## Thinking Path
> - Paperclip is the open source app people use to manage AI agents for
work
> - Agent adapters use provider-specific login flows
> - Codex device login needs a live pseudo-terminal (PTY), while the
shared channel still uses Claude-specific names
> - The old streamed-exec path does not provide the prompt transport
that Codex needs
> - This pull request moves Codex device login to the shared login PTY
and removes the dead streamed-exec path
> - The benefit is one controlled login transport with fail-closed
capability checks and safer credential reads
## Linked Issues or Issue Description
**Problem or motivation**
Codex device login used a streamed-exec path that did not provide the
required prompt transport. The shared login channel also exposed
Claude-specific names outside Claude code.
**Expected behavior**
The host selects a fixed login command from trusted adapter data. Codex
login uses the provider login PTY. Providers without that capability
fail closed.
**Proposed solution**
Use a server-controlled session home, create and validate it as a fresh
0700 directory, read credentials from one validated descriptor, and
rename shared channel names to the neutral login PTY family.
**Alternatives considered**
Keep the shared login PTY as the single transport. Do not keep the
removed streamed-exec path because it cannot provide the required prompt
transport.
**Roadmap alignment**
This change supports the planned login transport work. It does not add a
separate roadmap item.
## What Changed
- Route Codex device login through the shared login PTY transport.
- Select the login command from a closed internal command key.
- Carry a server-controlled session home through the launch contract.
- Create and validate the session home as a fresh 0700 directory owned
by the login user.
- Read the credential file with descriptor-relative, no-follow path
walking and final descriptor checks.
- Gate the login route and run lease on the provider login PTY
capability.
- Rename shared channel names to the neutral login PTY family.
- Remove the streamed-exec transport value, selector field, driver
branch, and related tests.
- Hide Codex login in the user interface when the provider lacks the
login PTY capability.
## Verification
- Server unit suites pass: 89/89.
- Adapter-utils suites pass: 262/262.
- Codex-local suites pass: 326/326.
- Credential-read reader suite passes: 20/20.
- Daytona login PTY suite passes: 30/30.
- Device-login suites pass: 56/56.
- TypeScript checks pass for server, adapter-utils, and UI.
- GitHub Actions must pass after pull request creation.
- Greptile review must reach 5/5 with no open P2 findings,
recommendations, or follow-ups.
## Risks
- Providers without a login PTY capability lose Codex login support by
design.
- The credential read rejects invalid ownership, mode, type, path, and
size.
- The launch-time sandbox directory race remains outside the threat
model because the login runs inside the sandbox and a hostile sandbox
already controls its credential.
## Model Used
OpenAI Codex, GPT-5, tool use and code review assistance. The exact
context window and reasoning mode are not exposed by the runtime.
## Checklist
- [x] I have included a thinking path that traces from project context
to this change
- [x] I have specified the model used (with version and capability
details)
- [x] I have checked ROADMAP.md and confirmed this PR does not duplicate
planned core work
- [x] I have searched GitHub for duplicate or related PRs and linked
them above
- [x] I have either (a) linked existing issues with `Fixes: #` / `Closes
#` / `Refs #` OR (b) described the issue in-PR following the relevant
issue template
- [x] I have not referenced internal/instance-local Paperclip issues or
links (only public GitHub `#NNN` / `github.com/paperclipai/paperclip`
URLs)
- [x] My branch name describes the change (e.g. `docs/...`, `fix/...`)
and contains no internal Paperclip ticket id or instance-derived details
- [x] I have run tests locally and they pass
- [x] I have added or updated tests where applicable
- [x] I have updated relevant documentation to reflect my changes
- [x] I have considered and documented any risks above
- [x] All Paperclip CI gates are green
- [x] Greptile is 5/5 with no open P2s, recommendations, or follow-ups
- [x] I will address all Greptile and reviewer comments before
requesting merge
---------
Co-authored-by: Paperclip <noreply@paperclip.ing>
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