codex_models

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

With no annotations, the description carries the behavioral disclosure burden. It clearly identifies the operation as a list and explicitly reveals cursor-based pagination via nextCursor. It does not mention side effects, but 'List' strongly implies a read-only operation and the pagination detail is meaningful disclosure.

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?

Two sentences, front-loaded with the core purpose, followed by the pagination instruction. No redundant content or filler.

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?

For a one-parameter list tool with no output schema, the description covers the essential behavior and pagination. It does not explicitly describe the response shape, but the name and 'list' semantics make the return value predictable enough. Slightly more detail about the first-page call would make it fully complete.

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 schema only provides 'cursor' as a string; schema coverage is 0%. The description compensates by explaining that cursor should be set to the nextCursor value to fetch another page, which gives the agent exact semantic guidance for the only parameter.

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 uses a specific verb 'List' with a clear resource, 'available Codex models', which is distinct from the sibling operations (start, message, stop, etc.). The agent can immediately tell this tool is for enumerating models, not running a session.

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 intended use case is implied by the listing purpose, but the description does not explicitly say when to use this tool versus the sibling tools or provide any exclusions. It would benefit from a note such as 'use before codex_start to select a model.'

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