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

Annotations already communicate that this is a mutating, non-idempotent operation, so the description does not need to restate that. It adds useful scope context ('pending', 'directed at the calling user'), but it does not disclose what happens after responding, such as whether the invite is consumed or what side effects accepting has.

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 two short, front-loaded sentences with no filler. The action and scope come first, then the parameter clarifications, making it easy to parse quickly.

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?

For a simple two-parameter action with full schema coverage, an output schema, and relevant annotations, the description is complete enough. It identifies the target resource, the caller-scope constraint, and the meaning of the decision parameter.

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%, and both parameters already have clear descriptions ('Campaign id.' and 'true to accept the invite; false to decline.'). The prose adds only minor natural-language clarification that campaignId is the campaign the invite belongs to and that accept decides yes/no.

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 states a specific verb and resource: 'Respond to a pending campaign invite directed at the calling user.' It clearly distinguishes this from sibling friend-request tools like play_accept_friend_request and play_decline_friend_request by specifying the campaign-invite scope.

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 phrase 'pending campaign invite directed at the calling user' gives clear conditions for when to use the tool. It does not explicitly name alternatives or exclusions, but the context is sufficient to route an agent to the correct tool without opening other schemas.

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