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

Annotations already declare readOnlyHint=true and openWorldHint=false, so safety is covered. The description adds genuinely useful non-schema behavior: per-call pricing (4 credits, with a credit-to-CAD conversion) and the billing guarantee that schema-invalid input is rejected before charging. It doesn't mention latency, truncation of long code, or what happens on model failure, which keeps it short of a 5.

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 tight sentences: purpose and output first, then the return contract, then pricing/billing. Front-loaded and every clause carries information an agent or caller would otherwise have to guess.

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?

There is no output schema, so the description assumes responsibility for the return contract and discharges it explicitly with a field-by-field shape. Combined with full schema coverage on inputs and annotations covering the safety profile, nothing material is missing.

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% and both parameters (code with 6,000-char limit, language with auto-detect) are fully documented in the schema. The description adds no parameter-level detail beyond that, so the baseline of 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?

States a specific verb and resource ('Reviews a code snippet') and enumerates exactly what it returns (bugs, security, performance, style issues with severity and fix). The inline return shape { language, summary, issues[] } makes the scope unambiguous, and no sibling tool in the list competes for this function.

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 only implied — the description makes clear this is for reviewing code, but never states when to choose it over alternatives or any prerequisites/exclusions. Since no sibling tool overlaps with code review, the omission is tolerable but the guidance is thin.

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