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

Annotations already declare destructiveHint=true, and the description's 'Cancel' is consistent. The description clarifies the scope ('one of the agent's scheduled tasks') but does not disclose side effects or irreversibility. Given the destructive hint, this is acceptable; the description adds some value but not extensive behavioral context.

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, concise sentence that front-loads the action. It is appropriately sized—no redundant words—though it could arguably include a note about cancellation being irreversible, but that would be optional. It is efficient and well-structured.

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 simple destructive operation with only two parameters, both fully documented in the schema, and with annotations indicating destructiveness, the description is adequate. It tells the agent exactly what the tool does. The absence of an output schema suggests minimal return value, and the description does not need to explain that.

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?

Both parameters have full descriptions in the schema (100% coverage) explaining how to obtain them (e.g., from list_agents and list_schedules). The description only adds 'by id', which is redundant given the schema. Thus the description provides minimal additional meaning 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?

The description states a clear verb ('Cancel') and a specific resource ('one of the agent's scheduled tasks by id'). It unambiguously identifies the action and distinguishes it from sibling tools like set_schedule and list_schedules by focusing on cancellation.

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 implies when to use the tool (when you want to cancel a scheduled task), but it does not explicitly state when not to use it or mention alternatives. The parameter descriptions in the schema add context about obtaining the schedule_id, but the description itself offers no exclusions or comparisons to other tools.

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