Text diff (unified + structured) (paid $0.001)

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

With no annotations, the description carries the full burden and does well by disclosing the payment requirement, the 402 challenge behavior, and the types of results returned. It doesn't cover edge-case errors, but the most important non-obvious behavior is transparently explained.

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 a single dense paragraph covering purpose, arguments, outputs, and payment flow. It is efficient overall, though it repeats the $0.001 fee already in the title, which is a minor redundancy.

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?

Despite lacking an output schema, the description names the three output forms (unified patch, op-list, stats), giving a sufficient expectation of results. It also fully explains the payment challenge flow, which is essential for a paid tool. Some internal structure of the op-list/stats is unspecified but tolerable.

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 71%, and the description largely restates default values and mode choices already present in the schema (e.g., 'default lines', 'context default 3'). It adds little new meaning for label_a/label_b, so the baseline of 3 is appropriate.

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 opens with 'Diff two texts' and lists specific outputs (unified patch, structured op-list, stats), clearly identifying the verb and resource. It distinguishes itself from sibling tools like encode/convert/hash, which are unrelated transformations.

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 tool's purpose implicitly defines when to use it, and the description provides concrete context about the paid workflow (x402 challenge and x_payment settlement). It doesn't explicitly contrast with alternatives, but no sibling tool performs diffs, so exclusions aren't necessary.

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