interceptor_browser_snapshot

Instructions

Implementation Reference

• src/index.ts:69-69 (registration)

  Registration call: registerDevToolsTools(server) is invoked to register all devtools tools including interceptor_browser_snapshot.

  registerDevToolsTools(server);

• src/tools/devtools.ts:118-122 (schema)

  Input schema for interceptor_browser_snapshot: target_id (string), selector (optional string, default 'body'), mode (optional enum 'default'|'ai', default 'default').

  {
    target_id: z.string().describe("Target ID from interceptor_browser_launch or interceptor_camoufox_launch"),
    selector: z.string().optional().default("body").describe("Root selector to snapshot (default: 'body')"),
    mode: z.enum(["default", "ai"]).optional().default("default").describe("Snapshot mode — 'ai' adds ref attributes for locator reuse"),
  },

• src/tools/devtools.ts:123-143 (handler)

  Handler implementation: resolves the Playwright Page via getPageForTarget, calls page.locator(selector).ariaSnapshot({mode}), and returns the snapshot text along with target_id, url, title, and root selector.

  async ({ target_id, selector, mode }) => {
    try {
      const page = await getPageForTarget(target_id);
      const snapshot = await page.locator(selector).ariaSnapshot({ mode });
      return {
        content: [{
          type: "text",
          text: truncateResult({
            status: "success",
            target_id,
            url: page.url(),
            title: await page.title().catch(() => ""),
            root: selector,
            snapshot,
          }),
        }],
      };
    } catch (e) {
      return { content: [{ type: "text", text: JSON.stringify({ status: "error", error: errorToString(e) }) }] };
    }
  },

• src/tools/devtools.ts:111-144 (registration)

  Registration function registerDevToolsTools which calls server.tool('interceptor_browser_snapshot', ...) to register the tool on the MCP server.

  export function registerDevToolsTools(server: McpServer): void {
    // ── snapshot ──────────────────────────────────────────────────
  
    server.tool(
      "interceptor_browser_snapshot",
      "Take an ARIA accessibility snapshot of the bound page (YAML-formatted role tree). " +
      "Great for LLM-driven page understanding without parsing HTML.",
      {
        target_id: z.string().describe("Target ID from interceptor_browser_launch or interceptor_camoufox_launch"),
        selector: z.string().optional().default("body").describe("Root selector to snapshot (default: 'body')"),
        mode: z.enum(["default", "ai"]).optional().default("default").describe("Snapshot mode — 'ai' adds ref attributes for locator reuse"),
      },
      async ({ target_id, selector, mode }) => {
        try {
          const page = await getPageForTarget(target_id);
          const snapshot = await page.locator(selector).ariaSnapshot({ mode });
          return {
            content: [{
              type: "text",
              text: truncateResult({
                status: "success",
                target_id,
                url: page.url(),
                title: await page.title().catch(() => ""),
                root: selector,
                snapshot,
              }),
            }],
          };
        } catch (e) {
          return { content: [{ type: "text", text: JSON.stringify({ status: "error", error: errorToString(e) }) }] };
        }
      },
    );

• src/browser/session.ts:127-137 (helper)

  getPageForTarget helper: resolves a target_id to a Playwright Page, handling both cloakbrowser (browser_*) and camoufox (camoufox_*) target types.

  export async function getPageForTarget(targetId: string): Promise<Page> {
    const entry = getEntry(targetId);
    if (isCamoufoxTargetId(targetId)) {
      return ensureCamoufoxPage(entry as CamoufoxEntryWithDriver);
    }
    const browserEntry = entry as BrowserTargetEntry;
    if (browserEntry.page.isClosed()) {
      throw new Error(`Page for browser target '${targetId}' is closed.`);
    }
    return browserEntry.page;
  }