PR: https://git.cafe/pingdotgg/t3code/pulls/26652
GitHub: https://github.com/pingdotgg/t3code/pull/26652
PR head: e0c99144210f165952d3bae500be4cb10b0d9b2a

BASELINE
$ git worktree add ../main github/main
HEAD 32ecd71726 (github/main fetched for this verification)
$ vp i
exit 0
$ T3CODE_DEV_SEED=0 setsid nohup timeout 3600 vp run dev
[dev-runner] serverPort=16733 webPort=8693 baseDir=/home/user/main/.t3
Browser: repository Playwright 1.60.0, /usr/bin/google-chrome, headless.
Paired through actual web app. Added project /home/user/t3code through Local folder.
Installed Devin 3000.11.234 through Settings > Providers > Add provider > ACP Registry.
Started real Devin thread: "Run pwd and git rev-parse --show-toplevel. Do not change files. Report the output."
Running server returned:
AcpRequestError: Please log in to use Devin. Use `/login` to authenticate again.
No terminal was created. Original credential leak could not be reproduced.
Stopped main dev process group by captured PID before starting PR.

PR HEAD
$ git checkout --detach e0c99144210f165952d3bae500be4cb10b0d9b2a
$ vp i
exit 0
$ T3CODE_DEV_SEED=0 setsid nohup timeout 3600 vp run dev --home-dir /home/user/t3code/.t3
[dev-runner] serverPort=13773 webPort=5733 baseDir=/home/user/t3code/.t3
Paired through actual web app. Added project /home/user/t3code through Local folder.
Installed Devin 3000.11.234 through ACP Registry and started same real thread.
Running server returned:
AcpRequestError: Please log in to use Devin. Use `/login` to authenticate again.

NEARBY REAL PATHS ON PR
Selected Codex GPT-6.1-Sol in composer and submitted a real provider turn.
Requested pwd, git rev-parse --show-toplevel, and printf PR26652_CODEX_OK.
Provider response in web client:
/home/user/t3code
/home/user/t3code
PR26652_CODEX_OK
Reloaded/reopened thread and retained response.
App terminal drawer: typed command, pressed Enter, observed:
$ printf 'PR26652_TERMINAL_OK\n'; pwd; git rev-parse --show-toplevel
PR26652_TERMINAL_OK
/home/user/t3code
/home/user/t3code

FOCUSED EXISTING CHECKS
Executed via blacksmith-check, dependencies installed in worker:
$ vp test run packages/provider-acp/src/server/clientTerminals.test.ts
Test Files 1 passed (1)
Tests 13 passed (13)

LIMIT
Codex and the app terminal drawer do not use the changed ACP client-terminal implementation.
Only Devin enables that implementation in the registry adapter.
Exact regression needs an unclaimed ACP session in a server inheriting an outer thread MCP environment.
No authenticated Devin account was available; neither before reproduction nor after verification of credential filtering was possible.
No mocks, fixtures, demo data, source edits, commits, or pushes.