Start or Continue Codex Turn

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

The description adds valuable behavioral details beyond annotations: it returns as soon as the turn is accepted, meaning it is asynchronous, and it warns that thread_id is not a permanent task identity. Annotations already mark the tool as destructive/open-world, so this context complements them 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 three sentences with the core action front-loaded, followed by important nuances about thread reuse and asynchronous behavior. Every sentence earns its place with no redundancy.

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 output schema, the description appropriately clarifies the return value ('returns as soon as turn/start is accepted') and where to get actual results ('observe separately'). It doesn't cover error cases or param interactions, but the schema descriptions and annotations adequately cover those aspects.

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 already covers all 7 parameters with descriptions (100% coverage), setting a baseline of 3. The description adds a useful caveat about thread_id not being permanent, but does not significantly enrich parameter understanding beyond what the schema provides.

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 starts or resumes a Codex turn on a persistent thread, using a specific verb+resource. It distinguishes itself from siblings by being the entry point to initiate/continue turns, unlike interrupt/observe/steer.

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?

It provides explicit guidance on when to reuse a thread ('Prefer continuing the same native thread when its context remains useful') and when a fresh thread is allowed. It also directs the agent to 'observe separately for events and completion', indicating this tool is not for getting results directly.

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