close_codex_agent

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

With no annotations, the description carries the full burden for behavioral disclosure. It does reveal the non-obvious behavior that the last known result is kept, which is helpful. However, it omits important traits for a mutating/destructive operation: whether the agent is terminated, idempotency, what happens if the agent is not idle, and any side effects or permission requirements.

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 a single, front-loaded sentence that states both the action and the key behavioral outcome. It contains no filler, redundancy, or irrelevant detail, making it highly efficient.

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 the tool's low complexity (one parameter), the presence of an output schema, and a clear one-sentence description, the core functionality is reasonably covered. However, it lacks usage guidance and behavioral caveats that would make it fully self-contained for an agent deciding whether and when to invoke it.

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?

Schema description coverage is 0%, so the description must compensate for the undocumented agent_id parameter. It does not explain the format, how to obtain it, or whether it refers to a session ID or process ID. The parameter name is self-explanatory at a basic level, but no additional semantic value is provided beyond the raw schema.

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 ('Close') and resource ('idle Codex agent'), and adds a meaningful outcome ('keep its last known result'). This clearly distinguishes it from sibling tools like spawn_codex_agent, wait_codex_agent, and list_codex_agents, which handle other lifecycle stages.

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 phrase 'idle Codex agent' implies it should be used when an agent has finished some work and no longer needs to execute, and 'keep its last known result' signals that results are preserved. However, it does not explicitly state when to use this versus waiting (wait_codex_agent) or listing (list_codex_agents), nor does it mention any exclusions.

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