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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It fully covers idempotency (duplicate confirm returns original receipt), polling semantics (never consumes), the distinction between keyed quotes and bearer tokens (agent_key required for keyed quotes), payment behavior (always pinned price, never card numbers), and the special case of payment_link quotes. This is exemplary for a tool with no 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 compact and front-loaded with the core action. Each sentence serves a purpose: execution semantics, idempotency, polling usage, payment handling, and keyed quotes. No redundant words. The structure flows logically from primary action to edge cases.

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?

Despite no output schema, the description provides enough information for an agent to call the tool correctly. It covers execution, polling, payment nuances, and security considerations. The tool is complex (5 params, nested objects, payment flows), but the description addresses all critical behavioral aspects. No obvious gaps remain.

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 100%, so the schema already documents all parameters in detail. The description adds value by clarifying payment_credential vs payment alias, the 'never both' constraint, and the agent_key security note, but these largely reinforce what's in the schema. The description does not introduce entirely new parameter semantics beyond summarizing the schema, so a 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?

The description clearly states the tool's primary function: 'Execute a quoted action. Confirming executes this action exactly once.' It specifies the resource (a quoted action) and the verb (execute/confirm). It also distinguishes itself from siblings like 'quote' by referencing the quote_id returned by quote and by covering polling for quotes awaiting approval, which is a distinct use case.

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 explicit guidance on when to use this tool: to execute a quoted action, to confirm a quote, and to poll quotes awaiting human approval. It also clarifies when not to use it or what to expect: duplicates return the original receipt, polling never consumes the quote, and payment_link quotes should be confirmed without a credential after human payment. It references the sibling 'quote' indirectly by noting the quote_id is returned by quote.

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