Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already cover safety (readOnlyHint, idempotentHint, non-destructive), so the description earns credit for adding provenance and trust context: it is machine-generated from the build manifest and never hand-typed, and the stale flag reflects a recurring upstream verification. That tells the agent how to weight the data, which no annotation conveys. It doesn't state result size or whether the list can be empty in a fully-hosted environment.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Three sentences, each carrying distinct payload: field inventory, provenance, and absence semantics. The lead phrase 'Per-source coverage' front-loads the purpose efficiently. 'Current-through or vintage' is slightly jargon-heavy but is offset by the immediately following last_verified and stale-flag explanation.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

There is no output schema, so the description must carry the return-value burden, and it does: it names every meaningful field and explains the interpretation of the stale flag and of a missing source. For a zero-parameter, read-only listing tool with closed-world scope, nothing an agent needs in order to call it or read it correctly is absent.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The tool takes zero parameters and the schema is trivially complete, so there is nothing to disambiguate. The description correctly spends no words on inputs and instead describes the shape of the returned rows, which is the more useful information here.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description plus title clearly state this is a per-source inventory list, and it enumerates what each row contains (section counts, current-through/vintage, last_verified, stale flag). It implicitly separates itself from retrieval siblings by framing the result as coverage metadata rather than legal text, though it never names law_search or law_get_section as the tools to use once coverage is confirmed.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Strong negative-result guidance: 'Absence from this list means we do not host that jurisdiction's text, not that no law exists there' tells the agent exactly how to interpret an empty match before falling back to other tools. What's missing is an explicit positive routing statement such as 'call this first to confirm coverage before law_for_location or law_search.'

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.