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

Goes well past the annotations: it discloses that linked tasks are kept, the daily creation allowance is not restored, an already-sent message is not recalled, in-progress delivery cannot be guaranteed cancelled, and repeated cancellation is safe. Those are exactly the edge cases an agent needs before a destructive call.

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?

Four short sentences, each carrying a distinct fact (source of id, task preservation, allowance, delivery limits, idempotency) with no repetition. Slightly dense but nothing wasted.

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 mutation tool with no output schema, it covers safety, side effects, allowance implications and idempotency. An agent has everything required to call it correctly and to warn the user about limitations.

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 coverage is 100% and the schema already clarifies that the id is the reminder id and not the numeric task id. The description only adds the provenance ('from list_reminders'), so the baseline of 3 is right.

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 and resource ('Cancel a specific reminder') and scopes it to a single reminder identified by id, which cleanly separates it from list_reminders and create_reminder. An agent can select it without opening the schema.

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?

Says to use it 'at the user's request, using its id from list_reminders,' which both names the trigger and routes the agent to the sibling that supplies the id. It lacks an explicit when-not-to-use statement, keeping it just below the top score.

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