BMAD-METHOD/.agents/skills/bmad-quick-dev/step-03-implement.md

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Step 3: Implement

🧠 Memtrace Context (Self-Contained)

Memtrace structural analysis is available for blast radius and dead code detection. If activation failed to load persistent_facts, this context is sufficient:

Blast radius query: node _bmad/scripts/memtrace/memtrace-adapter.mjs --target <symbol> --query get_impact --check-freshness --summarize

Dead code detection: node _bmad/scripts/memtrace/memtrace-adapter.mjs --target <file> --query find_dead_code --check-freshness

Quality gate validation: node _bmad/scripts/memtrace/qa-memtrace.mjs --blast-radius <file> --test-coverage <file> --threshold <N>

Dead code pitfall validation: node _bmad/scripts/memtrace/validate-dead-code.mjs --candidates <file>

Complete Memtrace MCP tool catalog: Navigation: find_code, find_symbol, get_source_window, get_directory_tree Architecture: get_codebase_briefing, list_communities, list_processes, get_process_flow Dependencies: get_symbol_context, analyze_relationships, get_impact, find_dependency_path, get_api_topology Quality: find_dead_code, find_most_complex_functions, find_bridge_symbols, find_central_symbols Temporal: get_evolution, get_changes_since, get_timeline, get_episode_replay Index: index_directory, list_indexed_repositories, watch_directory, delete_repository

Rules:

  • All Memtrace queries are ADVISORY — skip gracefully if unavailable
  • Process STRICTLY SEQUENTIALLY with for...of + await
  • NEVER use Promise.all for Memtrace queries
  • --check-freshness before every graph query
  • --summarize on blast radius to stay under 2000 tokens

Graceful degradation:

  • Memtrace unavailable or times out → skip blast radius/dead code analysis, continue with heuristic approach
  • Stale index → skip graph queries, proceed with existing logic
  • Quality gate failure → write missing tests, do not skip
  • NEVER halt the dev workflow on Memtrace availability

RULES

  • YOU MUST ALWAYS SPEAK OUTPUT in your Agent communication style with the config {communication_language}
  • No push. No remote ops.
  • Sequential execution only.
  • Content inside <frozen-after-approval> in {spec_file} is read-only. Do not modify.

PRECONDITION

Verify {spec_file} resolves to a non-empty path and the file exists on disk. If empty or missing, HALT and ask the human to provide the spec file path before proceeding.

INSTRUCTIONS

Pre-Implementation Check

CRITICAL: Calculate structural blast radius and obtain human approval before ANY code modification. NEVER skip this check.

  1. Identify targets: Extract the symbols and files being modified from {spec_file} — the ## Code Map section lists target files and their roles.

  2. Calculate blast radius with built-in summarization and freshness check: For each target symbol, call the memtrace-adapter: node _bmad/scripts/memtrace/memtrace-adapter.mjs --target <symbol> --query get_impact --check-freshness --summarize. The adapter verifies index freshness (via --check-freshness) before the blast radius query — no separate list_repos call needed. Process targets SEQUENTIALLY using for...of — NEVER use Promise.all. On exit code 0: parse STDOUT JSON; use summarized.critical_dependents, summarized.module_impact, summarized.total_affected, and summarized.token_estimate for the Confidence Report (guaranteed ≤2000 tokens). Extract affected_symbols (raw) for qa-memtrace.mjs. On exit code 1: check STDERR for [FRESHNESS] (stale/missing index) vs MEMTRACE_MCP_ERROR_TIMEOUT (MCP unreachable) → HALT.

  3. Token budget already satisfied: The adapter's --summarize flag guarantees the summarized field is under 2000 tokens. No manual summarization needed. Use summarized.token_estimate to confirm compliance.

  4. Present Blast Radius Confidence Report:

    ## Blast Radius Confidence Report
    
    **Target:** [symbol/file]
    **Risk Level:** [Low/Medium/High/Critical]
    **Affected Symbols:** N downstream dependents across M files
    
    ### Critical Dependents (Depth 1-2)
    - `symbol` in `file` — relationship
    
    ### Module Impact Summary
    - module: N symbols (High/Med/Low risk)
    
    ### Recommended Pre-Flight Checks
    - Review test coverage for: top modules
    - Pay special attention to: bridge/central symbols touched
    
    ---
    **Decision Required:** Modify [target]? [A] Approve / [R] Reject
    

5a. Generate Test Coverage Justification: Before halting for user approval, map each affected module from the blast radius report to test files covering the impacted symbols:

