Licenses of packages

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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the agent knows it's a safe read. The description adds meaningful behavioral details beyond annotations: the limit of 50, the list of ecosystems, optional version handling, the yes/no/check compatibility result, copyleft flagging, and the 'worst first' ordering. No contradiction with annotations.

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 a single, dense sentence with no filler. It front-loads the core action and then lists specifics efficiently. Every clause adds information: the package count, ecosystems, version handling, compatibility check, copyleft flag, and sorting. No redundancy.

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?

Given the tool's complexity (multiple ecosystems, version logic, compatibility assessment, copyleft flagging, ordering), the description covers all essential behaviors an agent needs to call it correctly. The output schema exists, so return format is handled elsewhere. The only minor omission is the exact meaning of 'check' in the compatibility result, but that's likely defined in the output schema and does not impede correct invocation.

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 only 50% (project has a description, packages does not). The description compensates by explaining the ecosystem list and that a version is optional ('a version, or the latest'), which clarifies the packages parameter's sub-fields. However, it doesn't explicitly map each schema field (name, version, ecosystem) to their roles, but the structure is obvious from the schema. The added value is moderate and helpful.

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 states a specific verb ('Looks up'), a clear resource ('licenses of packages'), and enumerates supported ecosystems and the optional version or latest behavior. It also explains the compatibility check and sorting ('Worst first'), which clearly distinguishes it from sibling tools like license_info (which likely just returns license data) and check_compatibility (which might check specific compatibility rules).

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 description provides clear context: up to 50 packages, which ecosystems, and that it checks compatibility against a project license when 'project' is provided. It implies when to use (when you need license compatibility screening) but does not explicitly name alternatives or exclusions. Sibling tools exist but are not referenced, so there's a slight gap in routing, but the context is strong enough.

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