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

Beyond the annotations (destructiveHint=true), the description adds critical context: 'Irreversible and outward-facing' and lists specific side effects (cleans up invites, affiliates, broadcasts). This fully discloses the behavioral impact beyond what annotations alone provide.

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 (two sentences) and front-loads the essential action and effects. Every sentence adds value: first the action and cleanup, second the irreversibility and prerequisites. No wasted 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 tool has no output schema, the description covers the main purpose, side effects, and prerequisites. However, it lacks any detail about the 'reason' parameter and does not mention what the response or confirmation looks like. For a simple mutation tool, it is close to complete but has a small gap.

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?

The schema has 0% description coverage for its 2 parameters. The description only states that event_id is required, but does not explain the purpose of the 'reason' parameter (maxLength 500). The user must infer from the tool name or schema that reason is optional and likely for display. This is insufficient.

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 'live event', with specific scope 'you manage'. It details the effects (marks cancelled, removes from public discovery, cleans up invites/affiliates/broadcasts), which distinguishes it from sibling tools like update_event or delete_event.

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 includes prerequisites ('requires event_id; you must be a host') and implies use for live events the user manages. However, it does not explicitly say when not to use this tool or name alternative tools among the extensive sibling list for similar actions like archiving or cancelling in a series.

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