dsh-llm-fallbacks

Minimal configuration

Add a fallbacks: section to the dsh settings document (default $DSH_HOME/settings.yaml):

fallbacks:
  enabled: true            # feature switch; defaults to false — set explicitly to enable
  rootChain:               # block 1: root agent's chain, tried in order after the primary model fails
    - anthropic/claude-3-5-sonnet
    - openai/*
  roles:                   # block 2: declare role entities first, then let rules reference them
    list:
      - id: reviewer       # unique id (/^[a-z0-9-]{1,32}$/); "inherit" is reserved
        persona: Code-review subagents
        chain:
          - openai/gpt-4o-mini
        fallback: inherit-root   # default: role chain, then append rootChain
    rules:
      - origin: subagent   # all subagents → reviewer role (own chain + inherited root)
        role: reviewer

No rule match → the built-in inherit → rootChain. enabled defaults to off — with no chains configured the plugin is a complete no-op. Full reference (role entities, fallback strategies, rules, selectors, preset roles) → docs/configuration.md.

Upgrade note (behavior change): an existing fallbacks: section without an explicit enabled key resolves to false after upgrading — add enabled: true to keep the plugin active.