## Thinking Path > - Paperclip manages AI agents and their work. > - Native runs must receive the files that users attach to their messages. > - Remote wake preparation returned file metadata without readable bytes. > - The historical chat reader also rejected every remote target. > - Command-backed sandboxes and SSH targets already provide a bound command transport. > - This pull request stages verified files through that transport and clears them after the turn. > - Agents can then open attached images with their normal image reader. ## Linked Issues or Issue Description Refs #19740. This change covers SSH and command-backed sandbox execution, including Daytona. Plugin Runner tasks without a command transport still need a separate versioned file-transfer contract. This PR does not close that broader issue. The open attachment-recovery PR #20778 concerns provider-session attachment journals, not input files. **What happened?** A user uploaded an image and sent it to an agent. The remote native run received its filename and size, but no readable file. Wake preparation reported `remote_workspace_staging_unsupported`. The historical read fallback also refused remote execution. **Expected behavior** Copy the exact admitted attachment into the bound remote workspace. Let the provider read the image. Preserve company, task, source-comment, size, and hash checks. Clear temporary file contents when the turn ends. **Steps to reproduce** 1. Select a native agent on a command-backed sandbox or Linux SSH environment. 2. Attach a PNG to its current task or in-app chat message. 3. Ask the agent to inspect it. 4. Check that wake preparation supplies a readable workspace-relative image path. ## What Changed - Add a remote staging owner with bounded commands, stdin transfer, hash verification, opaque paths, and safe image extensions. - Confine Linux filesystem operations through directory descriptors. Refuse symlinks and replacement files during cleanup. - Bind current wake files and authorized historical external-chat reads to the selected lease transport. - Join active writes during cancellation. Retain failed cleanup work until scope close. - Tell providers to open image files with an image-capable reader. - Handle stdin stream errors in the shared SSH transport. Failed uploads return failure instead of raising an unhandled EPIPE or reporting success. - Add database, transport, cancellation, integrity, cleanup, executor-wiring, and Linux filesystem regressions. Document support and limits. ## Verification - Prepared an isolated source checkout with `node scripts/agent-preflight.mjs --skip-rust-debug`. - Focused suites: `pnpm exec vitest run server/src/services/native-runtime/remote-attachment-staging.test.ts server/src/services/native-runtime/native-runner-file-handoff.test.ts server/src/services/native-runtime/chat-attachment-read.test.ts` — 74 passed, 4 Linux-only tests skipped. - Executor checks: `pnpm exec vitest run server/src/services/native-runtime/native-session-executor.test.ts -t 'attachment staging to the remote|stages from the authenticated|verifies frozen staged admission'` — 7 passed. - Server typecheck: `pnpm --filter @paperclipai/server typecheck`, followed by the server layered check after the final changes. - `git diff --check` passed. The local secret, PII, and private-reference diff scan found no matches. - `pnpm verify` returned exit 2 because the documentation change requires broad CI. No full local suite is claimed. - The four Linux filesystem tests were skipped locally because this macOS host has no available Docker daemon. Linux CI executed all 17 remote-staging tests successfully, including those four confinement tests: [server shard 10](https://github.com/paperclipai/paperclip/actions/runs/43102035096/job/130796646266). - SSH regression: the real pipe test reproduced two unhandled EPIPE errors before the fix, plus false success when the peer exited with code zero. The fixed SSH tests and existing argv tests pass (12 tests). The remote-staging transport suite also passes (13 tests; 4 Linux tests require CI). - `pnpm --filter @paperclipai/adapter-utils typecheck` passed after the SSH change. - Final revision `1c5a9288b8d5f267ddeac84638ff6075dbbbf8ec`: all applicable CI jobs passed, including typecheck, build, general and serialized tests, Runner checks, canary dry run, and all eight browser shards. [CI run](https://github.com/paperclipai/paperclip/actions/runs/43102035096). Linux CI also passed all 6 native SSH tests: [server shard 5](https://github.com/paperclipai/paperclip/actions/runs/43102035096/job/130796646349). - Greptile reviewed that final revision at 5/5 