Get the list of distributions available to build images with.

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

The description adds significant behavioral context beyond the annotations (readOnlyHint, openWorldHint). It specifies that only RHEL latest minor versions are supported, Fedora is similar but unofficial, and CentOS Stream is unsupported—important traits for an agent to know.

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 concise with a clear front-loaded purpose. The inclusion of emoji and extra details about distribution support adds value but could be slightly streamlined. Overall, 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?

With no parameters and an output schema present, the description covers all needed context: it specifies the output (list of distributions) and key constraints (RHEL, Fedora, CentOS). It is complete for an agent to use 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?

The input schema has zero parameters, so schema description coverage is 100%. The description does not need to elaborate on parameters. Baseline for 0 params is 4, and the description provides no parameter information, which is acceptable.

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 retrieves the list of distributions for building images. It uses a specific verb ('get') and resource ('list of distributions'), and the context 'available to build images with' distinguishes it from sibling tools like image-builder__get_blueprints.

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 includes 'CALL IMMEDIATELY - No information gathering required,' providing strong guidance on when to use the tool. It also details distribution-specific constraints (RHEL, Fedora, CentOS Stream), but it does not explicitly compare with siblings or state when not to use it.

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