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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds valuable behavioral context: it never errors when unidentified (returns a pairing path instead), explains the server-side session binding mechanism, and discloses the expiry times for session and grant tokens. This goes beyond what annotations provide, though it doesn't detail the exact response structure or error cases beyond the unidentified scenario.

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 compact and information-dense. Every sentence adds value: identity/hatch state, non-error behavior, session binding, expiry times, and the refresh_session fallback. It's front-loaded with the core purpose and then provides necessary operational details without fluff.

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 read-only identity check tool with no output schema, the description covers all essential aspects: what it returns, when it returns a pairing path, how session binding works, token expiry durations, and the next step if the session is expired. The sibling list shows related tools like poll_pairing and refresh_session, and the description correctly references both, making the tool's place in the workflow clear.

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?

Schema description coverage is 100%, so the schema already documents all three parameters. The description adds meaning by explaining the purpose of sessionToken (for connectors that cannot set Authorization headers) and the relationship between hatchId and tenantId (legacy alias). This is valuable context beyond the schema's basic descriptions.

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 clearly states the tool's function: returning the caller's current identity and hatch state. It distinguishes itself from siblings by explicitly mentioning the pairing path and session binding, which is unique among the listed tools.

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 explicit guidance on when to use this tool: after poll_pairing completes, and when sessionExpired is true, it directs the agent to call refresh_session. It also explains the sessionToken parameter's purpose for connectors that cannot set Authorization headers, which is a clear usage condition.

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