contextpulse-mcp

contextpulse-mcp

Real-time context budget tracking for any AI coding agent.

Plug into Claude Code, Cursor, or any MCP-compatible tool and get:

• 📊 Live token budget bar per agent run
• 🔁 Loop detection (when an agent calls the same tool 3× in a row)
• ⚠️ Warning / critical alerts before context overflow
• 🗄️ Full run history stored in PostgreSQL
• 📈 Budget timeline for every run
• 🔴 BullMQ alert queue for async threshold notifications
• 🔄 Run diff engine — compare two agent runs side by side

No cloud. No telemetry. Runs entirely on your machine.

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How it works

ContextPulse is a transparent MCP server. You call its tracking tools from your agent's workflow. It counts tokens using tiktoken, updates a live budget in memory, persists everything to PostgreSQL, and fires alerts when thresholds are crossed. Your agent → calls cp_track_tool_call → ContextPulse counts tokens

→ updates live budget

→ warns at configurable thresholds (70% / 90% by default, model-calibrated — see below)

→ detects loops

→ saves to DB

→ queues BullMQ alert jobs The contextpulse dashboard connects over WebSocket and visualizes everything in real time.

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Quick start

1. Start PostgreSQL

brew services start postgresql@16
# or Docker
docker run -d --name contextpulse-db -e POSTGRES_DB=contextpulse -p 5432:5432 postgres:16

2. Start Redis (required for BullMQ alert queue)

brew services start redis
# or Docker
docker run -d --name contextpulse-redis -p 6379:6379 redis:7

3. Add to Claude Code (~/.claude/settings.json)

{
  "mcpServers": {
    "contextpulse": {
      "command": "npx",
      "args": ["-y", "contextpulse-mcp"],
      "env": {
        "DATABASE_URL": "postgresql://apple@localhost:5432/contextpulse"
      }
    }
  }
}

4. Add to Cursor (~/.cursor/mcp.json)

{
  "mcpServers": {
    "contextpulse": {
      "command": "npx",
      "args": ["-y", "contextpulse-mcp"],
      "env": {
        "DATABASE_URL": "postgresql://localhost:5432/contextpulse"
      }
    }
  }
}

The DB schema is created automatically on first run.

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Usage in your agent

cp_start_session → get sessionId cp_start_run → get runId (optionally pass baselineOverheadTokens — see Accuracy & limitations) cp_track_tool_call → after every tool call (pass tool name, args, output) cp_get_budget → check current budget at any time cp_get_run_summary → full run summary with timeline cp_end_run → clean up

Example response from cp_track_tool_call

{
  "toolCallId": "a1b2c3...",
  "inputTokens": 142,
  "outputTokens": 87,
  "totalTokens": 229,
  "budget": {
    "used": 14820,
    "limit": 200000,
    "percentUsed": 7.41,
    "warningThresholdPct": 60,
    "criticalThresholdPct": 85
  },
  "budgetStatus": "ok",
  "alert": null
}

When budget hits the warning threshold (60% by default for Claude models — see Accuracy & limitations):

{
  "budgetStatus": "warning",
  "alert": "warning"
}

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Environment variables

| Variable | Default | Description | |---|---|---| | DATABASE_URL | postgresql://apple@localhost:5432/contextpulse | PostgreSQL connection string | | REDIS_URL | redis://localhost:6379 | Redis connection for BullMQ | | MODEL | claude-sonnet-4-6 | Model in use. Picks the default CONTEXT_LIMIT / thresholds below from a per-model profile (see Accuracy & limitations). | | CONTEXT_LIMIT | model-derived, else 200000 | Token limit per session. Set this to override the model's default. | | WARNING_THRESHOLD_PCT | model-derived, else 70 | Warning alert threshold (%). Set this to override the model's default. | | CRITICAL_THRESHOLD_PCT | model-derived, else 90 | Critical alert threshold (%). Set this to override the model's default. | | LOOP_DETECTION_THRESHOLD | 3 | Same tool calls before loop alert |

CONTEXT_LIMIT / WARNING_THRESHOLD_PCT / CRITICAL_THRESHOLD_PCT always win if set explicitly. Otherwise ContextPulse picks defaults from MODEL — currently claude, gpt, and gemini have profiles in src/config/index.ts; anything else falls back to 200k / 70% / 90%. Edit that file directly if your model isn't covered or the numbers don't match your plan.

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Accuracy & limitations

Be aware of two gaps before you treat the reported percentage as exact:

Token counts are an approximation. ContextPulse counts tokens with tiktoken's cl100k_base encoding, which is OpenAI's tokenizer, not Claude's — there's no public Claude tokenizer to use instead. It will drift from what Claude actually bills, especially on code. Treat percentUsed as a trend signal ("am I climbing toward the wall") rather than an exact remaining-token count.

This proxy can't see everything in the context window. ContextPulse only counts tokens that flow through cp_track_tool_call. It has no visibility into your agent's system prompt, other MCP servers' tool schemas, or any server-side context injection — all of which can be substantial (a single MCP server's tool definitions alone can run tens of thousands of tokens). So the tracked total is a floor, not the full picture.

Two ways to close the gap a bit:

• baselineOverheadTokens on cp_start_run — pass a rough estimate of what's already spent before the first tracked call (system prompt + other tool schemas), and it's added to the running total from the start.
• Per-model thresholds — claude profiles default to tighter thresholds (60% / 85%) than the generic default (70% / 90%) specifically to hedge against this blind spot. Tune WARNING_THRESHOLD_PCT / CRITICAL_THRESHOLD_PCT further if you find alerts firing early or late for your setup.

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What gets stored

cp_sessions -- one row per coding session

cp_runs -- one row per agent task

cp_tool_calls -- every intercepted tool call

cp_budget_snapshots -- token usage timeline per run

cp_alerts -- warnings, criticals, loop detections ---

Architecture

contextpulse-mcp/

src/

mcp/ ← MCP tool handlers

context/ ← token counting + budget engine

alerts/ ← BullMQ queue + worker

diff/ ← run diff engine

db/ ← PostgreSQL schema + queries contextpulse/ ← dashboard repo

app/dashboard/

components/ ---

Related

• contextpulse — Real-time Next.js dashboard for this server

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License

MIT