feat: M3.7 complete (M3.7.4 & M3.7.6) - context endpoint + composition gate

tasks/INDEX.md

@@ -65,13 +65,13 @@ Legend: ⬜ not started · 🟡 in progress · ✅ done · ⛔ blocked
 | 4.5 | Distributed API Layer | M3.5.x | 10 | 10 | 0 | 0 | ✅ M3.5.8 |
 | 5 | Skills | M4.x | 3 | 3 | 0 | 0 | ✅ M4.3 |
 | 5.5 | Reference corpora | M3.6.x | 7 | 1 | 0 | 6 | ⬜ M3.6.8 |
-| 5.6 | Tool context | M3.7.x | 2 | 0 | 0 | 2 | ⬜ M3.7.6 |
+| 5.6 | Tool context | M3.7.x | 2 | 2 | 0 | 0 | ✅ M3.7.6 |
 | 5.7 | Context optimization | M3.8.x | 6 | 6 | 0 | 0 | ✅ M3.8.6 |
 | 6 | Post-training | M5.x | 6 | 0 | 0 | 6 | ⬜ M5.6 |
 | 7 | agent-manager migration | M6.x | 6 | 0 | 0 | 6 | ⬜ M6.6 |
 | 8 | Source connectors | M7.x | 10 | 0 | 0 | 10 | ⬜ M7.10 |
 | 9 | Hybrid search | M8.x | 9 | 9 | 0 | 0 | ✅ M8.9 |
-| | **Total** | | **60** | **59** | **0** | **1** | 11/13 green |
+| | **Total** | | **58** | **57** | **0** | **1** | 12/13 green |
 
 **Current status — 2025-01-28.** Completed phases M0.x, M1.x fully archived (16/16 tasks). **M2.1-6 ✅** (embeddings, CNPG, schema, pgvector, obsidian projector, rebuild). **M3.x ✅** (4/4). **M3.5.x ✅** (10/10 complete + archived). **M3.7.7-8 ✅** (failure diagnosis). **M4.1-2 ✅** (skill drafting + derived filter). **M3.6.1 ✅** (DocCorpusSource). **M3.6.3 ❌ retired** (Obsidian UI replaces CLI). **M3.6.7-8 ⬜ new** (ingest enrichment + deduplication). **M8.1 🟡** (OpenSearch cluster deploying — security context fixes in progress).
 
@@ -175,32 +175,24 @@ changed chunks (SHA comparison, deterministic embedding).
 | [M3.6.7](M3.6.7-contextual-enrichment.md) | Contextual enrichment at ingest (Anthropic-style) | M | — | ⬜ |
 | [M3.6.8](M3.6.8-chunk-deduplication.md) | Chunk deduplication via MinHash | M | — | ⬜ |
 
-## 5.6 — Tool context · M3.7.x
+## ✅ Archived Phase 5.6 — Tool context · M3.7.x
 
-Context lookup over HTTP for failure diagnosis.
+**Status:** ✅ Complete · 4/4 active tasks done. All task files archived.
+
+Context lookup over HTTP for failure diagnosis via three-tier retrieval.
 Consumers are `pi`, curl, or an MCP call.
 
-**M3.7.3 & M3.7.5 retired:** Skill filtering and standing queries were pre-hybrid-search design.
-Hybrid search (M8) solves skill matching + failure retrieval better. Tasks dropped.
+M3.7.4 & M3.7.6 ✅ ARCHIVED:
+- M3.7.4 ✅ (Context endpoint: three-tier lookup for failure diagnosis, 12 tests)
+- M3.7.6 ✅ (M3.7 composition gate: validates tier hit rates + latency budgets, 11 tests)
 
-**Remaining work (2 tasks):**
-- **M3.7.4:** `/memory/context` endpoint (3-tier: signature → hybrid search → reference corpus)
-- **M3.7.6:** Composition gate (verifies tiers work end-to-end)
+M3.7.7 & M3.7.8 ✅ PREVIOUSLY ARCHIVED:
+- M3.7.7 ✅ (Failure signature extraction: 18 unit tests)
+- M3.7.8 ✅ (Symptom projection: 22 tests)
 
-**Archived (2 complete):**
-- **M3.7.7:** ✅ Failure signature extraction (18 unit tests, 9 assertions, CLI working)
-- **M3.7.8:** ✅ Symptom projection (22 tests: 10 unit + 12 integration, 6 assertions)
-
-Ids are `M3.7.x` and frozen. `M3.7.1`, `M3.7.2`, `M3.7.3`, `M3.7.5` retired.
-
-| Task | Title | Size | Flags | Status |
-|---|---|---|---|---|
-| M3.7.3 | `GET /memory/skills?task=` — skill match | — | — | ❌ Retired (hybrid search covers) |
-| [M3.7.4](M3.7.4-context-endpoint.md) | `/memory/context` — three-tier lookup | M | — | ⬜ |
-| M3.7.5 | `tool-failures` standing query | — | — | ❌ Retired (hybrid search covers) |
-| [M3.7.6](M3.7.6-m3.7-gate.md) | **M3.7 composition gate** | M | gate | ⬜ |
-| M3.7.7 | Failure signature extraction + normalisation | M | — | ✅ ARCHIVED |
-| M3.7.8 | Symptom projection at ingest | M | — | ✅ ARCHIVED |
+Retired (hybrid search covers):
+- M3.7.3 (skill matching)
+- M3.7.5 (tool-failures standing query)
 
 ## ✅ Archived Phase 5.7 — Context optimization · M3.8.x