Initial public release v0.0.1.alpha2

opencode-rails — production-grade Rails integration for OpenCode.

Rails companion to opencode-ruby. ActiveRecord-aware session lifecycle
(idempotent ensure!/recreate!/abort! with row-level locks), a Turn
orchestrator driving the Reply state machine and recovering from
session-not-found, an artifact pipeline backed by ActiveStorage,
sandbox seeding, and tool-display value objects for Turbo Stream
broadcasts. Drop into any Rails 7.1+ app that wants production-grade
OpenCode streaming without rolling boilerplate.

What this version ships:
  - Opencode::Session (AR-coupled lifecycle, row-level locks)
  - Opencode::Turn (Reply state machine, session-not-found recovery)
  - Opencode::Exchange (one turn = one request/response unit)
  - Opencode::Impostor (deterministic mock for tests)
  - Opencode::Sandbox / SandboxFile (per-session FS scratch space)
  - Opencode::Transform (host-rendered artifact pipeline)
  - Opencode::Artifact / MessageArtifacts (ActiveStorage-backed)
  - Opencode::UploadedFilesPrompt (system-prompt builder)
  - Opencode::ToolDisplay (Turbo Stream value objects)
  - Opencode::ErrorReporter (pluggable adapter — Honeybadger/Sentry/etc.)
  - examples/rails_integration.rb — canonical wiring blueprint

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

Ruby >= 3.2. Runtime deps: opencode-ruby = 0.0.1.alpha2,
activerecord/activestorage/activesupport >= 7.1, < 9.0.

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

test/opencode/sandbox_file_test.rb

@@ -0,0 +1,62 @@
+# frozen_string_literal: true
+
+require "test_helper"
+require "fileutils"
+require "tmpdir"
+require "marcel"  # SandboxFile#content_type uses Marcel::MimeType.for
+
+# Smoke test for Opencode::SandboxFile: instantiate against a real
+# pathname, verify basename/size/content/content_type readers and the
+# identity conversion to Opencode::Artifact via #as_artifact.
+class Opencode::SandboxFileTest < Minitest::Test
+  def setup
+    @tmpdir = Dir.mktmpdir("opencode-rails-sandbox-file-test-")
+    @path = File.join(@tmpdir, "notes.md")
+    File.write(@path, "# hello\nworld\n")
+    # SandboxFile uses `start_with?` against this prefix to detect path
+    # escape; it expects a String with trailing separator so that
+    # /sandbox-1 doesn't false-positive on /sandbox-10/foo.
+    @sandbox_prefix = File.join(@tmpdir, "")
+  end
+
+  def teardown
+    FileUtils.remove_entry(@tmpdir) if @tmpdir && File.exist?(@tmpdir)
+  end
+
+  def test_basic_readers
+    file = Opencode::SandboxFile.new(
+      path: @path, sandbox_prefix: @sandbox_prefix, max_bytes: 10_000
+    )
+
+    assert_equal "notes.md", file.basename
+    assert file.size.positive?
+    assert_equal "# hello\nworld\n", file.content
+    assert file.safe?, "small text file inside sandbox should be safe"
+  end
+
+  def test_content_type_detection_via_marcel
+    file = Opencode::SandboxFile.new(
+      path: @path, sandbox_prefix: @sandbox_prefix, max_bytes: 10_000
+    )
+    # Marcel detects .md as text/markdown.
+    assert_match(/markdown|text/, file.content_type)
+  end
+
+  def test_safe_rejects_files_over_size_cap
+    file = Opencode::SandboxFile.new(
+      path: @path, sandbox_prefix: @sandbox_prefix, max_bytes: 5
+    )
+    refute file.safe?, "file larger than max_bytes must be unsafe"
+  end
+
+  def test_as_artifact_returns_opencode_artifact_value
+    file = Opencode::SandboxFile.new(
+      path: @path, sandbox_prefix: @sandbox_prefix, max_bytes: 10_000
+    )
+
+    artifact = file.as_artifact
+    assert_instance_of Opencode::Artifact, artifact
+    assert_equal "notes.md", artifact.filename
+    assert_equal "# hello\nworld\n", artifact.content
+  end
+end