diffCompare two text files and return a unified patch from the first to the second with configurable context lines, helping you inspect changes.
Compare two text files and return a unified diff from a to b, like diff -u. Identical files give no hunks; binary and non-UTF-8 files are refused.
| Name | Required | Description | Default |
|---|---|---|---|
| a | Yes | First file to compare | |
| b | Yes | Second file to compare | |
| context | No | Number of context lines surrounding each change (default: 3) |
Changes observed during successful MCP inspections.
v2.4.1Input schema / $schemaAdded value: +"https://json-schema.org/draft/2020-12/schema"v2.0.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already cover read-only and closed-world behavior. The description adds useful behavioral detail beyond that: output is a unified diff, identical files produce no hunks, and binary/non-UTF-8 inputs are refused.
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?
Two tightly written sentences with no filler. The main behavior is front-loaded, and the edge cases are stated compactly.
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 simple read-only diff tool with fully described parameters and annotations covering safety, the description provides enough context: what it returns, how identical files behave, and what inputs are rejected.
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 parameters a, b, and context are already documented. The description adds the directional 'from a to b' framing but does not provide additional syntax or semantic detail beyond the schema.
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: compare two text files and return a unified diff from a to b. The 'like diff -u' analogy and mention of identical/binary handling make the tool's identity clear and distinguish it from siblings like read or search_text.
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 clearly establishes the use case: comparing two text files. It also gives exclusions by noting that binary and non-UTF-8 files are refused, but it does not explicitly name sibling alternatives or explain when to prefer them over this tool.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.