hank-model-authority

The model authority every product repository reads: which models exist (registry entries with their execution identity and per-family request facts), which model each capability uses (selection policy), and what each model costs (rate tables). The distribution depends on PyYAML and pydantic only, so Risk, Investment and Edgar take it without the gateway.

Design and rollout: docs/design/model-authority-registry-as-data-artifact-design-2026-09-29.md and its implementation plan.

Layout

The package root imports types and the loader, never current, so python -m model_authority check <dir> can check a candidate directory while the host directory is broken.

Which directory a process loads

HANK_MODEL_AUTHORITY_DIR set: that directory, resolved once at start; missing or unreadable fails the start. Unset: the packaged authority/ directory. Every loading unit sets it — /etc/hank/model-authority in production, ~/.config/hank/model-authority on this Mac — so the packaged copy is what tests and unwired tools load. Every process reports what it admitted through health_fact(): {"revision", "schema", "sha256", "source", "loader", "admits"}; source is the resolved release path (…/model-authority.d/<revision>-<sha12>/…) or packaged:<path>.

Schema

This loader implements model-authority/2.1 and admits 2.0 and 2.1 artifacts (health_fact()["admits"] is model-authority/2.0-2.1). Each entry's compat: key set is its protocol family's (schema.py, design §4d). 2.1 adds two anthropic.messages keys, each derived when absent so 2.0 artifacts load unchanged, and each refused when it contradicts the 2.0 key it refines:

The 2.0 keys stay required (a minor removes nothing), so an adapter that still reads can_disable or forced_tool_choice_requires_thinking_off keeps working; the gateway's Anthropic adapter reads both new keys. Sonnet 5.5 uses can_disable: false, off_value: between_tools: the legacy bool still means whether the literal thinking.type: disabled is legal.

Changing it

• A data change (a model, a default, a price, a compat value) edits authority/ and ships by scripts/deploy_model_authority.sh, not by a release (runbook). Declare the lowest schema minor that covers the fields the artifact uses.
• A schema change is a release: a new optional field or literal is a minor (SCHEMA_MINOR), a removal or redefinition a major. Deploy loaders before data that uses a new minor: a loader refuses an artifact whose minor is newer than its own, naming both.
• A capability or its executing process is a release (capabilities.py).

Check a candidate directory with the ordinary load:

python -m model_authority check <dir>   # prints the health fact, or exits 1 with the refusal

Tests: .venv/bin/python3 -m pytest packages/model-authority/tests -q (make test-area AREA=model_authority).