skill-cslib-implementation

name	skill-cslib-implementation
description	Implement CSLib proofs following Lean 4 and CSLib contribution standards. Invoke for cslib implementation tasks.
allowed-tools	Agent, Bash, Edit, Read, Write

CSLib Implementation Skill

Thin wrapper that delegates CSLib proof implementation to cslib-implementation-agent subagent.

Trigger Conditions

This skill activates when:

• Task type is "cslib"
• /implement command targets a CSLib task
• Lean 4 proofs or CSLib definitions need to be created or modified

Execution Flow

Stage 1: Input Validation

Validate task_number exists, task_type is "cslib", and an implementation plan is present.

Stage 2: Preflight Status Update

Update status to "implementing" BEFORE invoking subagent.

Stage 2b: Preflight Cache Warming

Ensure Mathlib cache is warm before delegating to the agent:

cd /home/benjamin/Projects/cslib && lake exe cache get 2>&1 || echo "Warning: cache fetch failed (non-fatal)"

This is non-blocking. Cache fetch failure does not prevent delegation. On a cache hit, this completes in ~1-2 minutes and prevents 30-45 minute Mathlib rebuilds during CI verification.

Stage 3: Prepare Delegation Context

Domain-specific context for the cslib-implementation-agent:

• CSLib coding standards from .claude/extensions/cslib/context/
• Verification: lake build, lake test, lake lint, lake exe checkInitImports, lake exe lint-style, lake shake
• lean-lsp MCP tools for proof state inspection (inherited via lean dependency)

{
  "session_id": "sess_{timestamp}_{random}",
  "delegation_depth": 1,
  "delegation_path": ["orchestrator", "implement", "skill-cslib-implementation"],
  "timeout": 7200,
  "task_context": {
    "task_number": N,
    "task_name": "{project_name}",
    "description": "{description}",
    "task_type": "cslib"
  },
  "plan_path": "specs/{NNN}_{SLUG}/plans/MM_{short-slug}.md",
  "orchestrator_mode": true,
  "metadata_file_path": "specs/{NNN}_{SLUG}/.return-meta.json"
}

Stage 4a: Memory and Literature Retrieval (Auto)

Retrieve relevant memories and literature briefing to inject into the delegation context.

Skip memory if: clean_flag is true (from --clean command flag).

# Check clean_flag
if [ "$clean_flag" != "true" ]; then
  memory_context=$(bash .claude/scripts/memory-retrieve.sh "$description" "$task_type" "" 2>/dev/null) || memory_context=""
fi

# memory_context will be empty string if:
# - clean_flag is true (skipped)
# - memory-index.json missing or empty
# - no keywords matched any entries
# - script exited with error

# Literature briefing injection (independent of clean_flag)
lit_context=""
if [ "$lit_flag" = "true" ]; then
  lit_context=$(bash .claude/scripts/literature-briefing.sh 2>/dev/null) || lit_context=""
fi

# lit_context will be empty string if:
# - lit_flag is not "true" (skipped)
# - specs/literature/ sub-index is empty or missing
# - script exited with error

Note: lit_flag is independent of clean_flag. Using --clean --lit suppresses memory retrieval but still injects literature briefing. Literature briefing is gated solely on lit_flag == "true".

Stage 4: Invoke Subagent

Use Agent tool with subagent_type: "cslib-implementation-agent".

Include memory_context and lit_context in the prompt if non-empty:

• If memory_context is non-empty, include it as a <memory-context> block after the delegation context.
• If lit_context is non-empty, include it as a <literature-briefing> block after the memory context.

Stage 4b: Self-Execution Fallback

CRITICAL: If you performed the work above WITHOUT using the Agent tool (i.e., you read files, wrote artifacts, or updated metadata directly instead of spawning a subagent), you MUST write a .return-meta.json file now before proceeding to postflight. Use the schema from return-metadata-file.md with the appropriate status value for this operation.

If you DID use the Agent tool, skip this stage -- the subagent already wrote the metadata.

Postflight (ALWAYS EXECUTE)

The following stages MUST execute after work is complete, whether the work was done by a subagent or inline (Stage 4b). Do NOT skip these stages for any reason.

Stage 5: Parse Subagent Return

Read the metadata file from specs/{N}_{SLUG}/.return-meta.json.

Stage 6: Update Task Status (Postflight)

Update state.json and TODO.md based on result.

Stage 7: Link Artifacts

Add artifact to state.json with summary. Update TODO.md per @.claude/context/patterns/artifact-linking-todo.md with field_name=**Summary**, next_field=**Description**.

Stage 8: Git Commit

Commit changes with session ID.

Stage 9: Return Brief Summary

MUST NOT (Postflight Boundary)

After the agent returns, this skill MUST NOT:

1. Edit .lean files - All CSLib proof work is done by agent
2. Run lake build/test/lint - Verification is done by agent
3. Use lean-lsp MCP tools - Domain tools are for agent use only
4. Grep for sorries - Debt analysis is agent work
5. Write summary/reports - Artifact creation is agent work

PROHIBITION: If the subagent returned partial or failed status, the lead skill MUST NOT attempt to continue, complete, or "fill in" the subagent's work. Report the partial/failed status and let the user re-run /implement to resume.

The postflight phase is LIMITED TO:

• Reading agent metadata file
• Updating state.json via jq
• Updating TODO.md status marker via Edit
• Linking artifacts in state.json
• Git commit
• Cleanup of temp/marker files

Reference: @.claude/context/standards/postflight-tool-restrictions.md

Return Format

Brief text summary (NOT JSON).