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

The description adds substantial behavior beyond the annotations: it states the operation is deterministic, has no side effects on stored state, and that payer velocity reservation happens atomically after facilitator verification. This gives the agent a clear, precise mental model of what the tool does and does not do, complementing the readOnly/idempotent/destructive hints. The 'reserved atomically ... before settlement' detail is exactly the kind of nuance annotations cannot convey.

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—two sentences—and front-loads the key action and its non-mutating nature. Every clause carries meaning, though the second sentence is dense and jargon-heavy ('verified-payer velocity is reserved atomically'). It earns high marks for efficiency without being as clear as it could be.

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 a complex input schema with three nested objects and zero schema descriptions, plus no output schema, the description leaves major gaps. It does not explain what the tool's output represents, how to interpret the evaluation result, or what conditions trigger approval or denial. The 'may be allowed' phrase hints at conditional behavior but never specifies the conditions. An agent could construct valid inputs but would not know what the response means.

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 0%, so the description must compensate by explaining the three top-level parameters (seller, offer, purchase), but it does not mention them at all. Terms like 'public terms' and 'verified-payer velocity' are referenced but never mapped to the schema fields. An agent receives no help understanding what values to populate in the deeply nested objects.

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 uses a specific verb ('pre-evaluates') and resource ('a public-price sale'), making the tool's function clear without needing to open the schema. It also distinguishes itself from the sibling tools, which are all monitor/endpoint/verify operations, via the 'Agent Commerce' domain. The phrase 'without sending, paying, settling' clarifies it is a pre-check, not an execution.

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 implies the tool is for pre-evaluation before a sale is finalized, but it never states when to use this tool versus an alternative. No sibling is mentioned (e.g., verify_risk), and there is no explicit 'use when' or 'do not use when' guidance. The context is only implied by 'before settlement,' which is not enough for an agent to confidently route.

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