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

With no annotations, the description carries the behavioral disclosure burden. It does disclose that the working directory inherits from the MCP process and that the return is clean Codex CLI output, which is useful. However, it does not mention potential side effects, permissions, or execution constraints, leaving notable gaps.

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 appropriately structured with a clear opening line, a brief explanatory paragraph, and then Args/Returns sections. It is mostly concise, though the cwd resolution explanation is slightly verbose. Overall, it earns its place.

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 simple tool with one parameter and an output schema, the description covers the essential operational detail (cwd resolution) and the return format. It is complete enough for an agent to invoke the tool correctly, though it could add a note about the parallel sibling.

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 provides zero parameter descriptions, but the description's 'Args' section explains that 'prompt' should contain all instructions/context needed for the task. This adds meaningful semantics beyond the raw schema, compensating for the lack of schema-description coverage.

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 spawns a Codex agent in the current working directory, providing a specific verb and resource. However, it does not explicitly distinguish from the sibling tool spawn_agents_parallel, so it falls short of a 5.

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 explains how the working directory is resolved but gives no explicit guidance on when to use this tool versus the parallel alternative. There is no mention of criteria like single vs. multiple agents, so the agent is left without clear selection cues.

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

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

With no annotations, the description carries the behavioral disclosure burden. It discloses that each spawned agent reuses the server's current working directory (os.getcwd()) and describes the return structure. This adds valuable context beyond the raw function name, though it does not cover all potential side effects or concurrency details.

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 concise and well-structured: a clear purpose sentence, a behavioral note, and compact Args/Returns sections. Every line earns its place with no redundant information.

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?

The description covers the tool's purpose, parameter shape, and return format, which is sufficient for its simplicity. It could be slightly more complete by explicitly referencing the singular spawn_agent alternative, but overall it provides all necessary operational context.

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 has zero description coverage, so the description fully compensates. It explains that agents must be a list of objects with a 'prompt' entry and provides a concrete example, which is much richer than the bare schema definition.

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 opens with 'Spawn multiple Codex agents in parallel,' which is a specific verb+resource statement. It clearly distinguishes itself from the sibling tool spawn_agent by emphasizing 'multiple' and 'in parallel'.

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 implies use when multiple agents need to be spawned concurrently ('Spawn multiple Codex agents in parallel'), and the sibling context reinforces this. However, it does not explicitly state when not to use this tool or mention alternatives by name.

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