implement

# Implement Feature Host-neutral workflow. Invoke by skill name (`implement`). Claude Code slash routing, YAML hook loaders, and `.claude/chain` live in `references/claude-code.md`. Parallel subagent execution for feature implementation with scope control and reflection. ## Quick Start ```bash implement user authentication implement --model=opus real-time notifications implement dashboard analytics ``` --- ## Argument Resolution ```python FEATURE_DESC = "$ARGUMENTS" # Full argument string, e.g., "user authentication" # $ARGUMENTS[0] is the first token, $ARGUMENTS[1] second, etc. (CC 2.1.59) # Model override detection (CC 2.1.72) MODEL_OVERRIDE = None for token in "$ARGUMENTS".split(): if token.startswith("--model="): MODEL_OVERRIDE = token.split("=", 1)[1] # "opus", "sonnet", "haiku", "fable" FEATURE_DESC = FEATURE_DESC.replace(token, "").strip() ``` Pass `MODEL_OVERRIDE` to all Agent() calls via `model=MODEL_OVERRIDE` when set. Accepts symbolic names (`opus`, `sonnet`, `haiku`, `fable` on harnesses whose Agent tool lists it; note fable is premium API spend after 2026-07-12) or full IDs (`claude-opus-5-5`) per CC 2.1.74. --- ## Step -1: MCP Probe + Resume Check **Run BEFORE any other step.** Detect available MCP servers and check for resumable state. ```python # Probe MCPs (parallel — all in ONE message): # memory is alwaysLoad in .mcp.json (CC 2.1.121+, #1541) — probe below kept as fallback for older CC: ToolSearch(query="select:mcp__memory__search_nodes") ToolSearch(query="select:mcp__context7__resolve-library-id") Write(".claude/chain/capabilities.json", JSON.stringify({ "memory": <true if found>, "context7": <true if found>, "timestamp": now() })) # Resume check: Read(".claude/chain/state.json") # If exists and skill == "implement": # Read last handoff (e.g., 04-architecture.json) # Skip to current_phase # "Resuming from Phase {N} — architecture decided in previous session" # If not: write initial state Write(".claude/chain/state.json", JSON.stringify({ "skill": "implement", "feature": FEATURE_DESC, "current_phase": 1, "completed_phases": [], "capabilities": capabilities, "budget_remaining_pct": 100 // advisory; see Budget Awareness below })) ``` ### Batch Size Governance (large refactors) For implementations touching **>10 files**, enforce max 5 files per agent batch, run tests between batches, commit green batches immediately, stop on red. Override via `--batch-size N`. Full rule: `Read("rules/batch-governance.md")`. ### Budget Awareness (Opus 5.5 task budgets, public beta) Opus 5.5 exposes per-task token budgets. Until the CC side is GA, OrchestKit tracks an advisory `budget_remaining_pct` in `state.json` so long runs self-throttle. Update after each phase: ```python # At end of every phase, estimate remaining budget: pct = tokensAsContextPct(tokensUsedSoFar) # from lib/context-window.ts remaining = max(0, 100 - pct) state["budget_remaining_pct"] = remaining Write(".claude/chain/state.json", JSON.stringify(state)) ``` Thresholds influence behavior: | Remaining | Behavior | |---|---| | `> 50%` | Normal — all optional depth (devil's advocate, visual capture, deep exploration). | | `20-50%` | Efficient — skip optional depth; keep core phases. Warn user once. | | `< 20%` | Conservation — finish current phase, emit a handoff with next steps, do not start new work. | When CC's native task-budget API ships GA, replace the estimate with the real signal; the thresholds and behavior stay the same. > Load: `Read("../chain-patterns/references/checkpoint-resume.md")` --- ## Step -0.5: Assess Verdict Gate If `.claude/chain/assess-verdict.json` exists with a `feature` matching this run and `verdict == "fail"` (composite < the 5.5 `min_pass` in `../assess/rubric.json`, or any dimension below its `min_blocker`), **BLOCK Phase 1**. Present each `blockers[]` entry (dimension, score, reason), then `AskUserQuestion` with plain label+description options (no `preview`): 1. **Fix blockers first (Recommended)** — address the blockers, re-run `assess`, then return here. 2. **Override and implement** — proceed anyway; record `"assess_gate": "overridden"` in `state.json` and carry the blockers into Phase 1 context. Missing file or `verdict == "pass"` → no gate; continue to Step 0. --- ## Step 0: Effort-Aware Phase Scaling (CC 2.1.76; `xhigh` added