Behavior Intelligence · Scoped answers

What persistent or custom instruction mechanisms are documented?

Claude Code, Gemini CLI, ChatGPT, and Cursor document persistent instruction mechanisms at different scopes: CLAUDE.md files, GEMINI.md context, ChatGPT custom and project instructions, and Cursor user or project rules. The selected Codex and Claude evidence does not establish comparable cross-project user instruction mechanisms. Those answers remain Not established; they do not claim the mechanisms are absent.

Six product answers

What the selected evidence establishes

Decide whether durable guidance belongs in user settings, repository files, workspace context, or another documented scope.

Open-source agentic coding interface

OpenAI Codex

Not established

Direct factual answer

The selected Codex evidence establishes repository guidance, but not a separate persistent user preference mechanism that applies across projects.

Surface: Not established
Model context: Not established
Configuration / version scope: Not established
Reviewed: 2026-08-11

Limits and uncertainty

Repository AGENTS.md behavior is answered separately from cross-project custom instructions.

Evidence

No supporting evidence is linked because the selected sources do not establish this behavior.

Web, desktop, and mobile AI assistant

Claude

Not established

Direct factual answer

The selected dated Claude product-prompt entries do not establish a persistent custom-instruction mechanism for the represented chat surfaces.

Surface: Not established
Model context: Not established
Configuration / version scope: Not established
Reviewed: 2026-08-11

Limits and uncertainty

This is a coverage gap, not a claim that no such product feature exists.

Evidence

No supporting evidence is linked because the selected sources do not establish this behavior.

Multi-surface agentic coding product

Claude Code

Documented

Direct factual answer

Claude Code documents persistent human-authored instructions through managed, user, project, and local CLAUDE.md scopes.

Surface: Claude Code terminal CLI · Claude Code IDE integrations
Model context: Not established
Configuration / version scope: Not established
Reviewed: 2026-08-11

Limits and uncertainty

Authored instructions are distinct from auto memory and enforced settings or hooks.

Evidence

Open-source agentic command-line interface

Gemini CLI

Documented

Direct factual answer

Gemini CLI documents global and workspace GEMINI.md context, and it also supports a configured full system-prompt replacement.

Surface: Gemini CLI
Model context: Not established
Configuration / version scope: Not established
Reviewed: 2026-08-11

Limits and uncertainty

A system-prompt override replaces the built-in prompt rather than adding a small preference layer.

Evidence

Multi-surface conversational AI product

ChatGPT

Documented

Direct factual answer

ChatGPT documents custom instructions that can apply across conversations and project instructions that remain associated with a Project.

Surface: ChatGPT web · ChatGPT apps
Model context: Not established
Configuration / version scope: Not established
Reviewed: 2026-08-11

Limits and uncertainty

Behavior can vary with product settings, model, plan, and surface.

Evidence

AI code editor and agentic coding product

Cursor

Documented

Direct factual answer

Cursor documents user rules that apply across projects and project rules that provide repository or path-specific guidance.

Surface: Cursor editor
Model context: Not established
Configuration / version scope: Not established
Reviewed: 2026-08-11

Limits and uncertainty

The selected evidence does not establish the complete instruction assembly.

Evidence