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

Annotations already declare this is a non-read-only, closed-world mutation, and the description adds real behavior beyond them: an auth requirement (write key) and an idempotency requirement, plus environment-specific setup. It does not disclose what happens to escrowed funds, whether cancellation is reversible, or what workers see — the main remaining behavioral gap.

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, front-loaded with the action and its precondition, then auth mechanics. Every sentence carries information; the sandbox note is slightly environment-specific but earns its place for MCP clients without headers.

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 mutation tool with no output schema, the description covers the action, precondition, auth, and idempotency — enough to call it correctly. The gaps (mandateId semantics, post-cancel effects on funds/job state) keep it from full completeness.

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 description coverage is only 25% (only apiKey documented), so the description must compensate and it partially does: it identifies idempotencyKey as required and points apiKey at get_sandbox_key. However mandateId — a live optional parameter — is never explained in either the schema or the description, leaving a real hole.

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 job") plus an ownership/precondition scope ("you posted before it is settled"), which separates it semantically from accept, deliver, dispute and request_revision. It does not explicitly name a sibling it is confusable with, and "settled" is unexplained jargon, so it stops just short of 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?

Gives a clear when-to-use condition (own job, pre-settlement) and prerequisite guidance (write key required, obtainable via get_sandbox_key on the sandbox door). It does not say when not to cancel (e.g. post-settlement, or when the correct path is dispute), so there is no explicit alternative routing.

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