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

With no annotations, the description fully carries the burden of behavioral disclosure. It explicitly states that this tool only stages a request and requires the owner to approve via a browser link with their agent PIN, and it gives a security directive to never ask for the PIN in chat. This discloses asynchronous behavior and an important operational constraint, going beyond what a simple 'cancel' would imply.

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 concise sentences with no wasted words. It front-loads the core purpose, then delivers the essential behavioral caveat and security warning. Every sentence earns its place, and the structure is easy to scan 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 tool with only two parameters, no output schema, and no annotations, the description is fully sufficient. It explains the purpose, the prerequisite (owning the workspace), the workflow (staged approval), and a critical safety rule (never ask for PIN). An agent can call this tool correctly with no additional guidance.

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 already has 100% description coverage for both parameters. The tool description adds value by explaining the purpose of the email parameter ('by the invited email') and giving practical guidance for the optional workspace parameter: 'Only needed when you own more than one — list_workspaces shows them.' This clarifies when the parameter should be provided, exceeding the baseline of 3.

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 ('cancel') and a precise target ('a pending invitation to a workspace you own, by the invited email'). It clearly distinguishes from siblings like invite_member or remove_member by focusing on pending invitations, and the term 'cancel' is unambiguous. The title and name align perfectly, and the description adds the critical qualifier of workspace ownership.

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 provides clear context: it is for canceling a pending invitation, not for removing an already-accepted member. It also explains the approval workflow, which tells the agent when to expect a deferred result. However, it does not explicitly name alternative tools for different scenarios (e.g., using remove_member for active members), though the distinction is implicit from the wording.

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