Convert cron between schedulers

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

Annotations already declare readOnlyHint=true and idempotentHint=true, so the description need not repeat those. It adds meaningful behavioral context beyond annotations: it specifies handling of seconds and year fields, ? rules, weekday numbering as names, and explicitly states it explains why when the target cannot express a conversion. This enriches the agent's understanding of edge cases and error behavior.

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 concise sentences with zero filler. The main action ('rewrites') and supported schedulers are front-loaded, followed by specific conversion rules and error behavior. Every word earns its place; no redundant information or repetition of schema fields.

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?

Given the tool's moderate complexity (3 params, output schema exists), the description covers the core conversion behavior and error handling ('says why when the target cannot express it'). The output schema covers return values, so that need not be described. It omits details about the input expression's accepted format, but that is largely covered by the schema's maxLength and the implied cron syntax. Overall, it provides sufficient context for correct invocation, though it could mention auto-detection of 'from' explicitly rather than relying on the schema.

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 description coverage is only 33% (only 'from' has a description: 'detected when omitted'). The description does not explain the 'expression' parameter or the 'to' parameter beyond listing allowed schedulers in the enum. It fails to compensate for the low coverage, leaving agents without guidance on how to format the expression or what the target scheduler value means semantically.

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 clearly states the tool's function: 'Rewrites a cron expression for another scheduler' and explicitly lists the six supported schedulers. It also mentions specific conversion details (seconds, year fields, ? rules, weekday numbering) that distinguish it from the sibling tools explain_cron and next_runs. The purpose is unambiguous and differentiates well from siblings.

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 cron conversion but does not explicitly mention when to use this tool versus alternatives like explain_cron or next_runs. There are no exclusion criteria or comparative guidance, leaving the selection to inference. The distinct verb 'rewrites' helps, but explicit routing is missing.

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