---
session_id: S-2026-0214-1951
timestamp: 2026-02-14T18:51:17Z
predecessor: S-2026-0214-1905
tasks_active: [T-058]
tasks_touched: [T-058, T-059]
tasks_completed: [T-059]
uncommitted_changes: 0
owner: claude-code
session_narrative: "Context recovery session. Picked up after context exhaustion killed the previous session mid-Phase-2. Verified all Phase 2 code was safely committed (76 tests passing). Ran full post-mortem: transcript analysis (72 agent spawns, 268K-532K byte outputs), damage assessment (zero code lost, stale handover), infrastructure research (strong recovery, zero prevention). Designed and implemented 5-layer defense-in-depth (T-059): CLAUDE.md P-009 rules, automatic tool-call counter hook, post-commit counter reset, emergency/checkpoint handover modes, pattern/practice records. Live-tested all layers successfully."
---

# Session Handover: S-2026-0214-1951

## Where We Are

Recovered from context exhaustion. All Watchtower Phase 1+2 code was safely committed. Implemented T-059 (context exhaustion protection) as defense-in-depth with 5 layers. Live-tested all layers — all pass. The `.claude/settings.json` hook will activate automatically on the next session. Watchtower Phase 3+4 remain.

## Work Done This Session

- **T-058 Phase 2**: Verified committed (commit `885408b`), 76 tests passing, server running on :3000
- **T-059**: Created and completed — 5-layer context exhaustion protection
- **Post-mortem**: Full root cause analysis with 3 parallel investigation agents

## Work in Progress

### T-058: Watchtower Command Center - Design Spec
- **Status:** started-work
- **Last action:** Phase 2 committed (kanban board, session cockpit, write actions)
- **Next step:** Phase 3 — Operational Intelligence (live metrics, error escalation viz, pattern browser)
- **Blockers:** None
- **Insight:** Parallel agent strategy works but burns context fast — use sparingly per P-009

## Gaps Register

**3 spec-reality gap(s) being watched** — see `.context/project/gaps.yaml`

- **G-001** [high]: Enforcement tiers are spec-only
- **G-004** [low]: Multi-agent collaboration untested
- **G-005** [medium]: Graduation pipeline has no tooling

Run `fw audit` to check if any trigger conditions are met.

## Decisions Made This Session

1. **Use tool-call count as context proxy (not tokens)**
   - Why: Token counting not exposed by Claude Code; tool calls are countable and correlate
   - Alternatives rejected: Token estimation heuristic, time-based warnings

2. **Never block tool calls from hooks (always exit 0)**
   - Why: Blocking could prevent the emergency handover itself from executing
   - Alternatives rejected: Block at critical threshold

3. **Post-commit resets counter (not handover)**
   - Why: Commits are real safety checkpoints; rewards commit-often behavior
   - Alternatives rejected: Reset only on handover generation

4. **Emergency handover has zero See git log sections**
   - Why: Works when AI cannot act — all data machine-gathered
   - Alternatives rejected: Reduced See git log count

## Things Tried That Failed

1. **None this session** — all implementations worked on first attempt

## Open Questions / Blockers

1. Are thresholds 40/60/80 correctly calibrated? Need real-world data from next session
2. Does stderr output from hooks actually appear in Claude Code conversation? (Untested in live hook)
3. Does the hook add perceptible latency? (checkpoint.sh is simple filesystem I/O, should be <10ms)

## Gotchas / Warnings for Next Session

- `.claude/settings.json` hook activates on session start — first session after this one will be the real test
- Run the test plan at `.context/working/context-protection-test-plan.md`
- Counter file `.context/working/.tool-counter` is gitignored (ephemeral)
- Post-commit hook v1.1 needs `fw git install-hooks --force` if hooks are reinstalled
- The test commit `3153ed3` is a no-op (just added a blank line to T-058)

## Suggested First Action

Check `.context/working/.tool-counter` after the first few tool calls to verify the PostToolUse hook is firing. Then follow the test plan at `.context/working/context-protection-test-plan.md`. After validation, continue with Watchtower Phase 3.

## Files Changed This Session

- Created: `agents/context/checkpoint.sh`, `.claude/settings.json`, `.context/working/context-protection-test-plan.md`
- Modified: `CLAUDE.md` (P-009), `agents/handover/handover.sh` (--emergency/--checkpoint), `agents/git/lib/hooks.sh` (post-commit v1.1), `bin/fw` (help text), `.context/project/practices.yaml` (P-009), `.context/project/patterns.yaml` (FP-004, SP-003), `.gitignore`
- Completed: `T-059` (moved to `.tasks/completed/`), `.context/episodic/T-059.yaml`

## Recent Commits

- 3153ed3 T-058: Test post-commit hook counter reset
- 995c59f T-059: Complete task and enrich episodic summary
- 7ea5302 T-059: Implement defense-in-depth against context exhaustion
- 7aa70ab T-058: Log Phase 2 completion in task journal
- 885408b T-058: Implement Watchtower Phase 2 — kanban board, session cockpit, write actions

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## Handover Quality Feedback (for next session to complete)

- Did this handover help? [ ]
- What was missing?
- What was unnecessary?
