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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint=false, and destructiveHint=false, so the safety profile is fully covered. The description adds that the payload includes aliases, distribution release requirements, and dependency-check limits, which is genuinely useful context, but it discloses nothing further about volume, currency/staleness of the catalog, or versioning.

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 sentences, both front-loaded with the enumerations an agent needs. The closing rule is compact but punningly terse ('must remain unknown'), which costs a little clarity for the sake of brevity.

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 parameters, full annotation coverage, and an output schema handling return structure, the description only needs to convey purpose and call timing, which it does. The catalog's freshness and how identities map into check_dependencies inputs are 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?

The tool takes zero parameters, so the schema-burden baseline of 4 applies. Nothing in the description needs to explain arguments, and the sentence about unknown identities is a behavioral rule rather than a parameter claim.

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 ('List') plus a precisely scoped resource ('supported OSV ecosystems, package-manager aliases, distribution release requirements, and dependency-check limits'), which is plainly distinct from the sibling tools check_dependencies, get_cve, and list_cve_updates. It stops short of naming a sibling to contrast with, so it is clear but not fully differentiating.

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?

'before choosing package identities' gives a concrete call-timing rule, and 'Unsupported or ambiguous identities must remain unknown' tells the agent not to guess ecosystem names. What is missing is an explicit pointer to check_dependencies as the follow-up tool once valid identities are known.

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