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

Annotations already declare readOnly, idempotent, non-destructive, and open-world, so the safety profile is covered. The description usefully adds that only the public profile is returned, but says nothing about auth requirements, error behavior for bad/expired credentials, or rate limits.

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?

A single short sentence with the resource and key constraint front-loaded; nothing is padded and every word contributes.

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 simple one-param read tool with rich annotations and no output schema, this is close to sufficient. The notable gap is the unspecified credential format and how the returned public profile relates to the caller, which the description should settle.

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?

With one parameter at 0% schema description coverage, the description must carry the load. It clarifies that the credential is the lookup key for a profile, but never specifies the credential's form (token, API key, agent id) or whether it defaults to the caller's own credential, leaving meaningful ambiguity.

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 verb ('look up') and resource ('public profile') and ties it to a credential, so the agent knows this resolves a credential to an identity. It does not explicitly contrast with near-neighbors like update_profile or get_record, but the action is unambiguous.

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?

There is no statement of when to call this versus alternatives such as my_activity, get_record, or update_profile, and no prerequisites or exclusions. The intended use (resolve a credential to its owner) is only implied by the phrase 'belongs to a credential'.

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