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

Annotations already say it is a non-read-only, non-destructive, non-idempotent mutation. The description adds real context beyond that: an ownership restriction and the fact that org-level MCP approval settings and business workflow approvals both govern whether the cancel can proceed.

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?

Two sentences and the key action plus ownership constraint come first. The trailing sentence on administrator-configurable approval requirements is useful but slightly tangential padding.

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 no explanation, and the mutation is well scoped. However, the description omits what state the request ends up in after cancellation and gives no guidance on sourcing requestId, which an agent needs to call this correctly.

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 0% and the single parameter requestId is never mentioned in the description. The schema supplies a uuid format and regex, but nothing explains what requestId refers to (an approval request id from a prior submit/find call) or how to obtain it.

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 an invoice approval request) plus the ownership scope (your own pending). Clearly separates it from submit_invoice_approval_request, decide_invoice_approval_request, and find_invoice_approval_request without needing 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?

Explicitly gives a when-not condition: cannot cancel another submitter's request, only your own pending one. It doesn't name the sibling (e.g. decide_ or find_invoice_approval_request) an agent should use instead in those cases, so it stops short of a full routing rule.

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