feat(sandbox): forward just-bash SandboxOptions through justbash(), enable python/js-exec

[arimxyer]

What

Forward just-bash's SandboxOptions through the justbash() backend (via JustBashSandboxCreateOptions → Sandbox.create(...)), and enable its bundled interpreters:

• Execution controls the backend previously hardcoded or omitted: timeoutMs, maxCallDepth, maxCommandCount, maxLoopIterations, defenseInDepth.
• Bundled-interpreter capability flags python (stdlib-only CPython via WebAssembly) and javascript (js-exec via QuickJS), both off by default.

justbash({ python: true }) now runs python3 inside the sandbox. Closes #431.

Why

justbash() built its interpreter with Sandbox.create({ cwd, env, fs, network }) and exposed only autoInstall, so an author couldn't set execution limits, an overall timeout, defense-in-depth, or — the driver behind #431 — enable python3 / js-exec. The capability flags live on just-bash's BashOptions, and just-bash's Sandbox.create (the call eve uses) didn't forward them; that upstream gap was fixed in vercel-labs/just-bash#284, shipped in just-bash 3.1.0.

Requires just-bash@^3.1.0 (peer floor raised from ^3.0.0)

This is load-bearing, not housekeeping: python/javascript only reach the interpreter through Sandbox.create as of 3.1.0. On older just-bash they are silently dropped — python: true would no-op rather than error — so the version floor is the only guard against that silent failure.

just-bash is added to minimumReleaseAgeExclude so the 3.1.0 bump resolves without waiting out the 2-day quarantine (it's a first-party vercel-labs package; the lockfile change is scoped to just-bash's own subtree). Happy to drop that and let 3.1.0 age out instead if you'd prefer.

Scope: why not commands / customCommands / fetch

#431 asks for python3 + js-exec, which this delivers. The other three just-bash capability flags are intentionally not surfaced: their just-bash types (CommandName[], CustomCommand, SecureFetch) can't be honestly restated as primitives, and exposing them would put just-bash's types on eve's public API — the same reason defenseInDepth is narrowed to a plain boolean here. They can follow later if there's demand.

Backward compatibility

No behavior change when the new fields are omitted — each forwards as undefined, i.e. just-bash's existing default (network still defaults to full internet access exactly as before).

Tests

• just-bash-capability-options.integration.test.ts (mock): forwarding assertions extended to python/javascript, plus the default-undefined case.
• just-bash.scenario.test.ts (real just-bash): two-sided e2e for each interpreter — justbash({ python: true }) runs python3 -c 'print(1 + 1)' and justbash({ javascript: true }) runs js-exec -c 'console.log(1 + 1)', both → exit 0, stdout 2; without the flag each command is not-found (exit 127).

Validation

turbo run typecheck --filter=eve, oxlint, the mock integration test, and the full just-bash scenario suite (21/21) all pass locally against just-bash 3.1.0. A minor changeset is included.

Supersedes #446

#446 forwarded only the already-supported limits/timeout fields and deferred the capability flags until just-bash#284 shipped. Now that 3.1.0 is out, this PR does the whole thing (limits + python/js-exec) off fresh main; I'll close #446 in favor of it.

🤖 Generated with Claude Code

[vercel]

@arimxyer is attempting to deploy a commit to the Vercel Team on Vercel.

A member of the Team first needs to authorize it.

[socket-security]

Review the following changes in direct dependencies. Learn more about Socket for GitHub.

Diff	Package	Supply Chain Security	Vulnerability	Quality	Maintenance	License
	npm/​just-bash@​3.1.0

View full report