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

Goes beyond the annotations by naming required scopes (numbers:write, billing:write), stating it never charges included or prepaid capacity, and disclaiming payment approval and activation. Annotations already cover safety/idempotency, but the description omits how long the reservation is held and what an agent should do after the review request.

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?

Three tight sentences with the action front-loaded, followed by prerequisites and then negative guarantees. No filler and nothing repeated from the schema or annotations.

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?

The scope, permissions, and boundaries are well covered, and the absence of an output schema means return values need not be described. However, with 0% parameter documentation and no note on how the resulting review is checked, an agent still lacks what it needs to construct and follow up on the call confidently.

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 0% across four required parameters, so the description carries the full burden and largely does not meet it. Only phone_number gains indirect meaning ("an exact pool number"); business_id, agent_id, and especially idempotency_key are never explained.

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?

Uses a specific verb ("Reserve") on a specific resource ("an exact pool number") and adds the secondary effect ("request an owner-only browser review of its recurring extra-line price"). It also explicitly contrasts with the sibling that handles a different case ("included allocation goes through attach_number"), so an agent can route without opening schemas.

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?

Gives a clear when-to-use context (exact pool number needing an owner review of recurring price) and an explicit when-not condition with the alternative tool for included capacity. It also rules out two expectations ("does not approve payment or prove activation"), though it never mentions the status-check sibling for follow-up.

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