fill_by_uid
Fill text into web form inputs using element UIDs from browser snapshots for automated testing and data entry.
Instructions
Fill text input/textarea by UID.
Input Schema
TableJSON Schema
| Name | Required | Description | Default |
|---|---|---|---|
| uid | Yes | Input element UID from snapshot | |
| value | Yes | Text to fill |
Implementation Reference
- src/tools/input.ts:193-217 (handler)MCP tool handler: validates uid/value args, gets Firefox instance via getFirefox(), calls firefox.fillByUid(uid, value), returns success/error response with UID error handling.
export async function handleFillByUid(args: unknown): Promise<McpToolResponse> { try { const { uid, value } = args as { uid: string; value: string }; if (!uid || typeof uid !== 'string') { throw new Error('uid parameter is required and must be a string'); } if (value === undefined || typeof value !== 'string') { throw new Error('value parameter is required and must be a string'); } const { getFirefox } = await import('../index.js'); const firefox = await getFirefox(); try { await firefox.fillByUid(uid, value); return successResponse(`✅ fill ${uid}`); } catch (error) { throw handleUidError(error as Error, uid); } } catch (error) { return errorResponse(error as Error); } } - src/tools/input.ts:62-79 (schema)Tool schema definition: specifies name 'fill_by_uid', description, and inputSchema requiring uid (string) and value (string).
export const fillByUidTool = { name: 'fill_by_uid', description: 'Fill text input/textarea by UID.', inputSchema: { type: 'object', properties: { uid: { type: 'string', description: 'Input element UID from snapshot', }, value: { type: 'string', description: 'Text to fill', }, }, required: ['uid', 'value'], }, }; - src/index.ts:131-147 (registration)Registration of fill_by_uid handler in the central toolHandlers Map, mapping 'fill_by_uid' to tools.handleFillByUid.
['click_by_uid', tools.handleClickByUid], ['hover_by_uid', tools.handleHoverByUid], ['fill_by_uid', tools.handleFillByUid], ['drag_by_uid_to_uid', tools.handleDragByUidToUid], ['fill_form_by_uid', tools.handleFillFormByUid], ['upload_file_by_uid', tools.handleUploadFileByUid], // Screenshot ['screenshot_page', tools.handleScreenshotPage], ['screenshot_by_uid', tools.handleScreenshotByUid], // Utilities ['accept_dialog', tools.handleAcceptDialog], ['dismiss_dialog', tools.handleDismissDialog], ['navigate_history', tools.handleNavigateHistory], ['set_viewport_size', tools.handleSetViewportSize], ]); - src/index.ts:175-180 (registration)Registration of fillByUidTool in the allTools array for listTools response.
tools.clickByUidTool, tools.hoverByUidTool, tools.fillByUidTool, tools.dragByUidToUidTool, tools.fillFormByUidTool, tools.uploadFileByUidTool, - src/firefox/dom.ts:166-183 (helper)Core implementation: Resolves UID to WebElement using snapshot resolveUid callback, clears the input field, sends the value via sendKeys, waits for events.
async fillByUid(uid: string, value: string): Promise<void> { if (!this.resolveUid) { throw new Error('fillByUid: resolveUid callback not set. Ensure snapshot is initialized.'); } const el = await this.resolveUid(uid); try { await el.clear(); } catch { // Some inputs may not support clear(); fall back to select-all + delete await el.sendKeys(Key.chord(Key.CONTROL, 'a'), Key.DELETE); } await el.sendKeys(value); // Wait for events to propagate await this.waitForEventsAfterAction(); }