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

It adds meaningful behavior beyond the annotations: the return payload includes evidence reasons, freshness, digests, and explicit limits, and the refresh=if_stale path requires an x-api-key. Annotations already indicate the tool is not read-only, not idempotent, and not destructive, so the description supplements rather than contradicts them.

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?

The description is tight and front-loaded: outcome, scope, then a key auth constraint. Each sentence provides distinct, non-redundant information with no filler.

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?

With an output schema available and only one required parameter, the description covers the main invocation concerns: what the tool returns, its role as a preflight gate, and the special auth condition. The main remaining gap is clearer semantics for policy_id and refresh, but the overall definition is sufficient for selecting and invoking the tool.

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?

Schema description coverage is only 33%, and only server_name is documented in the schema. The description partly compensates by explaining that refresh=if_stale requires an API key and that policy_id relates to a 'documented built-in install policy,' but the enum meanings for policy_id and refresh are still mostly left to inference.

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 states a specific verb ('Evaluate') and a clear object ('one exact MCP server under a documented built-in install policy'), and it defines the outcome categories (PASS, REVIEW, BLOCK). This separates it well from sibling census tools like census_lookup or census_policy_list.

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?

The description explicitly frames this as 'a first gate, not a security audit,' giving the agent a clear sense of when in a workflow to use it. It does not explicitly name sibling alternatives, but the first-gate framing provides adequate selection context.

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