Design the OKF task concept type + seed the board

Agentic "sprint board" architecture — a git-resident OKF task board worked by bounded, hook-governed Agent SDK loops approved the agentic board as a direction and explicitly deferred the schema: "a new OKF task concept type to be designed in Dossier — The Knowledge Model (v0) — hand-off to the Principal Knowledge-Format Architect; the schema is NOT designed here." This task closes that hand-off.

Scope

• Model: extend Dossier — The Knowledge Model (v0) with the task type — the spine (status / priority / owner / assignee / dependencies / acceptance_criteria), the coordination pair (claimed_by + lease_expires), and a "process vs workflow vs task" note. Conform to the base frontmatter exactly; id immutable; provenance always.
• Schema-as-code: mirror it in @dossier/okf (TaskSchema after DecisionSchema; wire builtinSchemas / builtinTypes / the registry exhaustive map / the barrel exports; add the task keys to io.ts KEY_ORDER; infer TaskAtom). status is free text (z.string), not an enum — verticals must extend without forking (Dossier — The Knowledge Model (v0) "Extensible by design").
• Seed: create tasks/index.md, tasks/log.md, and real seed task atoms drawn from Dossier's actual backlog (this very board).

Notes

This is itself a board task — Dossier dogfooding the board on the work of building the board. The done transition belongs to Principal Platform Architect/Adversarial QA & Knowledge-Integrity Reviewer once typecheck + tests are green and the model reads cleanly. Unblocks Build the PreToolUse claim/lease governance hook (the hook needs the claimed_by/lease_expires field contract this defines).

Closed 2026-06-17

The work landed in Agentic board v1 — build the git-resident OKF task board (deterministic offline core, SDK reserved), resolving DEC-0024's four open questions and dogfooding Dossier's own repo first (the build that designed the task type into Dossier — The Knowledge Model (v0) + the @dossier/okf schema-as-code and seeded this board). That decision's own Verification block recorded the criteria green; this card simply never got flipped — the canonical instance of the "progress happens in commits, but the atom's status is hand-edited and forgotten" pattern. Re-verified green this session (okf 143 / runtime 60) and the model reads cleanly, so the gate-condition above is met. Closed by the Principal Forward Deployed Engineer as board-hygiene while diagnosing why the board wasn't closing out backlog items.