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

Annotations give readOnlyHint=false, idempotentHint=true and destructiveHint=false, and the description adds real value on top: no charge/hold/reservation, preparing is not approval, and the idempotency rule ('one checkout per quote revision') which explains the idempotentHint. It does not describe failure modes or what happens to prior checkouts, keeping it short of a 5.

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 tightly packed sentences, front-loaded with the action and output, then the crucial 'not approval' disambiguation, then a structured 'Effects:' clause. Every sentence earns its place with no filler.

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?

With no output schema, the description telling the agent it returns a secure link is useful, and it fully covers the mutation's side effects. Minor gap: it does not say what the response contains beyond the link or what to do with the link, but for a 3-param tool this is close to 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?

Schema coverage is 67%, so the schema already documents quote_ref and request_key in detail. The description reinforces the quote/revision relationship ('one checkout per quote revision') but adds no format or syntax beyond the schema, so baseline 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?

States a specific verb and resource ('Creates (or returns the existing) checkout for a quote') plus the scope (one per quote revision) and points to the output (a secure link). It implicitly distinguishes itself from downstream approval, but does not name a sibling tool like anywayr_quote_booking or any approval step explicitly.

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 line 'Preparing is not approval; nothing is booked or charged here' clarifies the stage in the flow, which implies when to call it. However, it never states when to use this over alternatives or what upstream prerequisites (e.g., a completed quote) must hold, leaving usage to inference.

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