> ## Documentation Index
> Fetch the complete documentation index at: https://docs.benchspan.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Benchspan

> The prompt injection firewall for AI agents. Scan tool outputs and user messages before they reach your model.

Benchspan is a real-time classifier that blocks prompt injection attacks aimed at your AI agent. Drop the SDK into your existing LangChain, CrewAI, OpenAI Agents, Vercel AI, or Google ADK stack and every tool output and user message gets scanned before it reaches the LLM.

* **Inline.** Runs as a callback or middleware in your existing framework, not a separate service to orchestrate.
* **Built for the agent era.** Detects indirect prompt injection hiding in tool outputs, HTML, and email, not just user jailbreaks.
* **Free up to 50,000 requests / month, forever.** No credit card to start.

<CardGroup cols={2}>
  <Card title="Quickstart" icon="rocket" href="/quickstart">
    Install the SDK and run your first scan in under 2 minutes.
  </Card>

  <Card title="How it works" icon="shield" href="/concepts/how-it-works">
    What Benchspan scans, what it blocks, and the verdicts it returns.
  </Card>

  <Card title="Framework integrations" icon="plug" href="/integrations/langchain">
    LangChain, CrewAI, OpenAI Agents, Vercel AI, Google ADK, raw SDKs.
  </Card>

  <Card title="REST API" icon="code" href="/api-reference/overview">
    Use Benchspan directly from any language. Full HTTP reference.
  </Card>
</CardGroup>

## At a glance

```python Python theme={null}
from benchspan import BenchGuard
from langchain_anthropic import ChatAnthropic

guard = BenchGuard(api_key="ag_live_...")
llm = ChatAnthropic(model="claude-sonnet-4-6")

# Injection in any message will raise InjectionDetectedError before Claude is called.
result = llm.invoke(messages, config={"callbacks": [guard]})
```

```typescript TypeScript theme={null}
import { BenchGuard } from "@benchspan/sdk";

const guard = new BenchGuard({ apiKey: "ag_live_..." });

const { injection, verdict } = await guard.scan(toolOutput, { role: "tool" });
if (injection) throw new Error("Blocked by Benchspan");
```

## Who uses Benchspan

Teams shipping agents in production that read untrusted content: email, uploaded documents, web pages, third-party tool outputs. The attack surface expanded the moment your agent started calling tools. Benchspan sits between the tool and the model.