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

Annotations declare readOnlyHint=false with no explanation, and the description supplies it: reads/computes only but is charged per call. It also adds cost behavior ($0.003/call, first 25 free, failed calls free) that annotations cannot convey. It does not address the idempotentHint=false flag, which is the one remaining behavioral question.

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?

Front-loads the purpose and usage trigger before the pricing detail. It is compact, but the pricing/licensing clause is appended into an already dense sentence and mildly dilutes the core definition.

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 one-parameter, no-output-schema tool, the description still describes the return contents (name, meaning, retry recommendation) as well as the cost and no-write behavior. Nothing needed to call it correctly 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 coverage is 100% so the single 'code' parameter is documented as a baseline 3, but the description adds meaning beyond it: the valid 1xx-5xx range (the schema permits any integer down to negative values) and a worked example (code=429).

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 resource (HTTP status code) and what it returns: name, plain-language meaning, and retry guidance. It also scopes the range (1xx-5xx) and calls out notable codes, and no sibling tool overlaps this domain, so an agent can select it unambiguously.

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?

Gives an explicit trigger ('Use when handling API errors') plus a concrete example (code=429). There is no competing sibling to disambiguate against, so no when-not guidance is needed, but the usage context is clear and actionable.

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