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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is covered. The description adds genuinely non-obvious behavior beyond that: ranking is 'by relevance only, never by payment,' and the matching is lexical rather than semantic — both materially shape expectations about result ordering and recall.

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 tight sentences with zero filler, and the searchable-scope clause is front-loaded before the ranking caveat. Every clause carries information the agent cannot get from the schema or annotations.

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 two-parameter search tool with no output schema, the definition is workable but thin: it omits any handling of limit, pagination, or what the result set contains. The rule relaxing return-value explanation only applies when an output schema exists, so the absence here leaves a small but real gap.

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 coverage is 50%: query is documented ('at most 500 characters') while limit has no description at all despite being capped at 50. The description compensates partially by enumerating which fields the query is matched against, which clarifies what query strings should target, but it says nothing about the limit parameter.

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 verb and resource ('Lexical search over capability names, summaries, tasks and use-when conditions'), and the field list makes the search scope concrete. It does not name or differentiate against siblings such as get_capability or compare_capabilities, so an agent must infer this is the keyword-search entry point rather than a lookup or comparison.

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?

No when-to-use guidance is given: nothing says to use this for discovery versus get_capability for a known ID, or when to prefer compare_capabilities. There are no exclusions, prerequisites, or escalation paths to alternatives.

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