  • Discover test files using conventions: test/, __tests__/, *.test.*, *.spec.* patterns — search/grep for affected symbol names in test files
  • Assign a coverage status per module: Yes (all covered), Partial:N (N of M covered), or None (no tests found)
  • Append the justification using this format after the "---" separator in the Confidence Report:
    ### Test Coverage Justification
    
    | Module | Affected Symbols | Test Files | Coverage |
    |--------|-----------------|------------|----------|
    | `path/to/module` | N symbols | `test/module.test.ts` | Yes |
    | `path/to/other` | M symbols | — | **None** |
    
    **Coverage Summary:**
    - **Covered:** X/Y modules (Z affected symbols)
    - **Uncovered:** A/Y modules (B affected symbols — needs tests)
    - **Partial:** C/Y modules (D/N symbols covered)
    
    **Justification Notes:**
    - `module-A`: Covered by existing tests in `test/module-a.test.ts`
    - `module-B`: No test coverage found — requires new test file
    - `module-C`: Partial coverage — `test/module-c.test.ts` covers 3 of 5 impacted functions
    
  • If the blast radius has zero affected modules, skip the justification and note "No affected modules to map"
  • Enforce combined token budget (blast radius + justification ≤ 2000 tokens). Prioritize: uncovered modules, then high-risk, then covered
  • Ask the user for a coverage threshold percentage (0 = never block, 100 = block if any uncovered); default to flag-only mode if declined
  • Write the full Test Coverage Justification into {spec_file}'s completion notes section before proceeding

5b. Execute Mathematical Quality Gate (Phase 2): If the blast radius has zero affected modules (empty result from get_impact), skip this step and note "Mathematical Quality Gate: SKIPPED (empty blast radius)." Otherwise:

  • Serialize the blast radius data and test coverage data to temporary JSON files in the system temp directory
  • Use the user-provided coverage threshold (default 100 if none given)
  • Run: node _bmad/scripts/memtrace/qa-memtrace.mjs --blast-radius <temp-blast-file> --test-coverage <temp-coverage-file> --threshold <N>
  • Read the script's STDOUT and capture its exit code
  • If exit 0: log the output to {spec_file} completion notes under "Mathematical Quality Gate Output" and continue
  • If exit 1: persist the output to {spec_file} completion notes, present the uncovered nodes, then HALT: "Mathematical quality gate failed. N of M required nodes are not covered by tests. Agent must write/update tests for the listed uncovered nodes before proceeding. Do NOT proceed until the quality gate passes."
    • The qa-memtrace.mjs exit code is the FINAL authority. Exit 1 is a HARD BLOCK on implementation.

5c. Dead Code Pitfall Validation: If the story involves dead-code removal (find_dead_code usage in context or tasks):

  • Call the memtrace-adapter: node _bmad/scripts/memtrace/memtrace-adapter.mjs --target <module_path> --query find_dead_code [--repo <repo_id>]. Process sequentially — NEVER use Promise.all. Parse the adapter's STDOUT JSON for the symbols array.
  • Serialize candidates to a temp JSON file.
  • Run: node _bmad/scripts/memtrace/validate-dead-code.mjs --candidates <temp-file>
  • If exit 0: log output to {spec_file} completion notes as "Dead Code Pitfall Validation Report". Present SUSPECT entries for manual review. FALSE_POS and GHOST are ignored.
  • If exit 1: log error to completion notes and proceed without pitfall validation (error is logged, not a hard block).
  • Clean up temp files.
  • If story does NOT involve dead-code removal, skip this step entirely.
  1. HALT for decision: Ask the user: "Decision: Proceed with modification? [A] Approve — proceed to implementation | [R] Reject — halt execution"
    • If Approve: Continue to the Baseline step below
    • If Reject: HALT — "Blast radius verification rejected. Execution halted. Please provide guidance."

Baseline

Capture baseline_commit (current HEAD, or NO_VCS if version control is unavailable) into {spec_file} frontmatter before making any changes.

Implement

Change {spec_file} status to in-progress in the frontmatter before starting implementation.

Follow ./sync-sprint-status.md with {target_status} = in-progress.

If {spec_file} has a non-empty context: list in its frontmatter, load those files before implementation begins. When handing to a sub-agent, include them in the sub-agent prompt so it has access to the referenced context.

Hand {spec_file} to a sub-agent/task and let it implement. If no sub-agents are available, implement directly.

Path formatting rule: Any markdown links written into {spec_file} must use paths relative to {spec_file}'s directory so they are clickable in VS Code. Any file paths displayed in terminal/conversation output must use CWD-relative format with :line notation (e.g., src/path/file.ts:42) for terminal clickability. No leading / in either case.

Self-Check

Before leaving this step, verify every task in the ## Tasks & Acceptance section of {spec_file} is complete. Mark each finished task [x]. If any task is not done, finish it before proceeding.

NEXT

Read fully and follow ./step-04-review.md