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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive), so the bar is lower, and the description adds real value on top: it discloses the polling contract, the absence of identity/secret requirements, and the terminal states. It does not say what a pending/in-progress state looks like, but the added context is substantial.

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 purpose before the polling mechanics. Efficient overall, though the first sentence is dense with undefined jargon ('signed-webhook-backed entitlement') that costs a little parsing effort.

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 one-parameter tool with no output schema, the description usefully compensates by enumerating the terminal states (issued, denied, expired) that end polling. What remains missing is the pending/in-progress value and where the returned entitlement actually lives, but coverage is strong for the tool's complexity.

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% and the single onboarding_token is fully documented as private and never to be logged, so the schema does the heavy lifting. The description's 'without identity or secrets' hints at the token's confidentiality but adds no syntax or handling detail beyond the schema.

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 (Check) and resource (approval and entitlement), and the 'without identity or secrets' clause scopes what the check requires. However, it never names the sibling it differs from (e.g. complete_onboarding), and 'signed-webhook-backed entitlement' is jargon an agent must interpret.

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 concrete operational guidance: poll every 5 seconds, complete only when ready, stop on issued/denied/expired. This tells the agent how to drive the loop, but it does not name the alternative tool to call once the state is ready, leaving the handoff to inference.

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