Checking Configuration

Diagnose the configured backend without opening a session or making a provider request.

After reading this guide, you will know:

  • How to check offline configuration without provider credentials.
  • Which checks apply to each backend.
  • Why a local pass cannot qualify a live deployment.

Check an Offline Backend

require "ruby_llm/browser"

report = RubyLLM::Browser::Doctor.new(backend: RubyLLM::Browser::FakeBackend.new).report
puts report[:mode] # => offline
puts report[:ok]   # => true
puts report[:summary]
# => configuration checks passed; live provider guarantees are not verified

Doctor checks RubyLLM compatibility and the fake backend’s capabilities. It does not load the Stagehand SDK, inspect provider credentials or endpoint overrides, or open a session. You do not need provider credentials to run offline checks.

Interpret the Report

Use ok to decide whether configuration checks passed. Use mode to identify which backend the report describes, not whether that backend is supported. The existing summary and checks fields remain available. Each check has name, status, and detail; statuses are pass, warn, info, or fail. Any failure makes ok false.

Mode Meaning Checks
offline FakeBackend with fake server mode RubyLLM and backend capabilities; no provider environment or SDK checks
live Stagehand or another non-offline backend RubyLLM and backend capabilities; Stagehand also checks its SDK and environment
unconfigured No backend supplied RubyLLM and a failed backend/egress check

A custom backend does not depend on Stagehand diagnostics. Its capability checks still enforce unverified egress, an unpinned local server, and unapproved custom-header capabilities as failures. A backend’s enforced-egress assertion is not independent evidence of its deployment behavior.

Diagnose Stagehand Without Calling It

Pass your host-created Stagehand backend to Doctor.new(backend:). It reports live mode and a failed egress_isolation check because the built-in adapter is unsupported. Having an installed SDK or environment credentials cannot enable live operations.

Stagehand diagnostics report the SDK version, endpoint override names, and credential presence in the supplied environment without printing values. These observations do not configure the backend or replace explicit constructor credentials. Doctor never calls the provider to test credentials, billing, egress, or session cleanup.

Next Steps