search_packages

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

Annotations already declare readOnlyHint, idempotentHint, and openWorldHint, so safety is covered. The description usefully adds that only two of the seven enum ecosystems are searchable, but it does not say what actually happens if ecosystem='pypi' is passed (error vs. empty result), which is the one behavioral question an agent will have.

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?

Three short sentences, zero waste, and the applicability constraint is front-loaded before the fallback instruction. Every sentence earns its place.

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?

No output schema exists, and the description says nothing about the return shape (list of results, ranking, fields per result), which would help an agent plan next steps. Otherwise complete for a read-only search tool whose safety profile is carried by annotations.

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 0%, so the description must carry parameter meaning. It clarifies the most important parameter, ecosystem (only npm/cargo are valid despite the seven-value enum), but says nothing about query semantics or the limit cap of 25, leaving half the params unexplained.

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 (Search) with the resources it applies to (npm / crates.io) and immediately bounds the scope by naming the sibling that handles everything else. An agent can distinguish it from get_package without opening either schema.

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?

Explicitly says where search works (npm, crates.io), where it does not (PyPI), and what to do instead for other ecosystems (exact name via get_package). This is a full when/when-not/alternative routing statement.

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