context-mode

name	context-mode
description	Context window optimization for AI coding agents. Sandboxes tool output (98% reduction), persists session memory across compactions, and enforces routing across 17 platforms via MCP + hooks. Use when context window is filling up, tool outputs are too large, or session state needs to survive compaction. Works with Antigravity, Claude, Cursor, Codex, Copilot, OpenCode, and more. Source: https://github.com/mksglu/context-mode — MCP-layer sandboxing, local-only, no telemetry.
triggers	["context window","context optimization","session memory","compaction","ctx_execute","ctx_fetch","MCP sandbox","tool output size","98% reduction","context mode","ctx-stats"]

Context Mode Skill

Context Mode operates at the MCP protocol layer to sandbox tool outputs, persist session memory across compactions, and enforce routing across 17 AI platforms. Nothing leaves your machine — no telemetry, no cloud sync, all SQLite-local.

Local Reference

sap-router-skill\bundled\tools\context-mode\

Core Capabilities

Problem	Context Mode Solution
Tool output too large (7 MB API response)	ctx_fetch_and_index → 1.8 KB indexed summary
Context compaction loses session state	ctx_checkpoint persists tasks, files, decisions
20 Jira MCP calls flood context	Wrap with ctx_execute → compact result
Can't continue after compaction	ctx_restore rebuilds full session state

Installation

# Repository-owned snapshot (already bundled)
cd bundled/tools/context-mode
npm install

# Initialize for your agent (from project directory):
# Claude Code
npx context-mode init

# Antigravity (Gemini) — copies .agents plugin files
npx context-mode init --agent antigravity

# Codex
npx context-mode init --agent codex

# Cursor  
npx context-mode init --agent cursor

# Copilot
npx context-mode init --agent copilot

# OpenCode
npx context-mode init --agent opencode

MCP Tools Available

Execution Sandbox

ctx_execute          - Run code in isolated subprocess, return compact result
ctx_execute_file     - Run code over a file (project-boundary confined)
ctx_batch_execute    - Run multiple operations, aggregate summary only

Fetch & Index

ctx_fetch_and_index  - Fetch URL, store raw in SQLite, return <2 KB summary
                       Blocks dangerous schemes/IPs by default

Session Memory

ctx_checkpoint       - Save current session state (tasks, files, decisions)
ctx_restore          - Restore full session state after compaction
ctx_stats / ctx-stats - Show session event count, token savings, context health
ctx_doctor           - Diagnose storage config and environment

Security Model

Context Mode enforces your existing Claude/agent permission rules inside the sandbox:

{
  "permissions": {
    "deny": [
      "Bash(sudo *)",
      "Bash(rm -rf /*)",
      "Read(.env)",
      "Read(**/.env*)"
    ],
    "allow": [
      "Bash(git:*)",
      "Bash(npm:*)"
    ]
  }
}

Add to .claude/settings.json or ~/.claude/settings.json. All 17 platforms read this same format.

• deny always wins over allow
• Project-level rules override global
• ctx_execute_file is confined to project root — path traversal (../../) blocked
• Credentials auto-redacted: tokens, API keys, secrets masked to [REDACTED] before SQLite

Network Fetch Hardening

ctx_fetch_and_index blocks by default:

• file://, gopher://, javascript:, data: schemes
• Cloud metadata: 169.254.169.254 (AWS/GCP/Azure IMDS)
• Multicast, reserved IPs

# Strict mode (blocks RFC1918 too — for CI/hosted envs):
export CTX_FETCH_STRICT=1

Integration with SAP Router Skill

Context Mode is critical for SAP sessions that generate large outputs:

Large Output Handling

# Instead of letting healthcheck flood context:
ctx_execute("python scripts/healthcheck.py")
# → compact: "35/35 MCPs healthy | 2 warnings: mcp-sap-gui timeout"

# Large ABAP search results via ADT:
ctx_execute("python scripts/sap_router.py code_search --query ZCL_ROUTER --max 500")
# → compact summary with file list

# iFlow package analysis:
ctx_execute("python scripts/cpi_iflow_packager.py validate --input my.zip")
# → "Valid: 12/12 artifacts | 0 errors"

Session Memory for SAP Tasks

# Before starting long SAP task:
ctx_checkpoint({"task": "Implement ZROUTER_V3", "status": "planning", 
                "pending": ["create_class", "test_bapi", "transport"]})

# After compaction, agent restores:
ctx_restore()
# → Full task state recovered, no re-prompting needed

Fetch & Index SAP Documentation

# Fetch large SAP Help page:
ctx_fetch_and_index("https://help.sap.com/docs/SAP_NETWEAVER/...")
# → 2 KB indexed summary instead of 500 KB raw HTML

# Then query the index:
ctx_execute("query indexed content for BAPI_PO_CREATE1 parameters")

Storage Environment

# Custom storage location:
export CONTEXT_MODE_DIR="C:\Users\William Correa\.context-mode"

# MCP nudge frequency (re-inject routing guidance every N tool calls):
export CONTEXT_MODE_EXTERNAL_MCP_NUDGE_EVERY=10  # default

Routing Nudge Behavior

Every 10th external MCP tool call (Jira, Slack, Notion, etc.), Context Mode re-injects:

"Wrap large external-MCP payloads in ctx_execute for 98% context reduction"

This prevents guidance from being lost after compaction in long sessions.

Commands Reference

ctx stats          # Session stats (tool calls, tokens saved, context %)
ctx checkpoint     # Save session state now
ctx restore        # Restore after compaction
ctx doctor         # Diagnose storage and env config
/context-mode:ctx-stats  # In-chat command

References

• Repository: bundled/tools/context-mode/
• Contributing: bundled/tools/context-mode/CONTRIBUTING.md
• Issues tracker: https://github.com/mksglu/context-mode/issues
• Security: bundled/tools/context-mode/SECURITY.md (if present)
• License: Elastic License 2.0 (source-available, no SaaS repackaging)