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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, open-world), yet the description adds real behavioral value: ranking is npm relevance order and readiness is annotated rather than filtered, so CJS-only results remain visible. It stops short of mentioning rate limits, auth, or network failure behavior.

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?

Purpose is front-loaded in the first clause, and each subsequent phrase carries new information (readiness categories, entry file/size, ranking, non-filtering). The middle sentence is long and stacks several clauses, but nothing is redundant.

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 an output schema, a complete input schema, and rich annotations, the description supplies what those cannot: what the readiness annotations mean and that results are not silently dropped. Only the relationship to sibling resolution tools is left implicit.

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 query and limit are already documented, including the default of 5 and the maximum of 10. The description's "search for a need" phrasing reinforces that query is intent-based rather than a package name, but adds no syntax or format detail beyond 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?

States a specific verb and resource ("Search npm") plus a concrete example-driven notion of the input ("a need (e.g. 'date picker', 'markdown parser')"), and the added value (browser-readiness annotation for UNPKG lookup) distinguishes it from siblings like resolve_package or shield_check_packages.

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?

Usage is implied: this is the discovery entry point that produces candidates annotated for direct UNPKG file lookup. However, it never explicitly says when to prefer this over resolve_package or shield_check_packages, nor does it describe prerequisites or follow-up steps, so the agent must infer the routing.

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