Hermes

Hermes "Chromium browser is missing" / "Playwright Chromium not installed"

Last checked

The error

Chromium browser is missing. Install it with: npx agent-browser install --with-deps (or: npx playwright install --with-deps chromium)

hermes doctor:
  ⚠ Playwright Chromium not installed (browser_* tools will be hidden from the agent)
  ⚠ agent-browser not installed (requires npm/npx on PATH)
  ⚠ browser-use (system dependency not met)

Wording from v0.21.5. On v0.21.6 the install hint reads "hermes pm install chromium (system libraries: npx playwright install-deps chromium)" and the doctor line reads "agent-browser not installed (run: hermes pm install agent-browser)". In Docker the tool says to pull the latest image instead.

Hermes's local browser tools drive their own Chromium through agent-browser, and Hermes could not find that Chromium, so it hides the browser tools or refuses the browser command. Having Chrome installed is usually not enough. On v0.21.6 or later run hermes pm install chromium. On v0.21.5 or older run hermes tools post-setup agent_browser. In Docker, pull the current image, which bundles Chromium.

Why it happens

Before advertising browser tools, Hermes checks for a usable Chromium. Without one the agent-browser CLI would hang until its timeout, so Hermes blocks the tool and reports it as missing instead.

  1. Chromium was never downloaded: you installed with --skip-browser, the one-time download (about 170MB) failed, or lazy installs are turned off with security.allow_lazy_installs.
  2. Your own Chrome is not detected. v0.21.5 only checks AGENT_BROWSER_EXECUTABLE_PATH, google-chrome, chromium, chromium-browser or chrome on PATH, and the Playwright cache, so Chrome.app on macOS and chrome.exe on Windows are not found. From v0.21.6 only AGENT_BROWSER_EXECUTABLE_PATH or the Chromium that Hermes's package manager installed count.
  3. On a headless Linux server the binary exists but the system libraries it needs do not, so it fails to launch.
  4. In Docker you are on an old or custom image. The official image ships Chromium and Hermes skips the auto-install inside containers.
  5. doctor shows browser-use (system dependency not met): the Browser Use CLI is missing. If you set browser.backend to off, this warning is noise (PR #98109 is open to hide it).

The fix

  1. 1 Check your version: hermes --version.
  2. 2 v0.21.6 or later: hermes pm install chromium, and if doctor also flags agent-browser, hermes pm install agent-browser.
  3. 3 v0.21.5 or older: hermes tools post-setup agent_browser, or npx agent-browser install --with-deps.
  4. 4 Headless Debian or Ubuntu server: install the system libraries as root with npx playwright install-deps chromium.
  5. 5 To use a browser you already have, add AGENT_BROWSER_EXECUTABLE_PATH to ~/.hermes/.env, for example the macOS path /Applications/Google Chrome.app/Contents/MacOS/Google Chrome.
  6. 6 Docker: docker pull ghcr.io/nousresearch/hermes-agent:latest, recreate the container, then run hermes doctor and hermes gateway restart.
hermes pm install chromium

Headless servers and sandbox errors

When Hermes runs as root, inside Docker, or on Ubuntu 23.10 and later where AppArmor restricts unprivileged user namespaces, it adds --no-sandbox and --disable-dev-shm-usage to Chromium automatically through AGENT_BROWSER_ARGS.

If you set AGENT_BROWSER_ARGS yourself, that automatic injection turns off, so include those flags in your own value. A timeout that mentions the sandbox points here.

On Android Termux the docs say to run npm install -g agent-browser && agent-browser install instead of the Linux commands.

Still failing?

  • Run hermes doctor again: if Chromium shows as installed but browser calls still time out, the binary is present but cannot start, so install the system libraries.
  • Check that the browser toolset is enabled in your toolsets list, since a disabled toolset will never show browser tools even with Chromium present.
  • If you use a cloud browser, a CDP URL or Lightpanda, the local Chromium check is skipped, so look at that backend's credentials or endpoint instead.

Related errors

Full guideHermes Agent Installation Errors: 6 Current Fixes (and 5 That Are Already Patched)Every error, one pageHermes Agent Not Working? Couldn't Start, Backend Exited and Every Other Fix (v0.21.5)

Hit a different error?

Paste any agent error and get the cause and fix in seconds.

Open the decoder

Frequently asked questions

I have Google Chrome installed. Why does Hermes say Chromium is missing?

Hermes looks for its own Chromium or an explicit path, not for any Chrome on the machine. Set AGENT_BROWSER_EXECUTABLE_PATH to your Chrome binary in ~/.hermes/.env, or attach to a running browser with /browser connect in the interactive CLI.

Is there an exact "chrome not found" error?

Not in current Hermes source. The strings are "Chromium browser is missing" from the browser tool and "Playwright Chromium not installed" from hermes doctor. Search for either one in your logs.

Do I need Chromium at all?

Only for the local browser backend. Cloud browser providers, a CDP connection to your own browser, and the Lightpanda engine in Browser Use mode do not need a local Chromium.

Stop firefighting agent errors

Decoding errors one at a time is the manual version of what BetterClaw automates. Run your agents on a no-code AI agent platform with managed models, retries and config validation built in.

Deploy Your Agent — Start FreeBook a Demo

Free plan available · Pro $49/mo · BYOK · 7-day money-back guarantee