# What each client loads Checked against official documentation on 2026-10-20. Client behaviour changes; re-check the cited page before relying on a number, and report anything newer as fresh evidence. `UNVERIFIED` means the official pages read did not document it: treat it as unknown, never as a limit. `context_inventory.py` implements the project-local rules below. ## Codex - Per directory from the project root (usually the Git root) down to the working directory, at most one file: `AGENTS.override.md`, else `AGENTS.md`, else the first name in `project_doc_fallback_filenames`. Files are joined root first, so closer files appear later and win. - Global: `AGENTS.override.md` or `AGENTS.md` in `CODEX_HOME` (default `~/.codex`). - Limit: `project_doc_max_bytes`, default 32 KiB; files past the limit are not added. `project_root_markers` changes root detection; its default is `UNVERIFIED` (the probe assumes `.git`). - Imports: none documented. - Readback: no command that prints the loaded instructions is documented (`UNVERIFIED`); a model asked to list its sources is not a deterministic readback. Use `codex_context.py` for the file chain. - Sources: , . ## Claude Code - Project: `CLAUDE.md` or `.claude/CLAUDE.md`, and `CLAUDE.local.md` (personal, gitignored), in the working directory and every directory above it, joined root first; subdirectory files load when Claude works there. - Rules: `.claude/rules/**/*.md`. A rule without `paths:` frontmatter loads at start; with `paths:` it loads only for matching files. - `AGENTS.md`: read directly (v2.1.277 or later) only when no `CLAUDE.md`, `.claude/CLAUDE.md` or `CLAUDE.local.md` exists in the working directory or above. Adding any of them stops that unless the user-level setting `claude-md-and-agents-md` is chosen. A `CLAUDE.md` with `@AGENTS.md` works on every version and never reads `AGENTS.md` twice. - Imports: `@path`, relative to the importing file, up to four hops; imported files inherit the importing file's start-up or on-demand scope. With `--include-global`, the probe also expands imports from the user-level `~/.claude/CLAUDE.md`. Not expanded inside code spans or blocks. - Limits: guidance of under 200 lines per `CLAUDE.md`; the probe applies it to directly discovered `CLAUDE.md` files, not imported files, `AGENTS.md` fallbacks or `.claude/rules/*.md` rules. A file over 4 MiB is skipped. - Readback: `/context` (Memory files) and `/memory` in a fresh interactive session; the `InstructionsLoaded` hook logs loads (not for `AGENTS.md` read through the setting). `/doctor prompt-audit` (v2.1.283 or later) is a native report of stale or conflicting instructions. No non-interactive command is documented. - Source: . ## Gemini CLI - `~/.gemini/GEMINI.md`, then `GEMINI.md` in the workspace directories and their parents, then files found when a tool reads a directory. All are joined. - `context.fileName` in `settings.json` sets one name or a list, for example `["AGENTS.md", "GEMINI.md"]`. The probe reads only project `.gemini/settings.json`. - Imports: `@path`, default depth 5, circular imports blocked. With `--include-global`, the probe also expands imports from the user-level `~/.gemini/GEMINI.md`, using the same size, duplicate and goal-pointer checks. - Limit: none documented. - Readback: `/memory show` prints the combined memory. - Sources: , . ## Cursor - Project rules: `.cursor/rules`, `.mdc` files only (a plain `.md` there is ignored), with `description`, `globs` and `alwaysApply` frontmatter. `alwaysApply: true` applies to every request; the others attach by file match, agent choice or manual mention. - `AGENTS.md` in the root and subdirectories; nested files combine with their parents and the more specific one wins. - `.cursorrules`: not mentioned in the current docs (`UNVERIFIED`); the probe reports it as legacy. - Limit: guidance to keep each rule under 500 lines. - Readback: none documented. - Sources: , . ## GitHub Copilot - `.github/copilot-instructions.md` (repository-wide) and `.github/instructions/**/*.instructions.md` (path-specific, `applyTo`). - Agent files: `AGENTS.md` (nearest wins) and a root `CLAUDE.md` or `GEMINI.md`. - Support differs by surface: the cloud agent, the CLI and code review on GitHub.com read all three kinds; VS Code chat reads `AGENTS.md` but not `CLAUDE.md` or `GEMINI.md`; Copilot Chat on GitHub.com and code review in VS Code and Visual Studio read only `copilot-instructions.md`. - Limit: none documented; a character limit for code review is `UNVERIFIED`. - Readback: none documented. - Sources: , , . ## OpenCode - Project: the first `AGENTS.md` found walking up from the working directory; a `CLAUDE.md` only when no `AGENTS.md` exists. Global: `~/.config/opencode/AGENTS.md`, else `~/.claude/CLAUDE.md`. - `instructions` in the project `opencode.json`: extra paths, globs or URLs, all added. Config files may be JSON or JSONC (JSON with comments). The docs name `opencode.jsonc` for managed settings; a project `opencode.jsonc` is `UNVERIFIED`, and the probe reads it too. The probe resolves local paths and globs and never fetches URLs. Source: . - Limit: none documented. Readback: none documented. - Source: . ## Other clients The `AGENTS.md` format page lists further clients that read `AGENTS.md` (). Treat any client not covered above as `UNVERIFIED` until its own documentation is checked.