Files
PaperClipAI/server/src/__tests__/sandbox-capability-contract.test.ts
Nicky LeachandPaperclip 8161244284 feat(sandbox): add opt-in duplex command-stream foundation (capability, protocol, bounded host route, frame codec) (#11738)
## Thinking Path

> - Paperclip provides a control plane for companies that run AI agents.
> - Sandboxed agents need a safe execution path for persistent command
streams.
> - The existing callback transport does not provide a bounded, generic
duplex route.
> - The host must control capability access, route identity, protocol
limits, and close behavior.
> - This pull request adds an opt-in duplex command-stream foundation
across the sandbox layers.
> - The feature stays inert because no current provider declares the
capability.

## Linked Issues or Issue Description

**Subsystem affected**

Cross-cutting (multiple of the above)

**Problem or motivation**

Sandbox command execution needs a persistent host-to-sandbox stream. The
current callback bridge uses a file transport and does not provide this
generic route.

**Proposed solution**

Add a fail-closed provider capability, generic worker protocol messages,
a host-owned bounded route, cross-layer service mediation, and a
versioned newline-delimited frame codec.

**Alternatives considered**

Keep the file transport and add feature-specific commands. This does not
provide one reusable duplex contract or host-owned route bounds.

**Roadmap alignment**

This work supports the completed Cloud / Sandbox agents roadmap area and
the safe autonomy goal in the product definition.

**Additional context**

The change passed a two-stage security review. The final code review
verdict was approve after fixes for active-stream bounds and
service-layer capability mediation.

## What Changed

- Add the opt-in `duplexCommandStream` provider capability with
fail-closed narrowing.
- Add duplex open, write, stop, and close requests and data and exit
notifications to the plugin worker protocol.
- Add a host-owned route with bounds for chunk size, cumulative bytes,
lifetime, protocol errors, pending requests, and pre-bind buffering.
- Add close acknowledgement handling with worker retirement when the
close remains unconfirmed.
- Wire `openDuplexChannel` through the execution target, runtime
service, and plugin worker.
- Add a versioned frame codec with shared wire-compatibility vectors and
split UTF-8 handling.

## Verification

- `server/src/__tests__/plugin-worker-manager-duplex.test.ts` passes 18
tests.
- `server/src/__tests__/environment-execution-target-duplex.test.ts`
passes 11 tests.
- `packages/adapter-utils/src/duplex-frame-codec.test.ts` passes 38
tests.
- `server/src/__tests__/sandbox-capability-contract.test.ts` passes 15
tests.
- Setup-token pseudo-terminal regression tests pass 47 tests.
- Server TypeScript check passes.
- Continuous integration will run the full required test, typecheck,
build, and policy checks.

## Risks

- Providers that opt into the capability must implement the complete
worker protocol.
- Route limit defaults can close a stream when a workload exceeds the
configured bounds.
- The capability remains disabled for current providers, so current
production behavior does not change.

## Model Used

OpenAI GPT-5 (`gpt-5`), with tool use and code execution. The model
reviewed and prepared this pull request from the supplied implementation
and verification record.

