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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, so the safety profile is clear. The description adds useful behavioral details beyond annotations: it explains the LCS algorithm, exact comparison sensitivity, and how edits are represented as a removal plus an addition. This helps set expectations for the result format.

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?

Three sentences with no filler. The core behavior is front-loaded, and the extra details about edited lines and comparison sensitivity are directly useful. The source URL is a minor but reasonable inclusion.

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 two-parameter read-only tool with a full input schema and an output schema, the description is complete. It explains the algorithm, comparison semantics, and result interpretation. Nothing needed for correct invocation is missing.

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 schema already describes the two parameters (original left text, changed right text) with 100% coverage. The description adds meaning by explaining that comparison is line-by-line and exact, which clarifies how the parameters relate to each other. It does not merely repeat 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?

The description states a specific operation: comparing two texts line by line using a longest common subsequence diffhare, and reports which lines are added or removed. It clearly distinguishes this tool from the many calculator and text-manipulation siblings by specifying the exact diffing behavior and output style.

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 clear context: it is for line-by-line text comparison, with exact matching including spaces and case. It does not explicitly name alternatives or when not to use it, but the behavior is specific enough that an agent can infer its use case. No sibling tool directly competes with it.

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