Register WP-0007 (Distribute), WP-0008 (Read-before-Edit), WP-0009 (Measure)

Three workplans queued and registered with the State Hub (via REST — MCP write
layer is erroring this session):
- AGENTIC-WP-0007 Phase 3 Distribute: per-flavor distributor adapters render
  approved catalog patterns into proposed (HITL) artifacts, scoped by repo/domain.
- AGENTIC-WP-0008 Read-before-Edit reflex: act on the #1 friction finding.
- AGENTIC-WP-0009 Phase 4 Measure: baseline + before/after effectiveness + trend.
Proceeding in that order.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

workplans/AGENTIC-WP-0009-session-memory-phase4.md

@@ -0,0 +1,68 @@
+---
+id: AGENTIC-WP-0009
+type: workplan
+title: "Coding Session Memory — Phase 4 (Measure: effectiveness + fleet trend)"
+domain: helix_forge
+repo: agentic-resources
+status: ready
+owner: codex
+topic_slug: helix-forge
+created: "2026-06-07"
+updated: "2026-06-07"
+state_hub_workstream_id: "99f1d836-3be0-40e5-9f17-63d3ecc5fcca"
+---
+
+# Coding Session Memory — Phase 4 (Measure)
+
+Implements **Measure** (PRD §6.5, FR-M1–FR-M3) — the loop-closer. After patterns
+are distributed (Phase 3) and changes land (e.g. the State Hub skill
+[STATE-WP-0058] and the Read-before-Edit reflex
+[AGENTIC-WP-0008](AGENTIC-WP-0008-read-before-edit-reflex.md)), Measure answers:
+**did it actually help?**
+
+Reuses what is already captured — WP-0005 tool buckets, WP-0006 error mining — so
+this is computation over existing digests, not new capture.
+
+## Baseline Metrics Module + Persisted Baseline
+
+```task
+id: AGENTIC-WP-0009-T01
+status: todo
+priority: high
+state_hub_task_id: "e5c2016a-2d51-4382-a013-7153e053e8ed"
+```
+
+`session_memory/measure/metrics.py`: compute fleet metrics over real sessions
+(infra-overhead share, error rate, recurring-error count, schema-thrash, cost
+percentiles) and persist a **timestamped baseline snapshot**. Reuses
+`detect.signals.tool_bucket` and the digest `error_snippets`. Unit-tested.
+
+## Before/After Per-Pattern Effectiveness
+
+```task
+id: AGENTIC-WP-0009-T02
+status: todo
+priority: high
+state_hub_task_id: "aa097a00-3462-41da-a137-67e1d61d8d33"
+```
+
+Given a change/pattern with an applied-at date, compare sessions **after** it
+against the pre-change baseline (cost, error rate, infra-overhead, success) to
+surface **per-pattern effectiveness** so ineffective patterns can be revised or
+retired (FR-M1/FR-M2). Unit-tested.
+
+## Fleet-Trend Report + Entrypoint + Tests
+
+```task
+id: AGENTIC-WP-0009-T03
+status: todo
+priority: medium
+state_hub_task_id: "f1147d59-2fb7-4d35-baec-b8f001bb9d62"
+```
+
+`python -m session_memory.measure`: fleet-level trend (is the median session
+getting cheaper / more reliable over time, FR-M3) plus per-pattern effectiveness;
+markdown + JSON. Document in `session_memory/README.md`. After updates, notify the
+operator to run `make fix-consistency REPO=agentic-resources`.
+
+[STATE-WP-0058]: handed off to the state-hub repo worker