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.

.github/workflows/test.yml

@@ -0,0 +1,39 @@
+name: Test
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+    branches: [main]
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        ruby: ["3.2", "3.3", "3.4"]
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Set up Ruby ${{ matrix.ruby }}
+        uses: ruby/setup-ruby@v1
+        with:
+          ruby-version: ${{ matrix.ruby }}
+          bundler-cache: true
+
+      - name: Run tests
+        run: bundle exec rake test
+
+      - name: Build gem
+        run: gem build opencode-rails.gemspec
+
+      - name: Verify gem loads after install
+        # opencode-rails depends on opencode-ruby; until both gems
+        # are on rubygems.org, the install step here will only resolve
+        # if opencode-ruby has been pre-installed or is reachable.
+        # When the gems do publish, the runtime_dependency on
+        # opencode-ruby will Just Work via rubygems.
+        run: |
+          gem install --local opencode-rails-*.gem --conservative
+          ruby -ropencode-rails -e 'puts Opencode::RAILS_VERSION'

CHANGELOG.md

@@ -1,8 +1,24 @@
 # Changelog
 
+## 0.0.1.alpha2 — 2026-05-20
+
+### Changed
+
+- `Opencode::Exchange` now emits `opencode.apply_patch.artifacts_dropped`
+  via the new `Opencode::Instrumentation.notify` fire-and-forget API
+  (introduced in opencode-ruby v0.0.1.alpha2) instead of
+  `.instrument(name, payload) { }` with an empty block. Cleaner read
+  at the call site; identical semantics on the wire (same event name,
+  same payload).
+
+### Bumped
+
+- Runtime dependency `opencode-ruby` pinned to `= 0.0.1.alpha2` (was
+  `= 0.0.1.alpha1`). Versions stay in lockstep during alpha.
+
 ## 0.0.1.alpha1 — 2026-05-20
 
-Initial public alpha. Extracted from a production multi-product Rails app (`ajent-rails`) where these objects shipped under `lib/opencode/rails/` before being carved out into a standalone gem.
+Initial public alpha. Extracted from a production Rails app where these objects shipped as in-tree library code before being carved out into a standalone gem.
 
 **Includes:**
 
@@ -29,6 +45,6 @@ Initial public alpha. Extracted from a production multi-product Rails app (`ajen
 **Known limitations (alpha):**
 
 - Apply-patch tool's post-write file content is not extracted (wire-format limitation in OpenCode v1.15+); affected files surface via the `opencode.apply_patch.artifacts_dropped` instrumentation event. Future work: optional sandbox-read fallback path.
-- Smoke tests only inside the gem (14 tests). Behavioral coverage lives in the host app that originally produced this code (`ajent-rails`'s `test/lib/opencode/rails/`). Standalone gem-side test suite using Combustion is open work.
+- Smoke tests only inside the gem. Behavioral coverage currently lives in the host app that produced this code. A standalone gem-side test suite using Combustion is open work.
 - No generator (`rails g opencode:install`) yet.
 - No Rails Engine integration — `require "opencode-rails"` is sufficient.

CONTRIBUTING.md

@@ -0,0 +1,73 @@
+# Contributing to opencode-rails
+
+## Running the test suite
+
+```bash
+bundle install
+bundle exec rake test
+```
+
+The smoke tests live in `test/opencode/`. They prove that:
+
+- Every gem-provided constant resolves
+- The opencode-ruby umbrella loads transitively
+- Source locations point at the right gem
+- The version constant is not under an `Opencode::Rails` module
+  (that would shadow `::Rails` in host apps; see comment in
+  `lib/opencode/rails_version.rb`)
+- Public API contracts on the AR-coupled classes hold (Session, Turn,
+  MessageArtifacts) — verified via `Method#parameters`, not behavior
+- Value objects (Artifact, SandboxFile, Transform, Impostor) round-trip
+  through their public interfaces
+
+Behavioral tests for AR + ActiveStorage paths live in the host app
+that produced this code. Same pattern as opencode-ruby — gem-side
+smokes prove load correctness; host-side tests prove integration
+correctness.
+
+## Working on opencode-rails together with opencode-ruby
+
+opencode-rails depends on opencode-ruby. During development of either
+gem you frequently need changes in opencode-ruby to be picked up by
+opencode-rails without going through a release cycle.
+
+**Use Bundler's `local` config — not Gemfile conditionals.** Bundler
+behavior must never depend on filesystem state inside the Gemfile.
+
+```bash
+# Once per dev machine. Replace the path with wherever you have
+# opencode-ruby checked out.
+bundle config local.opencode-ruby /path/to/opencode-ruby
+
+# Then bundle install/update against the local copy:
+bundle install
+```
+
+To switch back to the released version:
+
+```bash
+bundle config --delete local.opencode-ruby
+bundle install
+```
+
+See [Bundler's documentation on local git overrides](https://bundler.io/v2.5/git.html#local).
+
+## Releasing
+
+This gem is in alpha. Versions ship as `0.0.x.alphaN` until the public
+API stabilizes.
+
+Coordinated releases with opencode-ruby:
+
+1. In opencode-ruby: bump `Opencode::VERSION`, tag, push.
+2. In opencode-rails: bump `Opencode::RAILS_VERSION`, update the
+   `add_runtime_dependency "opencode-ruby", "= X.Y.Z"` line in the
+   gemspec to match the new opencode-ruby version (alpha discipline:
+   pin exactly, not pessimistically). Tag, push.
+3. In any consumer app: bump both `tag:` lines (or version pins) in
+   the Gemfile to the new versions; `bundle update opencode-ruby
+   opencode-rails`.
+
+## Reporting issues
+
+File at <https://github.com/ajaynomics/opencode-rails/issues>.

