Assignment coordination for hosts#

Hosts can consume the kit-neutral assignment primitive through three package subpaths:

The package version versions these exports. Claim records independently carry schema_version: "1.0" and role: "AssignmentClaimRecord". The codec preserves unknown fields and emits two-space JSON plus a newline, matching the local writer. Its decoder checks the version envelope, with an optional role check; it is not full record validation. Hosts writing records can call findAssignmentClaimRecordProblems for required-field diagnostics. Byte round trips apply to canonical writer output, not arbitrary JSON whitespace. GitHub parsing applies the existing display sanitization; use the core codec for lossless record transport.

Subject identity and optional work_item_ref are opaque in the core. Only the GitHub renderer requires an issue-shaped reference. The local provider retains its existing sanitized, 64-character filename mapping: hosts must select subject keys that do not collide under sanitizeSegment.

Supply AssignmentLivenessSource.freshHolders from the host runtime. It returns only fresh holders, excludes the requesting actor, and uses canonical actor keys. resolveEffectiveState joins that reading with provider status: a live agent holds work, an absent agent makes it reclaimable, a human stays human-held, and absent assignment and liveness mean free. The stored actor_key takes precedence over re-serialized actor identity. Human-held work is never automatically eligible for takeover. decideTakeover returns eligibility and the required grace action; callers wait one heartbeat interval and re-read before superseding. The helper does not enforce a transaction or authorize a mutation. Builder retains when to claim/release and how to resume.

Host selection remains a separate integration requirement#

These exports let a host implement a shared store and supply liveness. They do not select that implementation for a Builder run. Current assignment settings accept only github and local-file; there is no public environment/MCP provider registration seam. ensure-session --assignment-provider <kind> --effective-state-json <path> accepts provider evidence, but still creates a local ownership mirror, and selected-work/lifecycle evidence reads that mirror. The original export proposal also leaves this path unchanged.

Consequently a host-selected Builder run with zero local claim files is not supported by this extraction. The bounded follow-up must define authoritative host-provider selection, selected-work provenance and lifecycle ownership/fencing together, then prove claim/release/resume use that store without a second local claim. Hosts must not infer this behavior from the provider interface or use evidence snapshots as a live authority bridge. No Station runtime or registry publication is proven here.

The detailed operations and existing CLI behavior are specified in the assignment provider contract.