
+  fs.mkdirSync(s01TasksDir, { recursive: true });
+
+  fs.writeFileSync(path.join(gsdDir, 'PROJECT.md'), '# My Project\n\nA test project.\n');
+  fs.writeFileSync(path.join(gsdDir, 'REQUIREMENTS.md'), [
+    '# Requirements',
+    '',
+    '## Active',
+    '',
+    '### R001 — Do the thing',
+    '',
+    '- Status: active',
+    '- Description: The core requirement.',
+    '',
+  ].join('\n'));
+
+  const roadmap = [
+    '# M001: Foundation',
+    '',
+    '**Vision:** Build the foundation.',
+    '',
+    '## Success Criteria',
+    '',
+    '- It works.',
+    '',
+    '## Slices',
+    '',
+    '- [x] **S01: Setup** `risk:low` `depends:[]`',
+    '  > After this: setup complete',
+    '- [ ] **S02: Auth System** `risk:medium` `depends:[S01]`',
+    '  > After this: auth works',
+  ].join('\n');
+  fs.writeFileSync(path.join(m001Dir, 'M001-ROADMAP.md'), roadmap);
+
+  // S01 — completed slice with research and a done task
+  fs.writeFileSync(path.join(s01Dir, 'S01-PLAN.md'), [
+    '# S01: Setup',
+    '',
+    '**Goal:** Set up the project.',
+    '',
+    '## Tasks',
+    '- [x] **T01: Init**',
+  ].join('\n'));
+  fs.writeFileSync(path.join(s01Dir, 'S01-RESEARCH.md'), '# Research\n\nSome research.\n');
+  fs.writeFileSync(path.join(s01Dir, 'S01-SUMMARY.md'), '---\nstatus: done\n---\n\nSlice done.\n');
+
+  fs.writeFileSync(path.join(s01TasksDir, 'T01-PLAN.md'), [
+    '# T01: Init Project',
+    '',
+    '**Slice:** S01 — **Milestone:** M001',
+    '',
+    '## Description',
+    'Initialize the project structure.',
+    '',
+    '## Must-Haves',
+    '- [x] package.json exists',
+    '- [x] tsconfig.json exists',
+    '',
+    '## Files',
+    '- `package.json`',
+    '- `tsconfig.json`',
+  ].join('\n'));
+  fs.writeFileSync(path.join(s01TasksDir, 'T01-SUMMARY.md'), [
+    '---',
+    'status: done',
+    'completed_at: 2025-01-15',
+    '---',
+    '',
+    '# T01: Init Project',
+    '',
+    'Set up package.json and tsconfig.json.',
+  ].join('\n'));
+
+  // S02 — not started: slice appears in roadmap but no slice directory
+  if (opts.withS02Dir) {
+    fs.mkdirSync(path.join(s02Dir, 'tasks'), { recursive: true });
+    fs.writeFileSync(path.join(s02Dir, 'S02-PLAN.md'), [
+      '# S02: Auth System',
+      '',
+      '**Goal:** Add authentication.',
+      '',
+      '## Tasks',
+      '- [ ] **T01: JWT middleware**',
+    ].join('\n'));
+    fs.writeFileSync(path.join(s02Dir, 'tasks', 'T01-PLAN.md'), [
+      '# T01: JWT Middleware',
+      '',
+      '**Slice:** S02 — **Milestone:** M001',
+      '',
+      '## Description',
+      'Implement JWT token validation middleware.',
+      '',
+      '## Must-Haves',
+      '- [ ] validateToken() returns 401 on invalid JWT',
+    ].join('\n'));
+  }
+
+  return gsdDir;
+}
+
+/** Build a two-milestone GSD-2 project. */
+function makeTwoMilestoneProject(tmpDir) {
+  const gsdDir = path.join(tmpDir, '.gsd');
+  const m001Dir = path.join(gsdDir, 'milestones', 'M001');
+  const m002Dir = path.join(gsdDir, 'milestones', 'M002');
+
+  fs.mkdirSync(path.join(m001Dir, 'slices', 'S01', 'tasks'), { recursive: true });
+  fs.mkdirSync(path.join(m002Dir, 'slices', 'S01', 'tasks'), { recursive: true });
