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

With no annotations, the description must disclose behavioral traits. It explains the cursor mechanism ('Pass the returned cursor back as since') and the set of events covered, which gives insight into how the tool behaves incrementally. It does not mention rate limits or error behavior, but for a read-only polling tool, this is sufficient.

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 three sentences, front-loaded with the core verb and resource. The cursor usage and intended use case are explained without redundant details. Every sentence contributes value, making it concise and well-structured.

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 no output schema and simple optional parameters, the description adequately covers the tool's purpose, event types, pagination, and a representative use case. It lacks an explicit statement about the return format (beyond the cursor), but this is reasonably inferable from a polling tool with these event types.

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 input schema has no descriptions, and the description compensates by explaining the 'since' parameter as a cursor from a previous call. However, 'limit' and 'principal' are not explicitly clarified; their meanings are only implicit from the context (e.g., 'a principal's mandates'). With 0% schema coverage, more explicit parameter guidance would be expected.

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 uses a specific verb 'Poll' and clearly enumerates the exact event types (spend, nearly-exhausted, exhausted, approval-required, revoked) on a principal's mandates. It also differentiates from siblings by emphasizing polling for events rather than static checks, making its purpose unmistakable.

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?

It states when to use this tool ('tell a principal their budget is running low or that a large payment is waiting on their approval') and provides context that this replaces manual checking. However, it does not explicitly name alternative tools or state when not to use it, so it falls short of a 5.

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