Diff two texts

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

With no annotations provided, the description carries the full burden. It discloses the tool's outputs (unified diff, line counts, similarity percentage) and its read-only nature implicitly. It does not list limitations or side effects, but since this is a pure comparison function, the disclosed behavior is adequate and clear.

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 two sentences with zero filler. The core behavior is stated first, followed by a direct usage recommendation. It is efficient and front-loaded, earning a perfect score for conciseness.

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 tool with three parameters, two required, and no output schema, the description adequately covers what the tool does and what it returns. It does not specify the exact diff format or similarity algorithm, but these are likely not essential for correct invocation. The description is sufficient for an agent to call this tool accurately.

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?

The input schema provides 100% coverage with descriptions for all parameters ('original text', 'changed text', 'context lines around each change'). The tool description itself adds no additional meaning to the parameters—it only mentions the purpose in general terms. Since schema coverage is full, 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 clearly states the tool's function: compare two versions of a text and return a unified diff, exact line counts added/removed, and a similarity percentage. It uses a specific verb and resource, and it differentiates from siblings by explicitly contrasting with manual description, making the purpose unambiguous.

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 description provides direct usage guidance by saying 'Use it rather than reading both versions and describing the difference,' which tells the agent when to prefer this tool over the obvious alternative. It does not discuss edge cases or exclusions, but for a simple diff tool this is sufficient context.

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