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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so safety is covered. The description adds real behavioral information beyond them: the result is entirely determined by the connection's credentials and cannot be redirected to another account, which tells the agent the call is non-parameterizable and cannot be used for arbitrary lookups. It does not mention behavior on invalid/expired credentials.

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 sentence with the primary purpose front-loaded and the constraint attached via a semicolon; 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?

For a zero-parameter read tool with full annotations and an output schema, the description covers purpose, input constraints, and credential-bound scope. Only minor gaps remain, such as error behavior when credentials are absent or invalid.

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 zero parameters the baseline is 4, and the description earns it by explaining why there are none ('never accepts an account selector') rather than leaving an empty schema unexplained. It adds meaning beyond the schema, which can only show an empty property set.

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 (identify) and a specific resource (the account bound to this connection's credentials), which is exactly the distinction an agent needs among a large sibling set of project/document/asset readers. The clause 'never accepts an account selector' further pins down what the tool is not, making it distinguishable without opening the 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 framing implies a clear use case: call this when you need to know which account the current credentials belong to. It does not name an explicit alternative or state what to do if the identity is needed for a different account, so it stops short of full when/when-not guidance, but the context is unambiguous.

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