Project Instructions: CLAUDE.md vs AGENTS.md

All three tools inject a project-level instructions file into the model’s context, but the filename, discovery, and merge rules differ. Claude Code uses CLAUDE.md; Codex and Kimi Code both use AGENTS.md — with different discovery rules between them.

File locations and precedence

Claude Code (CLAUDE.md)

Type	Location
Enterprise policy	macOS `/Library/Application Support/ClaudeCode/CLAUDE.md`; Linux/WSL `/etc/claude-code/CLAUDE.md`; Windows `C:\ProgramData\ClaudeCode\CLAUDE.md`
Project	`./CLAUDE.md` or `./.claude/CLAUDE.md` (commit to git)
User	`~/.claude/CLAUDE.md`
Project local	`./CLAUDE.local.md` — deprecated in favor of `@` imports

All memory files load into context at launch; higher levels in the table are loaded first and take precedence.
Lookup recurses up from the cwd to (not including) /, reading CLAUDE.md/CLAUDE.local.md on the way; nested CLAUDE.md files in subtrees load on demand when Claude reads files there.
No size cap is documented.

Codex (AGENTS.md)

Discovery runs once per run (or per TUI session):

Global scope (~/.codex): reads AGENTS.override.md if it exists, otherwise AGENTS.md — only the first non-empty file at this level.
Project scope: from the project root (typically the Git root; configurable via project_root_markers) walk down to the cwd. In each directory Codex checks AGENTS.override.md, then AGENTS.md, then the names in project_doc_fallback_filenames. At most one file per directory.
Merge: files are concatenated root-down, joined with blank lines; files closer to the cwd appear later and therefore override earlier guidance.

Empty files are skipped.
Combined size is capped at project_doc_max_bytes (default 32 KiB).

Kimi Code (AGENTS.md)

Project-level: AGENTS.md at the project root or .kimi-code/AGENTS.md. Content is injected into the system prompt as reference data (the ${agents_md} template variable).
Global Kimi-specific: $KIMI_CODE_HOME/AGENTS.md (default ~/.kimi-code/AGENTS.md); moves with KIMI_CODE_HOME.
Generic cross-tool: ~/.agents/AGENTS.md in the real OS home, shared across tools; does not move with KIMI_CODE_HOME.
Size limit: ? The docs do not specify an exact size cap or whether nested subdirectory AGENTS.md files merge; the changelog mentions a visible warning when AGENTS.md is truncated (previously silent), so a cap exists but is undocumented.

Import and override mechanisms

Mechanism	Claude Code	Codex	Kimi Code
Import other files	`@path/to/file` imports (relative/absolute, `@~/...` supported, recursive up to 5 hops, not evaluated in code spans)	No direct equivalent verified.	No direct equivalent verified.
Per-directory override	Nested CLAUDE.md files load on demand in subtrees	`AGENTS.override.md` replaces `AGENTS.md` in the same directory	No direct equivalent verified.
Replace built-in instructions	`--system-prompt` / `--system-prompt-file` CLI flags	`model_instructions_file` config key (replaces built-in instructions, not AGENTS.md)	`$KIMI_CODE_HOME/SYSTEM.md` replaces the default main agent’s system prompt
Quick add from the composer	`#` prefix prompts which memory file to append to	No direct equivalent verified.	No direct equivalent verified.

`/init` behavior

Claude Code: /init bootstraps (generates) a project CLAUDE.md.
Codex: /init generates an AGENTS.md scaffold in the current directory.
Kimi Code: /init (idle only) analyzes the codebase and generates AGENTS.md.

Porting your instructions

Claude Code → Codex or Kimi Code: rename CLAUDE.md to AGENTS.md. Unroll any @import lines first — neither Codex nor Kimi documents import syntax, so inline the imported content yourself. In Codex, keep the total under 32 KiB (project_doc_max_bytes) or raise the limit.
Codex → Claude Code: rename AGENTS.md to CLAUDE.md. Remember Codex concatenates multiple AGENTS.md files root-down while Claude loads nested CLAUDE.md files on demand, so a multi-file Codex setup may become a single file or a set of nested files in Claude.
Kimi Code → Claude Code / Codex: check all three Kimi locations (AGENTS.md or .kimi-code/AGENTS.md in the project, ~/.kimi-code/AGENTS.md, ~/.agents/AGENTS.md) and consolidate.
Automated importers: Kimi Code ships a built-in /import-from-cc-codex skill command that imports Claude Code and Codex instructions, skills, and MCP settings. Codex ships /import, which migrates Claude Code (or Cursor) setup, projects, and chats. Neither Claude Code nor Codex documents an importer from Kimi Code.

Last verified: 2026-09-07

Official sources:

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