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

Annotations already declare readOnlyHint=true and destructiveHint=false, so safety is covered. Description adds genuine value: name matches may be historical, and returns canonical IDs for filtering purposes. No contradiction with 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 tight sentences with purpose front-loaded in the first. The second sentence adds return-purpose and a historical-match caveat. Zero filler words; 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?

Complete for a read-only search tool: covers search criteria, return purpose, and caveats. No output schema exists, so per rules return values needn't be detailed. Minor gap is lack of explicit pagination/limit behavior, but schema defaults cover it.

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%, so the description must compensate. It does explain the query parameter's accepted formats (user ID, handle prefix, display name), which is valuable. However, limit and cursor pagination semantics are not addressed, and the description never names the parameters explicitly.

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?

Clear verb ('Find') + resource ('readable author candidates') + search criteria (platform user ID, handle prefix, stored display name). Distinguishes itself from get_author (fetch specific) by signaling discovery/filtering intent.

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?

Description implies usage context — search to obtain canonical IDs for filtering — but never explicitly contrasts with siblings like get_author or search_posts. No when-not-to-use guidance is provided.

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