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 states that differences are shown 'line by line', but it does not disclose the diff format (e.g., unified, +/− markers), whether the output is a string or structured data, or behavior on identical inputs. This is insufficient for an AI agent to predict the tool's exact output representation.

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 core description is a single, concise sentence that front-loads the primary purpose. However, the leading bracket '[PRO — 3 trial uses left]' is extraneous with respect to tool functionality, adding noise without value. This minor bloat prevents a perfect score.

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 tool is relatively simple with two string parameters and no output schema, so the description is somewhat adequate. Yet, the absence of any mention of return format or edge cases (e.g., large inputs) leaves a gap. The existence of a sibling json_diff tool suggests a note about text-vs-JSON usage would round out the context. Overall, it is minimally complete but lacks some helpful context.

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 clear descriptions for both parameters: 'First text (original)' and 'Second text (modified)'. Coverage is 100%, so the schema adequately explains the parameters. The description itself does not add any further semantic nuance beyond what the schema already provides, so a baseline score 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 uses a specific verb 'Compare' and clearly identifies the resource 'two text strings'. It also specifies the output type 'show the differences line by line', which distinguishes it from siblings like json_diff that compare JSON structured data rather than arbitrary text. The purpose is 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 implies usage for comparing plain text strings, but it does not explicitly state when to use this tool over alternatives. Since a sibling tool named json_diff exists, an explicit note about using diff for non-JSON text would improve clarity. However, the 'line by line' mention gives some contextual cue about the intended use case.

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