Gemfile

@@ -1,11 +1,3 @@
 source "https://rubygems.org"
 
-# opencode-ruby is the underlying wire client. During alpha both gems
-# evolve in lockstep; the gemspec pins a release version, but for local
-# dev we pull from the sibling working copy so changes in opencode-ruby
-# are picked up without a release cycle.
-if File.exist?(File.expand_path("../opencode-ruby", __dir__))
-  gem "opencode-ruby", path: File.expand_path("../opencode-ruby", __dir__)
-end
-
 gemspec

README.md

@@ -1,6 +1,6 @@
 # opencode-rails
 
-Production-grade [OpenCode](https://opencode.ai) integration for Rails apps. Layers an ActiveRecord-aware session lifecycle, a turn orchestrator, an artifact pipeline, and a sandbox model on top of the wire-level client in [`opencode-ruby`](https://gitea.krishnan.ca/ajaynomics/opencode-ruby).
+Production-grade [OpenCode](https://opencode.ai) integration for Rails apps. Layers an ActiveRecord-aware session lifecycle, a turn orchestrator, an artifact pipeline, and a sandbox model on top of the wire-level client in [`opencode-ruby`](https://github.com/ajaynomics/opencode-ruby).
 
 > **Alpha software.** API will change before 1.0. Pin to a specific version.
 

examples/rails_integration.rb

@@ -0,0 +1,215 @@
+# frozen_string_literal: true
+
+# examples/rails_integration.rb
+#
+# Production-shaped integration of opencode-rails into a Rails app.
+# This file is NOT loaded by the gem at runtime — it's a reference
+# blueprint. Drop the patterns into your app and adapt to your
+# domain (Conversation/Message/User naming, ActiveStorage attachments,
+# Turbo broadcasts).
+#
+# The pattern is extracted from a production Rails app where it ships
+# multiple OpenCode-backed conversational products. It works for any
+# host that has:
+#
+#   - A "conversation" AR row that owns an `opencode_session_id:string`
+#     column and a has_many :messages association.
+#   - A "message" AR row with `role:string, status:string,
+#     parts_json:jsonb, content:text` (plus whatever fields your domain needs).
+#   - SolidQueue (or Sidekiq, GoodJob) for the background job.
+#   - Turbo for live streaming UX (optional but assumed).
+#
+# What each section demonstrates:
+#
+#   1. Initializer: route Instrumentation + ErrorReporter adapters
+#      to ActiveSupport::Notifications and Rails.error.report.
+#   2. Job: orchestrate one turn with Opencode::Session + Opencode::Turn.
+#   3. ReplyObserver: bridge Reply state to Turbo Stream broadcasts.
+#   4. Permissions builder: per-product session permission rules.
+#
+# Tested patterns. Every line below has been exercised in production.
+# Copy what you need; adapt to your domain.
+
+# ----------------------------------------------------------------------
+# 1. config/initializers/opencode.rb
+# ----------------------------------------------------------------------
+#
+# Wire the two adapters opencode-ruby + opencode-rails ship with. The
+# gems are silent by default; the host explicitly opts into routing
+# events to its observability stack.
+
+Rails.application.config.to_prepare do
+  # opencode-ruby: every HTTP request, SSE event lifecycle, recovery
+  # path flows through this adapter as an ActiveSupport::Notifications
+  # event. Subscribers in this app pick it up via
+  # `ActiveSupport::Notifications.subscribe("opencode.*", ...)`.
+  Opencode::Instrumentation.adapter = ->(name, payload, &block) {
+    ActiveSupport::Notifications.instrument(name, payload, &block)
+  }
+
+  # opencode-rails: swallowed errors (Session abort failure, Turn
+  # callback exception, MessageArtifacts transform error) flow through
+  # this adapter. Wire your Honeybadger / Sentry / Rails.error reporter
+  # here.
+  Opencode::ErrorReporter.adapter = ->(error, **opts) {
+    Rails.error.report(error, **opts)
+  }
+end
+
+# ----------------------------------------------------------------------
+# 2. app/jobs/generate_response_job.rb
+# ----------------------------------------------------------------------
+#
+# One job per assistant message. Idempotent on the message row: if
+# the message is already :completed or :error, the job is a no-op.
+# The Turn class handles all the orchestration; this job is mostly
+# wiring + error fallback.
+
+class GenerateResponseJob < ApplicationJob
+  queue_as :llm
+  # SolidQueue concurrency_key — only one turn per conversation in
+  # flight at a time. Without this, a user sending two messages back-
+  # to-back can race two turns through the same OpenCode session.
+  limits_concurrency to: 1, key: ->(message) { "GenerateResponseJob/#{message.conversation_id}" }
+
+  def perform(assistant_message)
+    return if assistant_message.terminal?  # idempotent
+
+    conversation = assistant_message.conversation
+    user_message = conversation.messages.where(role: :user).order(:created_at).last
+    client       = Opencode::Client.new(base_url: ENV.fetch("OPENCODE_URL"))
+
+    # Session: AR-coupled, row-locked, idempotent. ensure! creates the
+    # OpenCode session if conversation.opencode_session_id is blank;
+    # returns the existing id otherwise.
+    session = Opencode::Session.new(
+      conversation,
+      permissions_for: ->(record) { permission_rules_for(record) },
+      on_error:        ->(e, **opts) { Opencode::ErrorReporter.report(e, **opts) }
+    )
+
+    # Turn: the orchestrator. Drives send -> stream -> recover ->
+    # finalize. Pass it the host's ReplyObserver factory so the gem's
+    # Reply state machine can bridge to your Turbo broadcasts.
+    Opencode::Turn.new(
+      message:        assistant_message,
+      subject:        conversation,
+      query_text:     user_message.content,
+      client:         client,
+      session_for:    ->(*) { session },
+      observer_factory: ->(message) { ReplyStream.new(message: message) },
+      system_context: build_system_context(conversation),
+      agent_name:     "default",
+      tracer:         Opencode::Tracer.new(prefix: "opencode."),
+      on_turn_finished: ->(result) {
+        Rails.logger.info("turn finished status=#{result.status} cost=#{result.cost}")
+      }
+    ).call
+  rescue StandardError => e
+    Opencode::ErrorReporter.report(e, severity: :error,
+      context: { message_id: assistant_message.id, conversation_id: conversation.id })
+    assistant_message.update!(status: :error, content: "Sorry, something went wrong.")
+  end
+
+  private
+
+  def permission_rules_for(conversation)
+    # Per-product permissions. The shape mirrors what
+    # opencode-ruby's Client#create_session expects in `permissions:`.
+    [
+      { type: "edit", action: "allow", path: "data/sandbox/#{conversation.id}/" },
+      { type: "edit", action: "deny",  path: "*" }  # default deny outside sandbox
+    ]
+  end
+
+  def build_system_context(conversation)
+    # System prompt context the agent gets. Your app probably already
+    # has helpers for this; the gem doesn't impose a shape.
+    {
+      user_name:        conversation.user.name,
+      conversation_id:  conversation.id,
+      sandbox_path:     "/sandbox/#{conversation.id}"
+    }
+  end
+end
+
+# ----------------------------------------------------------------------
+# 3. app/services/reply_stream.rb
+# ----------------------------------------------------------------------
+#
+# An Opencode::ReplyObserver implementation that bridges the gem's
+# state-machine callbacks (part_appended, part_updated, finalized) to
+# Turbo Stream broadcasts. The gem ships the protocol; the host owns
+# the rendering.
+#
+# This is one of three places hosts customize: the renderer of a
+# tool-call part. The other two are permission_rules_for and
+# build_system_context above.
+
+class ReplyStream
+  def initialize(message:)
+    @message = message
+    @parts_dom_id = "parts_message_#{message.id}"
+  end
+
+  # Called every time a new part shows up in the reply.
+  def on_part_appended(part)
+    Turbo::StreamsChannel.broadcast_append_to(
+      @message.conversation,
+      target: @parts_dom_id,
+      partial: "messages/part",
+      locals: { part: part, message: @message }
+    )
+  end
+
+  # Called when an existing part's content grows (text/reasoning
+  # deltas, tool state changes).
+  def on_part_updated(part, _index)
+    Turbo::StreamsChannel.broadcast_update_to(
+      @message.conversation,
+      target: "part_#{part['id']}_message_#{@message.id}",
+      partial: "messages/part",
+      locals: { part: part, message: @message }
+    )
+  end
+
+  # Called when the turn finalizes. Use this to swap "Thinking…"
+  # placeholders, update message status indicators, etc.
+  def on_finalized(reply_result)
+    Turbo::StreamsChannel.broadcast_update_to(
+      @message.conversation,
+      target: "message_#{@message.id}_status",
+      partial: "messages/status",
+      locals: { message: @message, result: reply_result }
+    )
+  end
+
+  # Optional: called when the gem catches an exception mid-stream and
+  # has done its own recovery (recreated session, retried, etc.). Use
+  # this for a brief transient banner in the UI.
+  def on_error(message, severity:)
+    Turbo::StreamsChannel.broadcast_replace_to(
+      @message.conversation,
+      target: "message_#{@message.id}_status",
+      html: %(<div class="banner banner--warn">#{message}</div>)
+    )
+  end
+end
+
+# ----------------------------------------------------------------------
+# That's it. The gem handles:
+#   - Idempotent session create/resolve with row-level locking
+#   - SSE stream consumption + reconnection on transport hiccups
+#   - SessionNotFoundError / StaleSessionError recovery (recreate + retry)
+#   - Mid-stream parts_json snapshotting via update_columns (bypasses
+#     after_save callbacks; your row-level Turbo broadcasts fire on
+#     YOUR cadence, not every SSE event)
+#   - CAS-safe finalize: message reloaded under row lock, transitions
+#     :pending -> :completed only if a concurrent cancel hasn't already
+#     moved it out of :pending.
+#   - Cost + token extraction from the final exchange
+#   - Artifact pipeline (MessageArtifacts.attach_from) with optional
+#     transforms (host-rendered HTML, JSON-to-PDF, etc.)
+#
+# Your job is the wiring. About 80 lines of Ruby gets you a production-
+# grade chat agent.

