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

Annotations already flag destructiveHint=true, idempotentHint=true, readOnlyHint=false, but the description adds real value beyond them: the resulting status ('canceled') and the failure modes (not_found for unknown id, bad_request for already-run or already-canceled schedules). The bad_request-on-recancel detail sits in mild tension with idempotentHint=true, though no state change occurs, so it is informative rather than contradictory.

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?

Front-loaded with the action and effect, then usage routing, then return/error semantics. Every sentence carries information an agent needs; no filler.

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?

With no output schema, the description still reports the return value ('the schedule with status canceled') and the error surface. For a single-parameter mutation tool this is complete enough to invoke confidently.

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 single schedule_id parameter is already documented with its source (list_schedules or create_schedule). The description adds no format or validation detail beyond the schema, so the baseline 3 applies.

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 pending scheduled pin') plus the effect ('so it never publishes'). An agent can distinguish this from delete_schedule, retry_schedule, and update_schedule without opening any 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?

Explicit when-to-use ('Use when the pin should not go out at all') and names two alternatives with the exact conditions that select them: delete_schedule for finished schedules, retry_schedule for failed ones. Nothing is left to inference.

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