diff_text

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

With no annotations, description covers idempotency ('Has no side effects — does not modify either input'), cost ('Free'), and limits ('Input is capped at 5000 lines per string'). Adequate behavioral disclosure.

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 cover output, side effects/cost, and use cases/limits. No wasted words, key info front-loaded.

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?

Despite no output schema, description fully specifies return value ('unified diff string, or '(no differences)' when inputs are identical') and input constraints. For a 5-param tool with schema coverage, it is complete.

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 coverage is 100%, so baseline 3. Description does not add new parameter details beyond what schema provides; only implies context lines and labels via mention of 'context lines'.

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?

Description clearly states 'Compare two text strings and return a unified diff', using a specific verb and resource. It distinguishes from sibling tools like count_tokens or hash_text by being the only diff tool.

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?

Explicitly lists use cases: 'Use for review agents, changelog generation, and patch creation.' No exclusions mentioned, but context is clear.

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