Context Mode

What it is

Context Mode is a free, local plugin that keeps tool output out of your coding agent’s context window. The README says every MCP tool call dumps raw data into that window, and compaction then makes the agent forget which files it was editing. Context Mode is an MCP server whose tools run code and read files in a sandbox on your machine. Only what the code prints reaches the model. A SQLite index with search lets the agent look up what it saved. Hooks track your edits, tasks and decisions, so a session can pick up after the conversation compacts.

1. The agent calls a Context Mode tool instead of a raw read
2. The code runs in a sandbox on your machine
3. Only what the code prints enters the conversation
4. Big output is indexed and searched for the part you need
5. Hooks save your edits and tasks for after compaction

Who it suits

Developers who work in long coding-agent sessions and watch logs, test output, web pages and API responses fill the context window. Skip it if your sessions are short. It adds hooks and a local database to your setup, and on some agents a routing file you copy, and that is a lot for a quick job.

Where to use it

The README documents these agents, each with its own install route. Routing is enforced only where an agent has hooks.

• Claude Code: a plugin with slash commands, hooks and 11 MCP tools
• Gemini CLI: the global package and one settings file that holds the MCP entry and the hooks
• VS Code Copilot and JetBrains Copilot: the global package, an MCP server (a file in VS Code, the Settings UI in JetBrains) and a hooks file
• GitHub Copilot CLI: the global package and a plugin that registers MCP, hooks and a skill, or an MCP entry and a hooks file by hand
• Cursor: a local plugin folder or a manual install, with hooks and a rules file
• Codex CLI: a plugin from the maker’s marketplace, with hooks turned on by two feature flags in the config (or MCP and hooks set by hand on builds without plugin_hooks)
• Kimi Code and Qwen Code: MCP plus hooks, set in each agent’s config

• OpenCode and KiloCode: a plugin named in the agent’s config file
• Pi Coding Agent and Oh My Pi: an extension or plugin with hook support
• OpenClaw: a native gateway plugin for Pi Agent sessions
• Kiro: hooks plus a steering file
• Antigravity CLI: a plugin with MCP, a skill and hooks
• Antigravity IDE and Zed: MCP only, with a routing file you copy by hand

How to set it up

Get it saves a zip of Mindket’s setup notes in your downloads folder, with a page for each agent from the maker’s README and docs. Claude Code installs a plugin. Most other agents take a global package and a config entry.

1. Install Node.js 22.5 or newer, then your agent.
2. In Claude Code, add the marketplace and install the plugin. Most other agents need the global package first. The README’s Codex plugin, OpenCode, KiloCode, OMP plugin and OpenClaw steps do not list it.
3. Add the MCP entry and the hooks that your agent’s page lists, and copy the routing file where it says to.
4. Restart the agent, then check the install.

/plugin marketplace add mksglu/context-mode
/plugin install context-mode@context-mode

Restart Claude Code, then run /context-mode:ctx-doctor. The README says every check should show [x]. For most other agents the first step is this line, and the rest is a config entry and a hooks file.

npm install -g context-mode

The MCP entry has the same shape in Cursor, Kiro, Antigravity, Pi and OMP, each in its own file. VS Code Copilot uses a servers key and Zed uses context_servers.

{
  "mcpServers": {
    "context-mode": {
      "command": "context-mode"
    }
  }
}

How to use it

Work as before. The hooks steer the agent toward the sandbox tools when a command or a file would flood the context, and you can ask for them by name. Two commands show what happened.

ctx stats
ctx doctor

Typing ctx stats shows context savings and call counts. ctx doctor checks runtimes, hooks, FTS5 and versions. In Claude Code the same commands are slash commands, such as /context-mode:ctx-stats. ctx index and ctx search add your own files to the index and query them.

Example

You want the Hacker News front page grouped by domain. The README says that without hooks one unrouted curl or Playwright snapshot can dump 56 KB into context. With the plugin, you send this prompt, which comes from the README’s Try It list:

Fetch the Hacker News front page, extract all posts with titles, scores,
and domains. Group by domain. Then run /context-mode:ctx-stats.

The README lists this prompt as one tool call, and says web pages are processed in the sandbox and never enter the context window. You get the posts grouped by domain, and ctx-stats then reports the savings.

For newcomers and experts

If you are new. A coding agent reads whatever its tools return, and all of it takes room in a window with a limit. When the window fills, the agent compacts the conversation and can lose the thread. Context Mode keeps the bulky part, such as a log, a web page or a test run, on your machine and hands the agent a short answer. It also keeps a local record of your edits and tasks. Start with the Claude Code plugin and run ctx doctor.

For experts. Search runs two strategies on SQLite FTS5, a Porter-stemmed match and a trigram substring match, and merges them with Reciprocal Rank Fusion. Results are reranked by how close the query terms sit, and a typo is corrected by Levenshtein distance before a second search. Fetched pages are cached for 24 hours by default, and a call can override that with ttl or force.

The SQLite backend is picked at runtime: bun:sqlite on Bun, node:sqlite on Linux with Node 22.5 or newer, and better-sqlite3 elsewhere. Hooks feed the session database. Before compaction a snapshot is built in priority tiers, and SessionStart restores it. Searches throttle: from the fourth call results shrink, and from the ninth they are blocked and sent to ctx_batch_execute.

Good to know

Most of it runs on your machine, and a few paths reach out.

• Your permissions: ctx_execute and ctx_batch_execute run arbitrary code with your user’s file access. The README says the project boundary guards ctx_execute_file only, and tells you to keep host-level sandboxing on
• Permission rules: the deny and allow rules in Claude Code’s settings (.claude/settings.json or ~/.claude/settings.json) also apply inside the sandbox on every platform, and on Codex CLI once its hooks are configured
• Data kept: hooks save file edits, tasks, git operations, errors and your prompts in a per-project SQLite database, in your home folder for most agents. platform-support.md puts VS Code and JetBrains Copilot sessions in the project’s .github/context-mode/sessions/. If you do not use --continue, the previous session’s data is deleted at once
• Network: ctx_fetch_and_index takes only http and https addresses and blocks cloud-metadata addresses. It allows private addresses unless CTX_FETCH_STRICT=1 is set
• A hosted page: ctx insight opens the maker’s hosted Insight dashboard in your browser. The maker’s site describes Insight as how a team works with coding agents “from Engine events” (Engine is its name for this plugin) and does not say how those events get there. The README says nothing leaves your machine, with no telemetry
• Upgrades: ctx upgrade pulls the latest version from GitHub and rebuilds
• Where hooks are missing: routing is a request in a file, not enforcement. Cursor cannot restore a session after compaction, and Codex can block a call but not rewrite it
• The maker’s other product: its site also offers a hosted gateway. This listing covers only the free plugin in the repository
• Removal: the README gives no uninstall steps except agy plugin uninstall for the Antigravity CLI. The maker’s site lists a remove command per agent for its own install route, such as context-mode setup --remove --agents claude-code. Mindket’s notes list what to remove by hand
• License: Elastic License 2.0, which the README calls source-available. You may use, fork, modify and distribute it, but not offer it as a hosted or managed service, get around its license key functionality, or remove its licensing notices. The LICENSE file names Mert Koseoglu, 2026