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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is covered. The description adds real behavioral context beyond that: the field set returned and the explicit 'or not-found' failure outcome, which tells the agent how to interpret a miss.

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?

Front-loaded with the usage trigger, then the return contract, then the exclusion — a sensible ordering with no filler. The middle enumeration sentence is dense and partially duplicative of the output schema, but it stays readable.

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?

An output schema exists, so the return-value enumeration is not strictly necessary, but the not-found disclosure and the when-to-use trigger round out the definition. Nothing an agent needs to call a single-id, read-only lookup correctly is missing.

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 the single jobId parameter is fully documented with type and constraints, so the schema carries this dimension. The description only implies the id selects one job ('one cron job's'), adding no format or lookup 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?

States a specific verb and resource (retrieve one cron job's details) and enumerates the retrievable fields, so the agent knows exactly what comes back. The closing clause 'Not for running the job' separates it from run_job without needing to open either schema.

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?

Gives a concrete trigger ('when someone asks about one cron job's schedule or target, or whether it is enabled and last succeeded') and an explicit exclusion ('Not for running the job'), which routes the agent toward run_job for execution. It does not name sibling tools like get_job_runs for run history, so the routing is clear but not exhaustive.

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