0.7.0 — Remove :adapter_error default retry, narrow AdapterCaller rescue

Breaking changes

Both changes target redundancy between ruby_llm-contract and upstream ruby_llm 1.14.x.

1. :adapter_error removed from DEFAULT_RETRY_ON

New default: [:validation_failed, :parse_error].

ruby_llm's Faraday middleware already retries transport errors (RateLimitError, ServerError, ServiceUnavailableError, OverloadedError, timeouts) with backoff. Retrying on :adapter_error against the same model re-ran what transport had already retried — retry × retry with no change in context.

:adapter_error remains available as explicit opt-in. It is meaningful primarily paired with escalate "model_a", "model_b" — a different model/provider can bypass what transport retry could not.

2. AdapterCaller narrows rescue from StandardError to RubyLLM::Error + Faraday::Error

Provider errors (the RubyLLM::Error hierarchy) and transport errors that escape ruby_llm's Faraday retry middleware after exhaustion (Faraday::TimeoutError, Faraday::ConnectionFailed) still produce :adapter_error as before.

Programmer errors that are neither — NoMethodError, adapter-code bugs — now propagate instead of being silently converted to :adapter_error and retried. Bugs should be fixed, not retried.

Known limitation: adapter code raising ArgumentError is still coerced into :input_error by Step::Base#run_once (which rescues ArgumentError for input-type validation). Disambiguating adapter-ArgumentError vs input-validation-ArgumentError requires a run_once refactor; tracked as a follow-up.

Migration

Restore pre-0.7 behavior:

retry_policy do
  attempts 3
  retry_on :validation_failed, :parse_error, :adapter_error
end

Preferred — pair with a model fallback chain:

retry_policy do
  escalate "gpt-4.1-nano", "gpt-4.1-mini"
  retry_on :validation_failed, :parse_error, :adapter_error
end

Why the narrative matters

Post-0.7, DEFAULT_RETRY_ON = [:validation_failed, :parse_error] reads cleanly as the gem's core value proposition: retry in ruby_llm-contract is against LLM output variance (malformed JSON, business-rule violations), not against transport or infrastructure. Transport concerns live in ruby_llm/Faraday where they belong; programmer bugs propagate for quick detection.