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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint=false and destructiveHint=false, so the safety profile is fully covered and the description does not contradict it. What is left undisclosed is matching behavior (prefix vs substring vs fuzzy), result limits, and whether results span all agents in the account — context an agent picking a mention would want.

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?

One sentence, front-loaded with the verb and scope, ending with the concrete context of use. Nothing is redundant and nothing could be cut without losing meaning.

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 one-parameter read-only lookup with an output schema (so return values need no explanation) and rich annotations, the description covers purpose, match field, and use context. The only residual gap is how matching and result capping work.

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 0% and the single `query` parameter carries only a maxLength constraint, so the description must compensate. "By name" usefully narrows the query to an agent name rather than arbitrary text, but matching semantics and case sensitivity remain unstated.

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 ("Search the account's agents"), plus the match field ("by name") and the consumer (the composer @-mention picker). That implicitly distinguishes it from list_agents and get_agent, though it never names a sibling explicitly.

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 phrase "for the composer @-mention picker" scopes usage to a specific UI flow, which is real implied guidance. There is no explicit statement of when not to use it, nor a pointer to list_agents for browsing agents outside the picker.

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