in 2.1.111) Read the `/effort` setting to scale implementation depth. The effort-aware context budgeting hook detects effort level automatically — adapt the phase plan accordingly: | Effort Level | Phases Run | Agents | Token Budget | |-------------|------------|--------|--------------| | **low** | 1 (Discovery) → 5 (Implement) → 10 (Reflect) | 2 max | ~50K | | **medium** | 1 → 2 → 5 → 7 (Scope Creep) → 10 | 3 max | ~150K | | **high** (default) | All 10 phases | 4-7 | ~400K | | **xhigh** (Opus 5, CC 2.1.111+) | All 10 phases + one additional healing iteration on test failures before escalating | 4-7 | ~550K | > **Override:** Explicit user selection in Step 0 (e.g., "Plan first" or "Worktree") overrides `/effort` downscaling. If user requests full exploration, respect that regardless of effort level. ## Step 0a: Project Context Discovery **BEFORE any work**, detect the project tier. This becomes the complexity ceiling for all patterns. Scan codebase signals and classify into tiers 1-6 (Interview through Open Source). Each tier sets an architecture ceiling and determines which phases/agents to use. Load tier details, workflow mapping, and orchestration mode: `Read("references/tier-classification.md")` ### Worktree Isolation (CC 2.1.49) For features touching 5+ files, offer worktree isolation to prevent conflicts with the main working tree: ```python AskUserQuestion(questions=[{ "question": "Isolate this feature in a git worktree?", "header": "Isolation", "options": [ {"label": "Yes — worktree (Recommended)", "description": "Creates isolated branch via EnterWorktree, merges back on completion"}, {"label": "No — work in-place", "description": "Edit files directly in current branch"}, {"label": "Plan first", "description": "Research and design in plan mode before writing code"} ], "multiSelect": false }]) ``` **If 'Plan first' selected:** ```python # 1. Enter read-only plan mode EnterPlanMode("Research and design: $ARGUMENTS") # 2. Research phase — Read/Grep/Glob ONLY, no Write/Edit # - Read existing code in the target area # - Grep for related patterns, imports, dependencies # - Check tests, configs, and integration points # - If context7 available: query library docs # 3. Design the plan — produce: # - File map: which files to create/modify # - Architecture decisions with rationale # - Task breakdown with acceptance criteria # - Risk assessment and edge cases # 4. Exit plan mode — returns plan to user for approval ExitPlanMode() # 5. User reviews plan. If approved → continue to Phase 1 (Discovery) # with the plan as input. If rejected → revise or stop. ``` If worktree selected: 1. Call `EnterWorktree(name: "feat-{slug}")` to create isolated branch 2. All agents work in the worktree directory 3. On completion, merge back: `git checkout {original-branch} && git merge feat-{slug}` 4. If merge conflicts arise, present diff to user via `AskUserQuestion` Load worktree details: `Read("references/worktree-isolation-mode.md")` --- ## Step 0b: Blast-Radius Clarification (ask "what" before "how") Before Phase 1, resolve the unknowns whose answers would **change the architecture**, in blast-radius order — schema/migration → auth → API contract → perf/scale → cosmetics (last). Grep first, then `AskUserQuestion` one at a time (highest first, cap ~5, skip the obvious). Each answer becomes a row in a Decisions table written to `.claude/chain/decisions.json` and the PR body, feeding Phase 4 (Architecture) as constraints. Do NOT start Phase 1 with an unresolved schema/auth question; skip in `low` effort. Full protocol: `Read("references/blast-radius-clarification.md")`. --- **Finish line.** Done means: every planned file is written, the new and existing tests pass, the scope-creep check found nothing unplanned, and E2E verification ran. Follow `Read("../../shared/rules/long-run-protocol.md")`: keep going when a step needs no input from the user, stop and ask only when you can't continue without them or before anything destructive, check each subagent's evidence before accepting it, and mark anything you couldn't confirm with where you looked. ## Task Management (MANDATORY) **BEFORE doing ANYTHING else, create tasks to track progress:** ```python # 1. Create main task IMMEDIATELY TaskCreate( subject="Implement: {feature}", description="Feature implementation