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

# Developer quickstart

> Build with SINT in 15 minutes. SDKs, first intercept, first bridge.

This quickstart assumes you've already run the [top-level quickstart](/quickstart) and have the gateway running on `localhost:3100`. Now we'll build against it.

## Install an SDK

<CodeGroup>
  ```bash TypeScript theme={null}
  pnpm add @sint/sdk
  ```

  ```bash Python theme={null}
  pip install sint-sdk
  ```

  ```bash Go theme={null}
  go get github.com/sint-ai/sint-sdk-go
  ```

  ```bash Rust theme={null}
  cargo add sint-sdk
  ```
</CodeGroup>

## Your first intercept

<CodeGroup>
  ```typescript TypeScript theme={null}
  import { SintClient } from "@sint/sdk";

  const client = new SintClient({
    gatewayUrl: "http://localhost:3100",
    agentDID:   "did:key:z6MkExample"
  });

  // Issue a capability token
  const token = await client.tokens.issue({
    scope: {
      resources: ["mcp://weather/*"],
      actions:   ["read"]
    },
    expiresIn: 3600
  });

  // Intercept a request
  const decision = await client.intercept({
    tokenRef: token.tokenId,
    resource: "mcp://weather/current",
    action:   "read",
    parameters: { location: "Los Angeles" }
  });

  if (decision.decision === "ALLOW") {
    // Proceed with the action
  }
  ```

  ```python Python theme={null}
  from sint_sdk import SintClient

  client = SintClient(
      gateway_url="http://localhost:3100",
      agent_did="did:key:z6MkExample"
  )

  token = client.tokens.issue(
      scope={
          "resources": ["mcp://weather/*"],
          "actions":   ["read"]
      },
      expires_in=3600
  )

  decision = client.intercept(
      token_ref=token.token_id,
      resource="mcp://weather/current",
      action="read",
      parameters={"location": "Los Angeles"}
  )

  if decision.decision == "ALLOW":
      # Proceed with the action
      pass
  ```
</CodeGroup>

## What just happened

<Steps>
  <Step title="Token issued">
    The gateway generated an Ed25519-signed capability token bound to your agent DID and scoped to `mcp://weather/*`.
  </Step>

  <Step title="Request intercepted">
    The intercept call sent a SintRequest to the gateway. The gateway validated the token, checked scope, computed the effective tier via the escalation function, and returned a PolicyDecision.
  </Step>

  <Step title="Ledger entry">
    The decision was written to the evidence ledger with a SHA-256 hash linking it to the previous entry. You can verify the chain via `/v1/ledger/verify`.
  </Step>
</Steps>

## Wiring up your agent

The intercept pattern works with any agentic framework. Wrap every tool call with an intercept check.

```typescript theme={null}
async function governedToolCall(tool: string, args: any) {
  const decision = await client.intercept({
    tokenRef: currentToken.tokenId,
    resource: `tool://${tool}`,
    action:   "invoke",
    parameters: args
  });

  if (decision.decision === "ALLOW") {
    return executeTool(tool, args);
  }

  if (decision.decision === "ESCALATE") {
    const approval = await client.approvals.await(decision.approvalId, {
      timeout: 30000
    });
    if (approval.resolved === "approved") {
      return executeTool(tool, args);
    }
    throw new Error("Action not approved");
  }

  throw new Error(`Action denied: ${decision.rationale.matchedRule}`);
}
```

## Framework integrations

<CardGroup cols={2}>
  <Card title="LangChain">
    Use `@sint/integration-langchain` to wrap every LangChain tool in a SINT-governed callback.
  </Card>

  <Card title="MCP">
    Deploy the SINT MCP bridge in front of any MCP server. See [bridges](/protocol/bridges).
  </Card>

  <Card title="ROS 2">
    Deploy the ROS 2 bridge node to intercept topics, services, and actions with physics-aware policy.
  </Card>

  <Card title="OpenClaw">
    Drop in `@sint/openclaw-adapter`. Every OpenClaw tool call passes through the Gateway.
  </Card>
</CardGroup>

## Read next

<CardGroup cols={2}>
  <Card title="SDKs" icon="code" href="/developers/sdks">
    Per-language SDK reference.
  </Card>

  <Card title="API reference" icon="book" href="/developers/api-reference">
    All gateway endpoints.
  </Card>

  <Card title="Deployment" icon="server" href="/developers/deployment">
    Production deployment recipes.
  </Card>

  <Card title="Contributing" icon="git-branch" href="/developers/contributing">
    Contribute to the protocol.
  </Card>
</CardGroup>