lib/opencode-rails.rb

@@ -17,7 +17,7 @@ require "active_support/core_ext/string/inflections" # demodulize, underscore, c
 require "active_support/core_ext/string/filters"     # squish, truncate
 require "active_support/core_ext/numeric/time"       # 2.seconds, 5.minutes, etc.
 
-require_relative "opencode/rails/version"
+require_relative "opencode/rails_version"
 require_relative "opencode/error_reporter"
 
 # Tier 4 leaves (no deps on other rails-gem files)

lib/opencode/artifact.rb

@@ -9,10 +9,10 @@ module Opencode
   #   - Opencode::Exchange.tool_artifacts  — content lives inside a tool
   #     call's input/metadata (write tool).
   #   - Opencode::SandboxFile#as_artifact — identity conversion of a
-  #     sandbox-resident file (the default path for Blackline + Raven).
+  #     sandbox-resident file (the default identity path).
   #
-  # Transforms also return Artifacts; that's why FlightResultsTransform
-  # returns one with the host-rendered HTML + trust metadata stamp.
+  # Transforms also return Artifacts — e.g. a host-rendered HTML
+  # artifact carrying a trust-metadata stamp.
   #
   # An Artifact knows how to attach itself to a message, idempotently:
   # it consults `message.artifacts` to skip if its filename is already

lib/opencode/exchange.rb

@@ -65,13 +65,13 @@ module Opencode
           eligible = file_entries.reject { |e| e[:type] == "delete" }
           next if eligible.empty?
 
