spawn_codex_agent

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

With no annotations, the description must fully disclose behavior. It mentions 'background' and 'Claude Code-style lifecycle' but does not explain important traits like how the worker is managed, how to interact with it, or what happens on timeout. This leaves significant ambiguity for an agent.

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 concise sentence that front-loads the action, containing no extraneous words. However, it is under-specified, so while structure is good, the content is minimal.

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 complexity (7 parameters, output schema) and lack of annotations, the description is too sparse. It does not clarify the lifecycle, return behavior, or parameter usage, making it insufficient for an agent to invoke correctly.

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% (no parameter descriptions in the schema), and the description does not explain any of the 7 parameters (prompt, cwd, model, sandbox, timeout, agent_type, description). It fails to compensate for the lack of schema information.

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 the verb 'Start' with a specific resource ('background Codex worker'), making the core function clear. It distinguishes itself from sibling tools like execute by specifying 'background' and 'Claude Code-style lifecycle', though it does not explicitly name alternatives.

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 no guidance on when to use this tool versus alternatives like execute or parallel_execute, nor does it mention any exclusions or prerequisites. The only hint is 'background', which implies async use, but there is no explicit context.

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