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 goes further by disclosing the exact return payload, including firing state (last_fired_at, next_fire_at) and any failure since the last successful firing — meaningful behavioral context that annotations cannot carry, and there is no output schema to do it either.

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?

One sentence, front-loaded with the action and scope, then the returned fields. No filler or repetition.

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 read-only getter with three fully documented parameters and no output schema, the description carries the return-value burden well by listing the payload fields. It omits edge behavior such as not-found or unauthorized responses, which is a minor gap rather than a blocker.

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 100%: all three required IDs carry pattern and format documentation. The description adds nothing about parameters, which is acceptable when the schema fully documents them, so the baseline 3 applies.

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 ("Returns one cron trigger") and enumerates the fields it yields, which clearly separates it from crons_list. It stops short of explicitly naming the sibling alternative, but the singular scope makes the distinction obvious.

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?

Usage is only implied: an agent infers this is the single-item retrieval for a known cron trigger ID, with crons_list for enumeration and crons_update for changes. There is no explicit when-to-use, prerequisite, or when-not statement.

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