/feature

name: feature
description: 'TDD-first feature development — crystallise API as a demo test, drive implementation to pass it, run quality stack and progressive review loop. TRIGGER when: user asks to build new functionality, add a capability, or implement a feature in a Python project; phrases: "add X", "implement Y", "build Z feature", "create a new module for". SKIP when: bug fixes (use `/develop:fix`); refactoring without new behaviour (use `/develop:refactor`); non-Python projects; `.claude/` config changes (use `/foundry:manage`).'
argument-hint: <goal> [--issue <N>] [--repo <owner/repo>] [--plan <path>] [--no-challenge] [--challenge] [--no-codemap] [--codemap] [--semble] [--team] [--worktree] [--accept-no-plan] [--keep "<items>"]
effort: xhigh
allowed-tools: Read, Write, Edit, Bash, Grep, Glob, Agent, Skill, TaskList, TaskCreate, TaskUpdate, AskUserQuestion, WebFetch, EnterWorktree, ExitWorktree
disable-model-invocation: true

<objective>

TDD-first feature development. Crystallise API as demo use-case test, drive implementation to pass it, close quality gaps with review, docs, quality stack.

NOT for:

• bug fixes (use `/develop:fix`)
• `.claude/` config changes (use `/foundry:manage` (requires foundry plugin))
• non-Python projects (JS/TS/Go/Rust) — toolchain assumes pytest; use language-native toolchain instead
• mixed refactor+feature tasks — run /develop:refactor first, then /develop:feature

</objective>

<compaction>

• Key boundary: end of Step 1 — scope analysis and plan complete, before Step 2 demo test writing.
• Second boundary: end of Step 3 — TDD loop complete, before Step 4 review/close gaps.
• Preserve at boundary 1: dev-dir (checkpoint.md), plan-file, scope from sw-engineer analysis, PYTEST_CMD, --keep items.
• Mid-loop refresh: after each Step 3 TDD cycle contract is rewritten with changed-files + checkpoint.md path — so mid-loop compaction resumes loop (re-run suite for green state) instead of restarting Step 2 demo.
• Preserve at boundary 2: dev-dir, changed files list, test outcomes, PYTEST_CMD.

</compaction>

<workflow>

<!-- Agent resolution: see _DEV_SHARED/agent-resolution.md (mounted by develop plugin init) -->

Agent Resolution

export CSID="${CLAUDE_CODE_SESSION_ID:-$PPID}"
_DEV_SHARED=$(python "${CLAUDE_PLUGIN_ROOT:-plugins/cc_develop}/bin/dev_shared_resolve.py" 2>/dev/null)  # timeout: 5000
[ -z "$_DEV_SHARED" ] && _DEV_SHARED="plugins/cc_develop/skills/_shared"
echo "$_DEV_SHARED" > "${TMPDIR:-/tmp}/dev-shared-${CSID}"  # cold resolve — every later block warm-reads this
# loads: compaction-contract.md
cat "$_DEV_SHARED/agent-resolution.md"

Contains: foundry check + fallback table. If foundry not installed: substitute each `foundry:X` with `general-purpose` per table. Agents this skill uses: `foundry:sw-engineer`, `foundry:qa-specialist`, `foundry:doc-scribe`, `foundry:linting-expert`, `foundry:challenger`.

export CSID="${CLAUDE_CODE_SESSION_ID:-$PPID}"
IFS= read -r _DEV_SHARED < "${TMPDIR:-/tmp}/dev-shared-${CSID}" 2>/dev/null || _DEV_SHARED=""  # timeout: 5000
[ -z "$_DEV_SHARED" ] && _DEV_SHARED="plugins/cc_develop/skills/_shared"
cat "$_DEV_SHARED/task-hygiene.md"

Project Detection

export CSID="${CLAUDE_CODE_SESSION_ID:-$PPID}"
IFS= read -r _DEV_SHARED < "${TMPDIR:-/tmp}/dev-shared-${CSID}" 2>/dev/null || _DEV_SHARED=""  # timeout: 5000
[ -z "$_DEV_SHARED" ] && _DEV_SHARED="plugins/cc_develop/skills/_shared"
cat "$_DEV_SHARED/runner-detection.md"

Sets `$TEST_CMD` (full suite) and `$PYTEST_CMD` (pytest flags). Run at skill start.

**Language preflight gate**: apply §Language preflight gate from `runner-detection.md` (loaded above) — sets `NON_PY` and runs the abort/continue question.

<!-- NON_PY and MULTI_LANG gates are mutually exclusive — NON_PY fires only when no Python markers exist; MULTI_LANG fires only when Python markers AND non-Python markers coexist. Both cannot be true on the same repo; never reorder so MULTI_LANG runs before NON_PY. -->

**Monorepo language-target gate**: if `NON_PY` empty (Python markers found) but non-Python markers also exist, confirm target language:

# timeout: 5000
MULTI_LANG=false
[ -f "pyproject.toml" ] && [ -f "package.json" ] && MULTI_LANG=true
[ -f "pyproject.toml" ] && [ -f "go.mod" ] && MULTI_LANG=true
[ -f "pyproject.toml" ] && [ -f "Cargo.toml" ] && MULTI_LANG=true

If `MULTI_LANG=true`: invoke `AskUserQuestion` — "Monorepo detected (Python + non-Python markers coexist). This skill targets Python/pytest. Is the feature you're building Python-only?" · (a) **Yes — Python only** — proceed · (b) **No — involves non-Python code too** — abort; use a language-native toolchain for the non-Python portion. On (b): stop.

**Optional `--plan <path>`**: if `$ARGUMENTS` contains `--plan <path>` (at any position), read plan file first. Extract `Affected files`, `Risks`, `Suggested approach` — use to populate Step 1 analysis instead of cold codebase exploration. Skip agent feasibility re-check (already done in `/develop:plan`). Store plan path as `PLAN_FILE`.

export CSID="${CLAUDE_CODE_SESSION_ID:-$PPID}"
IFS= read -r _DEV_SHARED < "${TMPDIR:-/tmp}/dev-shared-${CSID}" 2>/dev/null || _DEV_SHARED=""  # timeout: 5000
[ -z "$_DEV_SHARED" ] && _DEV_SHARED="plugins/cc_develop/skills/_shared"
cat "$_DEV_SHARED/preflight-helpers.md"

Execute --plan path extraction; sets `$PLAN_FILE`.

**Checkpoint init**: run block below to create `.developments/<TS>/` and capture path in `$DEV_DIR`. Write `checkpoint.md` inside `$DEV_DIR`. After each major step (1, 2, 3, 4, 5), append `step: N — completed` to `$DEV_DIR/checkpoint.md`. On skill start, check for existing `.developments/*/checkpoint.md` — if found, offer to resume from last completed step.

# timeout: 5000
export CSID="${CLAUDE_CODE_SESSION_ID:-$PPID}"
DEV_DIR=$(python "${CLAUDE_PLUGIN_ROOT:-plugins/cc_develop}/bin/dev_run_dir.py" 2>/dev/null)
echo "$DEV_DIR" > "${TMPDIR:-/tmp}/dev-featur