Compare alternative packages

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

Annotations already declare readOnly/idempotent/openWorld, and the description adds meaningful context: the result is a ranking by maintenance health and inputs must be 2-5 alternatives from one registry. It doesn't discuss caching, rate limits, or data freshness, so not a 5.

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: the capability and its concrete example come first, the usage cue second. No filler.

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 no output schema, the description telling the agent that results are ranked by maintenance health covers the key expectation for a read-only comparison tool. Return shape and scoring method remain unspecified, but nothing needed to invoke it is missing.

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 is 3; the description earns extra by adding the constraint that packages must come from the same registry, a rule the schema does not encode. Example values (moment vs dayjs) also aid interpretation, though per-item format is left to the schema.

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?

Specific verb (compare) plus resource (2-5 alternative packages from a registry or GitHub repos) with concrete examples and the ranking criterion (maintenance health). Combined with the title, it's immediately distinguishable from check_package (single) and scan_manifest (manifest-wide).

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?

'Use when choosing between libraries' gives a clear triggering context, and 'from the same registry' sets a precondition. It stops short of naming when not to use it or pointing at check_package/scan_manifest as alternatives.

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