+
+  fs.writeFileSync(path.join(gsdDir, 'PROJECT.md'), '# Multi-milestone Project\n');
+
+  fs.writeFileSync(path.join(m001Dir, 'M001-ROADMAP.md'), [
+    '# M001: Alpha',
+    '',
+    '## Slices',
+    '',
+    '- [x] **S01: Core** `risk:low` `depends:[]`',
+    '- [x] **S02: API** `risk:low` `depends:[S01]`',
+  ].join('\n'));
+
+  fs.writeFileSync(path.join(m002Dir, 'M002-ROADMAP.md'), [
+    '# M002: Beta',
+    '',
+    '## Slices',
+    '',
+    '- [ ] **S01: Dashboard** `risk:medium` `depends:[]`',
+  ].join('\n'));
+
+  return gsdDir;
+}
+
+// ─── Unit Tests ────────────────────────────────────────────────────────────
+
+describe('parseSlicesFromRoadmap', () => {
+  test('parses done and pending slices', () => {
+    const content = [
+      '## Slices',
+      '',
+      '- [x] **S01: Setup** `risk:low` `depends:[]`',
+      '- [ ] **S02: Auth System** `risk:medium` `depends:[S01]`',
+    ].join('\n');
+    const slices = parseSlicesFromRoadmap(content);
+    assert.strictEqual(slices.length, 2);
+    assert.deepStrictEqual(slices[0], { done: true, id: 'S01', title: 'Setup' });
+    assert.deepStrictEqual(slices[1], { done: false, id: 'S02', title: 'Auth System' });
+  });
+
+  test('returns empty array when no Slices section', () => {
+    const slices = parseSlicesFromRoadmap('# M001: Title\n\n## Success Criteria\n\n- Works.');
+    assert.strictEqual(slices.length, 0);
+  });
+
+  test('ignores non-slice lines in the section', () => {
+    const content = [
+      '## Slices',
+      '',
+      'Some intro text.',
+      '- [x] **S01: Core** `risk:low` `depends:[]`',
+      '  > After this: done',
+    ].join('\n');
+    const slices = parseSlicesFromRoadmap(content);
+    assert.strictEqual(slices.length, 1);
+    assert.strictEqual(slices[0].id, 'S01');
+  });
+});
+
+describe('parseMilestoneTitle', () => {
+  test('extracts title from first heading', () => {
+    assert.strictEqual(parseMilestoneTitle('# M001: Foundation\n\nBody.'), 'Foundation');
+  });
+
+  test('returns null when heading absent', () => {
+    assert.strictEqual(parseMilestoneTitle('No heading here.'), null);
+  });
+});
+
+describe('parseTaskTitle', () => {
+  test('extracts title from task plan', () => {
+    assert.strictEqual(parseTaskTitle('# T01: Init Project\n\nBody.', 'T01'), 'Init Project');
+  });
+
+  test('falls back to provided default', () => {
+    assert.strictEqual(parseTaskTitle('No heading.', 'T01'), 'T01');
+  });
+});
+
+describe('parseTaskDescription', () => {
+  test('extracts description body', () => {
+    const content = [
+      '# T01: Title',
+      '',
+      '## Description',
+      'Do the thing.',
+      '',
+      '## Must-Haves',
+    ].join('\n');
+    assert.strictEqual(parseTaskDescription(content), 'Do the thing.');
+  });
+
+  test('returns empty string when section absent', () => {
+    assert.strictEqual(parseTaskDescription('# T01: Title\n\nNo sections.'), '');
+  });
+});
+
+describe('parseTaskMustHaves', () => {
+  test('parses checked and unchecked items', () => {
+    const content = [
+      '## Must-Haves',
+      '- [x] File exists',
+      '- [ ] Tests pass',
+    ].join('\n');
