{"slug": "codex-reimplemented-in-8k-lines-of-c-1mb-binary", "title": "Codex reimplemented in 8k lines of C++, <1MB binary", "summary": "Paolo Anzini released MicroCodex, an ultra-lightweight coding agent written in C++23 that runs locally in the terminal, with a binary under 1MB and the codebase comprising 8,000 lines. The tool supports one-shot prompts, an interactive terminal UI, local coding tools, durable conversations, and automatic context compaction, and is available for macOS and Linux via GitHub releases or an install script. MicroCodex is not sandboxed, so model-requested commands run with the user's permissions, and it currently lacks MCP support and safe-command gating.", "body_md": "**MicroCodex** is an ultra-lightweight coding agent that runs locally in your terminal.\n\nMicroCodex is written in C++23 and provides one-shot prompts, an interactive terminal UI, local coding tools, durable conversations, and automatic context compaction.\n\nRun the following on Mac or Linux to install MicroCodex:\n\n```\ncurl -fsSL https://github.com/paoloanzn/microcodex/releases/latest/download/install.sh | sh\n```\n\nThen simply run `microcodex login`\n\nto sign in, followed by `microcodex`\n\nto get started.\n\n## You can also go to the [latest GitHub Release](https://github.com/paoloanzn/microcodex/releases/latest) and download the appropriate binary for your platform.\n\nEach GitHub Release contains these executables:\n\n- macOS\n- Apple Silicon/arm64:\n`microcodex-aarch64-apple-darwin.tar.gz`\n\n- x86_64:\n`microcodex-x86_64-apple-darwin.tar.gz`\n\n- Apple Silicon/arm64:\n- Linux\n- x86_64:\n`microcodex-x86_64-unknown-linux-gnu.tar.gz`\n\n- arm64:\n`microcodex-aarch64-unknown-linux-gnu.tar.gz`\n\n- x86_64:\n\nEach archive contains a single entry with the platform baked into the name (for example, `microcodex-aarch64-apple-darwin`\n\n), so you likely want to rename it to `microcodex`\n\nafter extracting it.\n\nThe installer selects the native build for the current architecture. Linux requires the libcurl and OpenSSL runtime libraries.\n\nTo install a specific release, set `MICROCODEX_RELEASE`\n\n:\n\n```\ncurl -fsSL https://github.com/paoloanzn/microcodex/releases/latest/download/install.sh | MICROCODEX_RELEASE=v0.1.0 sh\n```\n\nRun `microcodex login`\n\nand open the displayed URL in your browser. MicroCodex stores the resulting OAuth credentials under `$CODEX_HOME`\n\n, or `~/.codex`\n\nwhen `CODEX_HOME`\n\nis unset.\n\nYou can then start an interactive session or pass a one-shot prompt:\n\n```\nmicrocodex\nmicrocodex \"Find the failing test, fix it, and run the relevant test suite\"\n```\n\nWarning\n\nMicroCodex is not a sandbox. Model-requested commands and file operations run with the same permissions as the MicroCodex process.\n\nMicroCodex discovers the same filesystem skills installed for Codex under\n`$CODEX_HOME/skills`\n\n, or `~/.codex/skills`\n\nwhen `CODEX_HOME`\n\nis unset. Each\nskill must have a `SKILL.md`\n\nwith YAML frontmatter containing a `name`\n\nand\n`description`\n\n. Skill metadata is added to the agent instructions at session\nstartup; the complete skill is read only when its name or description matches\nthe task.\n\nBuilding requires a C++23 compiler, `make`\n\n, libcurl development files, and OpenSSL development files on Linux.\n\n```\ngit clone --recurse-submodules https://github.com/paoloanzn/microcodex.git\ncd microcodex\nmake\n```\n\nThe executable is written to `build/microcodex`\n\n. Run the test suite with `make test`\n\n.\n\n- MCP support is not implemented yet.\n- Text cannot currently be copied from the terminal while using MicroCodex.\n- Dangerous shell commands are not yet gated by a safe-command policy.\n\nThis repository is licensed under the [Apache-2.0 License](/paoloanzn/microcodex/blob/main/LICENSE).", "url": "https://wpnews.pro/news/codex-reimplemented-in-8k-lines-of-c-1mb-binary", "canonical_source": "https://github.com/paoloanzn/microcodex", "published_at": "2026-08-01 14:13:24+00:00", "updated_at": "2026-08-01 14:23:24.208521+00:00", "lang": "en", "topics": ["ai-agents", "developer-tools", "ai-products"], "entities": ["Paolo Anzini", "MicroCodex", "GitHub", "Codex", "Apache-2.0 License"], "alternates": {"html": "https://wpnews.pro/news/codex-reimplemented-in-8k-lines-of-c-1mb-binary", "markdown": "https://wpnews.pro/news/codex-reimplemented-in-8k-lines-of-c-1mb-binary.md", "text": "https://wpnews.pro/news/codex-reimplemented-in-8k-lines-of-c-1mb-binary.txt", "jsonld": "https://wpnews.pro/news/codex-reimplemented-in-8k-lines-of-c-1mb-binary.jsonld"}}