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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint, so safety is covered. The description adds valuable non-obvious behavior: results are 'active listings', 'ranked by relevance', and are 'public data only — never the private access link', which is privacy-critical context beyond what annotations express. This exceeds the baseline for annotation-covered tools.

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?

Two sentences with no filler. The first sentence leads with the action and resource, and the second adds the output and privacy characteristics. Every clause earns its place.

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 3-parameter tool with 100% schema descriptions, an output schema, and rich read-only annotations, the description is fully complete. It adds the only missing context: active listing status, relevance ranking, and the public-only privacy guarantee.

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 100%, so query, limit, and offset are already fully documented in the input schema. The description adds nothing about parameters beyond restating that the query is natural language, which the schema already covers. Baseline 3 is appropriate because the schema does the heavy lifting.

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 ('Search') and a specific resource ('Buy My Agent marketplace catalogue') with a clear scope: natural-language query, active listings, relevance ranking. It distinguishes from the sibling 'list_agents' implicitly through 'by natural-language query' and 'ranked by relevance', but it never names a sibling or explicitly contrasts itself, which keeps it from a 5.

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 implies the appropriate use case (searching a catalogue with plain-language queries) but provides no explicit guidance on when to choose this tool over alternatives like list_agents or get_agent. There are no exclusions, alternatives, or conditions, so the usage context is only implied rather than stated.

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