explain_cron

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

With no annotations provided, the description carries the burden of behavioral disclosure. It explicitly states the supported input format ('standard 5-field cron format') and the output nature ('plain English'). This adds valuable context about constraints, though it could mention error handling or unsupported variants. No contradictions.

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 description is two sentences long, front-loaded with the purpose and followed by a precise format specification. Every word earns its place; no redundancy or fluff.

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 tool with one parameter and no output schema, the description sufficiently covers the core function and output type ('plain English'). It also communicates the accepted input format. It could touch on edge cases (e.g., invalid expressions), but the described scope is clear and complete for typical usage.

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 'expression' parameter with examples (100% coverage), so the baseline is 3. The description adds meaning by explicitly enumerating the field order ('minute hour dom month dow'), which is not in the schema. This enriches understanding beyond the parameter description.

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 and resource: 'Explain a cron expression in plain English.' It clearly distinguishes from sibling date/time tools (now, date_diff, etc.) by targeting cron expression interpretation. The supported format is also specified, adding precision.

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 makes it clear when to use the tool: whenever a cron expression needs to be translated into human-readable text. It does not explicitly name alternatives or exclusions, but the context is evident from the sibling list and the description's clarity. No misleading guidance.

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