Route computer and playwright calls directly to the VM

[tnsardesai]

Summary

Default direct-to-VM routing now includes computer and playwright in addition to curl and telemetry/stream.

computer/screenshot and playwright/execute rewrite to {base_url}/... with the session JWT and drop Authorization. process/*, fs/*, and telemetry/events stay on the API origin.

KERNEL_BROWSER_ROUTING_SUBRESOURCES still overrides the default list. An empty value still disables routing.

Metro-api activity recording for /browser/kernel/* has been merged in kernel/kernel#3417. That was the hard gate for this allowlist flip. The kill switch is leaving base_url unset or setting KERNEL_BROWSER_ROUTING_SUBRESOURCES to empty.

Latency (eu-west)

Comparison script: https://gist.github.com/tnsardesai/6704dfc86e2c0785e03beaf274aa672d

Same eu-west session. Published @onkernel/sdk@0.93.0 still hits api.onkernel.com; this branch rewrites to metro-api.

creating eu-west browser…
session rao32cls5rhduxg9n1a732i5
region eu-west
base_url https://proxy.dub-unruffled-kowalevski.onkernel.com:8443/browser/kernel
cdp host proxy.dub-unruffled-kowalevski.onkernel.com:8443
rounds warmup=2 timed=8
control plane (@onkernel/sdk@0.93.0)
control-plane screenshot 498ms api.onkernel.com
control-plane screenshot 884ms api.onkernel.com
control-plane screenshot 647ms api.onkernel.com
control-plane screenshot 508ms api.onkernel.com
control-plane screenshot 614ms api.onkernel.com
control-plane screenshot 512ms api.onkernel.com
control-plane screenshot 509ms api.onkernel.com
control-plane screenshot 408ms api.onkernel.com
control-plane screenshot 622ms api.onkernel.com
control-plane screenshot 590ms api.onkernel.com
min 410ms p50 513ms p95 650ms max 650ms
direct to VM (kernel-node-sdk#hypeship/tier1-direct-allowlist)
direct-to-vm screenshot 648ms proxy.dub-unruffled-kowalevski.onkernel.com:8443
direct-to-vm screenshot 623ms proxy.dub-unruffled-kowalevski.onkernel.com:8443
direct-to-vm screenshot 321ms proxy.dub-unruffled-kowalevski.onkernel.com:8443
direct-to-vm screenshot 335ms proxy.dub-unruffled-kowalevski.onkernel.com:8443
direct-to-vm screenshot 332ms proxy.dub-unruffled-kowalevski.onkernel.com:8443
direct-to-vm screenshot 329ms proxy.dub-unruffled-kowalevski.onkernel.com:8443
direct-to-vm screenshot 345ms proxy.dub-unruffled-kowalevski.onkernel.com:8443
direct-to-vm screenshot 344ms proxy.dub-unruffled-kowalevski.onkernel.com:8443
direct-to-vm screenshot 339ms proxy.dub-unruffled-kowalevski.onkernel.com:8443
direct-to-vm screenshot 341ms proxy.dub-unruffled-kowalevski.onkernel.com:8443
min 324ms p50 337ms p95 347ms max 347ms
p50 delta control-plane 513ms vs direct 337ms (-176ms)

Test plan

• default allowlist includes curl, telemetry/stream, computer, playwright
• computer screenshot and playwright execute rewrite to the VM and drop Authorization
• process, fs, and telemetry/events stay on the API origin

---

Note

Medium Risk
Changes default request routing for computer and Playwright APIs (auth header dropped, JWT on VM URL). Env kill switch remains; process/fs/events stay on the control plane.

Overview
Default direct-to-VM routing now includes computer and playwright alongside curl and telemetry/stream. Screenshot and Playwright execute calls rewrite to the session base_url with a JWT query param and drop Authorization.

process, fs, and telemetry/events still go to the control plane. KERNEL_BROWSER_ROUTING_SUBRESOURCES still overrides the list (empty disables routing).

^{Reviewed by Cursor Bugbot for commit 386880d. Bugbot is set up for automated code reviews on this repo. Configure here.}

[rgarcia]

QA’d commit 8439fe5 from a developer’s perspective.

• Full Jest suite: 408 passed.
• Focused routing experiments covered all 12 computer/* methods, playwright/execute, request bodies, headers, VM errors, cache eviction, pool acquisition, env overrides, and control-plane fallback.
• Direct requests use {base_url}, inject the session JWT, and remove Authorization.
• process/*, fs/*, telemetry/events, logs, and replays remain on the API origin.
• Missing base_url and KERNEL_BROWSER_ROUTING_SUBRESOURCES="" correctly disable direct routing.

Non-blocking: the PR description mentions screenshot/execute, but the computer prefix routes the entire computer/* surface. It would be useful to state that explicitly and add a nested-path test such as computer/clipboard/read.

No blocking findings.