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

Annotations declare readOnlyHint=false, destructiveHint=false and openWorldHint=true; the description usefully clarifies that the side effect is only a report file and no email is dispatched, and that it returns an export id. It stops short of stating idempotency behavior (whether repeat calls spawn duplicate exports) or any rate limits, which the idempotentHint=false annotation alone leaves ambiguous.

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?

Three tight sentences, front-loaded with the action, then the return/poll path, then the safety caveat, ending with the endpoint. Nothing is redundant and the 60-day limit is embedded where it belongs.

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 3-parameter tool with full schema coverage and no output schema, the description supplies the missing pieces: what is returned (an export id), how to retrieve the result, and the 60-day window. An agent has everything needed to call it and follow up correctly.

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%, so baseline would be 3, but the description adds a constraint not present in the schema: the start date can be at most 60 days back. The two optional filters aren't discussed, but the schema documents both thoroughly, so the added value is real if partial.

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 ("Start a CSV export of the transactional email delivery report") with the exact scope (a period). It also names the sibling it hands off to (enginemailer_check_transactional_report_export), so an agent can separate the two without opening schemas.

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 explicit when-to-use context (a start date at most 60 days back), names the follow-up tool to poll with, and pre-empts the common misunderstanding with "Creates a report file only; nothing is sent." The exclusions and the alternative are both spelled out.

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