with parallel subagents", activeForm="Implementing {feature}" ) # 2. Create subtasks for each phase TaskCreate(subject="Research best practices and docs", activeForm="Researching best practices") # id=2 TaskCreate(subject="Micro-plan: scope, files, criteria", activeForm="Micro-planning") # id=3 TaskCreate(subject="Architecture design (parallel agents)", activeForm="Designing architecture") # id=4 TaskCreate(subject="Implement and write tests", activeForm="Implementing code") # id=5 TaskCreate(subject="Integration verification", activeForm="Verifying integration") # id=6 TaskCreate(subject="Scope creep check", activeForm="Checking scope creep") # id=7 TaskCreate(subject="E2E verification", activeForm="Running E2E verification") # id=8 TaskCreate(subject="Document and reflect", activeForm="Documenting decisions") # id=9 # 3. Set dependencies for sequential phases TaskUpdate(taskId="3", addBlockedBy=["2"]) # Plan needs research TaskUpdate(taskId="4", addBlockedBy=["3"]) # Architecture needs plan TaskUpdate(taskId="5", addBlockedBy=["4"]) # Implementation needs architecture TaskUpdate(taskId="6", addBlockedBy=["5"]) # Integration needs implementation TaskUpdate(taskId="7", addBlockedBy=["6"]) # Scope creep needs integration TaskUpdate(taskId="8", addBlockedBy=["7"]) # E2E needs scope check TaskUpdate(taskId="9", addBlockedBy=["8"]) # Docs need E2E # 4. Update status as you progress TaskUpdate(taskId="2", status="in_progress") # When starting TaskUpdate(taskId="2", status="completed") # When done — repeat for each subtask ``` --- ## Workflow (10 Phases) | Phase | Activities | Agents | |-------|------------|--------| | **1. Discovery** | Research best practices, Context7 docs, break into tasks | — | | **2. Micro-Planning** | Detailed plan per task (load `references/micro-planning-guide.md`) | — | | **3. Worktree** | Isolate in git worktree for 5+ file features (load `references/worktree-workflow.md`) | — | | **4. Architecture** | 4 parallel background agents (+ event-driven-architect when event/CQRS/queue-shaped) | workflow-architect, backend-system-architect, frontend-ui-developer, llm-integrator | | **5. Implementation + Tests** | Parallel agents, single-pass artifacts with mandatory tests | backend-system-architect, frontend-ui-developer, llm-integrator, test-generator | | **6. Integration Verification** | Code review + real-service integration tests | backend, frontend, code-quality-reviewer, security-auditor | | **7. Scope Creep** | Compare planned vs actual (load `references/scope-creep-detection.md`) | workflow-architect | | **8. E2E Verification** | Browser + API E2E testing (load `references/e2e-verification.md`) | — | | **9. Documentation** | Save decisions to memory graph | — | | **10. Reflection** | Lessons learned, estimation accuracy | workflow-architect | Load agent prompts: `Read("references/agent-phases.md")` For Agent Teams mode: `Read("references/agent-teams-phases.md")` > **Nested delegation (CC 2.1.172+):** Phase 4-6 specialist agents MAY be instructed to delegate a bounded sub-problem to their own declared sub-agents (e.g. backend-system-architect → database-engineer for schema design) instead of doing everything inline. Keep chains ≤ 3 levels deep; when sub-tasks are independent, flatten to parallel dispatch from this orchestrator. See chain-patterns Pattern 9 (CC 2.1.172+). ### Phase Handoffs (CC 2.1.71) Write handoff JSON after major phases. See `chain-patterns` skill for schema. | After Phase | Handoff File | Key Outputs | |-------------|-------------|-------------| | 1. Discovery | `01-discovery.json` | Best practices, library docs, task breakdown | | 2. Micro-Plan | `02-plan.json` | File map, acceptance criteria per task | | 4. Architecture | `04-architecture.json` | Decisions, patterns chosen, agent results | | 5. Implementation | `05-implementation.json` | Files created/modified, test results | | 7. Scope Creep | `07-scope.json` | Planned vs actual, PR split recommendation | ### Progressive Output (CC 2.1.76+) Output results **incrementally** after each phase — don't batch everything until the end. > **Focus mode (CC 2.1.101):** In focus mode (`/focus`), the user only sees your final message. Include a self-contained summary with all key results — don't assume they saw incremental outputs. | After Phase | Show User |