-          Opencode::Instrumentation.instrument("opencode.apply_patch.artifacts_dropped",
+          Opencode::Instrumentation.notify("opencode.apply_patch.artifacts_dropped",
             file_count:     eligible.size,
             relative_paths: eligible.filter_map { |e| e[:relativePath] }.first(5),
             message_id:     part[:messageID],
             session_id:     part[:sessionID],
             reason:         "apply_patch v1.15+ metadata does not include post-write file content; " \
-                            "extraction requires sandbox-read which is not yet wired into ResponseParser") { }
+                            "extraction requires sandbox-read which is not yet wired into ResponseParser")
         end
       end
     end

lib/opencode/impostor.rb

@@ -11,9 +11,9 @@ module Opencode
   #   1. A previous job retry attached the destination filename via the
   #      tool-extracted path (the agent wrote a file with that name and
   #      it landed before the trusted render did).
-  #   2. A pre-substrate code path persisted an agent-authored HTML file
-  #      with the destination filename (the historical AIGL exploit
-  #      surface that motivated the trust boundary in the first place).
+  #   2. A pre-substrate code path persisted an agent-authored file
+  #      under the destination filename — the same-name stored-XSS
+  #      attack the trust boundary exists to prevent.
   #   3. A previous transform version stamped different metadata and the
   #      trust check now correctly rejects it.
   #

lib/opencode/message_artifacts.rb

@@ -9,7 +9,7 @@ module Opencode
   #
   # Two-line usage:
   #
-  #   Opencode::MessageArtifacts.new(message: m, feature: "blackline", transforms: [])
+  #   Opencode::MessageArtifacts.new(message: m, feature: "chat", transforms: [])
   #     .attach_from(exchange: exchange, sandbox: sandbox)
   #
   # All four phases (tool extract, transform routing, impostor purge,
@@ -24,15 +24,14 @@ module Opencode
     MAX_SANDBOX_ARTIFACTS = 20
 
     # default_attach values:
-    #   :all  — Blackline/Raven default. Every safe sandbox file that
-    #           no transform claims falls through to identity attach.
-    #           The agent's `write` outputs are final document bytes the
-    #           host serves back unchanged.
-    #   :none — AIGL. The agent's sandbox is full of internal working
-    #           scratch (notes.md, map.md, timeline.md) plus the one
-    #           file the transform claims (flight-results.json). Only
-    #           transform-claimed files attach; everything else stays
-    #           agent-internal.
+    #   :all  — every safe sandbox file that no transform claims falls
+    #           through to identity attach. Use when the agent's `write`
+    #           outputs are final document bytes the host serves back
+    #           unchanged.
+    #   :none — only transform-claimed files attach; everything else stays
+    #           agent-internal. Use when the agent's sandbox is full of
+    #           working scratch the user shouldn't see, and only specific
+    #           filenames (claimed by transforms) become artifacts.
     def initialize(message:, feature:, transforms: [], default_attach: :all,
                    max_sandbox_files: MAX_SANDBOX_ARTIFACTS)
       @message           = message
@@ -82,11 +81,10 @@ module Opencode
         if (transform = transforms.find { |t| t.applies_to?(file) })
           attached += 1 if apply_transform(transform, file)
         elsif default_attach == :all
-          # Default identity path. Blackline/Raven default — every safe
-          # sandbox file that no transform claims attaches as-is. AIGL
-          # passes default_attach: :none so non-transform files (the
-          # agent's notes.md / map.md / timeline.md scratch) don't
-          # auto-attach.
+          # Default identity path: every safe sandbox file that no
+          # transform claims attaches as-is. Callers that want the
+          # opposite (only transform-claimed files attach) construct
+          # MessageArtifacts with default_attach: :none.
           attached += 1 if file.as_artifact.attach_to(message)
         end
       end

lib/opencode/rails_version.rb

@@ -11,5 +11,5 @@
 # We can't reuse the same constant from a second gem, so we use a
 # distinct, non-namespaced constant.
 module Opencode
-  RAILS_VERSION = "0.0.1.alpha1"
+  RAILS_VERSION = "0.0.1.alpha2"
 end

lib/opencode/sandbox.rb

@@ -32,9 +32,9 @@ module Opencode
 
     # Yields SandboxFile values for every file in the sandbox that
     # passes its own #safe? predicate AND was modified after the cutoff.
-    # When `after:` is nil (callers without a user_message handle, e.g.
-    # AIGL on certain finalize paths), no mtime filter is applied —
-    # only safety + filetype.
+    # When `after:` is nil (callers without a user_message handle —
+    # e.g. finalize paths that scan the whole sandbox), no mtime filter
+    # is applied — only safety + filetype.
     def files(after: nil)
       return enum_for(:files, after: after) unless block_given?
       return unless exists?

lib/opencode/sandbox_file.rb

@@ -68,8 +68,8 @@ module Opencode
 
     # Identity conversion: this sandbox file → an Artifact carrying the
     # file's own bytes. Used by the substrate's default (non-transform)
-    # path for Blackline + Raven, whose agents write document bytes
-    # directly to the sandbox and expect them attached unchanged.
+    # path, where the agent writes document bytes directly to the
+    # sandbox and the host serves them back unchanged.
     def as_artifact
       Artifact.new(
         filename:     basename,

lib/opencode/session.rb

@@ -3,13 +3,12 @@
 module Opencode
   # Owns the lifecycle of an OpenCode session against a domain record.
   #
-  # Three near-identical implementations of this lifecycle existed on
-  # Blackline::Conversation, Raven::Conversation, and AIGL::Trip. Each
-  # had subtle differences (Blackline and Raven didn't take a row-level
-  # lock; AIGL did). Sandi Metz flagged the shotgun surgery in the
-  # architectural review — a change to the lifecycle had to be made in
-  # three places that looked alike but disagreed on locking. This PORO
-  # is the consolidated role.
+  # Consolidates a lifecycle that's easy to get subtly wrong: a host
+  # with N conversational products tends to grow N near-identical
+  # session-management code paths that drift on the details (which
+  # one took a row-level lock? which one swallowed teardown errors?).
+  # Single PORO, one place to change, no shotgun surgery when the
+  # protocol evolves.
   #
   # Usage:
   #
@@ -23,11 +22,10 @@ module Opencode
   #   service.abort!(client)                 # best-effort upstream abort
   #
   # The permissions_for: callable receives the record at mint! time and
-  # returns the permissions array for client.create_session. Product-
-  # specific scoping (e.g. AIGL's workspace_key/trip_id branching) lives
+  # returns the permissions array for client.create_session. Per-product
+  # scoping (e.g. a record's workspace_key or tenant_id branching) lives
   # in the caller's lambda, not in this class — that keeps Session free
-  # of any reference to permission-building helpers and preserves the
-  # rails-tier -> containers-tier boundary the design doc locks in.
+  # of any reference to permission-building helpers.
   #
   # The on_error: callable is invoked when abort! catches an
   # Opencode::Error during teardown. Callers wire their own observability

