cron_next

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

With no annotations, the description carries the full burden and it largely succeeds: it states the computation behavior, supported aliases, UTC interpretation of from_iso, and the return structure. It does not explicitly say the operation is side-effect free or describe error behavior, but for a pure computation tool the disclosed details are sufficient.

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 well-structured and efficient: a one-sentence purpose, a short alias note, then labeled Args and Returns sections. Every sentence is informative and there is no repetition of schema information beyond what is useful.

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 three-parameter, no-output-schema tool with no annotations, the description is complete: it explains the input format, defaults, constraints, and the exact return keys. The only omitted details (e.g., invalid-expression error behavior) are minor for this utility class and do not hinder correct invocation.

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 0%, so the description must compensate. It fully documents all three parameters: expression includes a standard cron example and alias support; from_iso specifies ISO-8601/UTC and default 'now'; count states numeric range and default. This adds substantial meaning beyond the bare 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 begins with a specific verb and resource: 'Compute the next N runs of a 5-field cron expression.' This clearly states what the tool does and distinguishes it from the sibling utilities (e.g., convert_timezone, lookup_timezone) which handle different time-related tasks. Including alias support examples further clarifies the scope.

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 by defining the tool's purpose and arguments, and provides clear context such as UTC starting point and count range. It does not explicitly name alternative tools or state when not to use it, but none of the siblings overlap with cron computation, so the absence of an explicit exclusion is not a significant gap.

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