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

Annotations already cover read-only, idempotent, non-destructive, and closed-world. The description adds meaningful context beyond that: the 7-day staleness threshold and stale flag, warnings[] surfacing stale snapshots, the fact that names are never logged, and that matching is deterministic/offline with no AI. That is real behavioral disclosure, not restatement.

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?

Front-loaded with the per-list payload, then the response envelope, then the covered lists, then the usage trigger and privacy note — a sensible ordering. It is dense and slightly run-on (a comma-separated inventory in the opening sentence), but almost every clause carries actionable information, so little is wasted.

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?

For a zero-parameter, read-only status tool with rich annotations and an output schema, nothing an agent needs is missing: it knows the covered lists, the staleness rule, the warning mechanism, and when to consult it. The response-field enumeration mildly duplicates the output schema but reinforces rather than omits.

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, so there is no parameter semantics to convey and the baseline of 4 applies. Nothing in the description is needed to clarify inputs, and nothing misleads.

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?

States a specific resource (freshness and provenance of every bundled list) and enumerates exactly what is reported per list: entries, aliases, fetched_at, days_since_fetch, source URL, SHA-256, licence, and refresh failures. This reads as metadata/status, clearly distinct from the screening siblings (screen_name, screen_batch, explain_match).

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?

Gives an explicit trigger: 'Call it before relying on a "clear" result in a regulated process.' That is a concrete when-to-use condition. It does not, however, name alternatives or state when not to call it, so it stops short of full routing guidance.

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