+    const mh = parseTaskMustHaves(content);
+    assert.deepStrictEqual(mh, ['File exists', 'Tests pass']);
+  });
+
+  test('returns empty array when section absent', () => {
+    assert.deepStrictEqual(parseTaskMustHaves('# T01: Title\n\nNo sections.'), []);
+  });
+});
+
+describe('slugify', () => {
+  test('lowercases and replaces non-alphanumeric with hyphens', () => {
+    assert.strictEqual(slugify('Auth System'), 'auth-system');
+    assert.strictEqual(slugify('My Feature (v2)'), 'my-feature-v2');
+  });
+
+  test('strips leading/trailing hyphens', () => {
+    assert.strictEqual(slugify('  spaces  '), 'spaces');
+  });
+});
+
+describe('zeroPad', () => {
+  test('pads to 2 digits by default', () => {
+    assert.strictEqual(zeroPad(1), '01');
+    assert.strictEqual(zeroPad(12), '12');
+  });
+});
+
+// ─── Integration Tests ─────────────────────────────────────────────────────
+
+describe('parseGsd2', () => {
+  let tmpDir;
+  beforeEach(() => { tmpDir = createTempDir('gsd2-parse-'); });
+  afterEach(() => { cleanup(tmpDir); });
+
+  test('reads project and requirements passthroughs', () => {
+    const gsdDir = makeGsd2Project(tmpDir);
+    const data = parseGsd2(gsdDir);
+    assert.ok(data.projectContent.includes('My Project'));
+    assert.ok(data.requirements.includes('R001'));
+  });
+
+  test('parses milestone with slices', () => {
+    const gsdDir = makeGsd2Project(tmpDir);
+    const data = parseGsd2(gsdDir);
+    assert.strictEqual(data.milestones.length, 1);
+    assert.strictEqual(data.milestones[0].id, 'M001');
+    assert.strictEqual(data.milestones[0].title, 'Foundation');
+    assert.strictEqual(data.milestones[0].slices.length, 2);
+  });
+
+  test('marks S01 as done, S02 as not done', () => {
+    const gsdDir = makeGsd2Project(tmpDir);
+    const data = parseGsd2(gsdDir);
+    const [s01, s02] = data.milestones[0].slices;
+    assert.strictEqual(s01.done, true);
+    assert.strictEqual(s02.done, false);
+  });
+
+  test('reads research for completed slice', () => {
+    const gsdDir = makeGsd2Project(tmpDir);
+    const data = parseGsd2(gsdDir);
+    assert.ok(data.milestones[0].slices[0].research.includes('Some research'));
+  });
+
+  test('reads tasks from tasks/ directory', () => {
+    const gsdDir = makeGsd2Project(tmpDir);
+    const data = parseGsd2(gsdDir);
+    const tasks = data.milestones[0].slices[0].tasks;
+    assert.strictEqual(tasks.length, 1);
+    assert.strictEqual(tasks[0].id, 'T01');
+    assert.strictEqual(tasks[0].title, 'Init Project');
+    assert.strictEqual(tasks[0].done, true);
+  });
+
+  test('parses task must-haves', () => {
+    const gsdDir = makeGsd2Project(tmpDir);
+    const data = parseGsd2(gsdDir);
+    const mh = data.milestones[0].slices[0].tasks[0].mustHaves;
+    assert.deepStrictEqual(mh, ['package.json exists', 'tsconfig.json exists']);
+  });
+
+  test('handles missing .gsd/milestones/ gracefully', () => {
+    const gsdDir = path.join(tmpDir, '.gsd');
+    fs.mkdirSync(gsdDir, { recursive: true });
+    fs.writeFileSync(path.join(gsdDir, 'PROJECT.md'), '# Empty\n');
+    const data = parseGsd2(gsdDir);
+    assert.strictEqual(data.milestones.length, 0);
+  });
+
