## Thinking Path
> - Paperclip is the open source app people use to manage AI agents for
work
> - The Rust runner now owns a bounded ACPX session and a fail-closed
turn lifecycle
> - Provider questions pause a turn and must return structured answers
to the same persisted question set
> - JSON Schema validates the wire shape, but it cannot validate
identifiers and constraints across two documents
> - Unknown questions, invalid choices, and malformed custom answers
must fail before any provider receives them
> - This pull request adds only the package-local response validator and
tests
> - The benefit is a small trust boundary that later request-resolution
code can use without changing production selection
## Linked Issues or Issue Description
Refs #12419
## What Changed
- Validate `paperclip.question_response.v1` against its versioned JSON
Schema.
- Bound serialized responses to 768 KiB before validation.
- Require answer identifiers to match the exact persisted question set.
- Require answers for required questions and reject unknown question
identifiers.
- Enforce text, single-select, and multi-select answer modes.
- Match the existing TypeScript numeric syntax, including decimal,
exponent, hexadecimal, octal, and binary input.
- Match ECMAScript trimming exactly, including BOM whitespace while
rejecting Unicode NEL rather than inheriting Rust-specific whitespace
behavior.
- Enforce known options, custom-answer policy, text length, pattern, and
numeric constraints.
- Validate duplicate option IDs, inverted bounds, and dynamic patterns
before answer lookup so malformed optional questions fail closed even
when unanswered.
- Match JavaScript UTF-16 code-unit length semantics for text
constraints and the 100,000-unit response-field bound.
- Preserve the public optional `recommended` question-option field in
the versioned schema, generated schema bundle, and Rust validation path.
- Return typed validation errors for malformed inputs without panics.
- Export the validator from the Rust runner core.
- Add table-driven tests for valid, mismatched, malformed, oversized,
and numeric-boundary responses.
- Document the package-local structured-response boundary.
- Add `num-bigint` 0.4 and `num-traits` 0.2 as direct runner-core
dependencies for exact arbitrary-length radix parsing and one-step
JavaScript Number rounding; update only the package-local runner Cargo
lockfile.
- Do not change the repository PNPM lockfile, workflows, runnerd
selection, server behavior, UI, or migrations.
## Verification
- Replay base: `9a9fdf06ee4142f77427db30efccc4c43056f64b` (`master`
after #12419 merged).
- Exact replay head: `fad92b3fb348b66ddb10dde44b7b060e55c4fe96`.
- Stable patch ID: `4d6ffbd519dd081f7ea530977cd965bd4569fc75`; this is
the prepared two-commit delta plus the focused cross-language parity fix
found during replay review.
- The exact delta is 10 files, 712 additions, and 2 deletions, all in
`packages/paperclip-runner`.
- The package-local `packages/paperclip-runner/runner/Cargo.lock`
records the two direct runner-core dependencies; their already-resolved
versions and checksums are unchanged.
- The question-set schema source, generated TypeScript schema bundle,
and protocol manifest hash are updated together; the schema SHA-256 is
`42b5441a3d388851dacb6e4500dfd4a17d878eded2e724228078b647e7440d3f`.
- GitHub Actions run `33366812025`, attempt 2: **PASSED** on the exact
replay head (23/23 jobs passed; a failed-job-only retry cleared one
unrelated ACPX runtime-host timeout).
- Greptile: **5/5** on the exact replay head with zero unresolved review
threads; Superagent, Socket, Snyk, and contributor-trust checks also
passed.
- No local test result is claimed. GitHub Actions is the authoritative
verification environment for this replayed revision.
## Risks
- The validator compiles the embedded response schema for each
submission. Responses are user-paced and bounded, so this keeps the
slice simple without affecting a hot event path.
- The persisted question set is the source of truth for identifiers and
constraints. A malformed persisted set fails closed.
- Numeric input follows the existing structured-question contract,
including JavaScript-prefixed syntax. Optional whitespace-only answers
are rejected instead of being treated as an omitted value.
- Error messages identify the invalid field but do not include answer
text.
- No production path invokes this validator in this pull request.
Request resolution 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 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 and contains no internal
Paperclip ticket id or instance-derived details
- [ ] 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
## Thinking Path
> - Paperclip is the open source app people use to manage AI agents for
work.
> - Paperclip Runner needs a language-neutral contract between the
server and the runner process.
> - A shared contract must exist before TypeScript, Rust, transport, or
provider implementations can depend on it.
> - Required protocol versions must fail closed, while safe optional
fields must remain compatible.
