can1357/oh-my-pi · error · ToolError

Target ${payload.targetId} is no longer available on the att

Error message

Target ${payload.targetId} is no longer available on the attached browser

What it means

Thrown when an attached browser target exists but Puppeteer cannot produce a Page for it (`target.page()` returned null). This happens when the target dies or becomes non-page-backed between finding it via #findAttachedTarget and materializing its page, or when the target is a background/service-worker type with no page.

Source

Thrown at packages/coding-agent/src/tools/browser/tab-worker.ts:1106

			if (payload.mode === "headless") {
				// Create the target directly so its id is reportable before
				// Puppeteer waits for target/page initialization. If that wait
				// wedges, the supervisor can still close the created target.
				this.#page = await createTrackedHeadlessPage(this.#browser, targetId => {
					this.#transport.send({ type: "page-created", targetId });
				});
				this.#observeDialogs();
				await applyStealthPatches(this.#browser, this.#page, { browserSession: null, override: null });
				if (payload.emulateViewport !== false) await applyViewport(this.#page, payload.viewport);
				if (payload.dialogs) this.#applyDialogPolicy(payload.dialogs);
			} else {
				const target = await this.#findAttachedTarget(payload.targetId);
				// Post-timeout recycle: unblock the target BEFORE adopting the page — an open
				// modal dialog or hung navigation can stall `target.page()` / ready info, and a
				// stalled init used to time out and force-kill the tab.
				if (payload.recover) await this.#recoverAttachedTarget(target);
				const page = await target.page();
				if (!page) throw new ToolError(`Target ${payload.targetId} is no longer available on the attached browser`);
				this.#page = page;
				await this.#claimRelayTarget(page);
				this.#observeDialogs();
				if (payload.dialogs) this.#applyDialogPolicy(payload.dialogs);
			}
			if (payload.url) {
				await this.#page.goto(payload.url, {
					// Default to "load" because dev servers with HMR/WS never reach networkidle.
					waitUntil: payload.waitUntil ?? "load",
					timeout: payload.timeoutMs,
				});
			}
			this.#targetId = await targetIdForPage(this.#page);
			this.#transport.send({ type: "ready", info: await this.#currentReadyInfo() });
		} catch (error) {
			// A failed headless init leaves the worker's page orphaned in the shared
			// browser (the supervisor retries with a fresh worker), so close it before
			// reporting. Attach mode adopts an existing target — never close it.

View on GitHub (pinned to 9690622007)

Solutions

Re-list attached targets and pick a fresh, still-open targetId instead of the stale one
Reconnect or reopen the tab via the browser tool before retrying the operation
Catch this ToolError and fall back to opening a new tab with the intended URL
Guard long workflows by re-validating the target is still attached before each phase

Example fix

// before
const target = await worker.adoptTarget(staleTargetId);
// after
const targets = await worker.listTargets();
if (!targets.some(t => t.id === staleTargetId)) {
  await worker.openTab(url); // reopen instead of adopting a dead target
}

Defensive patterns

Strategy: try-catch

Validate before calling

const targets = await worker.listTargets();
if (!targets.some(t => t.id === targetId)) throw new Error(`target ${targetId} not attached`);

Type guard

function isTargetLive(targets: {id:string}[], id: string): boolean {
  return targets.some(t => t.id === id);
}

Try / catch

try {
  await worker.adoptTarget(targetId);
} catch (err) {
  if (err instanceof ToolError && /no longer available/.test(err.message)) {
    await worker.openTab(fallbackUrl);
  } else throw err;
}

Prevention

Refresh target listings before each phase of long workflows
Never cache target IDs across navigations or reconnects
Handle browser disconnect events by invalidating all known target IDs
Fall back to opening a new tab rather than assuming a cached target is alive

When it happens

Trigger: Calling the browser tab adopt/open path with payload.targetId whose target was closed by the browser (tab closed, crash, navigation to a non-page target) between lookup and `target.page()`.

Common situations: Automating a tab the user manually closed; browser tab crashed (Aw, Snap) under memory pressure; target ID cached/stale from a previous listing; target transitioned to a type without a page.

Related errors

AI-assisted analysis of can1357/oh-my-pi@9690622007 (2026-08-31). Data as JSON: /api/errors/7f5604784c62109e. Report an issue: GitHub.