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

With readOnlyHint and idempotentHint already supplied, the description still adds meaningful behavior: deterministic with no model calls, caller records are unverified, receipt verification is unavailable, and a pass grants no execution authority. Those caveats materially change how an agent should trust the result; only the return/finding shape is left undisclosed.

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?

Four short sentences, front-loaded with the core action and scale, followed by the most consequential caveats (determinism, unverified records, no authority). No sentence is redundant or padded.

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 six parameters, deep nesting, and no output schema, the description covers inputs and trust boundaries but says nothing about what a check returns or what a 'finding' looks like. The schema hints at 'forbid:<id>' findings, yet the description never explains the result, leaving a real gap for an agent that must interpret the output.

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 100%, so the six parameters, nested records, and enums are already well documented in the schema itself. The description adds only the 'one or up to 50' batching notion, which mirrors the schema's minItems/maxItems, so the baseline 3 applies.

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 gives a specific verb and resource ('Check one reply or up to 50 replies') plus the three rule families it enforces (explicit prices, forbidden phrases, supplied outcome records). It also implicitly separates itself from receipt-oriented siblings by stating 'receipt verification is unavailable here', though it never names validate_policy or verify_bundle directly.

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?

Usage is implied rather than stated: the tool checks replies against a policy, so an agent can infer it should be called after composing a reply. There is no explicit when-to-use/when-not guidance, and no routing to validate_policy for policy linting or to verify_bundle for receipt checks, even though those siblings exist.

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