Context Mode

---
name: context-mode
description: |
  Context-mode is an MCP server plugin that reduces context window usage by ~98% through
  sandboxed tool routing. MUST be applied whenever Claude is running inside a context-mode-enabled
  session — it is not optional. Trigger when: context-mode MCP server is present in the session;
  running Bash commands that produce more than 20 lines of output; reading files for analysis; fetching
  web pages and searching them; batch execution of multiple queries; or when you need to prevent raw
  tool outputs from flooding the context window. Key capabilities: routes Bash to ctx_execute /
  ctx_batch_execute (captures output, prevents bloat); routes Read to ctx_execute_file (raw content
  never enters context); routes WebFetch to ctx_fetch_and_index then ctx_search (fetch once, query
  indexed content on demand); enforces strict output rules (under 500 words, write artifacts to files,
  return only path + 1-line description). Ideal for: working in long-running sessions with large
  codebases; running multi-step debugging workflows that produce verbose output; any task where
  context window preservation is critical. Also for: batch operations over large project directories;
  running analysis across many files without consuming context space.
---

# context-mode

Context-mode routes data-heavy tool calls through sandboxed MCP tools, preventing raw outputs from flooding the context window.
Applies automatically when context-mode MCP server is running in the session. Always enforced — do not skip.

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## When Invoked
- Always active when context-mode MCP server is present in the session
- Detected automatically by the session environment
- No explicit user trigger needed — enforce at all times

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## Tool Routing Rules

Route every tool call to its sandbox equivalent:

| Instead of | Use | Why |
|---|---|---|
| Bash commands (>20 lines output) | `batch_execute` or `ctx_execute` | Captures output, prevents context bloat |
| Read for analysis | `ctx_execute_file` | Raw content never enters context |
| WebFetch | `ctx_fetch_and_index` then `search` | Fetch, index, then query by search |
| Follow-up searches | `ctx_search` | Query indexed content on demand |
| Batch commands/queries | `ctx_batch_execute` | One call replaces many steps |

---

## Forbidden Patterns

- **NEVER use Bash** for commands producing >20 lines of output — use `ctx_execute` or `ctx_batch_execute`
- **NEVER use Read** for analysis tasks — use `ctx_execute_file`
- **NEVER use WebFetch** — use `ctx_fetch_and_index` then `ctx_search`
- **NEVER use curl/wget in Bash** — use `ctx_execute` or `ctx_fetch_and_index`
- Bash is ONLY for: git, mkdir, rm, mv, navigation, and short commands (<20 lines)

---

## Output Rules

- Keep responses under 500 words
- Write artifacts (code, configs) to files — never return them as inline text
- Return only: file path + 1-line description

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## Local Dev Notes (for working on context-mode itself)

- Hook dispatcher: `context-mode hook <platform> <event>`
- Delete `server.bundle.mjs` during local dev to load changes from `build/server.js`
- Version must sync across 4 files
- Tests: `npm test` (Vitest, parallel), `npm run test:watch`
- TDD workflow: failing test first → minimum code → refactor
- Add tests to existing test files covering the same domain — do not create new test files