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

No annotations, so the description carries the burden. It discloses the useful extras of access cost ($0.01/call, USDC on eip155:8453) and the returned fields (phrase, category, explanation), but says nothing about result sizing, pagination tied to limit, or behavior when code and category are both supplied.

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 short sentences, core capability front-loaded, price last. The second sentence ("Use this when...") is near-redundant with the first, which slightly dilutes efficiency but not enough to hurt usability.

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?

A simple read-only reference tool with full schema coverage and no output schema or annotations to lean on; the description names the return fields and the two query modes. Missing only edge-case behavior (combined code+category, paging via limit), which is minor for such a tool.

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 baseline is 3. The description clarifies the code-vs-category mode selection (empty code → list by category), which maps to the schema's "Leave empty to list by category" hint but adds no further syntax, ranges, or limit semantics beyond what the schema provides.

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 response status codes) and the two supported operations (look up a single code, or list a whole category 1xx–5xx). No sibling tool covers HTTP status codes, so the agent can distinguish it from the surrounding dev_* utilities without opening the schema.

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?

"Use this when an agent needs to look up any HTTP status code's meaning" gives a triggering condition, and the lookup-vs-list duality is mentioned. But it largely restates the purpose line and offers no when-not guidance or alternative for adjacent needs (e.g. security_ssl_inspector for diagnosing a live response).

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