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

With no annotations, the description must disclose behavior. It states the operation and idempotency, but does not mention permissions, side effects (e.g., resource release), or what happens to a running session beyond cancellation. Adequate but leaves some gaps.

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?

Single sentence, 13 words, front-loaded with the verb and resource. Every word earns its place, no 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?

The tool is simple (1 param, no nested objects, has output schema). Description covers purpose and idempotency. Could mention output structure or side effects, but given low complexity, it is mostly complete.

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?

Only one parameter (session_id) with no description in the schema. The description does not elaborate on its format, constraints, or meaning beyond what the name implies. Since schema coverage is 0%, the description should compensate, but it fails to add value.

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?

Name and description clearly state the action (cancel) and resource (session). Idempotency detail distinguishes it from siblings, all of which are different operations.

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 explicitly says 'Cancel a session' and clarifies that it's a no-op if the session does not exist or is already finished, giving clear context on when to use it. No explicit alternatives are needed as no sibling tool performs cancellation.

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