[BUG] A slash command inside a collapsed [Pasted text #N] paste is never dispatched — it is submitted as a message

Preflight Checklist

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

What's Wrong?

When a paste is collapsed into a [Pasted text #N +M lines] placeholder, a slash command at the start of that paste is not dispatched. Pressing Enter takes the ordinary submit path instead of the command path — the command silently does not run, with no "unknown command" reply and no indication that the input was treated as a message.

Pasting the same content a second time expands the placeholder back to literal text (the composer footer hint reads paste again to expand), and Enter then dispatches the command correctly.

The discriminator is the collapse, not the paste and not the line count. I varied those independently and the pattern is clean — every collapsed input failed to dispatch, and every uncollapsed input dispatched:

| Payload | Delivered by | Lines | Chars | Collapsed? | /goal dispatched? |
|---|---|---|---|---|---|
| /goal x\ny | paste | 2 | 9 | no | yes |
| /goal x\ny\nz | paste | 3 | 11 | no | yes |
| /goal x\ny\nz\nw | paste | 4 | 13 | yes | no |
| /goal x\ny\nz\nw | typed (Ctrl+J newlines) | 4 | 13 | no | yes |
| /goal x\ny\nz\nw | paste twice | 4 | 13 | no (expanded) | yes |
| /goal <900 chars>\ny\nz | paste | 3 | 910 | yes | no |

Rows 3 and 4 are the same 4-line payload delivered two different ways: typed it dispatches, pasted it does not. Row 6 is only 3 lines but crosses the character threshold, collapses, and also fails to dispatch. So neither "it was pasted" nor "it has newlines" explains the failure — being collapsed does.

This is consistent with the thresholds reported in #85453 (~800 characters or more than 3 lines, described there as hardcoded, same version as this report). I varied line count and character count only; I did not vary pane width or terminal.

This looks like the same root cause as some already-open issues. #82846 reports that leading whitespace stops a slash command being dispatched and the line is sent to the model instead; #68038 reports the same symptom when a Remote Control prefix pushes the / off the first character. In all three cases the / is no longer the first character of the composer buffer at dispatch-check time — here because the buffer holds a [Pasted text #N …] token instead of the text. If that check has one call site, these may be one fix.

What Should Happen?

A slash command that leads the pasted content should dispatch whether or not the paste is currently collapsed — the placeholder is a display affordance, and Paste large content already says "The full content is still sent to Claude when you submit."

If instead this is deliberate — command dispatch intentionally disabled while a paste is collapsed — then the actionable defect is that nothing says so and nothing shows it. The footer hint says only paste again to expand. The slash-command and skills documentation says nothing about paste, and the paste documentation says nothing about command dispatch. A visible signal at submit time, plus one documented sentence, would be enough.

Worth noting that the same docs page already reasons about this exact combination for a different case: "In a shell mode command or a / command, where the removal would change what runs … Claude Code cancels the submission and keeps the original text in the input." So a / command whose input carries a paste placeholder is already a contemplated state, and elsewhere the product takes care not to silently change what runs.

Error Messages/Logs

# COLLAPSED (single paste of the 4-line payload) — no command dispatched
❯ [Pasted text #1 +3 lines]
────────────────────────────────────────────────────────────────────────────
  paste again to expand
# after Enter: the submit path is taken, and no goal indicator appears.
# (My repro session was logged out, so this shows routing only — see note below.)
⏺ Login expired · Please run /login

# EXPANDED (same payload pasted twice) — command dispatched
❯ /goal x
  y
  z
  w
# status line afterwards:
◎ /goal active (8s)

What I could not observe: because the repro session was logged out, no request completed, so I cannot say what the model actually receives for the collapsed case — prose, the literal [Pasted text #N] token, or empty content. #77946 and #82590 report pasted content arriving empty on the model side, so that is a live possibility. It does not affect this report either way: the command does not run.

Steps to Reproduce

Originally hit during ordinary interactive use — a multi-line /goal pasted into a running session arrived as a plain message. The scripted reproduction below was then run under tmux 3.6a on macOS; I did not vary the outer terminal, so I cannot rule out terminal-specific paste handling.

Manual

1. Run claude in any directory.
2. Copy a slash-command invocation of 4 or more lines, or over ~800 characters:

``
/goal x
y
z
w
``

1. Paste it into the prompt once. The input collapses to [Pasted text #1 +3 lines].
2. Press Enter. Observed: the command does not run; the input is submitted as a message.
3. Repeat, but paste the same content twice before Enter. The placeholder expands and the command dispatches.

Scripted

tmux paste-buffer -p wraps the buffer in bracketed-paste markers, so the CLI sees the same ESC[200~ … ESC[201~ framing a terminal paste produces:

tmux new-session -d -s pastebug
tmux send-keys -t pastebug 'claude' Enter
sleep 12                                     # wait for the composer

printf '/goal x\ny\nz\nw' > /tmp/payload.txt
tmux load-buffer -b p1 /tmp/payload.txt
tmux paste-buffer -b p1 -t pastebug -p       # collapses to the placeholder
tmux capture-pane -p -t pastebug -S -20      # ❯ [Pasted text #1 +3 lines]

tmux send-keys -t pastebug Enter
sleep 4
tmux capture-pane -p -t pastebug -S -30      # no goal indicator: not dispatched

Then repeat in a fresh session with two paste-buffer calls before Enter; the status line shows ◎ /goal active. Each case above was run in a freshly restarted Claude Code process, with the composer verified empty and no goal active before the case, so the goal indicator can only come from that case.

Claude Model

Not sure / Multiple models

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.1.226 (Claude Code)

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Other

Additional Information

Terminal was tmux 3.6a on macOS.

Adjacent fixes in this area suggest dispatch-after-paste has been treated as a defect before: v2.1.132 — "Fixed pasting text starting with / silently swallowing the input or triggering an unknown-command reply"; v2.1.147 — "Fixed slash commands followed by a tab or newline being treated as an unknown command."

Related but distinct: #82846 and #68038 (same symptom, different reason the / is not first), #77868 (commands highlighted mid-sentence but not dispatched), #85453 (the collapse thresholds), #56885 (a docs-clarification request on this surface, closed NOT_PLANNED). Issues about viewing or expanding the placeholder (#11033, #23134, #29375, #48829, #56722, #76801) cover readability rather than dispatch. #60673 is the desktop-app variant, closed NOT_PLANNED.