+  test('slice with no directory has empty tasks list', () => {
+    const gsdDir = makeGsd2Project(tmpDir);
+    const data = parseGsd2(gsdDir);
+    // S02 has no slice directory in the default fixture
+    const s02 = data.milestones[0].slices[1];
+    assert.strictEqual(s02.tasks.length, 0);
+    assert.strictEqual(s02.research, null);
+  });
+});
+
+describe('buildPlanningArtifacts', () => {
+  let tmpDir;
+  beforeEach(() => { tmpDir = createTempDir('gsd2-artifacts-'); });
+  afterEach(() => { cleanup(tmpDir); });
+
+  test('produces PROJECT.md, REQUIREMENTS.md, ROADMAP.md, STATE.md, config.json', () => {
+    const gsdDir = makeGsd2Project(tmpDir);
+    const data = parseGsd2(gsdDir);
+    const artifacts = buildPlanningArtifacts(data);
+    assert.ok(artifacts.has('PROJECT.md'));
+    assert.ok(artifacts.has('REQUIREMENTS.md'));
+    assert.ok(artifacts.has('ROADMAP.md'));
+    assert.ok(artifacts.has('STATE.md'));
+    assert.ok(artifacts.has('config.json'));
+  });
+
+  test('S01 (done) maps to phase 01 with PLAN and SUMMARY', () => {
+    const gsdDir = makeGsd2Project(tmpDir);
+    const data = parseGsd2(gsdDir);
+    const artifacts = buildPlanningArtifacts(data);
+    assert.ok(artifacts.has('phases/01-setup/01-CONTEXT.md'));
+    assert.ok(artifacts.has('phases/01-setup/01-RESEARCH.md'));
+    assert.ok(artifacts.has('phases/01-setup/01-01-PLAN.md'));
+    assert.ok(artifacts.has('phases/01-setup/01-01-SUMMARY.md'));
+  });
+
+  test('S02 (pending) maps to phase 02 with only CONTEXT and PLAN', () => {
+    const gsdDir = makeGsd2Project(tmpDir, { withS02Dir: true });
+    const data = parseGsd2(gsdDir);
+    const artifacts = buildPlanningArtifacts(data);
+    assert.ok(artifacts.has('phases/02-auth-system/02-CONTEXT.md'));
+    assert.ok(artifacts.has('phases/02-auth-system/02-01-PLAN.md'));
+    assert.ok(!artifacts.has('phases/02-auth-system/02-01-SUMMARY.md'), 'no summary for pending task');
+  });
+
+  test('ROADMAP.md marks S01 done, S02 pending', () => {
+    const gsdDir = makeGsd2Project(tmpDir);
+    const data = parseGsd2(gsdDir);
+    const artifacts = buildPlanningArtifacts(data);
+    const roadmap = artifacts.get('ROADMAP.md');
+    assert.ok(roadmap.includes('[x]'));
+    assert.ok(roadmap.includes('[ ]'));
+  });
+
+  test('PLAN.md includes frontmatter with phase and plan keys', () => {
+    const gsdDir = makeGsd2Project(tmpDir);
+    const data = parseGsd2(gsdDir);
+    const artifacts = buildPlanningArtifacts(data);
+    const plan = artifacts.get('phases/01-setup/01-01-PLAN.md');
+    assert.ok(plan.includes('phase: "01"'));
+    assert.ok(plan.includes('plan: "01"'));
+    assert.ok(plan.includes('type: "implementation"'));
+  });
+
+  test('SUMMARY.md strips GSD-2 frontmatter and adds v1 frontmatter', () => {
+    const gsdDir = makeGsd2Project(tmpDir);
+    const data = parseGsd2(gsdDir);
+    const artifacts = buildPlanningArtifacts(data);
+    const summary = artifacts.get('phases/01-setup/01-01-SUMMARY.md');
+    assert.ok(summary.includes('phase: "01"'));
+    assert.ok(summary.includes('plan: "01"'));
+    // GSD-2 frontmatter field should not appear
+    assert.ok(!summary.includes('completed_at:'));
+    // Body content should be preserved
