/implement

name: implement
license: MIT
compatibility: "Claude Code 2.1.277+. Requires memory MCP server, context7 MCP server, network access."
description: "Builds a new feature with parallel backend, frontend, test and security agents in worktrees, then verifies. Use when asked to build, add or scaffold a feature, endpoint or component. Not for fixing, reviewing or testing existing code."
argument-hint: "[feature-description]"
context: fork
# user-typed commands stay interactive; CC >= 2.1.218 backgrounds forks by default (#3093)
background: false
disable-model-invocation: false  # #3194: true also blocked USER-typed mid-turn invocations
user-invocable: true
allowed-tools: "SendMessage AskUserQuestion Bash Read Write Edit Grep Glob Agent TaskCreate TaskUpdate TaskStop ToolSearch WebFetch EnterWorktree ExitWorktree CronCreate CronDelete Monitor PushNotification mcp__context7__resolve-library-id mcp__context7__query-docs mcp__memory__search_nodes"
skills: [api-design, react-server-components-framework, testing-unit, testing-e2e, testing-integration, explore, verify, memory, scope-appropriate-architecture, chain-patterns]
model: sonnet
metadata:
  category: workflow-automation
  mcp-server: memory, context7
  version: "2.8.0"
  author: "OrchestKit"
  complexity: "medium"
  tags: "implementation, feature, full-stack, parallel-agents, reflection, worktree"
triggers:
  keywords: [implement, implment, build, create, add, make, scaffold, "set up", "file upload", "dark mode", "rate limiting"]
  examples:
    - "build a user authentication system with JWT"
    - "add dark mode support to the dashboard"
    - "implement the payment webhook handler"
  anti-triggers: [fix, debug, review, explore, test, assess, brainstorm]
paths:
  - "src/**/*.{ts,tsx,js,jsx}"
  - "package.json"
  - "tsconfig.json"
  - "CLAUDE.md"

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:

| 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 be