feat(agents): add analysis paralysis guard, exhaustive cross-check, and task-level TDD (#736)

- gsd-executor: Add <analysis_paralysis_guard> block after deviation_rules.
  If executor makes 5+ consecutive Read/Grep/Glob calls without any
  Edit/Write/Bash action, it must stop and either write or report blocked.
  Prevents infinite analysis loops that stall execution.

- gsd-plan-checker: Add exhaustive cross-check in Step 4 requirement coverage.
  Checker now also reads PROJECT.md requirements (not just phase goal) to
  verify no relevant requirement is silently dropped. Unmapped requirements
  become automatic blockers listed explicitly in issues.

- gsd-planner: Add task-level TDD guidance alongside existing TDD Detection.
  For code-producing tasks in standard plans, tdd="true" + <behavior> block
  makes test expectations explicit before implementation. Complements the
  existing dedicated TDD plan approach — both can coexist.

Co-authored-by: CyPack <GITHUB_EMAIL_ADRESIN>
Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>

agents/gsd-executor.md

@@ -171,6 +171,16 @@ Track auto-fix attempts per task. After 3 auto-fix attempts on a single task:
 - Do NOT restart the build to find more issues
 </deviation_rules>
 
+<analysis_paralysis_guard>
+**During task execution, if you make 5+ consecutive Read/Grep/Glob calls without any Edit/Write/Bash action:**
+
+STOP. State in one sentence why you haven't written anything yet. Then either:
+1. Write code (you have enough context), or
+2. Report "blocked" with the specific missing information.
+
+Do NOT continue reading. Analysis without action is a stuck signal.
+</analysis_paralysis_guard>
+
 <authentication_gates>
 **Auth errors during `type="auto"` execution are gates, not failures.**
 

agents/gsd-plan-checker.md

@@ -445,6 +445,8 @@ Session persists     | 01    | 3     | COVERED
 
 For each requirement: find covering task(s), verify action is specific, flag gaps.
 
+**Exhaustive cross-check:** Also read PROJECT.md requirements (not just phase goal). Verify no PROJECT.md requirement relevant to this phase is silently dropped. Any unmapped requirement is an automatic blocker — list it explicitly in issues.
+
 ## Step 5: Validate Task Structure
 
 Use gsd-tools plan-structure verification (already run in Step 2):

agents/gsd-planner.md

@@ -234,6 +234,26 @@ This prevents the "scavenger hunt" anti-pattern where executors explore the code
 
 **Why TDD gets own plan:** TDD requires RED→GREEN→REFACTOR cycles consuming 40-50% context. Embedding in multi-task plans degrades quality.
 
+**Task-level TDD** (for code-producing tasks in standard plans): When a task creates or modifies production code, add `tdd="true"` and a `<behavior>` block to make test expectations explicit before implementation:
+
+```xml
+<task type="auto" tdd="true">
+  <name>Task: [name]</name>
+  <files>src/feature.ts, src/feature.test.ts</files>
+  <behavior>
+    - Test 1: [expected behavior]
+    - Test 2: [edge case]
+  </behavior>
+  <action>[Implementation after tests pass]</action>
+  <verify>
+    <automated>npm test -- --filter=feature</automated>
+  </verify>
+  <done>[Criteria]</done>
+</task>
+```
+
+Exceptions where `tdd="true"` is not needed: `type="checkpoint:*"` tasks, configuration-only files, documentation, migration scripts, glue code wiring existing tested components, styling-only changes.
+
 ## User Setup Detection
 
 For tasks involving external services, identify human-required configuration: