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

Annotations already establish this as a safe, idempotent, closed-world read, so the bar is lower; the description still adds real context: key algorithms, encoding, that revoked keys are included in the result, and that fingerprints should be verified out of band. It does not explain result ordering or what is returned when no lookup key is supplied.

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?

Three dense sentences, front-loaded with what the tool returns, with no filler. The telegraphic, verbless phrasing of the first sentence costs a little readability but nothing is wasted.

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?

With no output schema, the description carries the return-value burden and does so by naming each field and its algorithm, which is exactly what an agent needs to interpret the response. Combined with the annotation-covered safety profile, the only minor omission is behavior with no arguments.

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 100%, so both parameters are already documented; the description only echoes the comma-separated batch format and the 50-item cap the schema states, without clarifying the single-name vs batch-names precedence or the no-argument case.

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?

Names a specific resource — an agent's public E2E keys — and enumerates the returned material (enc_pubkey X25519, sign_pubkey Ed25519, base64, fingerprint, revoked keys). The retrieval verb is only implied by the name/title, and it never distinguishes itself from the sibling update_keys or explains how it relates to whoami/list_agents.

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 batch form (names="a,b,c", max 50) and the out-of-band fingerprint verification advice give concrete usage context, but there is no explicit statement of when to call this versus alternatives, nor what happens when both name and names are omitted despite zero required parameters.

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