WebScout MCP

Instructions

Implementation Reference

• src/tools/interaction.js:68-100 (handler)

  The core handler function that executes the fill_form tool. It iterates over the fields array, fills each input using Playwright's page.fill and page.waitForSelector, optionally presses Enter, and clicks a submit button if provided. Returns success status and page info.
  export async function fillForm(sessionId, fields, submitButton = null) { const session = getSession(sessionId); const { page } = session; try { for (const field of fields) { const { selector, value, pressEnter = false } = field; await page.waitForSelector(selector, { timeout: 5000 }); await page.fill(selector, value); if (pressEnter) { await page.press(selector, "Enter"); await page.waitForTimeout(1000); } } if (submitButton) { await page.click(submitButton); await page.waitForTimeout(2000); } return { success: true, sessionId, currentUrl: page.url(), title: await page.title(), message: `Filled ${fields.length} field(s) successfully`, }; } catch (error) { throw new Error(`Failed to fill form: ${error.message}`); } }
• src/index.js:156-200 (schema)

  The input schema definition for the fill_form tool, including parameters sessionId, fields (array of selector/value/pressEnter), and optional submitButton. Defines types, descriptions, and required fields for MCP tool validation.
  { name: "fill_form", description: "Fill out one or multiple form fields in sequence, perfect for login forms, registration, search inputs, or any text entry. Supports pressing Enter after each field and clicking a submit button. Commonly used for authentication flows before accessing chat interfaces. Each field can be filled independently with optional Enter key press.", inputSchema: { type: "object", properties: { sessionId: { type: "string", description: "Session ID obtained from initialize_session", }, fields: { type: "array", description: "Array of form field objects to fill in sequence. Each field requires a CSS selector and value. Example: [{selector: 'input[name=\"email\"]', value: 'user@example.com'}, {selector: 'input[type=\"password\"]', value: 'mypassword'}]", items: { type: "object", properties: { selector: { type: "string", description: "CSS selector for the input field (e.g., 'input[name=\"username\"]', '#email', '.search-box')", }, value: { type: "string", description: "Text value to enter into the field", }, pressEnter: { type: "boolean", description: "Press Enter key after filling this field to submit or trigger search (default: false)", }, }, required: ["selector", "value"], }, }, submitButton: { type: "string", description: "Optional CSS selector for submit button to click after all fields are filled (e.g., 'button[type=\"submit\"]', '#login-button')", }, }, required: ["sessionId", "fields"], }, },
• src/index.js:459-475 (registration)

  The dispatch logic in the CallToolRequestSchema handler that validates parameters and calls the fillForm handler function for the fill_form tool.
  case "fill_form": { const { sessionId, fields, submitButton } = args; if (!sessionId) { throw new McpError( ErrorCode.InvalidParams, "sessionId parameter is required" ); } if (!fields || !Array.isArray(fields)) { throw new McpError( ErrorCode.InvalidParams, "fields parameter must be an array" ); } result = await fillForm(sessionId, fields, submitButton); break; }
• src/tools/reverseEngineer.js:16-16 (helper)

  Re-export of the fillForm function from interaction.js, allowing centralized imports in index.js.
  export { clickElement, fillForm, waitForElement } from "./interaction.js";