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

Annotations already set destructiveHint=true and idempotentHint=true, but the description adds real value beyond them by specifying exactly what is destroyed (pending items will never run) and what survives (already-executed items), plus the no-undo constraint. It does not mention permission requirements or the idempotency-key behavior, which is left to the schema.

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?

Three short sentences, zero filler, and the scope of destruction is front-loaded immediately after the verb. 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?

An output schema exists, so return values need not be described, and the description covers the key behavioral consequence of cancellation. It is nearly complete; only the absence of sibling routing (pause_job as the reversible alternative) leaves a small gap.

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%, including detailed documentation of both job_id and idempotency_key, so the baseline of 3 applies. The description adds no parameter-level detail of its own.

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 (Cancel) and resource (job), plus the exact scope of the operation: pending items are dropped while already-executed items are untouched. It does not explicitly distinguish itself from the adjacent pause_job/resume_job siblings, which would have made it a 5.

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?

Usage is implied rather than stated — the agent can infer 'use when you want a job to stop permanently' from the irreversibility note, but there is no explicit when-to-use or when-not-to-use guidance contrasting it with pause_job (reversible) or delete_scheduled_post.

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