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

The description discloses the state change (resolution='cancelled') and the effect on the recipient, beyond what annotations provide. It confirms the mutation (readOnlyHint=false) and non-destructive (destructiveHint=false) nature, with idempotency implied but not elaborated. No contradiction with annotations.

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?

The description is extremely concise with three short sentences, each adding crucial information: purpose, effect, and return value. No redundant words.

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 the simple tool with one parameter and an output schema, the description is mostly complete. It covers purpose, constraint, outcome, and return format. However, it could mention error scenarios (e.g., if not proposer or invitation already processed).

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 baseline is 3. The description does not add significant meaning beyond the schema's description of invitation_id as a UUID, but it confirms the parameter's role in the cancellation action.

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 clearly states the verb 'cancel' and the resource 'pending invitation you sent', with a scope constraint 'proposer only'. It effectively distinguishes this tool from its siblings like accept_invitation and decline_invitation.

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?

The description specifies the user must be the proposer and explains the effect (recipient cannot accept/decline). However, it does not explicitly state when not to use it or mention alternative tools, though the sibling context provides some guidance.

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