+    assert.ok(summary.includes('Init Project'));
+  });
+
+  test('config.json is valid JSON', () => {
+    const gsdDir = makeGsd2Project(tmpDir);
+    const data = parseGsd2(gsdDir);
+    const artifacts = buildPlanningArtifacts(data);
+    assert.doesNotThrow(() => JSON.parse(artifacts.get('config.json')));
+  });
+
+  test('multi-milestone: slices numbered sequentially across milestones', () => {
+    const gsdDir = makeTwoMilestoneProject(tmpDir);
+    const data = parseGsd2(gsdDir);
+    const artifacts = buildPlanningArtifacts(data);
+    // M001/S01 → phase 01, M001/S02 → phase 02, M002/S01 → phase 03
+    assert.ok(artifacts.has('phases/01-core/01-CONTEXT.md'));
+    assert.ok(artifacts.has('phases/02-api/02-CONTEXT.md'));
+    assert.ok(artifacts.has('phases/03-dashboard/03-CONTEXT.md'));
+  });
+});
+
+describe('buildRoadmapMd', () => {
+  test('produces milestone sections with checked/unchecked phases', () => {
+    const milestones = [{ id: 'M001', title: 'Alpha', slices: [] }];
+    const phaseMap = [
+      { milestoneId: 'M001', milestoneTitle: 'Alpha', slice: { done: true, title: 'Core' }, phaseNum: 1 },
+      { milestoneId: 'M001', milestoneTitle: 'Alpha', slice: { done: false, title: 'API' }, phaseNum: 2 },
+    ];
+    const roadmap = buildRoadmapMd(milestones, phaseMap);
+    assert.ok(roadmap.includes('## M001: Alpha'));
+    assert.ok(roadmap.includes('[x]'));
+    assert.ok(roadmap.includes('[ ]'));
+    assert.ok(roadmap.includes('Phase 01: core'));
+    assert.ok(roadmap.includes('Phase 02: api'));
+  });
+});
+
+describe('buildStateMd', () => {
+  test('sets current phase to first incomplete slice', () => {
+    const phaseMap = [
+      { milestoneId: 'M001', milestoneTitle: 'Alpha', slice: { done: true, title: 'Core' }, phaseNum: 1 },
+      { milestoneId: 'M001', milestoneTitle: 'Alpha', slice: { done: false, title: 'API Layer' }, phaseNum: 2 },
+    ];
+    const state = buildStateMd(phaseMap);
+    assert.ok(state.includes('Phase: 02'));
+    assert.ok(state.includes('api-layer'));
+    assert.ok(state.includes('Ready to plan'));
+  });
+
+  test('reports all complete when all slices done', () => {
+    const phaseMap = [
+      { milestoneId: 'M001', milestoneTitle: 'Alpha', slice: { done: true, title: 'Core' }, phaseNum: 1 },
+    ];
+    const state = buildStateMd(phaseMap);
+    assert.ok(state.includes('All phases complete'));
+  });
+});
+
+// ─── CLI Integration Tests ──────────────────────────────────────────────────
+
+describe('gsd-tools from-gsd2 CLI', () => {
+  let tmpDir;
+  beforeEach(() => { tmpDir = createTempDir('gsd2-cli-'); });
+  afterEach(() => { cleanup(tmpDir); });
+
+  test('--dry-run returns preview without writing files', () => {
+    makeGsd2Project(tmpDir);
+    const result = runGsdTools(['from-gsd2', '--dry-run', '--raw'], tmpDir);
+    assert.ok(result.success, result.error);
+    const parsed = JSON.parse(result.output);
+    assert.strictEqual(parsed.dryRun, true);
+    assert.ok(parsed.preview.includes('PROJECT.md'));
+    assert.ok(!fs.existsSync(path.join(tmpDir, '.planning')), 'no files written in dry-run');
+  });
+
+  test('writes .planning/ directory with correct structure', () => {
