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

Adds behavioral context beyond annotations: deterministic comparison, material-difference reporting, caller-supplied verification rules, and cost. Annotations already carry readOnly/openWorld/idempotent/non-destructive, and the description does not contradict them. It does not describe return shape, but that is less central for a read-only comparator.

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 clear front-loading of the function, followed by scope exclusions and cost. The phrasing 'trust identity permission / cannot select' is awkward and slightly ambiguous, but the description earns its length.

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?

With 5 parameters, 0% schema description coverage, and no output schema, the description leaves important operational details unspecified: expected/observed format, path-rule semantics, tolerance behavior, and output structure. It does provide domain exclusions and pricing, which help selection, but an agent would struggle to construct a correct call from this definition alone.

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% and the description only names 'expected' and 'observed' and loosely refers to 'caller-supplied verification rules' (likely the three optional keys). It never explains ignore_paths, required_paths, numeric_tolerance, their types, or how they interact. For a tool whose two required parameters are untyped, this is a significant gap.

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 operation: 'deterministically compares caller-supplied expected and observed values and reports material differences' under caller-supplied rules. This clearly separates it from policy-engine, control-plane, and preflight siblings, though nothing differentiates it from the many other trust_identity_permission_verification_* siblings. Domain intent is also given (trust identity permission).

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 scopes the tool: intended for trust identity permission, and 'do not use for legal, identity, sanctions, fraud, contractual, or regulatory adjudication.' It also flags that it is a paid resource, which is a use-condition. However, it does not name alternative sibling tools or state when to prefer this over another verification/policy tool.

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