Initial public release v0.0.1.alpha2

opencode-ruby — idiomatic Ruby client for OpenCode (HTTP + SSE).

Hand-rolled, opinionated Ruby SDK with block-form streaming, value-
object responses, and automatic SSE reconnection. Pluggable
Opencode::Instrumentation adapter for routing events to
ActiveSupport::Notifications, OpenTelemetry, stdout, or any custom
emitter. Companion to opencode-rails for AR-coupled Rails apps.

What this version ships:
  - Opencode::Client (Net::HTTP + SSE)
  - Opencode::Reply / Reply::Result / ReplyObserver
  - Opencode::Tracer, Opencode::Prompts
  - Opencode::ResponseParser, ToolPart, PartSource, Todo
  - Opencode::Instrumentation (instrument + notify)
  - Opencode::Error and seven subclasses
  - examples/conversation_recipe.rb — canonical Rails wiring blueprint

15 smoke tests. CI on Ruby 3.2/3.3/3.4.

Ruby >= 3.2. Runtime dep: activesupport >= 6.1, < 9.0.

See CHANGELOG.md for the alpha1 -> alpha2 delta.

lib/opencode/tracer.rb

@@ -0,0 +1,50 @@
+# frozen_string_literal: true
+
+module Opencode
+  # A namespacing trace emitter.
+  #
+  # Opencode::Turn emits unprefixed event names like "response.started"
+  # and "session.recreated". The host product wraps Turn in a Tracer
+  # whose job is to prepend a product prefix and forward to whatever
+  # actually emits trace events (typically the host job's
+  # `EventTraceable#trace_event`).
+  #
+  # Two responsibilities live here, and only here:
+  #
+  #   1. Callable interface: `tracer.call(name, **payload)` — the
+  #      contract Turn relies on.
+  #   2. Namespacing strategy: prepend "<prefix>." to every event name.
+  #
+  # A closure-based alternative that mixes both concerns looks like:
+  #
+  #     tracer: ->(name, **payload) { trace_event("myapp.#{name}", **payload) }
+  #
+  # That closure conflates the two responsibilities; every caller has
+  # to rediscover the prefix-with-period rule, and a typo only shows up
+  # in production trace data. Making it a real role removes that risk
+  # and makes the rule visible in one place.
+  #
+  # Usage:
+  #
+  #   Opencode::Tracer.new(prefix: "myapp", emitter: self)
+  #
+  # `emitter` must respond to `trace_event(name, **payload)`.
+  class Tracer
+    def initialize(prefix:, emitter:)
+      @prefix = prefix
+      @emitter = emitter
+    end
+
+    # Tracer is callable so existing call sites that treated the tracer
+    # as a lambda (`tracer.call(name, **payload)`) keep working without
+    # change. Turn uses this exclusively.
+    #
+    # Uses `send` because EventTraceable's `trace_event` is a private
+    # method of the including class — the convention is "private inside
+    # the job, but the substrate's Tracer is allowed to dispatch to it
+    # the same way the job's own perform method would."
+    def call(name, **payload)
+      @emitter.send(:trace_event, "#{@prefix}.#{name}", **payload)
+    end
+  end
+end