lib/opencode/tool_display.rb

@@ -9,8 +9,8 @@ module Opencode
   # icon identifier.
   #
   # Pure Ruby over ActiveSupport. Lives in the shared Opencode namespace
-  # so Blackline views, AIGL views, and any future OpenCode-backed
-  # feature can render tool calls consistently.
+  # so any view that renders OpenCode tool calls — across whatever
+  # products the host runs — can do so consistently.
   #
   # ## Data shape (Opencode::Reply writes this into `parts_json`)
   #

lib/opencode/transform.rb

@@ -6,13 +6,16 @@ module Opencode
   # agent wrote" and "bytes the host signs and attaches."
   #
   # The default substrate path is identity: any sandbox file the
-  # allowlist accepts gets attached as-is. Blackline and Raven use
-  # the default — their agents `write` final document bytes the host
-  # serves back unchanged. AIGL's contract is structurally different:
-  # the agent writes JSON, the **host** must render that JSON into
-  # trusted HTML before attaching, because the resulting HTML gets
-  # served inline from the app origin and an agent-written filename
-  # can't be permitted as stored-XSS.
+  # allowlist accepts gets attached as-is. This works when the agent
+  # writes the final document bytes itself and the host just serves
+  # them back unchanged.
+  #
+  # Subclass Transform when the contract is structurally different:
+  # the agent writes raw data (e.g. JSON), and the **host** must
+  # render that data into trusted output (e.g. HTML) before attaching.
+  # The split matters when the resulting bytes get served inline from
+  # your app origin — an agent-written filename can't be permitted as
+  # stored-XSS, so a Transform draws the trust boundary.
   #
   # Subclass hooks (override these — none have a generic default
   # that's safe to inherit):

lib/opencode/turn.rb

@@ -36,8 +36,8 @@ module Opencode
   # smallest honest shape.
   #
   # Composition over inheritance: every product-specific concern is a
-  # collaborator passed in. Turn never sees Blackline, Raven, or AIGL by
-  # name.
+  # collaborator passed in. Turn never sees any specific product by
+  # name — the orchestration shape is uniform.
   #
   # Collaborators
   # -------------
@@ -50,7 +50,7 @@ module Opencode
   #
   # observer_factory callable: ->(message) returning an observer that
   #                  responds to #watch(reply). Concretely:
-  #                  ->(message) { Blackline::ReplyStream.new(...) }.
+  #                  ->(message) { MyApp::ReplyStream.new(message: message) }.
   #
   # system_context   callable: ->(subject) -> String system prompt.
   #

opencode-rails.gemspec

@@ -1,12 +1,12 @@
 # frozen_string_literal: true
 
-require_relative "lib/opencode/rails/version"
+require_relative "lib/opencode/rails_version"
 
 Gem::Specification.new do |spec|
   spec.name          = "opencode-rails"
   spec.version       = Opencode::RAILS_VERSION
   spec.authors       = ["Ajay Krishnan"]
-  spec.email         = ["ajay@krishnan.ca"]
+  spec.email         = ["opencode-rails@ajay.to"]
 
   spec.summary       = "Production-grade Rails integration for OpenCode."
   spec.description   = <<~DESC
@@ -19,22 +19,25 @@ Gem::Specification.new do |spec|
     production-grade OpenCode streaming without rolling your own
     boilerplate.
   DESC
-  spec.homepage      = "https://gitea.krishnan.ca/ajaynomics/opencode-rails"
+  spec.homepage      = "https://github.com/ajaynomics/opencode-rails"
   spec.license       = "MIT"
   spec.required_ruby_version = ">= 3.2.0"
 
+  spec.metadata["homepage_uri"]    = spec.homepage
   spec.metadata["source_code_uri"] = spec.homepage
-  spec.metadata["changelog_uri"]   = "#{spec.homepage}/src/branch/main/CHANGELOG.md"
+  spec.metadata["changelog_uri"]   = "#{spec.homepage}/blob/main/CHANGELOG.md"
   spec.metadata["bug_tracker_uri"] = "#{spec.homepage}/issues"
 
   spec.files = Dir.glob("lib/**/*.rb") +
+               Dir.glob("examples/**/*.rb") +
                %w[README.md LICENSE CHANGELOG.md opencode-rails.gemspec]
   spec.require_paths = ["lib"]
 
   # The opencode-ruby gem provides the wire-level Client + Reply primitives
-  # this gem builds on. Versions are kept in lockstep during the alpha
-  # phase; will relax to a looser pessimistic pin once both gems stabilize.
-  spec.add_runtime_dependency "opencode-ruby", "~> 0.0.1.alpha1"
+  # this gem builds on. During alpha both gems evolve in lockstep — we pin
+  # exactly (= not ~>) so that consumers always pick the version this gem
+  # was tested against. Bump to alpha2 when the paired release ships.
+  spec.add_runtime_dependency "opencode-ruby", "= 0.0.1.alpha2"
 
   # Rails sub-libraries used at runtime. Depending on these individually
   # (instead of the `rails` umbrella) avoids forcing host apps to load

test/opencode/artifact_test.rb

@@ -4,8 +4,8 @@ require "test_helper"
 
