[BUG] Cowork UI: Responses not rendering until user types; "working through complex response" hangs indefinitely

[joshnava]

Preflight Checklist

• I have searched existing issues and this hasn't been reported yet
• This is a single bug report (please file separate reports for different bugs)
• I am using the latest version of Claude Code

What's Wrong?

In Claude Cowork (desktop app), two related UI issues make the app nearly unusable during longer sessions:

Issue 1: Responses don't render until the user types something
Claude's response completes processing but the UI does not display it. The response only appears after the user types a new message. This means the user cannot read Claude's output and cannot know what to do next — they only discover responses retroactively after sending a follow-up message.

Issue 2: "Working through a complex response" spinner hangs indefinitely
During sessions with multiple tool calls or background processing (file reads, Bash commands, agent tasks), the UI shows "Working through a complex response..." and hangs for several minutes with no progress. The response may have completed on the backend but the UI never updates.

Combined effect:
The user cannot have a functional conversation. They cannot see responses, cannot answer questions Claude asks, and lose typed input when the UI is stuck. This occurred repeatedly in a single session today (2026-02-19) causing significant workflow disruption and lost context.

Environment:

• App: Claude Cowork (desktop, macOS)
• • Session type: Long session with multiple tool calls (Bash, file reads, Notion MCP, Task agents)
• • • Vault: Obsidian vault mounted as working directory

What Should Happen?

Responses should render immediately when Claude finishes generating them, without requiring user input to trigger display. The "Working through a complex response" state should either resolve in a reasonable time or surface an error — it should never hang indefinitely with no feedback or recovery option.

Error Messages/Logs

Steps to Reproduce

1. Open Claude Cowork (macOS desktop app)
2. 2. Mount an Obsidian vault as the working directory
3. 3. Start a long session involving multiple tool calls (Bash commands, file reads/writes, Notion MCP calls, Task agent spawning)
4. 4. Claude completes a response after tool use
5. 5. Bug 1: The response does not appear in the UI. The chat window shows no new message. Type anything in the input box — the response appears only after sending the new message.
6. 6. For Bug 2: During a session with heavy processing (multiple sequential tool calls), observe the UI display "Working through a complex response..." and wait. The spinner persists for 3-5+ minutes with no resolution and no error message. The UI provides no way to cancel or recover.
      Notes:

• Both bugs appear more frequently as session length increases (longer context window)
• • Bug 1 appears to be a rendering/state update issue — the response exists but the UI doesn't reflect it
• • • Bug 2 may be related to the UI losing sync with the backend during long processing chains
• • • • Reloading the app clears the session context, so there is no viable recovery path

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

No response

Claude Code Version

2.1.45 (Claude Code) — running via Claude Cowork desktop app

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

No response

[github-actions]

Found 3 possible duplicate issues:

1. Agent goes to sleep during long independent actions, resumes only on user input #25068
2. v2.1.12 regression: UI freezes after work completes or on session resume (message rendering fix broke state recovery) #19569
3. Sessions hang indefinitely in Metamorphosing state with 0 tokens #26157

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🤖 Generated with Claude Code

[kasnikoo]

also just started having this issue

[benrodenhaeuser]

Same issue here

[pdussart]

Can confirm same problem. In my situation no complex scripting, integrations or other heavy lifting are being done.

[mezuny]

Same here, trying Cowork for the first time, keeps getting stuck, and if there's a response, it's not rendering (but showing in windows notifications)

[griffithsbs]

Same problem here, Claude for Mac version 1.1.3541 (1e65e4) 2026-02-18T19:23:37.000Z. Reproducible with a simple prompt without much going on, e.g. this one which pulls in the built-in Web search connector but no other context:

If I reply with "Bump", it will render the latest output.

[DominicStewart]

Same here.Started happening today.

[kentwar]

Very annoying. New issue today for me.

[LironBenHaim-RecoLabs2]

Same

[michaellevitz]

I am also having this issue

[Palvorin]

same here