## 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>
2026-08-19 13:39:13 -07:00

388 lines
16 KiB
TypeScript

import { describe, expect, it } from "vitest";
import {
SANDBOX_CAPABILITY_KEYS,
buildSandboxCapabilityNarrowing,
builtinSandboxProviderVerifiedMethods,
resolveEffectiveSandboxCapabilities,
} from "../services/environment-runtime.js";
// The worker verbs a fully-capable plug-in provider advertises.
const ALL_PLUGIN_METHODS = [
"environmentAcquireLease",
"environmentResumeLease",
"environmentReleaseLease",
"environmentDestroyLease",
"environmentExecute",
"environmentSyncIn",
"environmentSyncOut",
];
describe("sandbox capability contract normalizer", () => {
it("test_absent_declaration_defers_to_worker_supported_methods_discovery", () => {
// No declaration at all. The effective set must fall back to what the worker
// verified, so a third-party provider that implements the sync hooks keeps
// native sync without declaring it.
const effective = resolveEffectiveSandboxCapabilities({
verifiedMethods: ["environmentSyncIn", "environmentSyncOut"],
declared: null,
});
expect(effective.nativeSyncIn).toBe(true);
expect(effective.nativeSyncOut).toBe(true);
// The worker did not verify these verbs, so the baseline is false.
expect(effective.persistentProcessSessions).toBe(false);
expect(effective.reusableLeases).toBe(false);
});
it("test_effective_capabilities_are_subset_of_verified_and_declared", () => {
const verifiedMethods = ["environmentExecute"];
const declared = {
persistentProcessSessions: true,
independentControlCommands: false,
nativeSyncIn: true,
};
const effective = resolveEffectiveSandboxCapabilities({ verifiedMethods, declared });
// Verified + declared true.
expect(effective.persistentProcessSessions).toBe(true);
// Declared false, so removed even though verified.
expect(effective.independentControlCommands).toBe(false);
// Declared true but not verified, so removed.
expect(effective.nativeSyncIn).toBe(false);
// Every effective capability must be a subset of the verified set and the
// declaration: an effective `true` never appears where the worker did not
// verify or the declaration set `false`.
const verifiedOnly = resolveEffectiveSandboxCapabilities({ verifiedMethods });
for (const key of SANDBOX_CAPABILITY_KEYS) {
if (effective[key]) {
expect(verifiedOnly[key]).toBe(true);
expect((declared as Record<string, boolean | undefined>)[key]).not.toBe(false);
}
}
});
it("test_kubernetes_job_lease_disables_native_sync", () => {
const narrowing = buildSandboxCapabilityNarrowing({
leasePolicy: "ephemeral",
leaseMetadata: { backend: "job" },
});
const effective = resolveEffectiveSandboxCapabilities({
verifiedMethods: ALL_PLUGIN_METHODS,
declared: { nativeSyncIn: true, nativeSyncOut: true },
narrowing,
});
expect(effective.nativeSyncIn).toBe(false);
expect(effective.nativeSyncOut).toBe(false);
// A non-sync capability is unaffected by the job-lease narrowing.
expect(effective.persistentProcessSessions).toBe(true);
// The `nativeFileSyncUnsupported` lease flag narrows the same way.
const flaggedNarrowing = buildSandboxCapabilityNarrowing({
leasePolicy: "ephemeral",
leaseMetadata: { nativeFileSyncUnsupported: true },
});
expect(flaggedNarrowing.nativeSyncIn).toBe(false);
expect(flaggedNarrowing.nativeSyncOut).toBe(false);
});
it("test_persistent_process_sessions_follow_the_verified_and_declared_capability", () => {
// Session-output streaming now follows the capability snapshot alone, not a
// config flag. A provider that declares and verifies persistent process
// sessions keeps the capability when no narrowing removes it.
const verifiedMethods = ["environmentExecute"];
const declared = { persistentProcessSessions: true };
const narrowing = buildSandboxCapabilityNarrowing({
leasePolicy: "ephemeral",
leaseMetadata: {},
});
// A normal lease adds no persistent-session narrowing.
expect(narrowing.persistentProcessSessions).toBeUndefined();
const effective = resolveEffectiveSandboxCapabilities({
verifiedMethods,
declared,
narrowing,
});
expect(effective.persistentProcessSessions).toBe(true);
});
it("test_config_resolution_failure_fails_closed_on_persistent_process_sessions", () => {
const verifiedMethods = ["environmentExecute"];
const declared = { persistentProcessSessions: true };
// Config resolution failed, so the provider is untrusted. The narrowing must
// deny persistent process sessions instead of allowing them through. Without
// the fail-closed guard this narrowing key stays undefined and
// `persistentProcessSessions` resolves to true.
const narrowing = buildSandboxCapabilityNarrowing({
leasePolicy: "ephemeral",
leaseMetadata: {},
configResolutionFailed: true,
});
expect(narrowing.persistentProcessSessions).toBe(false);
const effective = resolveEffectiveSandboxCapabilities({
verifiedMethods,
declared,
narrowing,
});
expect(effective.persistentProcessSessions).toBe(false);
// Native sync and reusable lease enforcement stay unchanged on failure.
