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

Beyond the annotations (destructive=true, idempotent=true), it discloses concrete effects: the emailed link stops working, pending invites are never sent, and nothing is emailed either way. It also names the 400 refusal case for already-accepted/cancelled invites and states the return shape, which the annotations alone cannot convey.

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-loads the core action and effect, then prerequisites and error behavior. Three compact sentences, each carrying distinct information with no redundancy.

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?

There is no output schema, but the description supplies the return value ({ message: 'Invite cancelled' }), the side effects, the auth requirement, and the failure mode. For a two-parameter destructive tool, an agent has everything needed to call it 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 100%, so both parameters are already documented, including the inviteId source (_id from list_project_invites or the inviteId from invite_to_project). The description adds only marginal framing about which invite states are eligible; baseline 3 applies when the schema does the heavy lifting.

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 ('project invite'), and immediately disambiguates the two invite states (emailed link vs. awaiting confirmation). This clearly separates it from fastero_invite_to_project and fastero_list_project_invites.

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 the use case ('withdraw an invite to a wrong or unwanted address') and the hard exclusion ('it cannot remove someone who has already accepted'). It also adds necessary prerequisites ('Owner or Admin role') and the refused-state condition (already accepted/cancelled returns 400), leaving nothing to inference.

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