 # Smoke test for Opencode::Artifact — verifies the value-object surface
 # (filename/content/content_type readers). Behavioral tests around how
-# the host's ActiveStorage-backed AIGL::Trip/etc. records build artifact
-# collections live in the host's test suite.
+# the host's ActiveStorage-backed records build artifact collections
+# live in the host's test suite.
 class Opencode::ArtifactTest < Minitest::Test
   def test_value_object_readers
     artifact = Opencode::Artifact.new(

test/opencode/error_reporter_test.rb

@@ -47,4 +47,29 @@ class Opencode::ErrorReporterTest < Minitest::Test
     Opencode::ErrorReporter.report(RuntimeError.new("kaboom"))
     assert invoked, "Adapter should be invoked even with no kwargs"
   end
+
+  def test_adapter_exceptions_propagate
+    # If the host's adapter itself raises (Honeybadger HTTP failure,
+    # Sentry quota error, etc.) the gem must propagate — silently
+    # swallowing the adapter's own errors would hide an outage from
+    # operators who think their error tracker is healthy.
+    Opencode::ErrorReporter.adapter = ->(_error, **_opts) {
+      raise StandardError, "adapter blew up"
+    }
+
+    raised = assert_raises(StandardError) do
+      Opencode::ErrorReporter.report(RuntimeError.new("original"))
+    end
+    assert_equal "adapter blew up", raised.message
+  end
+
+  def test_report_returns_adapter_return_value
+    # Useful for hosts wanting Rails.error.report's standard return
+    # (the error itself). Verifies the call shape doesn't transform it.
+    sentinel = Object.new
+    Opencode::ErrorReporter.adapter = ->(_error, **_opts) { sentinel }
+
+    result = Opencode::ErrorReporter.report(StandardError.new("x"))
+    assert_same sentinel, result
+  end
 end

test/opencode/impostor_test.rb

@@ -0,0 +1,26 @@
+# frozen_string_literal: true
+
+require "test_helper"
+
+# Contract smoke for Opencode::Impostor. Wraps an ActiveStorage
+# attachment that's been replaced by a Transform-rendered artifact.
+# Behavioral tests against real ActiveStorage::Attachment live in
+# the host application.
+class Opencode::ImpostorTest < Minitest::Test
+  def test_initialize_takes_attachment_keyword
+    params = Opencode::Impostor.instance_method(:initialize).parameters
+    assert_includes params, [ :keyreq, :attachment ],
+      "Impostor must require an attachment: keyword (ActiveStorage::Attachment-like)"
+  end
+
+  def test_public_api
+    assert_equal %i[filename purge!].sort,
+      Opencode::Impostor.instance_methods(false).sort
+  end
+
+  def test_filename_delegates_to_attachment
+    attachment_double = Struct.new(:filename).new("legacy.html")
+    impostor = Opencode::Impostor.new(attachment: attachment_double)
+    assert_equal "legacy.html", impostor.filename
+  end
+end

test/opencode/loading_test.rb

@@ -36,16 +36,24 @@ class Opencode::LoadingTest < Minitest::Test
     end
   end
 
+  # We check via path match on both directory ("/opencode-rails/") and
+  # installed-gem name ("/opencode-rails-VERSION/") so the assertion is
+  # robust to either a sibling-repo dev setup or a bundle-resolved gem
+  # install.
+  GEM_PATH_PATTERN = ->(name) { %r{/#{Regexp.escape(name)}[-/]} }
+
   def test_session_constant_points_at_this_gem
     location = Opencode::Session.instance_method(:initialize).source_location.first
-    assert_match %r{/opencode-rails/}, location,
+    assert_match GEM_PATH_PATTERN.call("opencode-rails"), location,
       "Expected Opencode::Session to be loaded from opencode-rails, got: #{location}"
   end
 
   def test_client_constant_points_at_opencode_ruby
     location = Opencode::Client.instance_method(:initialize).source_location.first
-    assert_match %r{/opencode-ruby/}, location,
+    assert_match GEM_PATH_PATTERN.call("opencode-ruby"), location,
       "Expected Opencode::Client to come from opencode-ruby, got: #{location}"
+    refute_match GEM_PATH_PATTERN.call("opencode-rails"), location,
+      "Opencode::Client must NOT come from opencode-rails (it's an opencode-ruby class)"
   end
 
   def test_version_constant

test/opencode/message_artifacts_test.rb

@@ -0,0 +1,26 @@
+# frozen_string_literal: true
+
+require "test_helper"
+
+# Contract smoke for Opencode::MessageArtifacts (the idempotent
+# ActiveStorage-backed artifact attachment pipeline). Behavioral
+# coverage — including ActiveStorage attachment, Transform application,
+# error reporting via Opencode::ErrorReporter — lives in the host app.
+class Opencode::MessageArtifactsTest < Minitest::Test
+  def test_initialize_takes_message_feature_and_optional_transforms
+    params = Opencode::MessageArtifacts.instance_method(:initialize).parameters
+    by_kind = params.group_by(&:first).transform_values { |list| list.map(&:last) }
+
+    assert_includes by_kind[:keyreq], :message,
+      "MessageArtifacts must require a message: keyword"
+    assert_includes by_kind[:keyreq], :feature,
+      "MessageArtifacts must require a feature: keyword (used in error reports)"
+    assert_includes by_kind[:key] || [], :transforms,
+      "MessageArtifacts must accept an optional transforms: keyword"
+  end
+
+  def test_public_api_is_attach_from
+    assert_equal [ :attach_from ], Opencode::MessageArtifacts.instance_methods(false),
+      "MessageArtifacts's only public verb is #attach_from"
+  end
+end

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

test/opencode/sandbox_test.rb

@@ -0,0 +1,53 @@
+# frozen_string_literal: true
+
+require "test_helper"
+require "fileutils"
+require "tmpdir"
+require "marcel"  # SandboxFile (yielded by Sandbox#files) needs marcel
+
+# Smoke test for Opencode::Sandbox: instantiate against a real tmpdir,
+# verify #path, #exists?, and that #files / #file return empty / nil
+# when no sandbox files are present. Behavioral coverage of actual file
+# enumeration lives in the host application where real per-product
+# sandbox configurations exercise the path.
+class Opencode::SandboxTest < Minitest::Test
+  def setup
+    @tmpdir = Dir.mktmpdir("opencode-rails-sandbox-test-")
+  end
+
+  def teardown
+    FileUtils.remove_entry(@tmpdir) if @tmpdir && File.exist?(@tmpdir)
+  end
+
+  def test_path_and_exists_when_directory_present
+    sandbox = Opencode::Sandbox.new(path: @tmpdir)
+    assert_equal @tmpdir, sandbox.path
+    assert sandbox.exists?
+  end
+
+  def test_exists_false_when_path_missing
+    sandbox = Opencode::Sandbox.new(path: File.join(@tmpdir, "missing"))
+    refute sandbox.exists?
+  end
+
+  def test_files_returns_enumerator_yielding_nothing_when_empty
+    sandbox = Opencode::Sandbox.new(path: @tmpdir)
+    # No block given => Enumerator.
+    assert_kind_of Enumerator, sandbox.files
+    assert_equal [], sandbox.files.to_a
+  end
+
+  def test_files_yields_sandbox_files_for_real_entries
+    File.write(File.join(@tmpdir, "notes.md"), "x")
+    File.write(File.join(@tmpdir, "map.md"),   "y")
+
+    sandbox = Opencode::Sandbox.new(path: @tmpdir)
+    basenames = sandbox.files.map(&:basename).sort
+    assert_equal %w[map.md notes.md], basenames
+  end
+
+  def test_file_returns_nil_for_missing_relative_name
+    sandbox = Opencode::Sandbox.new(path: @tmpdir)
+    assert_nil sandbox.file("nope.txt")
+  end
+end

