## Thinking Path
> - Paperclip is the open source app people use to manage AI agents for
work.
> - Paperclip Runner provides a durable execution boundary for supported
providers.
> - The current production runtime supports Codex but cannot execute
OpenCode sessions.
> - OpenCode needs a qualified transport, strict input mapping, and
normalized events.
> - This pull request adds the OpenCode runtime as one isolated provider
unit.
> - The benefit is a reviewable provider expansion that does not weaken
the existing Codex path.
## Linked Issues or Issue Description
**Subsystem affected**
Cross-cutting: packages/paperclip-runner and the Codex-local adapter
configuration contract.
**Problem or motivation**
Paperclip Runner has provider-neutral contracts, but the production
backend factory cannot start a qualified OpenCode session. This blocks
OpenCode from using the durable runner path.
**Proposed solution**
Add the qualified OpenCode app-server proxy, driver, MCP bridge,
backend, fixtures, and factory wiring. Keep existing Codex behavior
unchanged.
**Alternatives considered**
Keeping OpenCode only on the direct adapter path would avoid this
runtime work, but it would not provide durable runner recovery or
normalized provider events.
**Roadmap alignment**
ROADMAP.md does not list a conflicting provider-runtime project. This
change extends the existing Paperclip Runner architecture.
## What Changed
- Added the qualified OpenCode app-server proxy and input queue.
- Added collaboration-mode and provider-event normalization.
- Added the OpenCode MCP bridge and native session backend.
- Added strict fixtures and focused unit coverage.
- Added only the package exports and adapter configuration required by
this runtime.
- Kept deferred SDK, lab, eval, and public package surfaces out of this
change.
## Verification
- GitHub Actions is the authoritative verification environment for this
PR.
- Run the package type checks and focused OpenCode tests in CI.
- Run repository typecheck, test, build, security, and policy gates
through the stack-aware workflow.
- Local tests were not run because this checkout is resource
constrained.
## Risks
- OpenCode protocol changes could affect event normalization or
recovery.
- The driver fails closed on malformed input and unsupported runtime
behavior.
- Existing Codex selection remains unchanged unless the stored provider
is OpenCode.
> For core feature work, check [ROADMAP.md](ROADMAP.md) first and
discuss it in #dev before opening the PR. Feature PRs that overlap with
planned core work may need to be redirected.
## Model Used
OpenAI Codex, GPT-5.6, with repository tools, code execution, and
parallel agent review.
## 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 linked existing issues or described the issue in-PR
following the relevant issue template
- [x] I have not referenced internal or instance-local Paperclip issues
or links
- [x] My branch name describes the change and contains no internal
Paperclip ticket id
- [ ] I have run tests locally and they pass — GitHub Actions is
authoritative for this resource-constrained checkout
- [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
- [ ] All Paperclip CI gates are green
- [ ] Greptile is 5/5 with no open P2s, recommendations, or follow-ups
- [x] I will address all Greptile and reviewer comments before
requesting merge
## Stack
- Position: 1 of 4
- Base: master
- Next: additional qualified provider runtimes