check_entitlement

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

No annotations are provided, so the description carries the disclosure responsibility. It adds the meaningful detail that the entitlement must be 'active', which is a behavioral condition. However, it does not explicitly state return type, side effects (though likely read-only), or any error/edge-case behavior. For a simple check tool, this is adequate but not rich.

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 a single, front-loaded sentence that conveys the core purpose immediately. There is no fluff or repetition. Every word earns its place.

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 tool's simplicity (2 params, no output schema, no annotations), the description is minimal but lacks an explicit statement of return value or behavior on invalid input. It checks if an entitlement is active, but does not clarify whether the response is a boolean, a status object, or something else. A more complete description would specify the return format.

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 baseline is 3. The description adds a small amount of value by providing concrete examples of entitlement IDs ('premium', 'pro'), which clarifies the expected format beyond the schema's generic 'The entitlement identifier to check.'

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: checking if a user has an active entitlement. The verb 'check' is specific and the resource 'entitlement' is well-defined. It implicitly distinguishes itself from sibling tools like grant_entitlement and revoke_entitlement (which modify entitlements) and get_subscriber (which fetches broader subscriber data).

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 no explicit guidance on when to use this tool versus alternatives. It does not mention exclusions, prerequisites, or other tools. Usage is only implied by the function name and description, but there is no direct comparison to siblings.

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