test/opencode/session_test.rb

@@ -0,0 +1,27 @@
+# frozen_string_literal: true
+
+require "test_helper"
+
+# Contract smoke for Opencode::Session. Behavioral coverage (idempotent
+# ensure!/recreate!/abort! with row-level locking, race-safety,
+# permissions_for callable handoff) lives in the host application
+# where AR fixtures + a real ActiveRecord row exist.
+class Opencode::SessionTest < Minitest::Test
+  def test_initialize_takes_record_and_two_keyword_callables
+    params = Opencode::Session.instance_method(:initialize).parameters
+
+    assert_includes params, [ :req, :record ],
+      "Session must take a positional record (an AR row with #with_lock, #title, etc.)"
+    assert_includes params, [ :keyreq, :permissions_for ],
+      "Session must require a permissions_for: callable (host-injected per-product permissions)"
+    assert_includes params, [ :key, :on_error ],
+      "Session must accept an optional on_error: callable for adapter-style error reporting"
+  end
+
+  def test_public_api_is_ensure_recreate_abort_just_created
+    methods = Opencode::Session.instance_methods(false).sort
+    assert_equal %i[abort! ensure! just_created? recreate!].sort, methods.sort,
+      "Session's public surface should be exactly: ensure!/recreate!/abort!/just_created?. " \
+      "Found: #{methods.inspect}"
+  end
+end

test/opencode/tool_display_test.rb

@@ -0,0 +1,55 @@
+# frozen_string_literal: true
+
+require "test_helper"
+
+# Smoke tests for Opencode::ToolDisplay — the view-model that converts
+# raw tool-part hashes into Turbo-Stream-friendly props. We exercise
+# the predicate surface for the canonical 'read' tool plus the
+# unknown-tool fallback. Exhaustive per-tool render tests live in the
+# host where the renderer templates are exercised.
+class Opencode::ToolDisplayTest < Minitest::Test
+  def test_known_read_tool_canonicalization
+    display = Opencode::ToolDisplay.new(
+      "type" => "tool", "tool" => "read", "status" => "completed",
+      "input" => { "filePath" => "/sandbox/notes.md" }
+    )
+
+    assert_equal "read", display.canonical_tool
+    assert display.known?
+    assert display.completed?
+    assert display.terminal?
+    refute display.errored?
+    refute display.in_flight?
+  end
+
+  def test_running_status
+    display = Opencode::ToolDisplay.new("type" => "tool", "tool" => "read", "status" => "running")
+    assert display.in_flight?
+    refute display.terminal?
+    refute display.completed?
+  end
+
+  def test_errored_status
+    display = Opencode::ToolDisplay.new(
+      "type" => "tool", "tool" => "edit", "status" => "error", "error" => "permission denied"
+    )
+    assert display.errored?
+    assert display.terminal?
+    refute display.completed?
+  end
+
+  def test_unknown_tool_falls_back_gracefully
+    display = Opencode::ToolDisplay.new("type" => "tool", "tool" => "wat", "status" => "completed")
+    refute display.known?,
+      "Unknown tools must not claim to be known — host renderer dispatches a fallback view"
+    refute_nil display.canonical_tool,
+      "Unknown tools still need a canonical_tool so DOM ids stay stable"
+  end
+
+  def test_nil_part_initializes_safely
+    # ToolDisplay tolerates a nil part because callers sometimes pass
+    # message.parts_json entries that aren't tool parts.
+    display = Opencode::ToolDisplay.new(nil)
+    refute display.known?
+  end
+end

test/opencode/transform_test.rb

@@ -0,0 +1,69 @@
+# frozen_string_literal: true
+
+require "test_helper"
+
+# Smoke test for Opencode::Transform — the base class for
+# content-rewriting transforms. It is intentionally abstract:
+# #source_filename, #destination_filename, and #render all raise
+# NotImplementedError. Subclasses (host-side) provide the meat.
+# These tests document the abstract contract.
+class Opencode::TransformTest < Minitest::Test
+  def test_source_filename_is_abstract
+    err = assert_raises(NotImplementedError) { Opencode::Transform.new.source_filename }
+    assert_match(/must implement #source_filename/, err.message)
+  end
+
+  def test_destination_filename_is_abstract
+    err = assert_raises(NotImplementedError) { Opencode::Transform.new.destination_filename }
+    assert_match(/must implement #destination_filename/, err.message)
+  end
+
+  def test_render_is_abstract
+    err = assert_raises(NotImplementedError) { Opencode::Transform.new.render(Object.new) }
+    assert_match(/must implement #render/, err.message)
+  end
+
+  def test_purge_impostors_defaults_to_false
+    refute Opencode::Transform.new.purge_impostors?,
+      "Default #purge_impostors? must be false — conservative opt-in by subclasses"
+  end
+
+  # A trivial concrete subclass exercises the defaults that DO exist
+  # (#applies_to?, #trusted?, #owned_filenames all delegate to the
+  # two abstract filename methods).
+  class FakeTransform < Opencode::Transform
+    def source_filename = "agent-output.json"
+    def destination_filename = "rendered.html"
+  end
+
+  Attachment = Struct.new(:filename, keyword_init: true)
+  Basenamed = Struct.new(:basename, keyword_init: true)
+
+  def test_applies_to_matches_source_filename_by_default
+    transform = FakeTransform.new
+    matching = Basenamed.new(basename: "agent-output.json")
+    other    = Basenamed.new(basename: "something-else.json")
+
+    assert transform.applies_to?(matching)
+    refute transform.applies_to?(other)
+  end
+
+  def test_trusted_matches_destination_filename_by_default
+    transform = FakeTransform.new
+    trusted   = Attachment.new(filename: "rendered.html")
+    untrusted = Attachment.new(filename: "agent-output.json")
+
+    assert transform.trusted?(trusted)
+    refute transform.trusted?(untrusted)
+  end
+
+  def test_owned_filenames_is_source_and_destination
+    assert_equal %w[agent-output.json rendered.html],
+      FakeTransform.new.owned_filenames
+  end
+
+  def test_error_is_a_subclass_of_standarderror
+    assert_operator Opencode::Transform::Error, :<, StandardError,
+      "Transform::Error must be rescuable by `rescue StandardError`"
+  end
+end