> - The contract also needs deterministic fixtures and a drift gate for
later cross-language work.
> - This pull request adds that contract without adding runtime
behavior.
> - The benefit is a small, reviewable source of truth for the next
implementation pull requests.
## Linked Issues or Issue Description
**Subsystem affected**
Cross-cutting. This pull request adds a private package contract for
later server, TypeScript, and Rust work.
**Problem or motivation**
Paperclip Runner does not have a small language-neutral protocol
boundary on `master`. A runtime implementation without this boundary can
drift between languages, accept unsupported required versions, or
silently change canonical fixtures.
**Proposed solution**
Add PRP v1 JSON Schemas, accepted and rejected fixtures, a Codex
structured-question fixture, and a generated SHA-256 manifest. Run
compatibility and manifest checks during the package build. Keep the
package private and export nothing in this pull request.
**Alternatives considered**
The combined runner branch contains schemas together with providers,
SDKs, labs, and server behavior. That change is too large for normal
review. Generating TypeScript validators in this pull request would also
cross into the next review unit.
**Roadmap alignment**
This contract supports the governed tool and control-plane direction in
`ROADMAP.md`. It does not enable a new production adapter or endpoint.
**Additional context**
Refs #12084 and #11962. This pull request was reviewed as a stack on
#12084, then rebased and retargeted to `master` after #12084 merged. The
current delta is 38 files.
## What Changed
- Added 20 PRP v1 JSON Schemas with stable identifiers and resolved
references, including explicit cross-language conformance input and
output schemas.
- Added canonical replay, cross-language, and Codex question fixtures.
- Added accepted cases for additive optional fields and a rejected case
for an unsupported required protocol version.
- Added a deterministic manifest with SHA-256 digests for every schema
and fixture.
- Added package-local schema-instance, schema-reference, compatibility,
question-ID, conformance-pair, and drift checks.
- Added a private workspace package with no public exports and no
production runtime behavior.
- Added the package manifest to the Docker dependency-stage inventory
required for every workspace package. This does not copy or build runner
runtime code into the production image.
- Kept the provider descriptor and question fixture Codex-only. No
deferred provider package or dependency is present.
## Verification
- `pnpm install --frozen-lockfile` passed with Node 24.19.0 and pnpm
9.15.4. No lockfile change is committed.
- `pnpm --filter @paperclipai/paperclip-runner check:protocol` passed
with 8 tests.
- The committed AJV 2020-12 gate accepted every canonical v1 replay,
question, and cross-language conformance fixture. It rejected the
required v2 fixture, a replay fixture with a missing required command
ID, and conformance output with a missing session ID.
- `pnpm -r typecheck` passed.
- `pnpm build` passed and ran the protocol manifest drift check.
- `pnpm check:token-gates` passed.
- `node ./scripts/check-docker-deps-stage.mjs` passed.
- `git diff --check` passed.
- The delta against its declared base is 38 files.
- `pnpm test:run` completed with 4,687 passing tests, 19 skipped tests,
and 29 failures across 9 unchanged server files. The failures reproduce
macOS path aliases, local listener probes, workspace-runtime
assumptions, and one connection-retry timeout. No changed-file test
failed. Linux CI must pass before this pull request is ready.
- `pnpm check:tokens` reports existing personal-name references outside
this pull request. A scoped scan of `packages/paperclip-runner` found no
secret-like values, internal references, or deferred-provider names.
- PR #12084 was squash-merged, and this branch was rebased onto that
merge and retargeted to `master`. The first master-base policy run
correctly caught the missing Docker dependency-stage manifest copy;
commit `4fa1ea7c` fixes that gate, and the complete Linux matrix is
green.
- Serialized server shard 1 initially hit an unchanged heartbeat
test-harness timeout and a later assertion in the same file. Its
isolated rerun passed in 3m57s. All other shards passed on their first
attempt.
- Greptile reviewed the final commit at 5/5 with no blocking failure.
Both earlier actionable validation threads are resolved, and no review
thread remains open.
## Risks
Low production risk. The package is private and has no exports, server
adapter, endpoint, or process. AJV is a package-only development
dependency that the server workspace already uses. The main risk is
contract churn before the TypeScript and Rust consumers land. The
generated manifest and compatibility fixtures make that churn explicit.
I checked `ROADMAP.md`. This change defines a contract for planned
control-plane work and does not add overlapping product behavior.
## Model Used
OpenAI Codex with GPT-5 was used. The exact serving model ID and context
size were not exposed. The model used high reasoning, repository tools,
GitHub tools, and local 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 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
- [ ] 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>
Dotta