Worker checks

metewand check --workers extends the ordinary repository check by launching trusted local workers. Use it before a benchmark run to verify protocol support and exercise each problem's independent evaluator:

metewand check --workers
metewand check --manifest path/to/metewand.yaml --workers --output json

The command resolves every declared generated-dataset materializer, implementation, and problem evaluator before launching any worker. It checks local executor requirements and negotiates each worker's protocol role and content identity. Every declared implementation capability must appear in the worker's hello response. The report labels selected capabilities verified_now and also records additional reported capabilities without selecting them. Fixed datasets have no worker to negotiate.

For every problem, the command evaluates all reference cases in contract order. The evaluator receives the problem definition's parameter-defaults, or an empty object when defaults are absent. These parameters must satisfy the contract's parameter schema. Reference cases therefore need to describe that configuration, independently of experiment parameter matrices.

Reference paths resolve from the repository root. A dataset reference may name a directory containing dataset-manifest.json and its declared files, or a single data file. For a single file or a directory without an inventory, Metewand creates the same complete inventory used for fixed datasets. The inventory must satisfy one of the contract's accepted dataset schemas. Dataset-free cases omit dataset and receive an empty directory.

A result reference may name an artifact directory containing result.json, a result envelope file, or a file containing only scientific result data. A raw data file is wrapped in a version-1 result envelope with the contract's result schema and no auxiliary files. Expected metrics similarly accept a metrics envelope or raw metric data, either as a file or in a directory containing metrics.json. Envelopes and scientific data must satisfy their public and problem-owned schemas. References with auxiliary result files must use an artifact directory.

The evaluator must return reached and write schema-valid metrics whose canonical data exactly match the expected metrics. The command rejects malformed artifacts, missing capabilities, protocol failures, nonmatching metrics, and changes to staged reference inputs or resolved worker inputs. Repository identities are checked again before reporting success.

All staging and evaluator outputs live in temporary directories. The command does not execute implementation callbacks, materialize generated datasets, fetch remote sources, install packages, create a cache, or publish a run. Workers use the existing trusted local execution boundary, bounded logs, phase deadlines, and process cleanup. Environments that require provisioning fail explicitly, as they do for the current local run path.

Human, JSON, and JSON Lines output come from the same report. A successful worker check adds workers and reference_cases to the ordinary check result, and worker_launches counts negotiated workers. Each worker entry includes its component, role, resolved identity, evidence, selected capabilities, and reported capabilities. Each reference entry includes the problem name, zero-based case index, and matching metrics. A failure emits the stable worker_check_failed diagnostic and exits with status 3. Plain check retains its side-effect-free behavior and emits neither worker evidence nor reference execution results.

This adds an optional version-1 machine result shape and conformance vectors. The public schema compatibility version remains 1 because existing check results and envelopes remain valid. Manifest, identity, execution-semantics, and wire-protocol compatibility versions are unchanged: the command uses their existing contracts without changing their representations.