Scan packages against OSV advisories

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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint and destructiveHint=false, so the safety profile is covered and the description's "Read-only" is redundant. What it adds beyond annotations is the required scope ("aegis:read") and the behavioral consequence of omitting versions (advisory listing rather than precise matching). Output shape is also noted, though an output schema exists.

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 core capability is front-loaded in the first sentence, followed by return contents, safety, scope, and a caveat. Every sentence carries information, though the ecosystem list and "Read-only" partially duplicate the schema enum and annotations.

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 a rich schema, full description coverage and an output schema, the only things the description must supply are scope, external dependency (OSV.dev) and version-matching caveat, all of which are present. Minor gaps: no mention of the 20-package cap, error behavior, or how results map back to each queried package.

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 100%, so the nested PackageQuery fields, the ecosystem enum and the version default are already documented. The description reinforces the package/version pairing semantics and the ecosystem scope but adds no new constraints beyond the schema, such as the 20-item batch limit or behavior on partial matches.

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 gives a specific verb and resource ("Query OSV.dev for vulnerabilities affecting one or more package/version pairs") and enumerates supported ecosystems, so the agent knows exactly what the tool does. It does not explicitly distinguish itself from siblings like lookup_cve or search_vulnerabilities, forcing the agent to infer the boundary from the package-oriented framing.

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 rather than stated: the agent can infer this is the batch/package-oriented scan versus a single-CVE lookup, but no sibling is named and no when-not-to-use condition is given. The one real guideline is "Caller must supply installed versions for precise matching," which is useful but narrow.

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