Context Mode MCP — Cas d'usage, Installer & Démo en direct

Pourquoi l'utiliser

Fonctionnalités clés

98% context reduction via sandboxed tool execution
Per-session SQLite FTS5 index survives compaction
Automatic routing hooks (PreToolUse, PostToolUse, PreCompact, SessionStart)
12 platforms supported (Claude Code, Cursor, Codex, Gemini CLI, Copilot…)
'Think in code' paradigm — have the LLM write scripts, not process data itself

Démo en direct

Aperçu en pratique

context-mode-mcp.replay ▶ prêt

0/0

Installer

Choisissez votre client

~/Library/Application Support/Claude/claude_desktop_config.json · Windows: %APPDATA%\Claude\claude_desktop_config.json

{
  "mcpServers": {
    "context-mode-mcp": {
      "command": "npx",
      "args": [
        "-y",
        "context-mode"
      ]
    }
  }
}

Ouvrez Claude Desktop → Settings → Developer → Edit Config. Redémarrez après avoir enregistré.

~/.cursor/mcp.json · .cursor/mcp.json

{
  "mcpServers": {
    "context-mode-mcp": {
      "command": "npx",
      "args": [
        "-y",
        "context-mode"
      ]
    }
  }
}

Cursor utilise le même schéma mcpServers que Claude Desktop. La config projet l'emporte sur la globale.

VS Code → Cline → MCP Servers → Edit

{
  "mcpServers": {
    "context-mode-mcp": {
      "command": "npx",
      "args": [
        "-y",
        "context-mode"
      ]
    }
  }
}

Cliquez sur l'icône MCP Servers dans la barre latérale Cline, puis "Edit Configuration".

~/.codeium/windsurf/mcp_config.json

{
  "mcpServers": {
    "context-mode-mcp": {
      "command": "npx",
      "args": [
        "-y",
        "context-mode"
      ]
    }
  }
}

Même format que Claude Desktop. Redémarrez Windsurf pour appliquer.

~/.continue/config.json

{
  "mcpServers": [
    {
      "name": "context-mode-mcp",
      "command": "npx",
      "args": [
        "-y",
        "context-mode"
      ]
    }
  ]
}

Continue utilise un tableau d'objets serveur plutôt qu'une map.

~/.config/zed/settings.json

{
  "context_servers": {
    "context-mode-mcp": {
      "command": {
        "path": "npx",
        "args": [
          "-y",
          "context-mode"
        ]
      }
    }
  }
}

Ajoutez dans context_servers. Zed recharge à chaud à la sauvegarde.

claude mcp add context-mode-mcp -- npx -y context-mode

Une seule ligne. Vérifiez avec claude mcp list. Supprimez avec claude mcp remove.

Cas d'usage

Usages concrets : Context Mode

Stop wasting context on raw tool output

👤 Heavy Claude Code users who hit compaction mid-session ⏱ ~15 min intermediate

Quand l'utiliser : You feel your agent "forget" after 30 minutes and burn $$ on re-reads.

Prérequis

Claude Code v1.0.33+ — brew upgrade claude-code or npm update -g @anthropic-ai/claude-code

Déroulement

Install

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

→ Plugin registers hooks + 6 sandbox tools
Verify

/context-mode:ctx-doctor✓ Copié

→ All checks [x]
Use normally

Now do a big task that would normally blow context — e.g. analyze all .log files under /var/log✓ Copié

→ ctx_execute used instead of raw Read; output indexed not dumped
Check savings

/context-mode:ctx-stats✓ Copié

→ Per-tool reduction ratio reported

Résultat : Same task, 10x longer before compaction, and the agent remembers.

Pièges

Other MCPs bypass the routing — Pass their tool calls through ctx_batch_execute for consistent accounting

Combiner avec : serena

Resume a long task seamlessly after the model compacts

👤 Devs on multi-hour agent sessions ⏱ ~5 min beginner

Quand l'utiliser : Your task is too big to fit in one context window.

Déroulement

Start with --continue

[CLI flag] claude --continue✓ Copié

→ Prior session's SQLite loaded
Observe

What did I last ask you about? What tasks are in progress?✓ Copié

→ Accurate recap from FTS5 index, not hallucinated

Résultat : A genuinely resumable workflow.

Pièges

Forgetting --continue starts fresh — Persistence requires --continue; absence means deliberate fresh start

Combinaisons

Associez-le à d'autres MCPs pour un effet X10

context-mode-mcp + serena

Serena for semantic code nav, context-mode for keeping its output out of context

Use serena for the lookup, ctx_execute to post-process the results.✓ Copié

context-mode-mcp + playwright

Page snapshot output stays sandboxed

Snapshot the page via playwright, let context-mode hold it — search it instead of dumping.✓ Copié

Outils

Ce que ce MCP expose

Outil	Entrées	Quand appeler	Coût
ctx_execute	code: str (js/python)	Run a script to process data; output only what's needed	free
ctx_batch_execute	ops: [{tool, args}]	Wrap multiple tool calls through the sandbox	free
ctx_index	content: str, tags?: []	Stash data for later retrieval	free
ctx_search	query: str	Retrieve from session index	free
ctx_fetch_and_index	url: str	Pull a URL, keep it out of context but searchable	free
ctx_stats	none	See how much context was saved	free

Coût et limites

Coût d'exécution

Quota d'API: Local
Tokens par appel: Dramatic reduction — quoted 98% on real sessions
Monétaire: Free (ELv2 license)
Astuce: The bigger the session, the bigger the win — use on long tasks

Sécurité

Permissions, secrets, portée

Stockage des identifiants : Session SQLite in ~/.context-mode/

Sortie de données : None

SQLite persists across sessions only if you use --continue — otherwise it's wiped

Dépannage

Erreurs courantes et correctifs

ctx-doctor shows missing hooks

Restart Claude Code fully after install; hooks register at startup

Vérifier : Re-run /context-mode:ctx-doctor

Sandbox won't execute code

Node/Python runtime missing. Doctor tells you which. Install with brew/asdf.

Search returns nothing

Verify FTS5 built: sqlite3 ~/.context-mode/session.db "SELECT name FROM sqlite_master". Reinstall if broken.

Alternatives

Context Mode vs autres

Alternative	Quand l'utiliser	Compromis
Raw Claude Code (no plugin)	Short sessions that never hit compaction	No context saving
claude-mem	You want the memory layer without the sandbox-tool paradigm	Different tradeoff — memory only, no tool output sandbox

Plus

Ressources

📖 Lire le README officiel sur GitHub

🐙 Voir les issues ouvertes

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