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

With no annotations, the description carries the full behavioral burden. It discloses the return shape (status phrase and class) and the no-argument fallback to the whole code map, which is genuinely useful. It omits error behavior for unknown codes, whether the lookup is local or network-backed, and rate/limit detail beyond the trial-call note.

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?

A single front-loaded sentence that delivers purpose, return value, and the no-argument behavior with no filler. The trailing free-trial-call marketing line adds little to tool selection, slightly diluting otherwise tight structure.

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 lookup with no output schema and no annotations, the description covers what the tool returns in both modes and how the parameter changes behavior. Adequate for calling it correctly; the main omission is any differentiation from the overlapping HTTP-status siblings.

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 there is one parameter, so the description must compensate, and it does: it explains that supplying 'code' yields a specific status phrase/class while omitting it returns the entire known-code map. That is the essential semantic an agent needs. It does not state the expected format (numeric string vs. symbolic), which is a minor 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 verb and resource: returns the status phrase and class for an HTTP code. The dual-mode behavior (single code vs. whole map) is clear. However, it does not distinguish itself from close siblings such as x402-http-status, which an agent would need to disambiguate before choosing.

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?

It implies two usage modes: pass a code for one lookup, omit it for the full map. That is useful context, but there is no explicit guidance on when to prefer this over x402-http-status or x402-http-analyze, and no exclusions or prerequisites are stated.

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