Behavior Intelligence · Scoped answers
Codex and Gemini CLI document planning in their selected coding-agent evidence. Claude Code documents Plan mode, and Cursor documents a reviewable implementation plan before building. ChatGPT deep research provides a research plan users can modify. These are different workflows, not equivalent execution controls. Claude Research documents iterative investigation that chooses follow-up searches. Neither research workflow establishes permission to edit repository files.
Six product answers
Understand whether planning is an established interface or tool in the covered product context before relying on it in a workflow.
The selected Codex prompt excerpt explicitly names making and updating plans as part of the assistant's working interface.
Claude Research performs successive searches that build on earlier results and selects what to investigate next. This establishes iterative research work decomposition in Claude chat, not a separately reviewable implementation plan or coding-agent permission mode.
Plan mode researches and proposes changes before source edits. It can run exploratory shell commands and write a plan. Outside sessions with bypass permissions available, source edits remain blocked until plan approval. Command review depends on mode, settings, and version; approval exits planning into the selected execution mode. CLI evidence is not a universal read-only sandbox claim.
The selected Gemini CLI tools reference includes planning among the documented tool categories available to the CLI.
Deep research in Chat proposes a research plan that the user can review and modify before research. Availability and usage depend on plan and workspace controls. This does not establish a general coding-agent Plan mode or identical behavior in Work and Codex.
The editor agent researches the codebase, asks clarifying questions, and creates a reviewable plan before building. Plans can be edited and saved to the workspace. This describes a workflow, not a universal permission or isolation guarantee.