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

With no annotations, the description carries the full burden and does so strongly: it discloses per-call cost, final/non-refundable payments, direct provider payment, HTTP 402 until payment is presented, and that the relay never receives funds. It also states that processing runs locally on n-gram models and no external service sees the text.

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?

The description is readable and front-loads important payment terms, but it repeats cost and final-payment details across the main text and the untrusted-provider block. Some sentences, such as the redundant 'Language detect' heading and repeated payment warnings, do not earn their place.

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?

The description covers cost, payment mechanics, HTTP 402 behavior, local privacy, and the high-level return type, which is good for a tool with no annotations. However, it omits explicit topN semantics and the exact returned structure, leaving some uncertainty about optional parameter behavior and output format.

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 low at 33%, yet the description adds little parameter-level meaning beyond what the schema already provides. It does not explain that topN controls how many ranked candidates are returned, and the minLength explanation largely duplicates the schema's existing description.

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 clearly states a specific function: 'Detects the language of a text sample and returns ranked ISO 639-3 candidates with confidence.' This gives a concrete verb, resource, and result type, and clearly distinguishes it from the unrelated sibling tools.

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?

The intended use is implied through 'Detects the language...' and contextual notes like local execution and minLength refusal, but there is no explicit 'use when' or 'do not use when' guidance. No alternatives are named, though the sibling set does not contain a comparable language tool.

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