diff --git a/.github/workflows/build-and-test.yml b/.github/workflows/build-and-test.yml
index 728c61d..7bc55bd 100644
--- a/.github/workflows/build-and-test.yml
+++ b/.github/workflows/build-and-test.yml
@@ -9,11 +9,7 @@ on:
 jobs:
   linux-go-build:
     runs-on: ubuntu-latest
-    name: Linux Go ${{ matrix.go }} build
-    strategy:
-      matrix:
-        go:
-          - '1.25'
+    name: Linux Go build
     steps:
       - uses: actions/checkout@v6
         with:
@@ -21,7 +17,7 @@ jobs:
       - name: Setup Go
         uses: actions/setup-go@v6
         with:
-          go-version: ${{ matrix.go }}
+          go-version-file: '.go-version'
           check-latest: true
       - name: Build and test
         run: |
@@ -31,7 +27,7 @@ jobs:
         uses: shogo82148/actions-goveralls@v1
         with:
           path-to-profile: profile.cov
-          flag-name: Linux-Go-${{ matrix.go }}
+          flag-name: Linux-Go
           parallel: true
 
   windows-go-build:
@@ -44,7 +40,7 @@ jobs:
       - name: Setup Go
         uses: actions/setup-go@v6
         with:
-          go-version: '1.25'
+          go-version-file: '.go-version'
       - name: Build
         run: go build ./...
       - name: Test
diff --git a/.github/workflows/lint.yml b/.github/workflows/lint.yml
index 8068788..df7fe37 100644
--- a/.github/workflows/lint.yml
+++ b/.github/workflows/lint.yml
@@ -10,7 +10,7 @@ jobs:
       - uses: actions/checkout@v6
       - uses: actions/setup-go@v6
         with:
-          go-version: '1.25'
+          go-version-file: '.go-version'
       - name: golangci-lint
         uses: golangci/golangci-lint-action@v9
         with:
diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index 654d36c..2462a93 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -20,7 +20,7 @@ jobs:
       - name: Setup Go
         uses: actions/setup-go@v6
         with:
-          go-version: '1.25'
+          go-version-file: '.go-version'
           check-latest: true
 
       - name: Setup Node.js
diff --git a/.go-version b/.go-version
new file mode 100644
index 0000000..5e2b950
--- /dev/null
+++ b/.go-version
@@ -0,0 +1 @@
+1.25
diff --git a/AGENTS.md b/AGENTS.md
new file mode 100644
index 0000000..0d98fd9
--- /dev/null
+++ b/AGENTS.md
@@ -0,0 +1,293 @@
+# AGENTS.md - Inbucket
+
+Guidance for AI agents working in this codebase.
+
+## Project Overview
+
+Inbucket is an email testing service that accepts messages for any email address and makes them available via web, REST, and POP3 interfaces. It's a self-contained Go application with an Elm-based web UI.
+
+**Tech Stack:**
+- Backend: Go 1.25+
+- Frontend: Elm 0.19.1 with Parcel bundler
+- Logging: zerolog
+- Testing: testify (assert/require/suite), goldiff for golden file tests
+- HTTP Router: gorilla/mux
+- Configuration: envconfig (environment variables)
+- Optional: Lua scripting for extensions (gopher-lua)
+
+## Essential Commands
+
+### Build
+
+```bash
+# Build Go binaries (inbucket server + client CLI)
+make build
+
+# Or build directly
+go build ./cmd/inbucket
+go build ./cmd/client
+
+# Build UI (required before running server)
+cd ui && yarn install && yarn build
+```
+
+### Test
+
+```bash
+# Run all Go tests with race detection
+make test
+# or
+go test -race ./...
+
+# Run tests for a specific package
+go test -race ./pkg/storage/...
+
+# Run tests with coverage
+go test -race -coverprofile=profile.cov ./...
+```
+
+### Lint
+
+```bash
+# CI uses golangci-lint
+golangci-lint run
+
+# Make's lint target (older, uses golint)
+make lint
+```
+
+### Run Development Server
+
+```bash
+# Build everything first
+make build
+cd ui && yarn build && cd ..