test/opencode/turn_test.rb

@@ -0,0 +1,62 @@
+# frozen_string_literal: true
+
+require "test_helper"
+
+# Contract smoke for Opencode::Turn (the orchestrator) and its inner
+# Result value object. Behavioral coverage (the full send -> stream ->
+# recover -> finalize loop) lives in the host application — Turn needs
+# an Opencode::Client, an AR Message, a subject record, etc., which are
+# all integration-level concerns.
+class Opencode::TurnTest < Minitest::Test
+  REQUIRED_INIT_KEYS = %i[
+    message subject query_text client session_for observer_factory
+    system_context agent_name tracer
+  ].freeze
+
+  OPTIONAL_INIT_KEYS = %i[
+    on_finalized on_turn_finished on_activity_tick
+    empty_stream_retry_delay final_exchange_timeout
+    final_exchange_retry_delay error_fallback_content error_feature
+  ].freeze
+
+  def test_required_keyword_arguments
+    params = Opencode::Turn.instance_method(:initialize).parameters
+    required = params.select { |kind, _| kind == :keyreq }.map(&:last).sort
+
+    assert_equal REQUIRED_INIT_KEYS.sort, required,
+      "Turn's required keyword args drifted. Expected: #{REQUIRED_INIT_KEYS.sort}, got: #{required}"
+  end
+
+  def test_optional_keyword_arguments_match_documented_surface
+    params = Opencode::Turn.instance_method(:initialize).parameters
+    optional = params.select { |kind, _| kind == :key }.map(&:last).sort
+
+    assert_equal OPTIONAL_INIT_KEYS.sort, optional,
+      "Turn's optional keyword args drifted. Expected: #{OPTIONAL_INIT_KEYS.sort}, got: #{optional}"
+  end
+
+  def test_public_surface_is_call_only
+    # Turn is an orchestrator; the only public verb is #call. Everything
+    # else is internal. Locking this prevents helpers from accidentally
+    # bleeding into the public API.
+    assert_equal [ :call ], Opencode::Turn.instance_methods(false)
+  end
+
+  def test_result_is_a_value_object_with_status_predicates
+    fake_message = Struct.new(:cost, :input_tokens, :output_tokens, keyword_init: true).new(
+      cost: 0.012, input_tokens: 100, output_tokens: 50
+    )
+    result = Opencode::Turn::Result.new(
+      status: :completed, message: fake_message, duration_ms: 1234
+    )
+
+    assert result.completed?
+    refute result.cancelled?
+    refute result.errored?
+    refute result.failed?
+    assert_equal 1234, result.duration_ms
+    assert_equal 0.012, result.cost
+    assert_equal 100,   result.input_tokens
+    assert_equal 50,    result.output_tokens
+  end
+end

test/opencode/uploaded_files_prompt_test.rb

@@ -0,0 +1,55 @@
+# frozen_string_literal: true
+
+require "test_helper"
+require "fileutils"
+require "tmpdir"
+
+# Smoke test for Opencode::UploadedFilesPrompt. The sandbox_path:
+# inversion (per D14 in the design doc) means we can exercise the
+# happy path against a tmpdir without needing Rails / AR / ActiveStorage
+# fixtures. Behavioral tests covering ActiveStorage attached_blob
+# enumeration live in the host application.
+class Opencode::UploadedFilesPromptTest < Minitest::Test
+  # Minimal stub for a user message: #content (the raw user text) and
+  # #files (an ActiveStorage-like collection with #attached?). Real
+  # behavior is exercised in the host's test suite.
+  FakeMessage = Struct.new(:content, :files, keyword_init: true)
+  EmptyFiles = Struct.new(:attached) do
+    def attached? = attached
+  end
+
+  def setup
+    @tmpdir = Dir.mktmpdir("opencode-rails-uploaded-prompt-test-")
+  end
+
+  def teardown
+    FileUtils.remove_entry(@tmpdir) if @tmpdir && File.exist?(@tmpdir)
+  end
+
+  def test_initialize_takes_three_required_keywords
+    params = Opencode::UploadedFilesPrompt.instance_method(:initialize).parameters
+    required = params.select { |kind, _| kind == :keyreq }.map(&:last).sort
+
+    assert_equal %i[sandbox_name_for sandbox_path user_message], required,
+      "UploadedFilesPrompt requires user_message:, sandbox_path:, sandbox_name_for:"
+  end
+
+  def test_text_returns_raw_content_when_no_files_attached
+    message = FakeMessage.new(content: "hello world", files: EmptyFiles.new(false))
+    prompt = Opencode::UploadedFilesPrompt.new(
+      user_message:     message,
+      sandbox_path:     @tmpdir,
+      sandbox_name_for: ->(file) { file.filename.to_s }
+    )
+
+    assert_equal "hello world", prompt.text,
+      "No attached files => text is the raw user content"
+    assert_equal({}, prompt.sandbox_file_names,
+      "No attached files => sandbox_file_names map stays empty")
+  end
+
+  def test_public_surface
+    assert_equal %i[sandbox_file_names text].sort,
+      Opencode::UploadedFilesPrompt.instance_methods(false).sort
+  end
+end