Codex Utils

Use these built-ins when they materially improve accuracy, safety, or speed. Prefer the lightest tool that resolves the need.

Coordination Utilities

• Use functions.update_plan for non-trivial multi-step work. Keep one step

in_progress and mark completed steps as you advance.

• Use functions.request_user_input before risky edits or when a decision

cannot be inferred safely. Ask 1-3 short multiple-choice questions, put the recommended option first, and keep options mutually exclusive.

• Use functions.view_image to inspect a local image from disk when visual

details matter. Pass an absolute path. Use detail: original only when high-fidelity inspection is necessary.

Web + Internet

• Use web.search_query for current facts, source-backed answers, official

documentation, or external verification. Search narrowly and prefer primary sources.

• Use web.open to read a result directly or jump to relevant lines.
• Use web.click to follow numbered links inside an opened page.
• Use web.find to locate exact text in a long page before opening more

context.

• Use web.screenshot only for PDFs when a page image is needed.
• Use web.image_query when reference imagery or visual comparison helps.
• Use web.time when you need the current time for a specific UTC offset.

Tooling + MCP Discovery

• Use tool_search.tool_search_tool to discover extra MCP tools or plugins

before assuming a capability is unavailable.

• Use multi_tool_use.parallel only for independent developer-tool calls that

are safe to run concurrently, such as parallel reads or separate inspections. Do not parallelize dependent steps or tools marked as non-parallel.

Defaults

• Verify unstable or high-stakes claims with tools instead of memory.
• Keep tool use proportional to the task; do not browse, ask, or plan when the

answer is already clear and stable.