Token status

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

Beyond the readOnlyHint annotation, the description discloses path-dependent behavior: Path B uses debug_token to report validity, scopes, expiry, and days-left with a refresh warning, while Path A has no introspection endpoint and reports expiry honestly as unknown. This is substantial behavioral context that annotations alone do not provide.

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?

The description is front-loaded with the core purpose, then efficiently organizes path-specific details in separate clauses, ending with the read-only note. Every sentence and clause adds necessary information without fluff or redundancy.

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?

Given the output schema is present and the annotation declares read-only, the description fully covers the operational behavior: it states what is reported, how each auth path is handled, the warning behavior, and the honest unknown for Path A. Nothing essential for an agent to select and invoke the tool is missing.

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 single optional parameter 'account' is already fully described in the schema with a clear explanation and default behavior. With schema coverage at 100%, the description doesn't need to add parameter detail; it doesn't, so the baseline score of 3 is appropriate.

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?

The description leads with a specific verb-resource pair ('Report the active credential') and enumerates exactly what is reported: auth path, token configured, account ID, validity/scopes/expiry on Path B. It clearly distinguishes itself from sibling media/account operations by focusing solely on token/credential status.

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 provides clear context for when to use this tool: when credential status, expiry, or account resolution are needed. It doesn't explicitly name alternatives because no sibling tool serves this purpose, but the coverage of what it does makes the use case unambiguous and there are no exclusions.

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