search_packages

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

Annotations already declare readOnlyHint=true, destructiveHint=false, idempotentHint=true, openWorldHint=true. The description adds value by confirming no GitHub API usage, no rate limits, and detailing return types (PyPI: exact match with specific fields; npm: multiple results with links). No contradictions.

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 two sentences, front-loaded with the most critical clarification (not GitHub). Every sentence provides essential information with no redundancy or 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?

Given the tool's low complexity (3 params, simple read-only behavior) and no output schema, the description fully explains what to expect for both ecosystems and suggests chaining. It is complete for an agent to decide when and how to invoke it.

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 adds meaning by explaining that 'limit' only applies to npm and PyPI returns an exact match regardless of limit, which goes beyond the schema's description. It also implies the 'ecosystem' parameter selects behavior.

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 it searches packages on PyPI or npm, explicitly excludes GitHub, and distinguishes itself from siblings like search_repos. It specifies the exact verb 'search' and the resource 'packages', and details the different behaviors for each ecosystem.

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 usage context: for looking up package metadata and versions, and suggests chaining with search_repos. It also clarifies what it does not do (GitHub API, rate limits). Although it doesn't explicitly state when not to use, the guidance is sufficient.

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