bluetieroperations-create/blackwall-mcp

**A guardrail for AI agents, as an MCP server.** Your agent calls one tool — forecast — before any irreversible action (send email, move money, run SQL, delete data, post content). It gets back a risk score (0–100), a reversibility class, a GO / CAUTION / STOP recommendation, and named red flags in a few seconds (~4-8s).
Works in any MCP host: **Claude Desktop, Claude Code, Cursor, Windsurf**, and any agent framework with MCP support.
> The wall between your agent and disaster. A BLUETIER product.
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1. Get an API key
Sign up free at **https://blackwalltier.com** → Dashboard → API keys → Create key.
Free tier: ~100 forecasts/month, no card. Your key looks like bw_live_….
2. Add the server to your MCP host
Claude Desktop
Edit claude_desktop_config.json (Settings → Developer → Edit Config):
Restart Claude Desktop. You'll see a forecast tool available.
Cursor
Settings → MCP → Add new global MCP server, then in mcp.json:
Claude Code
Run locally (any host / testing)
3. Use it
Once added, instruct your agent: *"Before any irreversible action, call the forecast tool and stop if it returns STOP."* The model will call it automatically when it's about to do something risky.
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The forecast tool
| Parameter | Type | Required | Description |
|-----------|------|----------|-------------|
| action | string | ✅ | The action type, e.g. send_email, make_payment, run_sql, delete_file, post_content |
| inputs | object | ✅ | Concrete parameters: recipient, amount_usd, SQL statement, file path, message body, URL, etc. |
| context | object | — | Optional: { agent_role, user_intent, environment } |
| depth | standard \| deep | — | Analysis depth. standard is the default. |
**Returns:** recommendation (GO/CAUTION/STOP), risk_score (0–100), reversibility (class + rollback cost), gate (proceed/confirm/human-required), confidence, red_flags[], predicted_result, alternative_actions[].
Example
Agent about to run DELETE FROM users; (no WHERE clause) →
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Observe mode — try it with zero risk
Not ready to let a guardrail block your agents? Start in **observe mode**. It scores and logs every action but **never tells the agent to stop** — your agents behave exactly as they do today. After a week, review your dashboard and see what it *would* have caught.
Then see *"what your agents almost did"* in your dashboard. Flip BLACKWALL_MODE to enforce (or just remove it — enforce is the default) when you're ready to actually block.
Two tools
The server exposes **two MCP tools**:
- **forecast** — pre-action risk check. Returns GO / CAUTION / STOP, risk score, named red flags, reversibility class, and a verifiable receipt.
- **observe** — post-action outcome report. Tells BLACK_WALL what actually happened after the action ran (or after the agent obeyed a STOP verdict). Closes the loop so the system can track prediction accuracy over time. FREE — no tokens charged.
Wire your agent to call forecast before any irreversible action, then call observe afterwards with the forecast_id from the original response. observe accepts an outcome_class (matched / over_scope / under_scope / no_op / diverged / aborted) and optional divergence_severity and details. See the forecast example below; the same wiring applies to observe.