docs: add state hub agent skill workplan

workplans/STATE-WP-0058-agent-skill-hub-interaction.md

@@ -0,0 +1,85 @@
+---
+id: STATE-WP-0058
+type: workplan
+title: "State Hub Agent Skill — front-load tool schemas + batched writes"
+domain: custodian
+repo: state-hub
+status: ready
+owner: codex
+topic_slug: custodian
+created: "2026-06-07"
+updated: "2026-06-07"
+state_hub_workstream_id: "163b5646-163e-41a0-b60d-c402b578a4d1"
+---
+
+# State Hub Agent Skill — front-load tool schemas + batched writes
+
+**Origin:** requested by the `helix_forge` domain from a data-driven friction
+assessment of captured agent coding sessions
+(`agentic-resources/docs/ASSESSMENT-infra-friction.md`, AGENTIC-WP-0005). Across
+27 real coding sessions, **~17.6 % of all tool calls were hub/task/schema
+plumbing**, and `ToolSearch` (loading the *deferred* State Hub MCP tool schemas)
+fired in **22 of 27 sessions (81 %)**. State Hub MCP alone was 10.3 % of calls,
+with one session making **231 hub calls**.
+
+This workplan cuts that overhead at the source. Two levers:
+
+1. **Front-load tool knowledge** so agents stop re-discovering hub tool schemas
+   via `ToolSearch` every session.
+2. **Batch the writes** so a session makes a handful of coarse hub calls instead
+   of hundreds of fine-grained ones.
+
+Effectiveness will be re-measured later by Helix Forge against the recorded
+baseline (infra-overhead share: median 11.7 %, p90 26.1 %; `ToolSearch` in 81 %
+of sessions).
+
+## Skill Scaffold — Front-load Common Hub Tool Schemas
+
+```task
+id: STATE-WP-0058-T01
+status: todo
+priority: high
+state_hub_task_id: "6f211ccc-e505-419d-90cc-25874ba98f39"
+```
+
+Author a Claude Code skill (`SKILL.md` + supporting reference) for State Hub
+interaction that front-loads the high-frequency tool signatures so agents do not
+re-discover them via `ToolSearch`. Cover at minimum: `get_domain_summary`,
+`create_workstream`, `create_task`, `update_task_status`, `add_progress_event`,
+`record_decision`, `get_messages` / `send_message` — with argument signatures, the
+session-start orientation flow, and the ADR-001 files-first boundary (hub is a read
+model). Directly targets the `ToolSearch`-thrash finding.
+
+## Batched Writes + Bulk Task-Status Sync Op
+
+```task
+id: STATE-WP-0058-T02
+status: todo
+priority: high
+state_hub_task_id: "2138505a-ea49-4ccc-9dec-a176badaa7a5"
+```
+
+Add a **bulk task-status sync** endpoint/op so a session updates N task statuses in
+one call instead of N (the single biggest call-volume driver — one session made
+231 hub calls). Document batched-write guidance in the skill: fewer, coarser
+progress events; sync at checkpoints, not per event. Keep the hub a read model and
+preserve the automatic `progress_event` semantics on each write.
+
+## Validate Against Friction Baseline + Coordinate Back to helix_forge
+
+```task
+id: STATE-WP-0058-T03
+status: todo
+priority: medium
+state_hub_task_id: "cf8d41f8-7831-4c1b-9dfa-58660174294b"
+```
+
+Verify the skill + bulk op reduce plumbing overhead (dry-run a representative
+session flow; confirm `ToolSearch` calls drop and task updates batch). Reply to the
+helix_forge coordination message with completion and the new bulk-op signature so a
+later Measure pass can compare infra-overhead share against the baseline. After
+workplan updates, notify the operator to run from `~/state-hub`:
+
+```bash
+make fix-consistency REPO=state-hub
+```