Codex Plan Review

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

With no annotations, the description must carry behavioral disclosure. It does state what the tool produces—critique of gaps, risks, edge cases, improvements—but it does not mention whether the operation is read-only, whether it only returns text, or any side effects or prerequisites.

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?

One sentence, front-loaded with the action and resource, and every clause adds useful information. No filler or repetition of the tool name or title.

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 is enough to understand the core purpose, but with no annotations and no output schema, it leaves out useful context such as return format/behavior and how this tool relates to sibling codex_plan_perf. The schema handles parameter documentation, so the remaining gap is guidance on alternatives and output expectations.

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 80%, so the baseline is 3. The description's mention of 'implementation plan' aligns with the required plan parameter but adds little semantic detail beyond the schema's own descriptions for threadId, constraints, and codebasePath.

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 ('critique') and identifies the resource ('implementation plan'), and lists concrete outcomes: gaps, risks, missing edge cases, and improvements. It clearly distinguishes from code review and explanation tools, though it does not explicitly differentiate from the sibling codex_plan_perf, which also targets plans.

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 is implied: bring an implementation plan to get a critical review. However, it provides no explicit when-to-use guidance, no exclusions, and no alternative routing such as 'use codex_plan_perf for performance-specific plan review.'

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