List packages

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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint, so the safety profile is covered. The description adds genuine behavioral value on top: the 403 refusal for non-reseller accounts and the MXROUTE_USERNAME configuration constraint that makes the tool unavailable.

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 tight sentences with the purpose front-loaded before the access caveats. Slightly compressed notation (`reseller|user` form) but no wasted words.

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?

With zero parameters, no nested objects and no output schema, the description covers what the agent needs: the shape of the result (names) and the conditions under which the call fails. Only minor gaps remain, such as whether a non-reseller call errors or returns empty.

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?

The tool takes zero parameters, so the baseline is 4. There is nothing for the description to disambiguate, and it correctly implies no filtering arguments are accepted.

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 (Lists) and resource (the reseller's packages) and narrows the return to names, which distinguishes it from get_package, create_package and the other package siblings. An agent can tell immediately what it gets back and that it is a read-only enumeration.

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 when-not condition: reseller accounts only, regular accounts refused with 403, and unavailable while MXROUTE_USERNAME is in `reseller|user` form. It stops short of naming an alternative tool (e.g. get_package for detail on a single package), so it is clear context rather than full routing.

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