Codex Performance Plan

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

No annotations are provided, so the description carries the burden. The description discloses that it 'identifies bottlenecks' and produces 'ranked optimizations with expected impact', which gives some behavioral context about output. However, it doesn't disclose whether it modifies code (mutating) or only produces a plan, required permissions, side effects, or how the plan is delivered. For a tool whose verb is 'ask Codex to analyze', the mutating-vs-read nature is ambiguous.

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?

Two sentences, both substantive, with zero waste. The first sentence states the purpose, the second elaborates on what analysis entails. Front-loaded and 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?

The tool has 6 parameters and no output schema, so the description needs to convey what the user gets back. It mentions 'ranked optimizations with expected impact' which hints at the deliverable. However, for a tool with no annotations and no output schema, it doesn't fully clarify whether the output is a plan document, an in-conversation response, or a written artifact, nor the mutability/side-effect profile. Adequate but with clear gaps.

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 83%, so most parameters (target, context, metrics, threadKey, constraints) are already documented in the schema. The description adds the 'target' purpose implicitly as the optimization focus. With high schema coverage, baseline is 3, and the description adds little beyond what the schema already provides, though 'metrics' enum values align with performance focus.

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 verb ('analyze performance and create an improvement plan'), identifies the resource (Codex), and specifies scope ('identifies bottlenecks, proposes ranked optimizations with expected impact'). It distinguishes from siblings like codex_query and codex_review_code by focusing specifically on performance analysis and improvement planning, though it doesn't explicitly name sibling 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 implies when to use it (performance analysis/optimization scenarios) but provides no explicit exclusions or comparisons to alternatives such as codex_review_code or codex_review_plan. There's no guidance on when this tool should NOT be used or how it differs from the review/plan siblings, so the usage context is only implied rather than explicit.

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