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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds value by noting it is 'Deterministic' (a behavioral trait) and by disclosing the cost ('Paid resource; x402 price is $0.002 USD per call'). 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 three sentences with no fluff. It front-loads the purpose, gives usage guidance, and includes relevant cost information. Every sentence earns its place.

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 tool with two parameters, no output schema, and no parameter descriptions, the description covers the purpose and usage well but leaves gaps: it does not explain what the tool returns (e.g., a risk verdict, evidence list, or score), nor does it detail the input structure. Given the safety profile is handled by annotations, a 3 is appropriate – it is adequate but not fully 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 description coverage is 0%, so the description must compensate. It mentions 'operation identity, idempotency keys, replay windows and prior fingerprints,' and explicitly references 'prior_fingerprints' as a parameter, but it does not explain the structure or format of the 'requests' array or what 'prior_fingerprints' contains. The mapping from concepts to actual parameters is vague, leaving the agent to guess the expected input schema.

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 a specific verb ('Deterministic analysis') and resource ('mutating agent requests for duplicate-effect and replay exposure'), and specifies the method (operation identity, idempotency keys, replay windows, prior fingerprints). It is distinct from siblings by its focus on idempotency and replay, and is not a tautology.

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?

Explicitly tells when to use it ('before retrying or replaying a mutating action') and when not to use it ('Do not use it for unrelated general knowledge or unsupported legal, identity, sanctions, fraud, contractual, or regulatory adjudication'). This provides clear context and exclusions, even though it does not name specific alternative tools.

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