codex_capabilities

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

The description adds behavioral context beyond the annotations: it clarifies that the operation is free and makes no model call. The annotations already indicate read-only, idempotent, and non-destructive behaviors, so the description complements them well without contradiction.

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 extremely concise with two short sentences. It front-loads the core purpose and adds useful caching information without any extraneous text.

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 no parameters, a rich set of annotations, and an output schema present, the description is fully adequate. It explains what the tool lists, that it is free, and that caching is supported based on the fingerprint.

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 has no parameters, and the input schema is fully covered (100%). According to the rubric, zero parameters baseline is 4, and the description does not need to add parameter details.

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 this server's tools, tiers, and the result fingerprint. The verb 'list' specifies the action, and the resource 'capabilities' is well-defined. It distinguishes from sibling tools like codex_consult and codex_models because it is the only one providing an overview of available tools and tiers.

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 valuable context: it is free with no model call, and clients can cache by the fingerprint. While it does not explicitly state when to avoid using this tool or name alternatives, the context is clear and helpful for deciding when to invoke it.

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