+
+# Run with dev config
+./etc/dev-start.sh
+
+# Or run directly with defaults
+./inbucket
+```
+
+Default ports:
+- Web UI: http://localhost:9000
+- SMTP: localhost:2500
+- POP3: localhost:1100
+
+### UI Development
+
+```bash
+cd ui
+
+# Install dependencies
+yarn install
+
+# Development server with HMR (proxies to Go backend)
+yarn start
+
+# Production build
+yarn build
+
+# Clean build artifacts
+yarn clean
+```
+
+## Code Organization
+
+```
+cmd/
+  inbucket/           # Main server binary
+  client/             # CLI client for REST API
+
+pkg/
+  config/             # Environment-based configuration
+  extension/          # Lua extension system
+    luahost/          # Lua VM pool and bindings
+    event/            # Extension event types
+  message/            # Message manager (storage abstraction)
+  metric/             # Expvar metrics
+  msghub/             # Real-time message pub/sub
+  policy/             # Email address/domain policies
+  rest/               # REST API v1/v2 controllers
+    client/           # Go client library for REST API
+    model/            # JSON API models
+  server/
+    smtp/             # SMTP server
+    pop3/             # POP3 server
+    web/              # HTTP server, handlers, helpers
+  storage/            # Storage interface and implementations
+    file/             # File-based storage
+    mem/              # In-memory storage
+  stringutil/         # String utilities
+  test/               # Test utilities and integration tests
+  webui/              # Web UI controllers
+
+ui/
+  src/
+    Main.elm          # Elm app entry point
+    Api.elm           # API client
+    Page/             # Page modules (Home, Mailbox, Monitor, Status)
+    Data/             # Data models
+  tests/              # Elm tests
+```
+
+## Configuration
+
+Inbucket uses environment variables for all configuration. Key variables:
+
+| Variable | Default | Description |
+|----------|---------|-------------|
+| `INBUCKET_LOGLEVEL` | `info` | debug, info, warn, error |
+| `INBUCKET_MAILBOXNAMING` | `local` | local, full, or domain |
+| `INBUCKET_SMTP_ADDR` | `0.0.0.0:2500` | SMTP listen address |
+| `INBUCKET_WEB_ADDR` | `0.0.0.0:9000` | HTTP listen address |
+| `INBUCKET_POP3_ADDR` | `0.0.0.0:1100` | POP3 listen address |
+| `INBUCKET_STORAGE_TYPE` | `memory` | `memory` or `file` |
+| `INBUCKET_WEB_UIDIR` | `ui/dist` | Path to built UI files |
+
+Run `./inbucket -help` for complete list.
+
+See `doc/config.md` for detailed documentation.
+
+## Code Patterns
+
+### Error Handling
+- Use zerolog for structured logging
+- Return errors up the call stack; log at the top level
+- Use `github.com/pkg/errors` patterns for wrapping
+
+### HTTP Handlers
+Handlers follow this pattern in `pkg/server/web/`:
+```go
+func Handler(f func(http.ResponseWriter, *http.Request, *Context) error) http.Handler
+```
+
+Controllers return errors; the wrapper handles HTTP responses.
