List Packages

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

Annotations already declare readOnlyHint=true, so the safety profile is covered. The description adds the success/error return shape, but since an output schema is present, this largely duplicates structured information. It does not disclose additional behavior such as ordering, pagination, auth requirements, or performance characteristics.

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?

The description is short and front-loaded with the core purpose. The Returns block is a bit verbose relative to the simple purpose, but it is clear and structured. No unnecessary filler beyond the redundant repetition of 'all packages' in the success case.

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 zero-parameter, read-only listing tool with an output schema and clear annotations, the description is fully adequate. An agent can invoke it without further clarification, and the result format is explicitly described.

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 has zero parameters, so there is nothing for the description to explain. With 100% schema coverage and no parameters, the baseline of 4 is appropriate; the description does not need to compensate for missing parameter documentation.

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 clearly states the operation: 'Get list of all packages.' It uses a specific verb and resource, and the Returns section confirms the output is package names. This distinguishes it from sibling tools like list_classes and list_methods.

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?

The first line gives clear context for when to use the tool: when a list of all packages is needed. It does not explicitly name alternatives or exclusions, but the tool's scope is unambiguous and no sibling tool offers the same 'all packages' behavior.

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