## Thinking Path
> - Paperclip is the open source app people use to manage AI agents for
work
> - The Rust runner now owns validated, scoped ACPX reducer events and
safe session suspension
> - Durable PRP transport must receive provider-neutral events rather
than sidecar-native envelopes
> - Semantic calls and questions must retain the exact run, session,
turn, item, and provider-request authority used by the durable command
stream
> - Terminal, result, assistant, process, and diagnostic events also
need one reviewed projection boundary
> - Permission requests remain impossible under the pinned Codex policy
and must fail closed if they reach projection
> - This pull request adds only that package-local projection without
selecting ACPX in runnerd
## Linked Issues or Issue Description
Refs #12422
## What Changed
- Add a validated durable ACPX event projection context bound to one
run, normalized session, turn, and item.
- Pass already normalized activity events through without reintroducing
provider-native envelopes.
- Project authorized tool calls into canonical semantic input receipts
with exact correlation and content digests.
- Project structured questions into provider-neutral
`paperclip.runtime_request.v2` events.
- Preserve both the public projected request identity and the original
provider request identity so responses resolve the exact sidecar
request.
- Project dynamic semantic operation results as `semantic_tool.result`;
only reserved finish/block operations may propose the run result.
- Project semantic completion results into `run.result.proposed`.
- Project terminal-flushed assistant messages on the final channel and
turn terminal states into existing provider-neutral event families.
- Project sanitized process metadata and diagnostics into bounded
harness diagnostics.
- Validate runtime-request origins against their strict durable shape
and fall back from empty optional titles to a valid question prompt.
- Reject invalid identities, projected-identity collisions, unstable
semantic receipt identities, permission requests, and cross-turn
projection fail closed.
- Add integration coverage across reducer event families, correlation,
identity validation, projected question resolution, and pinned-policy
denial.
- Document the durable projection boundary.
- Do not change dependencies, lockfiles, workflows, runnerd selection,
server behavior, UI, or migrations.
## Verification
- Replay base: `80639f4f69c8938eb74bdc0833df93e0ed91dab3` (`master`
after #12422 merged).
- Exact replay head: `3cb29581d2bcbc4b47f8069baffd721c6ce4e444`.
- Stable patch ID: `92910b56575e67ae83960177d467a565019ba282`.
- The exact delta is 22 files, 1,206 additions, and 59 deletions, all in
`packages/paperclip-runner`; it contains no lockfile, workflow, server,
UI, dependency, or migration change.
- `git diff --check` and the Cargo formatting check pass on the replayed
delta.
- Exact-head GitHub Actions run `33372209037` (attempt 2): **PASSED**
with 23/23 jobs passed.
- Greptile reviewed exact head
`3cb29581d2bcbc4b47f8069baffd721c6ce4e444`: **5/5**, with zero
unresolved review threads.
- Superagent, contributor trust, Socket, and Snyk security checks:
**PASSED**.
- No local test result is claimed. GitHub Actions is the authoritative
verification environment for this replayed revision.
## Risks
- This function accepts reducer output, not raw sidecar frames. Callers
must preserve the existing scope-first decode and reduction order.
- Semantic input includes the already sanitized provider input while its
content receipt uses the same canonical digest.
- Structured input preserves the validated provider-neutral question set
and sanitized origin.
- Noncanonical provider request identities are deterministically
projected for PRP while the original identity remains authoritative for
the sidecar resolution command.
- Existing PRP v1 identifiers remain schema-compatible; the only public
ID-schema change widens turn/item limits from 160 to 240 characters. The
internal ACPX sidecar wire schema now mirrors the stable IDs its Rust
transport already enforced.
- The projector verifies event-carried terminal and assistant turn
identifiers against the durable context.
- No production path invokes this projector in this pull request.
Durable command execution remains the next slice.
> 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 — check the roadmap
first. See `CONTRIBUTING.md`.
## Model Used
- OpenAI Codex with GPT-5.6, agentic reasoning, tool use, and code
execution.
## 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 linked the preceding public PR or described the issue in-PR
- [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
- [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
1ee738cf48