Get current CNB user

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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint and destructiveHint=false, so the safety profile is covered. The description adds that the token is 'upstream' and that this is an auth verification step, but says nothing about failure behavior (e.g. what an invalid/expired token returns) or the shape of the returned user.

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 short sentences, front-loaded with what is returned and followed by the practical guidance. No redundancy or filler.

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?

A simple, zero-parameter read tool with full annotation coverage and no output schema; the description covers purpose, identity source, and the recommended first-call usage. Only minor gap is the absence of any note on auth-failure behavior, which would help; an output schema would have removed the need to describe the return value.

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, which is the baseline-4 case. The description correctly implies no inputs are needed and clarifies that the caller's identity comes from the upstream token rather than any argument.

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: returns the CNB user associated with the upstream token. Clear and unambiguous, and distinct from all siblings (repo/issue/pr/build tools) which operate on repositories rather than identity.

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?

Gives explicit usage guidance: 'Use this first to verify authentication works.' That tells the agent when to call it, though it doesn't name an alternative or say when not to use it (trivial here, since there is no alternative identity tool).

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