Harden remote sandbox runtime probes, timeouts, and installs (#5685)

## Thinking Path

> - Paperclip orchestrates AI agents for zero-human companies
> - Each agent runs inside a sandbox environment so its CLI is isolated
from the host
> - Sandbox-backed adapter runs go through a small set of shared helpers
— `ensureAdapterExecutionTargetCommandResolvable`, the sandbox callback
bridge runner, and per-adapter `SANDBOX_INSTALL_COMMAND` strings
> - When standing up new sandbox provider plugins, the existing helpers
timed out, missed install fallbacks, or leaned on assumptions that only
held for E2B
> - Local adapters (`claude-local`, `codex-local`, `gemini-local`,
`opencode-local`) needed slightly hardened probes so they could install
themselves and validate inside *any* remote sandbox transport, not just
E2B
> - This pull request bundles those runtime fixes so future sandbox
provider plugins inherit a working baseline
> - The benefit is that adding a new sandbox provider plugin no longer
requires touching adapter-utils or each local-adapter probe — the
supporting infra is already correct

## What Changed

- `packages/adapter-utils/src/execution-target.ts`: introduce
`DEFAULT_REMOTE_SANDBOX_ADAPTER_TIMEOUT_SEC = 1800` and
`resolveAdapterExecutionTargetTimeoutSec(...)`. Local and SSH adapters
keep the historical "0 means no adapter timeout" behavior;
sandbox-backed runs without an explicit `timeoutSec` get an explicit
30-minute default so remote installs and warm-up don't time out at the
per-RPC default. Plumbed `timeoutSec` through
`ensureAdapterExecutionTargetCommandResolvable` so install probes inside
a sandbox honor adapter-level overrides instead of the bridge's 5-minute
default.
- `packages/adapters/opencode-local/src/index.ts`: switch
`SANDBOX_INSTALL_COMMAND` from `npm install -g opencode-ai` to `curl
-fsSL https://opencode.ai/install | bash`. The npm package reifies four
large prebuilt-binary subpackages in parallel even though only one
matches the host arch; on bandwidth-constrained sandboxes that blew
through the 240s install budget. The official installer fetches one
arch-specific binary and adds `$HOME/.opencode/bin` to PATH via
`~/.bashrc`, which the sandbox-callback-bridge login-shell script
already sources.
- `packages/adapters/{claude,codex,gemini,opencode}-local/`: harden
remote-target probes — pass `--skip-git-repo-check` for Codex when
probing outside a repo, normalize permission flags for Claude, and add
`*.remote.test.ts` coverage that exercises the remote-sandbox path
explicitly for each adapter.
- `packages/adapter-utils/src/sandbox-install-command.{ts,test.ts}`
(new): add `buildSandboxNpmInstallCommand` helper.
`server/src/adapters/registry.ts` + new
`server/src/__tests__/adapter-registry.test.ts`: wire adapter install
commands so they fall back to a writable `$HOME/.local` prefix when
global install isn't available.
- `server/src/__tests__/plugin-worker-manager.test.ts` + new
`server/src/__tests__/fixtures/plugin-worker-delayed.cjs`: pin per-call
timeout overrides so plugin worker exec calls honor the caller's timeout
instead of the worker's default.

## Verification

- `pnpm typecheck`
- `pnpm exec vitest run --no-coverage
packages/adapter-utils/src/execution-target-sandbox.test.ts
packages/adapter-utils/src/sandbox-install-command.test.ts`
- `pnpm exec vitest run --no-coverage
server/src/__tests__/plugin-worker-manager.test.ts
server/src/__tests__/adapter-registry.test.ts
server/src/__tests__/claude-local-adapter-environment.test.ts
server/src/__tests__/claude-local-execute.test.ts
server/src/__tests__/gemini-local-adapter-environment.test.ts`
- `pnpm exec vitest run --no-coverage
packages/adapters/codex-local/src/server/test.remote.test.ts
packages/adapters/opencode-local/src/server/test.remote.test.ts
packages/adapters/codex-local/src/server/codex-args.test.ts
packages/adapters/codex-local/src/server/execute.remote.test.ts
packages/adapters/gemini-local/src/server/execute.remote.test.ts`

All passing locally.

## Risks

- Touches shared `adapter-utils` and several `*-local` adapters. The
30-minute default applies only when both (a) the target is
`remote+sandbox` and (b) no `timeoutSec` is configured — local + SSH
paths are unchanged. New test coverage was added alongside each behavior
change to pin the contracts.
- Switching OpenCode's install command to the official installer is a
behavior change for any operator running OpenCode inside a remote
sandbox. Local installs are unaffected (the `SANDBOX_INSTALL_COMMAND`
only runs when an adapter is being installed inside a sandbox).
- Low risk overall — no migrations, no API surface change.

## Model Used

- Provider: Anthropic
- Model: Claude Opus 4.7 (1M context)
- Capabilities used: extended reasoning, tool use (Read/Edit/Bash/Grep),
no code execution beyond local repo commands

## 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 run tests locally and they pass
- [x] I have added or updated tests where applicable
- [ ] If this change affects the UI, I have included before/after
screenshots — N/A, no UI change
- [x] I have updated relevant documentation to reflect my changes
- [x] I have considered and documented any risks above
- [x] I will address all Greptile and reviewer comments before
requesting merge

Co-authored-by: Paperclip <noreply@paperclip.ing>

packages/adapters/opencode-local/src/index.ts

@@ -3,7 +3,29 @@ import type { AdapterModelProfileDefinition } from "@paperclipai/adapter-utils";
 export const type = "opencode_local";
 export const label = "OpenCode (local)";
 
-export const SANDBOX_INSTALL_COMMAND = "npm install -g opencode-ai";
+// Use OpenCode's official installer instead of `npm install -g opencode-ai`.
+// The npm package reifies four large Linux x64 prebuilt-binary subpackages
+// (linux-x64, linux-x64-musl, linux-x64-baseline, linux-x64-baseline-musl) in
+// parallel even though only one matches the sandbox; on bandwidth-constrained
+// sandboxes (e.g. Cloudflare) that exceeded the 240s install budget. The
+// official installer fetches a single arch-specific binary and adds
+// `$HOME/.opencode/bin` to PATH via `~/.bashrc`, which sandbox `sh -lc`
+// invocations source.
+//
+// Security tradeoff: this is `curl | bash` without a SHA-256 verification of
+// the install script. We accept this because:
+//   1. The install runs inside an isolated, ephemeral sandbox — blast radius
+//      is bounded to that sandbox's secrets and disk.
+//   2. The prior `npm install -g opencode-ai` is also unverified code
+//      execution from a third-party registry; this is not strictly worse.
+//   3. OpenCode does not publish per-release SHA-256 checksums in a stable
+//      location, and pinning a version + hash here would require manual
+//      version bumps on every OpenCode release.
+// The `set -e` (implied by Bash's default with `-fsSL` upstream of a piped
+// shell) and `curl -fsSL` give us fail-fast behavior on HTTP errors. If
+// OpenCode starts publishing a stable checksum/signature, switch to fetching
+// a versioned tarball + verifying the digest before exec.
+export const SANDBOX_INSTALL_COMMAND = "curl -fsSL https://opencode.ai/install | bash";
 
 export const DEFAULT_OPENCODE_LOCAL_MODEL = "openai/gpt-5.2-codex";