Description

When streaming responses from the Anthropic API, build_chunk occasionally receives a non-Hash value (e.g. true) instead of the expected Hash, causing:

NoMethodError: undefined method 'dig' for true
  ruby_llm-1.13.1/lib/ruby_llm/providers/anthropic/streaming.rb:15:in 'build_chunk'
  ruby_llm-1.13.1/lib/ruby_llm/streaming.rb:33:in 'block in handle_stream'
  ruby_llm-1.13.1/lib/ruby_llm/streaming.rb:97:in 'block in handle_sse'

Root Cause

handle_data in streaming.rb:102 parses the SSE event data with JSON.parse(data). When Anthropic's stream emits a bare JSON true (or any other non-Hash JSON value), the guard on line 104 correctly identifies it's not a Hash error payload and returns it as-is:

def handle_data(data, env)
  parsed = JSON.parse(data)
  return parsed unless parsed.is_a?(Hash) && parsed.key?('error')
  # ...
end

This non-Hash value propagates up through handle_sse (line 97) → handle_stream (line 33), where build_chunk(data) is called. Since build_chunk assumes data is a Hash and calls data.dig('delta', 'type'), it crashes.

Suggested Fix

Guard against non-Hash data in handle_stream:

def handle_stream(&block)
  build_on_data_handler do |data|
    block.call(build_chunk(data)) if data.is_a?(Hash)
  end
end

The current check is if data, which passes for true. Tightening it to data.is_a?(Hash) safely skips non-Hash values (heartbeats, keep-alives, or unexpected payloads) that no provider's build_chunk can handle.

Version

ruby_llm 1.13.1