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

With no annotations, the description carries the full transparency burden. It states the action and the granularity of the output ('per-field differences'), implying a read-only, side-effect-free operation. It does not disclose error handling or the exact output format, but for a simple comparison tool, this is adequate. The description adds meaningful behavioral context beyond a naive 'compare'.

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?

A single, front-loaded sentence with no waste. It states the core action and expected output in 11 words, making it highly scannable and efficient.

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 has only two string parameters and no output schema or annotations. The description conveys the function and result shape at a high level ('per-field differences'), which is sufficient for an agent to select and invoke it. However, it does not detail the output structure (e.g., a map of field names to values/differences), leaving a minor gap.

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%, with each parameter ('first' and 'second') already described as cron expressions. The tool description's 'Compare two cron expressions' does not add further parameter-specific meaning, so the schema carries the weight. Baseline 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'), names the resource ('two cron expressions'), and states the outcome ('return per-field differences'). It clearly differentiates from sibling tools like explain_cron (which explains a single expression) and validate_cron (which validates).

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 implies when to use it: when you need to compare two cron expressions. It does not explicitly exclude alternatives or mention sibling tools, but the verb 'compare' naturally distinguishes it from explain, generate, validate, and next_runs. Slightly more explicit guidance (e.g., 'use instead of explain_cron when comparing two expressions') would make it a 5.

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