What Is Context Mode? Freeing Up a Coding Agent's Context Window: Setup, Tools, License

When a coding agent calls a tool (a browser snapshot, a GitHub issue list, a log file), the entire output enters the context window. In the README's examples, a Playwright page snapshot takes 56 KB and 20 GitHub issues take 59 KB; after half an hour, 40% of the context is gone. When the context fills up, the agent compacts the conversation and forgets which file it was editing and which task was left half done. Context Mode targets both sides: keeping raw data out of the context and bringing back where it left off after compaction.

MCP is a common connection format that lets an assistant connect to a service outside itself or to a program on your computer. This server sits in the middle of that bridge: the assistant passes the request to it, it queries the target and brings the answer back.

The "think in code" principle: instead of the agent reading 50 files one by one to count them, the README recommends it write a small script that does the counting and prints only the result; Context Mode runs that script in a subprocess, and only what the script prints enters the context. It doesn't interfere with the style of the reply: writing short or long is up to the model and your instructions.

Who it helps: developers who work in long sessions with Claude Code, Codex or Cursor, deal with large logs and API output, and see the context fill up and get compacted often. In short conversations the difference is small.

The README's figures are the maker's own measurements: it states that in a full session 315 KB of raw output dropped to 5.4 KB and session length went from about 30 minutes to 3 hours; ~98% savings on platforms with hook support, ~60% on those without. No independent measurement is given in the official sources.

Search limit: within the same session, search calls 4–8 return fewer results and a warning, and after the 9th call you're redirected to ctx_batch_execute (README "Progressive Throttling").

• Node.js 22.5 or later, or Bun. On Linux, if Node is older than 22.5 and Bun isn't present, the installation deliberately stops (because of a crash issue with the SQLite extension on older Node).
• What runs during installation: the npm package downloads its dependencies (including better-sqlite3) and runs an install script (postinstall); this script repairs the context-mode entries in Claude Code's ~/.claude/plugins/installed_plugins.json and ~/.claude/settings.json files, and fixes paths on Windows.
• Data folder: sessions and statistics are in the platform's default folder (e.g. ~/.claude/context-mode), the index under ~/.context-mode/content/; change it with CONTEXT_MODE_DIR.

After installing, you work with your agent as usual; on a platform with hooks, calls with large output go to the sandbox automatically. The requests below come from the README's "Try It" section; the figures in parentheses are the maker's measurements, and the outputs are described as far as the README describes them.

What you get: instead of reading commits into the context one by one, the agent writes a script that counts them and runs it in the sandbox; only the summary table enters the context (README: one call, 5.6 KB of context). ctx stats shows, per tool, how many KB stayed out of the context.

What you get: the page is fetched with ctx_fetch_and_index, converted to Markdown and written to the local index; the raw page doesn't enter the context, and ctx_search returns only the matching chunks (README: 2 calls, 1.8 KB of context). If the same address is requested again within 24 hours, it isn't downloaded again.

What you get: according to the README, after more than 20 tool calls ctx stats shows the session's event count; when the context is compacted, the model restores tasks, files and decisions and continues from your last request, so you don't have to rewrite it.

The same commands also have terminal equivalents: context-mode doctor, context-mode index . --source project:my-app, context-mode search "…". In Claude Code, an optional status line shows the savings in the session ("statusLine": {"type": "command", "command": "context-mode statusline"} in ~/.claude/settings.json).

The README's table lists 17 clients and the OpenClaw gateway: Claude Code, Qwen Code, Gemini CLI, VS Code Copilot, JetBrains Copilot, GitHub Copilot CLI, Cursor, OpenCode, KiloCode, OpenClaw, Codex CLI, Kimi Code, Antigravity, Antigravity CLI, Kiro, Zed, Pi and OMP. The site's Engine page says "18 AI coding tools".

!Context Mode is not an operating-system sandbox: approving the execution tool means approving that the code the agent writes runs with your file access.

Context Mode also applies Claude Code's permission rules to its own tools (e.g. if Bash(sudo *) is denied, it's denied in the sandbox too).

Context Mode's license is Elastic License 2.0 (ELv2). The source code is public and readable, but this license isn't a full open source license: the README itself says "source-available". The main difference: you can't offer the software to others as a hosted or managed service, and you can't remove the license notices. Because GitHub doesn't show this license in its recognized list, the license appears as "Other" on the repository page.

Summary based on the Elastic License 2.0 text in the LICENSE file; not legal advice. If you violate the license, your rights end automatically; they come back if you stop the violation within 30 days of receiving notice.

The local version (the one this guide covers, called "Context Mode Engine" on the site) is free: it requires no account, card or sign-up. The same company (MKSF LTD, London) also sells a hosted Context Mode service: your agent's requests pass through the company's gateway, and your own Anthropic or OpenAI account pays the model costs.

According to the pricing page, at the limit the agent keeps working and requests go directly to the model; only the features stop. Enterprise is by contract (100,000+ requests per month; the company's cloud, a dedicated server or your own Cloudflare account). There's no Turkish lira pricing; paying by card from Turkey is not clear in the official sources.

Official pricing page last checked on November 3, 2026.

1. 1First delete the index (optional): Type ctx purge in the chat or /context-mode:ctx-purge: all content in the index is permanently deleted.
2. 2Plugin: In Claude Code, /plugin → Installed → context-mode → Uninstall.
3. 3If you installed MCP only: claude mcp remove context-mode (Claude Code's general command); for a global npm install, npm uninstall -g context-mode.
4. 4Leftover files: Remove the session and index folders (CONTEXT_MODE_DIR or the default folder, ~/.context-mode/) and, if you added it manually, the status line setting.