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

implement user authentication
implement --model=opus real-time notifications
implement dashboard analytics

Argument Resolution

Check the target first, before any other step. This skill forks and cannot see the conversation. Load Read("../../shared/rules/target-resolution.md"): if the target, flags stripped, is a bare pronoun or deictic (this, them, that one) or empty, return exactly TARGET_UNRESOLVED: <word> and stop. The caller resolves it and re-invokes.

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.

# 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:

# 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:

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:

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. low is right only for spec-complete, mechanical work, and a low run always hands off to /ork:verify at high: Read("references/effort-ladder.md").

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")

Load project context. A fork skill never runs frontmatter hooks (#4683), so run the loader yourself and keep its additionalContext in mind:

echo '{"tool_name":"Bash","tool_input":{}}' | node "${CLAUDE_PLUGIN_ROOT}/hooks/bin/run-hook.mjs" skill/project-convention-loader
echo '{"tool_name":"Bash","tool_input":{}}' | node "${CLAUDE_PLUGIN_ROOT}/hooks/bin/run-hook.mjs" skill/implement-standards-loader
git rev-parse HEAD  # note it as the start sha for the Phase 6 pattern check

Worktree Isolation (CC 2.1.49)

For features touching 5+ files, offer worktree isolation to prevent conflicts with the main working tree:

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:

# 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:

# 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)

Load agent prompts: Read("references/agent-phases.md")

Phase 6 pattern check. The fork cannot run the enforcer per Write/Edit (#4683); pipe each changed file into node "${CLAUDE_PLUGIN_ROOT}/hooks/bin/run-hook.mjs" skill/pattern-consistency-enforcer once, as Read("references/phase-6-pattern-check.md") shows.

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.

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.

When agents run with run_in_background=true, output each agent's findings as soon as it returns — don't wait for all agents to finish. This gives users ~60% faster perceived feedback and enables early intervention if an agent's approach diverges from the plan.

Teammate background tasks survive turn-end (CC 2.1.183): A run_in_background task started by a teammate is no longer killed when that teammate finishes its turn. A parallel architecture/test teammate can launch a long build and let it outlive its own turn; the lead collects the result later. Pre-2.1.183 the lead had to own every background task to keep it alive.

Monitor Tool for Background Streaming (CC 2.1.98)

Use Monitor to stream real-time events from background build/test scripts instead of polling output files:

# Start a long-running build in background
Bash(command="npm run build 2>&1", run_in_background=true)
# Stream its output line-by-line as notifications (no polling)
Monitor(pid=build_task_id)

# For background agents with test suites:
Agent(subagent_type="ork:test-generator", run_in_background=true, isolation="worktree", ...)
# Monitor agent progress via task notifications (CC 2.1.98 partial progress)

Full pattern reference (when to use vs. TaskOutput, until-condition gates, partial-result salvage, anti-patterns): Read("../chain-patterns/references/monitor-patterns.md").

Partial results (CC 2.1.98): if a worktree-isolated agent crashes mid-implementation, salvage its partial output — git diff --name-only in its worktree, commit what's usable, flag incomplete items — instead of re-spawning; escalate a BLOCKED agent to the user. Full salvage logic: the monitor-patterns reference above.

Worktree-Isolated Implementation

Spawn parallel implementation agents with Agent(isolation="worktree"). The subagent bypass of the worktree-isolation guard was fixed in CC 2.1.154 and completed in 2.1.203; ork's floor is >= 2.1.220, so every supported session gets real isolation. Full pattern, plus the 2.1.206 caveat that EnterWorktree now prompts for confirmation on ork's out-of-tree ../<repo>-<task> convention: Read("../chain-patterns/references/worktree-agent-pattern.md")

Historical (CC <= 2.1.153 only): the param thrashed the primary worktree's HEAD and cut agents off at ~60 tool uses (Yonatan-HQ/platform#3224). The manual pre-create workaround that fixed it is superseded and kept only as a record: references/manual-worktree-pattern.md.

Post-Deploy Monitoring (CC 2.1.71)

After final PR, schedule health monitoring:

# Guard: Skip cron in headless/CI (CLAUDE_CODE_DISABLE_CRON)
# if env CLAUDE_CODE_DISABLE_CRON is set, run a single check instead
CronCreate(
  schedule="0 */6 * * *",
  prompt="Health check for {feature} in PR #{pr}:
    gh pr checks {pr} --repo {repo}.
    If healthy 24h → CronDelete. If errors → alert."
)

context7 with Detection

if capabilities.context7:
  mcp__context7__resolve-library-id({ libraryName: "next-auth" })
  mcp__context7__query-docs({ libraryId: "...", query: "..." })
else:
  WebFetch("https://docs.example.com/api")  # T1 fallback

Issue Tracking

If working on a GitHub issue, run the Start Work ceremony from issue-progress-tracking and post progress comments after major phases.