with no remaining findings. The review thread is resolved. GitHub reports the PR mergeable with a clean merge state. - No live model turn or deployed release is claimed. ## Risks - Remote staging requires Linux, Node, and a command transport bound to the selected lease. Plugin Runner tasks without that transport retain their unavailable result. - Each file uses bounded independent commands. Slow transports can delay preparation or cleanup. File bytes stay out of command arguments and provider-facing error messages. - An abrupt controller or remote-host failure can bypass cleanup. Ephemeral sandbox disposal remains the backstop. Retained files are never blindly overwritten or deleted. - Previous-release provider sessions and checkpoints retain their format and identity. New turns receive newly staged input files. Existing restart-admission checks still apply. No migration, runner-image change, or account-credential transfer is required. ## Model Used OpenAI `gpt-6.1-sol` through the Codex harness in T3 Code, with xhigh reasoning, repository inspection, code execution, and tests. No subagents were used. The context-window size is not exposed by this 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>
@paperclipai/adapter-utils
Shared utilities for Paperclip adapters: process spawning, environment injection, sandbox/SSH transport, workspace sync, and the round-trip helpers that move code between the local execution-workspace cwd and wherever the agent actually runs.
For the adapter-author guide see
docs/adapters/creating-an-adapter.md
and the in-repo notes at packages/adapters/AUTHORING.md.
Sandbox bridge deadlines
Command-managed bridge control operations (queue reads, input delivery, setup, and cleanup) have a host-enforced deadline of at most 30 seconds per shell command. A shorter configured timeout still applies. These operations cannot inherit the agent run's hours-long lifetime or wait forever on a provider that ignores its timeout. Long-lived agent session commands keep their own limits.
A control timeout reports a transport failure. It does not prove that the remote command stopped and does not replay an uncertain write. The process session closes failed input delivery and uses its existing shutdown path; normal execution settlement must still verify termination.
Native archive transfer deadlines
Native syncIn and syncOut calls accept an optional minimumTimeoutMs budget. The
server validates this budget and extends the worker RPC deadline. Providers can
honor this field for file transfers without changing their configuration. Daytona
uses the larger of this minimum and its configured timeout. Other providers keep
their existing behavior. The minimum is limited to 30 minutes and does not change
sandbox lifetimes, stored settings or the timeout for other commands.
The remote-workspace archive path uses the verified capture size for downloads and the local archive size for uploads. Large archives get one second per MiB plus 60 seconds, capped at 30 minutes. Small archives keep the existing provider timeout when that calculation is no greater than five minutes. Archive size, checksum, confinement and host space checks still apply.
An exact retained-sandbox resume keeps its recorded provider timeout and RPC overhead. It uses the normal one-minute fallback only when no timeout was recorded. A five-minute cold restore must not be cut off by that fallback. Resume still targets the recorded allocation and does not acquire a replacement.
No-remote-git contract
The local execution-workspace cwd is the only persistence boundary across runs. No adapter may depend on a git remote for cross-run state.
Adapters that run the agent on a different host should use the SSH round-trip
helpers in src/ssh.ts:
prepareWorkspaceForSshExecution({ spec, localDir, remoteDir })— bundles the local cwd (tracked files, dirty edits, untracked additions, and the git history needed to reconstruct it) toremoteDirbefore the run starts. Runs with nogit remoteconfigured.restoreWorkspaceFromSshExecution({ spec, localDir, remoteDir, ... })— syncs the remote cwd back intolocalDirafter the run, including any new commits the agent created. Also runs with nogit remoteconfigured.
prepareRemoteManagedRuntime in
src/remote-managed-runtime.ts wraps both
calls for adapters that want a per-run remote workspace and an automatic
restoreWorkspace() finally hook.
The invariant is pinned by the no-remote-git contract case in
src/ssh-fixture.test.ts, which asserts that a
remote-only commit propagates to the local worktree through the
prepare → restore round-trip with no git remote configured at any point. Do
not regress that test.