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

Adds behavioral detail beyond annotations: 'deterministically' indicates reproducible output, 'reports material differences' describes output, and 'Paid resource; x402 price is $0.002 USD per call' discloses cost. Annotations already cover readonly/idempotent/destructive, so the description's additions are valuable context without contradiction.

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 sentences with no filler: operation, scope/exclusions, cost. Each sentence earns its place and the key function is front-loaded.

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?

The description covers purpose, exclusions, and cost, but with 5 parameters, 0% schema coverage, and no output schema, it leaves a gap: the meaning of the three optional verification-rule parameters is not explained, and the exact return behavior is only hinted at ('reports material differences'). Sibling differentiation is present through exclusions but not explicit alternatives. Adequate but not 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?

With 0% schema description coverage, the description carries the burden. It names the two required parameters ('expected and observed values') and vaguely refers to 'caller-supplied verification rules' for the optional ignore_paths/required_paths/numeric_tolerance. This adds some meaning but does not explain the semantics of the rule parameters, leaving the agent to infer from names alone.

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: 'Deterministically compares caller-supplied expected and observed values and reports material differences under caller-supplied verification rules.' This clearly names the operation and scope, distinguishing it from sibling verification domains by stating 'Intended for outcome assurance' and excluding legal, identity, sanctions, fraud, contractual, and regulatory adjudication.

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?

Provides explicit when-not exclusions ('Do not use for legal, identity, sanctions, fraud, contractual, or regulatory adjudication') and a positive scope ('Intended for outcome assurance / cannot select'). However, it does not name alternative sibling tools, so the routing guidance is context-rich but not fully explicit about which tool to use instead.

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