Feedback Loop

Maintain checkpoints after each task. Load triggers: Read("references/feedback-loop.md")

Test Requirements Matrix

Phase 5 test-generator MUST produce tests matching the change type. Each change type maps to specific required tests and testing rules.

Load test matrix, real-service detection, and phase 9 gate: Read("references/test-requirements-matrix.md")

Key Principles

• Verification gate (terminal, mandatory) — before declaring ANY task done you MUST Read("../../shared/rules/verification-gate.md") and satisfy EVERY check: every changed file verified, tests green, scope-creep scored. A partial pass is NOT done; "should work now" is not evidence.
• Agent status protocol — all subagents report DONE / DONE_WITH_CONCERNS / BLOCKED / NEEDS_CONTEXT per Read("../../shared/status-protocol.md")
• Tests are NOT optional — each task includes its tests, matched to change type (see matrix above)
• Parallel when independent — use run_in_background: true, launch all agents in ONE message
• Output limits (CC 2.1.77+): the Opus tier defaults to 64k output tokens (128k upper bound). Generate complete artifacts in a single pass when possible; chunk across turns if output exceeds the limit
• Micro-plan before implementing — scope boundaries, file list, acceptance criteria
• Detect scope creep (phase 7) — score 0-10, split PR if significant
• Real services when available — if docker-compose/testcontainers exist, use them in Phase 6
• Reflect and capture lessons (phase 10) — persist to memory graph
• Clean up agents — teammates wind down at turn end (CC 2.1.178+ implicit team); press Ctrl+F twice to stop lingering background agents. Note: /clear (CC 2.1.72+) preserves background agents
• Exit worktrees — call ExitWorktree(action: "keep") in Phase 10 if worktree was entered in Step 0; never leave orphaned worktrees

Next Steps (suggest to user after implementation)

verify {FEATURE}              # Grade the implementation
cover {FEATURE}               # Generate test suite
commit                        # Commit changes
/loop 10m npm test                 # Watch tests while iterating
/loop 30m verify {FEATURE}    # Periodic quality gate

PushNotification on Completion (CC 2.1.110+)

implement runs commonly take 10–30 min with parallel agents. At the final synthesis step, after the PR is opened and tests are green, call PushNotification — the user has almost certainly context-switched.

PushNotification(
  message=f"ork:implement complete — {FEATURE}: {tests_passing}/{tests_total} tests · PR #{pr_num} opened · ready for verify",
  status="proactive"
)

Full rule (when to fire, body content limits, graceful fallback for users without Remote Control): load Read("../chain-patterns/rules/push-notification-on-completion.md").

Agent Coordination

Dispatch envelope (CC 2.1.142+ flags — M146-6 / #1849)

When dispatching subagents — whether via the in-session Agent tool or a headless claude -p --bare from a wrapper script — set explicit --permission-mode and --effort per agent role so behaviour is deterministic across interactive vs CI runs:

In-session Agent tool calls inherit the parent session's permission mode; the table is the policy for what those defaults should be. For genuinely headless invocations (cron, CI), pass the flags explicitly to claude -p --bare:

claude -p --bare \
  --permission-mode dontAsk \
  --effort low \
  --max-turns 8 \
  "<prompt>"

Context Passing

All spawned agents receive: changed files list, project tier, architectural constraints, and decisions from prior phases (discovery, plan). Pass via the agent prompt, not just "implement X".

SendMessage (Active Coordination)

Cross-session replies land in the parent (CC 2.1.248): when a subagent sends SendMessage to another session, the reply is delivered to the parent session's conversation, never to the subagent; a subagent sends and moves on, the parent reads the answer. Cross-session SendMessage / ListAgents also work on Bedrock, Vertex and Foundry and with telemetry disabled (CC 2.1.248).

When backend and frontend agents need to align on API contracts:

SendMessage(to="frontend-ui-developer", message="API endpoint is POST /api/auth with {token, refreshToken} response shape")
SendMessage(to="test-generator", message="Backend uses JWT — mock auth middleware in test fixtures")

Skill Chain

After implementation completes, chain to verification:

TaskCreate(subject="Verify implementation", activeForm="Verifying changes")
TaskUpdate(taskId=verify_id, addBlockedBy=[impl_task_id])
# Then: verify {feature}

Quality Bar

Done means all of these hold:

• every changed file verified per the terminal verification gate — never "should work"
• each Phase 5 task ships its tests matched to change type; the suite ran green with the summary line cited
• scope creep scored 0-10 in Phase 7; PR split when the delta is significant
• worktrees entered in Step 0 are exited via ExitWorktree — no orphans

Related Skills

• ork:explore: Explore codebase before implementing
• ork:verify: Verify implementations work correctly
• ork:issue-progress-tracking: Auto-updates GitHub issues with commit progress

References

Load on demand with Read("references/<file>"):