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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description adds real value beyond them by disclosing the authorization requirement (explicit profile:read scope) and the nature of the payload (private profile plus attributed activity), which annotations cannot convey.

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 short sentences, front-loaded with the primary action and followed by the authorization precondition and the exclusion boundary. No filler, no repetition of the title.

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 parameters, no output schema, and a fully self-contained schema, the description carries only the burden of stating what is returned and under what authorization. It does that ('private profile and attributed activity', 'profile:read scope'), though it gives no detail on the shape of the returned payload.

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?

The tool takes zero parameters, so per the rubric the baseline is 4. There is nothing for the description to disambiguate, and the schema is trivially complete.

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 (read) and resource (the verified key owner's private profile and attributed activity), and explicitly scopes out public identity, research, and payment data. This lets an agent distinguish it from sibling tools like profile_identities_read, research, and keryx_purchase_outcomes without opening any schema.

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 description names the required 'profile:read' scope, which is actionable precondition guidance, and the exclusion clause ('No public identity, research or payment') implicitly routes the agent away from this tool for those needs. It stops short of naming the alternative tools to use instead, so it is clear context without explicit alternatives.

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