feat: adopt symlink approach for cross-tool instruction files

Replace 4 separate instruction files with 1 real file + symlinks:
- .github/copilot-instructions.md is the canonical instruction file
- CLAUDE.md and .cursorrules are symlinks to it
- AGENTS.md stays as global config (not a project instruction file)

This eliminates all sync/merge logic - changes propagate automatically.

Changes:
- AGENTS.md: rewrite Cross-Tool Instruction Files section for symlink convention
- librarian.md: simplify to maintain single instruction file + verify symlinks
- lead.md: simplify PHASE-WRAP and Documentation Completion Gate
- commands (init, bootstrap-memory, save-memory): update for symlink model
- doc-coverage skill: verify symlinks exist and point correctly

.config/opencode/commands/bootstrap-memory.md

@@ -60,26 +60,13 @@ constraints). Include rationale when known.
 - If research artifacts are discovered, create `.memory/research/<topic>.md`
   with findings and references.
 
-## Step 6: Delegate instruction file creation to librarian
+## Step 6: Update instruction file
 
-After `.memory/knowledge.md` is populated, dispatch the `librarian` subagent to
-create or update all cross-tool instruction files from `.memory/knowledge.md`:
+If `.github/copilot-instructions.md` exists, update it with any new project knowledge
+discovered during bootstrap (architecture, conventions, commands). The symlinks
+(`AGENTS.md`, `CLAUDE.md`, `.cursorrules`) will automatically reflect changes.
 
-- `AGENTS.md`
-- `CLAUDE.md`
-- `.github/copilot-instructions.md`
-- `.cursorrules`
-
-Each file should include the same core project guidance:
-- project overview and purpose
-- tech stack
-- architecture summary
-- coding conventions/patterns
-- build/test/lint commands
-- project structure overview
-
-If any of these files already exist, preserve existing project-specific content
-and merge in new knowledge instead of overwriting wholesale.
+If the instruction file doesn't exist, note that `/init` should be run to create it.
 
 ## Guidelines
 

.config/opencode/commands/init.md

@@ -45,10 +45,10 @@ Delegate to the `coder` subagent with explicit mode (`new_project` or `existing_
 
 - Required scaffold targets:
   - `README.md` — title, purpose, tech stack, quick-start, project structure overview
-  - `AGENTS.md` — project-specific workflow notes (code style, test commands, linting, build commands, commit conventions); do **not** duplicate global `AGENTS.md` policies — only add project-specific details
-  - `CLAUDE.md` — project instructions for Claude Code (same core content as `AGENTS.md`, adapted for Claude)
-  - `.github/copilot-instructions.md` — project instructions for GitHub Copilot
-  - `.cursorrules` — project instructions for Cursor
+  - `.github/copilot-instructions.md` — real instruction file containing shared project guidance
+  - `AGENTS.md` — symlink to `.github/copilot-instructions.md`
+  - `CLAUDE.md` — symlink to `.github/copilot-instructions.md`
+  - `.cursorrules` — symlink to `.github/copilot-instructions.md`
   - `docs/architecture.md` — stub with title + purpose
   - `.gitignore` — add stack-appropriate ignores (e.g., `node_modules/`, `__pycache__/`, `target/`)
   - `.memory/` — create and/or update `knowledge.md`, `decisions.md`, `plans/`, `research/`
@@ -59,11 +59,15 @@ Delegate to the `coder` subagent with explicit mode (`new_project` or `existing_
   - create or fill in only missing pieces
   - **do not overwrite existing files**
   - explicitly instruct coder to check existence before creating each target
-  - if any cross-tool instruction files are missing (`AGENTS.md`, `CLAUDE.md`, `.github/copilot-instructions.md`, `.cursorrules`), create them
-  - if they exist, verify they are in sync with `AGENTS.md` for core project knowledge (purpose, stack, conventions, commands, structure)
+  - ensure `.github/copilot-instructions.md` exists as the real instruction file
+  - create missing symlinks:
+    - `ln -s .github/copilot-instructions.md AGENTS.md`
+    - `ln -s .github/copilot-instructions.md CLAUDE.md`
+    - `ln -s .github/copilot-instructions.md .cursorrules`
+  - if `.github/copilot-instructions.md` is missing but `AGENTS.md` exists as a real file, move AGENTS content into `.github/copilot-instructions.md`, then recreate `AGENTS.md` as a symlink
   - if `.memory/` is missing, create the full `.memory/` directory structure
   - examples:
-    - if `README.md` exists and `AGENTS.md` is missing, create only `AGENTS.md`
+    - if `README.md` exists and only `AGENTS.md` is missing, create `AGENTS.md` as a symlink to `.github/copilot-instructions.md`
     - if `docs/` is missing, create it and add `docs/architecture.md`
 
 ## Step 4 — Documentation review (delegate to `librarian`)
@@ -71,8 +75,8 @@ Delegate to the `coder` subagent with explicit mode (`new_project` or `existing_
 Always delegate to the `librarian` subagent, for both new and existing projects.
 
 - Ensure `README.md` is accurate and complete for the current project state.
-- Ensure `AGENTS.md` captures project-specific workflow decisions from Step 2.
-- Verify cross-tool instruction files are consistent with each other (`AGENTS.md`, `CLAUDE.md`, `.github/copilot-instructions.md`, `.cursorrules`).
+- Ensure `.github/copilot-instructions.md` exists and captures project-specific workflow decisions from Step 2.
+- Verify `AGENTS.md`, `CLAUDE.md`, and `.cursorrules` are symlinks to `.github/copilot-instructions.md`.
 - Ensure stubs are explicitly marked for later completion.
 - Keep edits additive and non-destructive for existing projects.
 

.config/opencode/commands/save-memory.md

@@ -55,18 +55,11 @@ Example cross-reference:
 Re-read updated `.memory/` files to confirm they reflect current understanding.
 Report what was added/updated and where.
 
-## Step 6: Delegate instruction file sync to librarian
+## Step 6: Update instruction file if project knowledge changed
 
-If `.memory/knowledge.md` was **materially** updated in this save (architecture,
-conventions, commands — not just plans/research), dispatch the `librarian`
-subagent to:
-
-1. Read all cross-tool instruction files (`AGENTS.md`, `CLAUDE.md`,
-   `.github/copilot-instructions.md`, `.cursorrules`)
-2. Check for knowledge in instruction files not yet in `.memory/knowledge.md`
-   and merge it inward
-3. Update instruction files to reflect new `.memory/knowledge.md` content
-4. Report sync status
+If `.memory/knowledge.md` was **materially** updated (architecture, conventions,
+commands — not just plans/research), update `.github/copilot-instructions.md` to
+reflect the changes. The symlinks automatically propagate to all tools.
 
 If updates were only plans/research/tracking details, skip this step.