diff

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It explicitly states the encoding auto-detection and the 50,000-line cap per file, which are key behavioral traits. It also implies read-only behavior and unified diff output. This goes beyond what the input schema provides, though it could mention error handling for oversized files.

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 extremely concise: two sentences, front-loaded with the core purpose. Every sentence adds value without 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?

Given no output schema and no annotations, the description covers essential behavior (comparison, output format, encoding, line limit) but lacks details on return format structure, error conditions (e.g., file not found, too large), and the meaning of context_lines parameter. It is minimally adequate but has gaps.

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 does not add new meaning to individual parameters beyond the schema's descriptions. It provides general context (encoding, line caps) but no parameter-specific guidance.

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 it compares two files and outputs a unified diff. It distinguishes itself from siblings like 'patch' (which applies diffs) and 'checksum' (hash comparison). The verb 'compares' and resource 'files' are specific, leaving no ambiguity.

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 context about encoding detection and line limits, helping the agent know when this tool is appropriate (e.g., for text files under 50k lines). However, it lacks explicit guidance on when NOT to use it (e.g., binary files, very large files) and does not mention alternatives from the sibling list, like 'patch' for applying diffs or 'grep' for pattern search.

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