+    makeGsd2Project(tmpDir);
+    const result = runGsdTools(['from-gsd2', '--raw'], tmpDir);
+    assert.ok(result.success, result.error);
+    const parsed = JSON.parse(result.output);
+    assert.strictEqual(parsed.success, true);
+    assert.ok(parsed.filesWritten > 0);
+    assert.ok(fs.existsSync(path.join(tmpDir, '.planning', 'ROADMAP.md')));
+    assert.ok(fs.existsSync(path.join(tmpDir, '.planning', 'STATE.md')));
+    assert.ok(fs.existsSync(path.join(tmpDir, '.planning', 'PROJECT.md')));
+    assert.ok(fs.existsSync(path.join(tmpDir, '.planning', 'phases', '01-setup', '01-01-PLAN.md')));
+  });
+
+  test('errors when no .gsd/ directory present', () => {
+    const result = runGsdTools(['from-gsd2', '--raw'], tmpDir);
+    const parsed = JSON.parse(result.output);
+    assert.strictEqual(parsed.success, false);
+    assert.ok(parsed.error.includes('No .gsd/'));
+  });
+
+  test('errors when .planning/ already exists without --force', () => {
+    makeGsd2Project(tmpDir);
+    fs.mkdirSync(path.join(tmpDir, '.planning'), { recursive: true });
+    const result = runGsdTools(['from-gsd2', '--raw'], tmpDir);
+    const parsed = JSON.parse(result.output);
+    assert.strictEqual(parsed.success, false);
+    assert.ok(parsed.error.includes('already exists'));
+  });
+
+  test('--force overwrites existing .planning/', () => {
+    makeGsd2Project(tmpDir);
+    fs.mkdirSync(path.join(tmpDir, '.planning'), { recursive: true });
+    fs.writeFileSync(path.join(tmpDir, '.planning', 'OLD.md'), 'old content');
+    const result = runGsdTools(['from-gsd2', '--force', '--raw'], tmpDir);
+    const parsed = JSON.parse(result.output);
+    assert.strictEqual(parsed.success, true);
+    assert.ok(fs.existsSync(path.join(tmpDir, '.planning', 'ROADMAP.md')));
+  });
+
+  test('--path resolves target directory', () => {
+    const projectDir = path.join(tmpDir, 'myproject');
+    fs.mkdirSync(projectDir, { recursive: true });
+    makeGsd2Project(projectDir);
+    // Run from tmpDir but point at projectDir
+    const result = runGsdTools(['from-gsd2', '--path', projectDir, '--dry-run', '--raw'], tmpDir);
+    assert.ok(result.success, result.error);
+    const parsed = JSON.parse(result.output);
+    assert.strictEqual(parsed.dryRun, true);
+    assert.ok(parsed.preview.includes('PROJECT.md'));
+  });
+
+  test('completion state: S01 done → [x] in ROADMAP.md', () => {
+    makeGsd2Project(tmpDir);
+    runGsdTools(['from-gsd2', '--raw'], tmpDir);
+    const roadmap = fs.readFileSync(path.join(tmpDir, '.planning', 'ROADMAP.md'), 'utf8');
+    assert.ok(roadmap.includes('[x]'));
+    // S02 is pending
+    assert.ok(roadmap.includes('[ ]'));
+  });
+
+  test('SUMMARY.md written for completed task, not for pending', () => {
+    makeGsd2Project(tmpDir, { withS02Dir: true });
+    runGsdTools(['from-gsd2', '--raw'], tmpDir);
+    // S01/T01 is done → SUMMARY exists
+    assert.ok(fs.existsSync(path.join(tmpDir, '.planning', 'phases', '01-setup', '01-01-SUMMARY.md')));
+    // S02/T01 is pending → no SUMMARY
+    assert.ok(!fs.existsSync(path.join(tmpDir, '.planning', 'phases', '02-auth-system', '02-01-SUMMARY.md')));
+  });
+});