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

Annotations already declare read-only, idempotent, and non-destructive behavior. The description adds useful behavioral constraints such as 'registry=all is NOT supported here' and mentions the 25-tag limit for Docker Hub, plus registry-specific extras in the output, which goes beyond annotations.

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 main action, then a critical constraint, and finally a summary of output contents. Every sentence earns its place with no redundancy or fluff.

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 two parameters and no output schema, the description provides a solid overview: supported registries, the 'all' limitation, and what each item contains. It could be more explicit about pagination for non-Docker registries, but for a simple list tool, it covers the essential usage context.

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% with descriptive fields for both 'name' and 'registry'. The description adds minimal new parameter-level information, mostly reinforcing that a single registry must be chosen, which is already implied by the enum. The output details (extras) are more about return values than parameters.

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 the tool lists published versions for npm/PyPI, image tags for Docker Hub, and extension versions for VS Code. It distinguishes itself from sibling tools by focusing specifically on version/tag enumeration, and even clarifies that 'registry=all' is not supported, making the purpose unambiguous.

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 context on when to use the tool (list versions/tags for a package) and explicitly instructs to pick a single registry. However, it does not explicitly contrast with alternatives like get_package or get_downloads, so it lacks a full 'when-not-to-use' guidance.

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