const syncNarrowing = buildSandboxCapabilityNarrowing({
leasePolicy: "reuse_by_environment",
leaseMetadata: { backend: "job" },
configResolutionFailed: true,
});
expect(syncNarrowing.reusableLeases).toBe(true);
expect(syncNarrowing.nativeSyncIn).toBe(false);
expect(syncNarrowing.nativeSyncOut).toBe(false);
});
it("test_builtin_provider_branch_uses_same_normalizer_as_plugin_branch", () => {
const declared = { reusableLeases: true, persistentProcessSessions: true };
// A built-in provider maps its own methods to the same verb names.
const builtinMethods = builtinSandboxProviderVerifiedMethods({
supportsReusableLeases: true,
execute: () => undefined,
});
const builtinEffective = resolveEffectiveSandboxCapabilities({
verifiedMethods: builtinMethods,
declared,
});
// A plug-in provider that advertises the equivalent verbs.
const pluginEffective = resolveEffectiveSandboxCapabilities({
verifiedMethods: [
"environmentResumeLease",
"environmentReleaseLease",
"environmentDestroyLease",
"environmentExecute",
],
declared,
});
// The one normalizer drives both branches, so equivalent verb sets resolve
// to the identical effective capabilities.
expect(builtinEffective).toEqual(pluginEffective);
expect(builtinEffective.reusableLeases).toBe(true);
expect(builtinEffective.persistentProcessSessions).toBe(true);
// A built-in provider has no native sync hooks, so it never verifies sync.
expect(builtinEffective.nativeSyncIn).toBe(false);
// A built-in provider without an execute method verifies no exec capability.
const noExec = resolveEffectiveSandboxCapabilities({
verifiedMethods: builtinSandboxProviderVerifiedMethods({ supportsReusableLeases: false }),
declared: { persistentProcessSessions: true },
});
expect(noExec.persistentProcessSessions).toBe(false);
});
it("test_present_declaration_never_grants_beyond_verified_supported_methods", () => {
// One case per capability: the declaration sets the flag `true`, the worker
// lacks a prerequisite verb, and the effective value stays `false`.
for (const key of SANDBOX_CAPABILITY_KEYS) {
const effective = resolveEffectiveSandboxCapabilities({
verifiedMethods: [],
declared: { [key]: true },
});
expect(effective[key]).toBe(false);
}
// A single missing prerequisite verb is enough: reusable leases needs
// resume, release, and destroy, so resume alone does not grant it.
const resumeOnly = resolveEffectiveSandboxCapabilities({
verifiedMethods: ["environmentResumeLease"],
declared: { reusableLeases: true },
});
expect(resumeOnly.reusableLeases).toBe(false);
});
it("test_reusable_provider_without_destroy_support_resolves_false", () => {
// A provider that verifies resume and release but not destroy is not
// eligible for reusable leases. The reuse path destroys a stale lease when a
// resume fails, so a provider without destroy support would strand the lease.
const resumeAndReleaseOnly = resolveEffectiveSandboxCapabilities({
verifiedMethods: ["environmentResumeLease", "environmentReleaseLease"],
declared: { reusableLeases: true },
});
expect(resumeAndReleaseOnly.reusableLeases).toBe(false);
// Adding the destroy verb makes the same provider eligible.
const allReuseVerbs = resolveEffectiveSandboxCapabilities({
verifiedMethods: [
"environmentResumeLease",
"environmentReleaseLease",
"environmentDestroyLease",
],
declared: { reusableLeases: true },
});
expect(allReuseVerbs.reusableLeases).toBe(true);
});
it("test_generic_one_shot_provider_does_not_get_session_output_streaming", () => {
// The regression: a generic one-shot provider (for example Modal) verifies
// `environmentExecute` and declares the two broad session capabilities, yet
// it never emits incremental session output. Both broad capabilities resolve
// true, but `incrementalSessionOutput` must stay false because the provider
// did not declare the opt-in behavior. The session-output streaming gate
// reads `incrementalSessionOutput`, so this provider keeps the poll path.
const effective = resolveEffectiveSandboxCapabilities({
verifiedMethods: ["environmentExecute"],
declared: {
persistentProcessSessions: true,
independentControlCommands: true,
},
});
expect(effective.persistentProcessSessions).toBe(true);
expect(effective.independentControlCommands).toBe(true);
// Opt-in denied: the provider did not declare incremental session output.
expect(effective.incrementalSessionOutput).toBe(false);
});
it("test_incremental_session_output_is_opt_in_and_needs_a_declaration", () => {
// An absent declaration denies the opt-in capability even when the worker
// verifies the prerequisite verb. This differs from a worker-property
// capability, which defers to the verified baseline.
const undeclared = resolveEffectiveSandboxCapabilities({
verifiedMethods: ["environmentExecute"],
declared: null,
});
expect(undeclared.incrementalSessionOutput).toBe(false);
// A provider that declares the capability and verifies the prerequisite gets
// the streaming path.
