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

Annotations already convey idempotent, non-read-only, and non-destructive hints. The description adds valuable operational behavior beyond those annotations: the $0.75 x402 payment requirement, the challenge-signature flow, the need to preserve _salt19_operation_id across retries, and the at-most-once semantic. The 'required' vs 'recommended but optional' wording around _salt19_operation_id introduces mild confusion, but it does not contradict the 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 front-loaded with the primary purpose, and the following sentences cover payment and retry semantics without excessive length. It is slightly repetitive around _salt19_operation_id, and the required-versus-optional phrasing could be tightened, but overall each sentence contributes useful information.

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?

For a paid verification tool with an output schema and six parameters, the description covers the essential purpose, result type, payment flow, and idempotent-retry contract. The output schema already exists, so not detailing return values is acceptable. It does not discuss alternatives or exclusions, but that gap is already reflected in the usage-guidelines score.

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 100%, and the schema already explains _salt19_handoff_id, _salt19_operation_id, and _x402_payment_signature in detail. The tool description reinforces the operation-id and payment-signature behavior but does not add much meaning beyond the schema for goal, plan, or constraints. Baseline of 3 is appropriate because the schema carries the parameter documentation burden.

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 states a specific verb ('Verify') and resource ('an autonomous agent plan before execution'), and enumerates the exact areas checked: missing preconditions, destructive steps, unsafe ordering, goal misalignment, constraint violations, and repair actions. It also names the bounded GO/WARN/BLOCK result, which clearly differentiates it from sibling output-verifier and preflight/gate tools.

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?

'Before execution' gives clear context for when to use the tool, and the payment/retry instructions clarify the operational sequence. However, it does not explicitly mention when not to use it or name any sibling alternatives, so it stops short of full routing guidance.

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