[Bug] Tool calls and messages being delayed until I send new prompts

[ElleNajt]

Running the latest versions, running into a bug where agent-shell can end up in a state where tool calls flash up on the screen but disappear after I make my selection, and responses from Claude don't appear until I send my next message. This is unfortunately inconsistent, but once a shell gets into this state it stays in it for a while. (I was about to say and never leaves, but then a shell did leave this state.)

This is some of what I'm seeing in the log:

STDERR >

No onPostToolUseHook found for tool use ID: toolu_01RpWkQEw2dMhWpVskgkrtpq

API-ERROR >

No onPostToolUseHook found for tool use ID: toolu_01RpWkQEw2dMhWpVskgkrtpq

These errors appearing seem to be related. Sorry the transcripts where I've encountered this are sensitive, I'll provide more logs if I get encounter it on something else.

[ElleNajt]

Maybe a clue as to what is going on (this reply appears instantly after I sent "?")

[ElleNajt]

Hmm, this might be upstream somehow in claude-code-acp? I'm getting messages from Claude about how it's seeing the same tool call result multiple times, and these are sandwiched like:

User: .
Claude: I already saw that result from tool call A, blah blah
User: . (sending a period to get it to progress)
Claude: I already saw that result from tool call A, blah blah (almost the same)

[xenodium]

Replied on email

[ElleNajt]

Here's a replication of the issue. Seems to be related to tool calls returning at different times.

Here's a summary of the video from Claude:

  1. You send a prompt
  2. I respond and launch background tasks
  3. The prompt/response is "done" from agent-shell's perspective
  4. Later, a background task completes
  5. A notification comes in, I generate text about it
  6. But this text needs somewhere to go - and it gets queued up as my "next response"
  7. When you send your next message, that queued response gets flushed out
  8. Your actual message doesn't reach me until *after* all those queued responses are cleared

I'm not sure about what is actually happening at 5., but this is roughly what it looks like from the outside.

Screen.Recording.2026-01-29.at.8.15.43.PM.mov

[ElleNajt]

I upgraded claude-code-acp to 0.13.2 and claude code to 2.1.25 and now I can't reproduce it. Perhaps it's fixed?

[xenodium]

I sure hope so. This is a hairy one. I'll upgrade too. Let's keep this issue open for a bit longer and monitor things.