const declared = resolveEffectiveSandboxCapabilities({
verifiedMethods: ["environmentExecute"],
declared: { incrementalSessionOutput: true },
});
expect(declared.incrementalSessionOutput).toBe(true);
// A declaration never grants the capability without the verified verb.
const declaredButUnverified = resolveEffectiveSandboxCapabilities({
verifiedMethods: [],
declared: { incrementalSessionOutput: true },
});
expect(declaredButUnverified.incrementalSessionOutput).toBe(false);
});
it("test_config_resolution_failure_fails_closed_on_incremental_session_output", () => {
// Config resolution failed, so the provider is untrusted. The narrowing must
// deny incremental session output even with a positive declaration, so the
// session-output streaming gate fails closed to the poll path.
const narrowing = buildSandboxCapabilityNarrowing({
leasePolicy: "ephemeral",
leaseMetadata: {},
configResolutionFailed: true,
});
expect(narrowing.incrementalSessionOutput).toBe(false);
const effective = resolveEffectiveSandboxCapabilities({
verifiedMethods: ["environmentExecute"],
declared: { incrementalSessionOutput: true },
narrowing,
});
expect(effective.incrementalSessionOutput).toBe(false);
});
it("test_concurrent_sync_operations_is_opt_in_and_needs_both_sync_verbs", () => {
// Parallel bidirectional file sync is opt-in and direction-neutral. It needs
// both sync verbs, so a provider that verifies only one direction cannot get
// the capability. An absent declaration denies it even with both verbs.
const undeclared = resolveEffectiveSandboxCapabilities({
verifiedMethods: ["environmentSyncIn", "environmentSyncOut"],
declared: null,
});
expect(undeclared.concurrentSyncOperations).toBe(false);
// A positive declaration with both verified verbs resolves true.
const bothVerbs = resolveEffectiveSandboxCapabilities({
verifiedMethods: ["environmentSyncIn", "environmentSyncOut"],
declared: { concurrentSyncOperations: true },
});
expect(bothVerbs.concurrentSyncOperations).toBe(true);
// Only the inbound verb: the outbound prerequisite is missing, so it resolves
// false.
const inOnly = resolveEffectiveSandboxCapabilities({
verifiedMethods: ["environmentSyncIn"],
declared: { concurrentSyncOperations: true },
});
expect(inOnly.concurrentSyncOperations).toBe(false);
// Only the outbound verb: the inbound prerequisite is missing, so it resolves
// false.
const outOnly = resolveEffectiveSandboxCapabilities({
verifiedMethods: ["environmentSyncOut"],
declared: { concurrentSyncOperations: true },
});
expect(outOnly.concurrentSyncOperations).toBe(false);
});
it("test_duplex_command_stream_absent_declaration_resolves_false", () => {
// The duplex channel is opt-in and fail-closed. An absent declaration denies
// the capability even when the worker verifies the duplex open verb. This
// matches the incremental-session-output pattern: an opt-in behavioral
// guarantee needs a positive declaration, not just a verified verb.
const undeclared = resolveEffectiveSandboxCapabilities({
verifiedMethods: ["duplexChannelOpen"],
declared: null,
});
expect(undeclared.duplexCommandStream).toBe(false);
});
it("test_duplex_command_stream_needs_verified_worker_method", () => {
// A declaration never grants the capability without the verified duplex open
// verb. A provider that declares the capability but whose worker does not
// report the duplex open method resolves false.
const declaredButUnverified = resolveEffectiveSandboxCapabilities({
verifiedMethods: ["environmentExecute"],
declared: { duplexCommandStream: true },
});
expect(declaredButUnverified.duplexCommandStream).toBe(false);
});
it("test_duplex_command_stream_declared_and_verified_resolves_true_but_narrowing_removes_it", () => {
// A provider that declares the capability and whose worker verifies the
// duplex open verb gets the capability.
const granted = resolveEffectiveSandboxCapabilities({
verifiedMethods: ["duplexChannelOpen"],
declared: { duplexCommandStream: true },
});
expect(granted.duplexCommandStream).toBe(true);
// Per-target narrowing still removes a verified and declared capability, so a
// lease that cannot use the duplex channel keeps the file bridge.
const narrowed = resolveEffectiveSandboxCapabilities({
verifiedMethods: ["duplexChannelOpen"],
declared: { duplexCommandStream: true },
narrowing: { duplexCommandStream: false },
});
expect(narrowed.duplexCommandStream).toBe(false);
});
it("test_unknown_or_unavailable_verification_resolves_false", () => {
const declaredAll = {
reusableLeases: true,
nativeSyncIn: true,
nativeSyncOut: true,
persistentProcessSessions: true,
independentControlCommands: true,
incrementalSessionOutput: true,
concurrentSyncOperations: true,
};
for (const verifiedMethods of [null, undefined, [] as string[]]) {
const effective = resolveEffectiveSandboxCapabilities({ verifiedMethods, declared: declaredAll });
for (const key of SANDBOX_CAPABILITY_KEYS) {
expect(effective[key]).toBe(false);
}
}
});
});