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

Annotations declare readOnlyHint=true, and the description adds that the output is a plain-English breakdown and next run times in UTC. It does not explicitly state that 'next few' are relative to the current time, but with readOnly hint and output schema present, this is adequate.

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?

Two sentences, front-loaded with the core action and then the usage rationale. No redundant words; every clause adds value.

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 a single parameter and an output schema, so the description does not need to explain return structures. It covers the input format, output nature, and timezone, which is complete for this simple utility.

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% and includes an example, but the description further clarifies the field order ('minute hour day-of-month month day-of-week'), which is not in the schema's brief '5-field cron expression' text. This adds meaningful semantics beyond the 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 uses a specific verb ('Parse') and identifies the exact resource (standard 5-field cron expression) and the two outputs (plain-English breakdown and next run times). It clearly distinguishes this from sibling tools, none of which relate to cron parsing.

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 suggests when to use it ('Use to sanity-check a schedule instead of guessing what the fields mean'), which tells the agent the intended context. It doesn't mention exclusions or alternatives, but no sibling tool overlaps, so the guidance is sufficient.

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