create_checkin

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

Annotations already declare readOnlyHint=false, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds a useful workflow detail: the body's expected fields must be discovered by reading the matching GET or /schema endpoint. It doesn't describe side effects, auth requirements, or idempotency behavior, but with annotations present a 3 is appropriate.

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 very short and front-loaded with the purpose. The endpoint line and the body note each add useful information without fluff or redundancy. Every sentence 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?

For a tool with a hidden, openWorld body and an output schema present, the description provides the essential discovery mechanism by directing the agent to the GET or /schema endpoint. It doesn't explain the domain meaning of 'check into an item' or the relationship to delete_checkin, but the agent has enough to invoke it correctly with the schema guidance.

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 schema only defines 'body' as a free-form object with additionalProperties true and zero descriptions. The description compensates by explaining that body is the request payload and by pointing the agent to the matching GET or /schema endpoint to learn the expected fields. This is meaningful guidance for an openWorld parameter.

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 verb 'Check into' and the resource 'an item' via the POST /checkin endpoint. It conveys the core action, though it does not explicitly distinguish create_checkin from sibling tools like create_scrobble_start or delete_checkin.

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 gives no guidance on when to use this tool versus alternatives such as delete_checkin or the scrobble endpoints. It only instructs the agent to read the matching GET or /schema endpoint before sending a request, which is procedural but not comparative.

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