+
+### Storage Interface
+New storage backends implement `storage.Store` interface (`pkg/storage/storage.go`):
+```go
+type Store interface {
+    AddMessage(message Message) (id string, err error)
+    GetMessage(mailbox, id string) (Message, error)
+    GetMessages(mailbox string) ([]Message, error)
+    MarkSeen(mailbox, id string) error
+    PurgeMessages(mailbox string) error
+    RemoveMessage(mailbox, id string) error
+    VisitMailboxes(f func([]Message) (cont bool)) error
+}
+```
+
+Register in `cmd/inbucket/main.go` init():
+```go
+storage.Constructors["mytype"] = mystore.New
+```
+
+### JSON Tag Convention
+JSON fields use kebab-case (configured in `.golangci.yml` tagliatelle):
+```go
+type Example struct {
+    FieldName string `json:"field-name"`
+}
+```
+
+### Elm Architecture
+The UI follows The Elm Architecture:
+- `Main.elm` - App shell, routing
+- `Page/*.elm` - Page modules with Model, Msg, init, update, view
+- `Data/*.elm` - Data types and JSON decoders
+- `Api.elm` - HTTP client for REST API
+
+## Testing
+
+### Test Structure
+- Unit tests: alongside source files (`*_test.go`)
+- Integration tests: `pkg/test/integration_test.go`
+- Test utilities: `pkg/test/`
+
+### Test Frameworks
+- Standard `testing` package
+- `github.com/stretchr/testify/assert` - assertions
+- `github.com/stretchr/testify/require` - fatal assertions  
+- `github.com/stretchr/testify/suite` - test suites
+- `github.com/jhillyerd/goldiff` - golden file testing
+
+### Test Utilities
+Located in `pkg/test/`:
+- `StoreStub`, `ManagerStub` - mock implementations
+- `DeliverToStore()` - create test messages
+- `StoreSuite()` - table-driven storage tests
+- `NewLuaState()` - Lua testing helper
+
+### Golden File Tests
+Input in `pkg/test/testdata/*.txt`, expected output in `*.golden`:
+```go
+goldiff.File(t, got, "testdata", "basic.golden")
+```
+
+### Running Specific Tests
+```bash
+# Run tests matching pattern
+go test -race -run TestIntegration ./pkg/test/
+
+# Run with verbose output
+go test -race -v ./pkg/storage/mem/
+
+# Run storage suite for specific implementation
+go test -race -run TestMemStore ./pkg/storage/mem/
+```
+
+## CI/CD
+
+GitHub Actions workflows in `.github/workflows/`:
+
+- `build-and-test.yml` - Build and test on Linux/Windows, coverage to coveralls
+- `lint.yml` - golangci-lint
+- `docker-build.yml` - Docker image builds
+- `release.yml` - goreleaser for releases
+
+## Important Gotchas
+
+1. **UI must be built before running server** - The Go server serves static files from `ui/dist/`
+
+2. **Storage type affects persistence** - `memory` storage loses all data on restart; use `file` for persistence
+
+3. **Port conflicts** - Default ports (9000, 2500, 1100) may conflict with other services
+
+4. **Lua scripting is optional** - If `inbucket.lua` is not present, the server runs without extensions
+
+5. **Test coverage requires race detector** - CI always runs with `-race`
+
+6. **golangci-lint v2 config** - Uses v2 format in `.golangci.yml`
+
+7. **Windows paths in storage** - Use `$` instead of `:` in file storage paths (e.g., `D$/inbucket`)
+
+## REST API
+
+Base URL: `http://localhost:9000/api/`
+
+### API v1 Endpoints
+- `GET /v1/mailbox/{name}` - List messages
+- `GET /v1/mailbox/{name}/{id}` - Get message
+- `PATCH /v1/mailbox/{name}/{id}` - Mark as seen
+- `DELETE /v1/mailbox/{name}` - Purge mailbox
+- `DELETE /v1/mailbox/{name}/{id}` - Delete message
+- `GET /v1/mailbox/{name}/{id}/source` - Get raw source
+
+### API v2 Endpoints
+- `GET /v2/monitor/messages` - WebSocket for real-time messages
+
+Go client available: `github.com/inbucket/inbucket/v3/pkg/rest/client`
+
+## Development Tips
+
+1. **Quick iteration** - Use `make reflex` for auto-rebuild on Go file changes
+
+2. **UI development** - Run `yarn start` in `ui/` for HMR; it proxies API requests to the Go server
+
+3. **Debug network** - Run with `-netdebug` flag to dump SMTP/POP3 traffic
+
+4. **Test email sending** - Use swaks or the test scripts in `etc/swaks-tests/`
+
+5. **Check configuration** - Run `./inbucket -help` to see all env vars and defaults