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

The description goes beyond the annotations by explaining the checkout flow, the need for user interaction with the payment_url, and automatic token crediting after payment. It also discloses the authentication requirement ('Requires PULSE_API_KEY'). This adds significant behavioral context that annotations do not cover, and it does not contradict the annotations.

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 concise and well-structured. It opens with the main purpose, then provides a critical usage instruction, followed by a note on post-payment behavior. Every sentence adds value without unnecessary fluff.

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 description covers the essential aspects: what the tool does, how to handle the response, the post-payment effect, and required credentials. It is sufficiently complete given the simple single-parameter input and the presence of an output schema. It could mention session expiration or error behavior, but these are not critical for basic usage.

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 provides a complete description of the 'pack' parameter (enum values and description). The tool description adds no additional parameter semantics beyond the schema, but since schema coverage is 100%, a baseline of 3 is appropriate.

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 tool's function: 'Create a Stripe Checkout session for a Pulse token pack.' It uses a specific verb ('Create') and names the resource ('Pulse token pack'). This distinguishes it from siblings like list_token_packs and get_token_balance, and the return of a payment_url is specified.

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 for when to use the tool (to purchase a token pack) and gives explicit instructions on handling the result: 'DO NOT submit it programmatically; surface it to the user.' However, it does not explicitly compare with alternatives such as request_payment_link 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.