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

Annotations already mark the tool as destructive and non-read-only. The description adds the critical behavioral boundary that accepted invites cannot be revoked this way and states the expected return shape. This meaningfully supplements the annotations without contradicting them.

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 tight sentences: the action, the use case and limitation, the parameter source, and the return shape. Every sentence earns its place and the most important scoping constraint is front-loaded.

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?

Given no output schema, the description still discloses the return value. The required parameter is sourced, the optional org behavior is in the schema, the accepted-invite edge case is handled, and destructive intent is already covered by annotations. Nothing material is missing for correct invocation.

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 100%, so the schema already documents both org and inviteId clearly. The description reinforces the inviteId source ('from list_invites') but adds little beyond what the schema provides, which lands at the baseline for fully covered schemas.

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 opens with a specific verb ('Cancel') and a precise resource ('a pending organization invitation'), and distinguishes the action from related invite flows by noting it only applies before acceptance. This is immediately disambiguated from list_invites and invite_member.

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?

It explicitly states when to use the tool ('an invite sent in error'), when it no longer applies ('once someone has accepted, they are a member'), and how to obtain the required parameter ('Find the id with list_invites'). This gives an agent clear decision-making context.

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