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

Beyond the annotations (readOnly, idempotent, non-destructive), the description adds that the package closes autonomously and mentions payment flows (USDC) and no consult requirement. This gives behavioral context about the business process, though it's not entirely clear if this tool itself has any side effects. It doesn't contradict 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 longer than average but each sentence adds value—usage trigger, pricing details, add-ons, closure mechanism. The bold emphasis on 'The package closes autonomously' helps highlight key info. Slightly rambling but not wasteful.

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 complexity of pricing (free, flat fee, add-ons, autonomous closure, USDC), the description covers all relevant aspects and even includes special cases (card cap, specialist track). With output schema present, this is complete.

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?

With zero parameters, the schema is fully covered. The description provides all needed meaning about what the tool returns (free tier + package details, add-ons) and the context of its use, making it highly informative.

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 returns pricing information, specifically the Free tier and the 450 package, and identifies the trigger ('when an end user asks about pricing'). It distinguishes from siblings like request_invoice or start_checkout which are action tools, making its purpose specific.

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 says 'Use this when an end user (or upstream agent) asks about pricing,' providing a clear trigger condition. It also notes that requires_consult is false and that a specialist track is optional, clarifying when not to require consultation. However, it doesn't directly name alternatives among siblings, but the usage context is clear enough.

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