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

Annotations already signal side effects (readOnlyHint=false), and the description enriches this by explaining the Stripe Checkout link flow, the pay-as-you-go card-on-file mechanism, the credit expiration policy, and the signed-in vs anonymous distinction. It fully discloses the operational behavior without contradiction.

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?

A single, well-organized paragraph that front-loads the purpose and then covers each case efficiently. No filler, every sentence earns its place, and the structure naturally guides the reader through the input states.

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 the single optional parameter and no output schema, the description fully covers what an agent needs to call the tool correctly: all input behaviors, user authentication states, and the nature of the returned links. Nothing essential is missing.

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 description already covers the pack parameter (100% coverage), but the description adds value by explaining what each pack actually does, what PAY_AS_YOU_GO does, and that leaving it empty lists options. This goes far beyond the schema's enum list.

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 opens with 'Ways to pay for Underpriced AI scans,' a specific verb-resource pair that clearly distinguishes it from the scanning/pricing siblings. It then details the exact behavior for each input state, so an agent knows precisely what the tool does.

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 explicitly states what happens with no pack, with a pack, with PAY_AS_YOU_GO, and for anonymous callers, giving complete when-to-use guidance. Though it names no alternative tools, the context makes it obvious this is the payment tool, and no other sibling overlaps.

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