Get the list of distributions available to build images with.

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

Annotations indicate readOnlyHint and openWorldHint. The description adds important behavioral context beyond annotations, such as the limited version support for RHEL and the unsupported status of CentOS Stream. This helps the agent understand the tool's behavior without contradicting 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 very concise, using sections, emoji, and bold for clarity. Every sentence adds value: immediate usage instruction, key distribution details, and return type. No 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?

Given zero parameters and an existing output schema, the description is complete. It explains what distributions are included/excluded and returns a list, providing sufficient context for the agent.

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?

There are no parameters (schema coverage 100%). The description explains the return value ('List of distributions'), adding meaning beyond the schema. Since no parameters, it effectively covers what the tool outputs.

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 a list of distributions for image building. It specifies support for RHEL (only latest minor version), Fedora (similar but no official versions), and explicitly mentions CentOS Stream is not supported, distinguishing it from other image-builder tools.

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,' which provides explicit usage guidance. It also explains distribution specifics, helping the agent decide when to use this tool, though it does not directly compare to siblings.

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