Summary

Adds a new PreToolUse hook validate-issue-structure.sh that fires on gh issue create and enforces a body-shape schema per bracketed title prefix. Closes the gap where agents bypass the interactive /feature / /task / /bug skills and file raw gh issue create with bespoke body shapes.

The rule was already in .claude/rules/ticket-vocabulary.md and the individual skill docs, but until now it was self-discipline. This hook is the mechanical backstop: if the body doesn't have the required sections for its prefix, the issue-creation call exits 2 with a message naming the missing sections and pointing at the right skill.

• New hook: .claude/hooks/validate-issue-structure.sh (~340 LOC)
• Config integration: reads .ticket.required_sections + .ticket.skip_marker via the shared reader from [Chore] Make ticket-prefix whitelist + schema project-configurable (not hardcoded) #109. Extended .claude/project-config.defaults.json with the mapping (Feature → [User Story, Acceptance Criteria]; Chore/Refactor/Testing/CI → [Driver, Scope, Acceptance Criteria]; Docs → [Driver, Acceptance Criteria]; Bug → [Given / When / Then, Repro]).
• Wired into .claude/settings.json — PreToolUse matcher on Bash(gh issue create *).
• New section 11 in docs/rule-audit.md for the rule; mechanized count bumped.
• 15 test cases covering every prefix's pass + fail + the empty-section path + the skip marker.

How it works

1. Matches gh issue create only. Silent pass on everything else.
2. Parses --title and --body / --body-file / -F <path> (lifted the arg-extractor style from block-private-refs-in-public-repos.sh, with awk-based multi-line body handling so bodies with \n survive intact — sed is line-oriented and would have truncated).
3. Extracts the bracketed prefix ([Feature], [Chore], etc.), lowercases for the whitelist match, preserves canonical case for the required-sections lookup. Blocks if the prefix isn't whitelisted.
4. For each required section, greps for ## <name> (case-insensitive, with tolerance for ## Given/When/Then vs ## Given / When / Then vs ## given/when/then).
5. Empty-content check: after each heading, awk from the heading line to the next ## (or EOF) and strip whitespace — an empty range fails.
6. Skip marker: <!-- validate-issue-structure: skip --> in the body bypasses with a visible stderr WARN. For epics, meta-threads, parking-lot issues that don't fit the schema.
7. Silent pass conditions: no body (interactive gh issue create), prefix not in the schema, config completely absent.

Testing

$ bash .claude/hooks/tests/test_validate_issue_structure.sh
PASS: Feature with User Story + Acceptance Criteria → pass
PASS: Feature missing Acceptance Criteria → block
PASS: Chore with all three sections → pass
PASS: Chore missing Scope → block
PASS: Bug with Given / When / Then + Repro → pass
PASS: Bug with Given/When/Then compact heading → pass
PASS: Bug missing Repro → block
PASS: Feature with empty User Story section → block
PASS: skip marker bypasses validation
PASS: unknown title prefix → block
PASS: title without bracketed prefix → pass
PASS: non gh-issue-create command → no-op
PASS: gh issue create with no body → no-op
PASS: Docs with Driver + Acceptance Criteria → pass
PASS: --body-file path with valid Feature body → pass
Passed: 15  Failed: 0

Rebased cleanly onto the current dev HEAD after #111 landed — auto-merge of .claude/project-config.defaults.json (nested ticket subtree gained required_sections + skip_marker) and docs/rule-audit.md (new row at section 11). Both resolved without conflict.

Scope — what this does NOT do

• Does not touch the /feature / /task / /bug skill files — they already reference config in their Rules sections (landed in [Chore] Make ticket-prefix whitelist + schema project-configurable (not hardcoded) #109).
• Does not change validate-pr-create.sh — that's separate ([Chore] Require Testing section in PR body (extend validate-pr-create.sh) #113 / [Chore] Enforce single Closes-keyword per PR body (one ticket per PR) #114).
• --body-file - (stdin) shape is a known gap — the hook silently skips rather than trying to read stdin, same pattern as sibling hooks. Low frequency, noted in the header comment.

Follow-ups

• If short or generic prefixes emerge ([Infra], [Scaffold], [Design], [Security]) — teams extend by adding to .ticket.prefix_whitelist + .ticket.required_sections in their per-fork project-config.json. No framework edits required per apexyard#109's config-driven design.

Glossary

Closes #107