agentic-dev/docs/work/2026-05-14-library-evaluation-policy/03-claude-hooks/_story.md

id, epic, title, type, status, feature, depends-on, blocks

id	epic	title	type	status	feature	depends-on	blocks
03-claude-hooks	2026-05-14-library-evaluation-policy	Claude PreToolUse / PostToolUse hooks for library-policy nudge	technical-story	done	tooling

Goal

Write .claude/hooks/library-policy-nudge.sh — a single hook script that dispatches on tool_use_type to handle both PreToolUse (Bash invocations matching pnpm add / pnpm i <pkg>) and PostToolUse (Edit/Write on any **/package.json). On match, emit a non-blocking system-reminder pointing the agent at the evaluate-library skill with the exact invocation pattern. Register the hook in .claude/settings.json following the same pattern as generator-first-nudge.sh.

Why

Agents (and developers) running pnpm add by reflex bypass the policy before the pre-commit gate fires. The PreToolUse hook injects the skill reminder before the install runs — the cheapest possible intervention point. The PostToolUse hook catches the rarer case where an agent edits package.json directly without running the install command.

Done when

• .claude/hooks/library-policy-nudge.sh exists, is executable, dispatches on CLAUDE_TOOL_USE_TYPE (or equivalent hook env var), and emits the reminder to stdout when a pnpm add/pnpm i <pkg> bash command is detected or when an Edit/Write tool targets a path matching **/package.json.
• The hook is registered in .claude/settings.json (or .claude/settings.local.json if per-repo convention) under both PreToolUse and PostToolUse event types, matching the registration pattern of generator-first-nudge.sh.
• The reminder text includes the literal string /evaluate-library and the argument template <name> --tier <feature|core|app> --target <package-path> so the agent sees the exact invocation.
• Bash smoke tests (same style as any existing hook tests): pipe a mocked Claude hook payload { "tool_input": { "command": "pnpm add foo" } } into the script and assert stdout contains the skill-reminder marker; pipe a payload for pnpm add -D foo (devdep) and assert no reminder emitted; pipe an Edit payload on src/feature.manifest.ts and assert no reminder emitted.
• pnpm lint && pnpm fallow:audit pass.

In scope

• .claude/hooks/library-policy-nudge.sh — the hook script.
• .claude/settings.json (or equivalent) — hook registration lines.
• Bash smoke tests for the hook script.

Out of scope

• Hook auto-deny or blocking behavior — the hook is advisory only (non-blocking system-reminder).
• Hooks for npm install / yarn add — the repo is pnpm-only.
• Integration with the skill implementation (Story 04) — the hook emits a text reminder; the skill is a separate file.

Tasks

• Investigate how generator-first-nudge.sh is registered (read .claude/settings.json and the existing hook script) to confirm the env-var names, payload shape, and registration keys; then write .claude/hooks/library-policy-nudge.sh + register it in the settings file + write bash smoke tests covering pnpm add <pkg> (reminder), pnpm add -D <pkg> (no reminder), Edit on non-package.json (no reminder), Edit on package.json (reminder); all gates pass on this single commit.