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

Annotations already cover read-only, idempotent, non-destructive, open-world behavior, so the description's added value is its negative-result semantics: only packages with something known are listed, and with complete=true a miss means nothing is known against that name. That is genuinely useful behavior the annotations cannot express, though it says nothing about rate limits or result volume.

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?

One dense paragraph with zero filler: scope first, negative semantics second, follow-up routing third, exclusion last. Every sentence carries a distinct decision-relevant fact.

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?

An output schema exists, so return values need no explanation. For a multi-ecosystem lookup tool, the description covers coverage scope, empty-result meaning, and the handoff to check_package, leaving nothing an agent needs in order to call it correctly.

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% and the single parameter is already well documented with the two-character minimum and full-name examples. The description still adds matching semantics beyond the schema by clarifying that the term may be the start of a name (prefix matching), which the schema states only implicitly.

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: find open-source packages with known vulnerabilities or malicious reports, enumerated by ecosystem (npm, PyPI, Maven, Go, crates.io, NuGet, RubyGems, Packagist, VSCode). It clearly separates itself from check_package (details) and find_product (a different resource), so an agent can route without opening a 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?

Gives explicit when-to-use (partial name lookups), when-not (Linux distribution packages are excluded), and the alternative to use instead (check_package with the release directly). It also tells the agent the follow-up step: pass a result's ecosystem and name to check_package.

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