Selenix-MCP

Instructions

Implementation Reference

• src/index.ts:38-57 (handler)

  Handler logic that processes the 'get_screenshot' tool result by formatting it as an image content object for MCP.

  if (name === 'get_screenshot' && result.screenshot) {
    const screenshotStr = result.screenshot as string
    const base64Data = screenshotStr.replace(
      /^data:image\/\w+;base64,/,
      ''
    )
    return {
      content: [
        {
          type: 'image' as const,
          data: base64Data,
          mimeType: 'image/jpeg',
        },
        {
          type: 'text' as const,
          text: `Screenshot of: ${result.title || 'unknown'} (${result.url || 'unknown'})`,
        },
      ],
    }
  }

• src/tools.ts:5-13 (schema)

  Definition and schema for the 'get_screenshot' tool.

  {
    name: 'get_screenshot',
    description:
      'Capture a screenshot of the active browser window in Selenix playback. Returns a base64-encoded JPEG image.',
    inputSchema: {
      type: 'object' as const,
      properties: {},
    },
  },

• src/bridge-client.ts:24-72 (helper)

  The BridgeClient class acts as the transport layer, calling the Selenix backend API via HTTP. The tool handler uses this to fetch the actual screenshot data.

  export class BridgeClient {
    async call(endpoint: string, body: Record<string, unknown> = {}): Promise<unknown> {
      // Re-read config on every call so we pick up new tokens after Selenix restarts
      const config = readConfig()
  
      return new Promise((resolve, reject) => {
        const data = JSON.stringify(body)
        const req = http.request(
          {
            hostname: '127.0.0.1',
            port: config.port,
            path: `/api/${endpoint}`,
            method: 'POST',
            headers: {
              'Content-Type': 'application/json',
              Authorization: `Bearer ${config.token}`,
              'Content-Length': Buffer.byteLength(data),
            },
            timeout: 180000, // 3 minutes for long-running operations like run_test
          },
          (res) => {
            let responseData = ''
            res.on('data', (chunk: string) => (responseData += chunk))
            res.on('end', () => {
              try {
                resolve(JSON.parse(responseData))
              } catch {
                resolve({ raw: responseData })
              }
            })
          }
        )
        req.on('error', (err) =>
          reject(
            new Error(
              `Cannot connect to Selenix bridge at 127.0.0.1:${config.port}. ` +
                `Is Selenix running with MCP Server enabled? (${err.message})`
            )
          )
        )
        req.on('timeout', () => {
          req.destroy()
          reject(new Error('Request timed out after 180 seconds'))
        })
        req.write(data)
        req.end()
      })
    }
  }