version: "1.0.1" name: swarm description: 'Dispatch explicit disjoint packets exactly once through a caller-selected executor. Triggers: "swarm", "dispatch disjoint packets", "parallel explicit tasks".' practices: [team-topologies, design-by-contract] hexagonal_role: driving-adapter consumes: [explicit-disjoint-packets] produces: [per-packet-results] context_rel: [] skill_api_version: 1 user-invocable: true metadata: tier: execution dependencies: [] capabilities: [dispatch_once] effects: [invoke_selected_executor] canonical_status: canonical disposition: keep_optional_adapter output_contract: per-packet candidate, evidence, or error

Swarm

Swarm exposes one optional factory port:

dispatch_once(explicit_disjoint_packets, executor)
  -> per-packet candidate | evidence | error

The caller supplies every complete packet, proves their write scopes disjoint, and chooses the executor. Swarm dispatches each packet once, preserves packet and context identities, collects results, and stops.

Write scopes must be workspace-relative and canonical — symlink-resolved and already normalized. The disjointness check is lexical: it case-folds prefixes so scopes differing only by case are treated as a collision (safe on case-insensitive filesystems), but it cannot see a symlink that aliases two scopes onto one target. Supplying non-canonical or symlinked scopes forfeits the disjointness guarantee; a non-empty write_scope.exclude is rejected, not silently ignored, because the proof cannot honor it.

Exactly-once dispatch over proven-disjoint scopes is why parallel failures stay independent: no packet can observe, block, or corrupt another, so N packets yield N verdicts about N experiments rather than one tangle.

Named failure mode — partial-batch launch: dispatching valid packets before discovering an invalid one, leaving the batch half-run; validate the entire batch before the first call.

Anti-pattern: re-dispatching a packet whose executor returned an error. Corrective: return the error as that packet's factual result; retry is the caller's decision, not the dispatcher's.

The reference implementation is `scripts/dispatch_once.py`. It validates the entire explicit batch before the first call, invokes the supplied executor exactly once for each packet, and returns executor exceptions as factual per-packet errors.

Swarm's own effect is invoking the selected executor once per packet; the real blast radius rides on the packets. Each packet's transitive effects — whatever its executor writes, runs, or reaches — are the caller's to declare on the packet, not Swarm's to bound.

Swarm does not select work, create packets, schedule from a backlog, persist a queue, claim ownership, retry, validate, integrate, close, use Git, or deliver. Executor failures remain executor evidence and cannot become core phase or verdict state.