Context Mode 🔌 MCP server Free

What it does

Context Mode is an MCP server, packaged with hooks, that keeps bulky tool output out of your coding agent's context window. The agent does not read large files, logs or API responses directly. It runs code in a sandboxed subprocess and only the printed result comes back. Longer output is indexed into a local SQLite full-text store, and the agent pulls back only the sections that match what it is looking for. The same store records file edits, git operations, tasks and decisions, so the agent can recover its working state when a conversation is compacted. On platforms with hooks, it also steers the agent toward these tools and away from raw shell or file reads.

Tools it gives your agent

• ctx_execute, ctx_execute_file and ctx_batch_execute run code in 12 languages, including JavaScript, Python, Shell, Go and Rust, and return only stdout
• ctx_index, ctx_search and ctx_fetch_and_index chunk, search and cache documents and web pages with BM25 ranking
• ctx_stats, ctx_doctor, ctx_upgrade and ctx_purge for savings reports, diagnostics, upgrades and wiping the index

Works with

It runs locally. The README has setup steps for Claude Code, where it ships as a plugin with slash commands, as well as Gemini CLI, VS Code and JetBrains Copilot, GitHub Copilot CLI, Cursor, OpenCode, Kilo Code, Codex CLI, Kiro, Antigravity, Zed and others. Routing enforcement depends on how well each client supports hooks.

How to connect

The full Claude Code plugin, or the MCP-only option:

/plugin marketplace add mksglu/context-mode
/plugin install context-mode@context-mode
claude mcp add context-mode -- npx -y context-mode

Cost and limits

Free to use. It needs Node.js 22.5+ or Bun. The licence is the Elastic License 2.0, which makes it source-available rather than open source: you can use, modify and redistribute it, but you cannot offer it as a hosted service.

Safety notes

The execute tools run arbitrary code with your user's filesystem access. They apply the same deny and allow rules you set in Claude Code's settings.json. ctx_execute_file is confined to the project root by default. URL fetching blocks cloud-metadata addresses, and CTX_FETCH_STRICT=1 also blocks private network ranges. The project says nothing leaves your machine, although the optional Insight dashboard is hosted. The hooks change how your agent routes its tool calls, so review them before installing.