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

Annotations already declare the safe-read profile (readOnly, idempotent, non-destructive), so the description's real contribution is behavioral: it discloses ranked output ('best match first') and that the index spans both agents and plans. It does not cover result limits or pagination, but adds meaningful context beyond the annotations.

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, zero filler, with the ranked-retrieval behavior front-loaded before the usage example. 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 two-parameter search tool with full schema coverage, rich annotations, and no output schema, the description covers purpose, intent, and ranking adequately. Minor gaps remain around result volume/pagination, but nothing essential to correct invocation is missing.

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 both parameters (query, lang) are already documented, giving a baseline of 3. The description reinforces query semantics as keyword-based and free-form ('in their words') but adds no syntax, length, or language-handling detail beyond the schema.

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 (keyword search), the resource (agents and plans), and the ordering semantics (best match first), which implicitly contrasts with the enumeration siblings list_agents/list_plans. It stops short of naming those siblings explicitly, so the differentiation is inferred rather than stated.

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 second sentence gives a clear when-to-use context ('find the agent for a task') plus two concrete example queries that anchor intent. There is no guidance on when to prefer list_agents/get_agent instead, so exclusions are absent.

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