docs: description and Open Graph title on every page and the playground

- camera.NewService and SetAccessibility; AttachWorld wires the accessibility settings
- tests/camera: priorities, blends, cuts, zones, follow, bounds, outputs, shake, zero allocations, BrainStep benchmark
- integration: rewind restores the camera state across a zone change
- camera2d.Adjuster passes the view by value (no per-frame allocation), D304 updated
- modules/camera/module.mk: test-camera in CI, bench-camera

.dockerignore

@@ -5,3 +5,4 @@ site
 exports
 **/.aego
 *.test
+.claude

.github/workflows/ci.yml

@@ -3,6 +3,7 @@ name: ci
 on:
   push:
     branches: [master]
+    tags: ["v*"]
   pull_request:
 
 permissions:
@@ -111,4 +112,39 @@ jobs:
       - name: example project
         run: |
           /tmp/aego check examples/native-rotator
-          /tmp/aego run examples/native-rotator --headless --frames 60
+          /tmp/aego run examples/native-rotator --headless --frames 60
+
+  release:
+    needs: [checks, build]
+    if: github.event_name == 'push'
+    runs-on: ubuntu-24.04
+    permissions:
+      contents: write
+    env:
+      CGO_ENABLED: "1"
+      GITEA_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+      GITEA_API: ${{ github.server_url }}/api/v1/repos/${{ github.repository }}
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-go@v5
+        with:
+          go-version-file: go.mod
+      - name: linux packages
+        run: sudo apt-get update && sudo apt-get install -y $LINUX_PKGS
+      - uses: actions/cache@v4
+        continue-on-error: true
+        with:
+          path: .cache/native
+          key: native-linux_amd64-${{ hashFiles('third_party/sdl/version.txt', 'tools/bootstrap-native.sh') }}
+      - run: bash tools/bootstrap-native.sh
+      - name: windows tools
+        run: sudo apt-get install -y mingw-w64 nsis zip
+      - name: publish
+        env:
+          REQUIRE_WINDOWS: "1"
+          GITEA_RESOLVE: git.akarpov.ru:443:79.142.92.250
+        run: |
+          case "$GITHUB_REF" in
+          refs/tags/v*) sh tools/release/release.sh "$GITHUB_REF_NAME" ;;
+          refs/heads/master) sh tools/release/release.sh nightly ;;
+          esac

Makefile

@@ -38,7 +38,7 @@ BENCH_PHYSICS_PKGS :=
 .DEFAULT_GOAL := bootstrap
 -include modules/*/module.mk
 
-.PHONY: bootstrap build test test-nonative test-editor test-runtime test-gl vet lint depcheck smoke run genfont genicons icons icons-doc res genpreviews golden golden-update site-headless bench bench-baseline bench-scripts bench-build bench-compare bench-profile bench-scripts-run bench-allocs playground playground-size site site-check cli example example-platformer check-all ci clean fuzz runtime export-smoke editor-app shaders test-wasm web-smoke web-smoke-update try-size
+.PHONY: bootstrap build test test-nonative test-editor test-runtime test-gl vet lint depcheck smoke run genfont genicons icons icons-doc res genpreviews golden golden-update site-headless bench bench-baseline bench-scripts bench-build bench-compare bench-profile bench-scripts-run bench-allocs playground playground-size site site-check cli example example-platformer check-all ci clean fuzz runtime export-smoke editor-app shaders test-wasm web-smoke web-smoke-update try-size shots shots-check
 
 XVFB := $(shell command -v xvfb-run 2>/dev/null)
 GL_OVERRIDE = MESA_GL_VERSION_OVERRIDE=3.3 MESA_GLSL_VERSION_OVERRIDE=330
@@ -98,6 +98,7 @@ vet: bootstrap
 
 lint: bootstrap
 	go run honnef.co/go/tools/cmd/staticcheck@$(STATICCHECK_VERSION) $(LINT_PKGS)
+	go run honnef.co/go/tools/cmd/staticcheck@$(STATICCHECK_VERSION) -tags aego_editor ./editor/... ./app/... ./tests/...
 
 # All graph variants, the semantic pass and the negative rule tests.
 depcheck:
@@ -211,7 +212,7 @@ site: cli
 	@$(TRY_SIZE_CHECK)
 
 playground:
-	@if GOOS=js GOARCH=wasm go list -deps ./cmd/aego-playground | grep -E '^aego/(platform/sdl|gpu/gl33|asset/pipeline|asset/importers|modules/render3d)'; then echo "playground graph pulls a native or pipeline package"; exit 1; fi
+	@if GOOS=js GOARCH=wasm go list -deps ./cmd/aego-playground | grep -E '^aego/(platform/sdl|gpu/gl33|asset/pipeline|asset/importers)'; then echo "playground graph pulls a native or pipeline package"; exit 1; fi
 	$(MAKE) site
 
 site-headless:
@@ -281,7 +282,29 @@ fuzz:
 	go test -run '^$$' -fuzz '^FuzzDecodeVerify$$' -fuzztime $(FUZZTIME) ./script/verify
 	go test -run '^$$' -fuzz '^FuzzDecodeVerifyV3$$' -fuzztime $(FUZZTIME) ./script/verify
 
-ci: build vet lint depcheck test test-nonative test-editor test-runtime test-wasm runtime smoke fuzz golden test-gl cli playground web-smoke site-check example example-platformer check-all export-smoke $(MODULE_CI) bench-allocs
+ci: build vet lint depcheck test test-nonative test-editor test-runtime test-wasm runtime smoke fuzz golden shots-check test-gl cli playground web-smoke site-check example example-platformer check-all export-smoke $(MODULE_CI) bench-allocs
+
+
+# Documentation screenshots of the real editor on the platformer example, under a clean user profile.
+SHOTS_TMP = $(CURDIR)/.cache/shots
+ifneq ($(XVFB),)
+SHOTS_ENV = $(XVFB) -a -s "-screen 0 1600x900x24" env SDL_VIDEODRIVER=x11 LIBGL_ALWAYS_SOFTWARE=1 GALLIUM_DRIVER=llvmpipe $(GL_OVERRIDE)
+else
+SHOTS_ENV = $(GL_ENV)
+endif
+SHOTS_RUN = rm -rf $(SHOTS_TMP)/project $(SHOTS_TMP)/home && mkdir -p $(SHOTS_TMP)/home && cp -R examples/platformer $(SHOTS_TMP)/project && \
+	rm -rf $(SHOTS_TMP)/project/.aego $(SHOTS_TMP)/project/exports && \
+	sed -i.bak 's|=> ../..|=> $(CURDIR)|' $(SHOTS_TMP)/project/go.mod && \
+	XDG_CONFIG_HOME=$(SHOTS_TMP)/home XDG_DATA_HOME=$(SHOTS_TMP)/home $(SHOTS_ENV) env AEGO_SHOTS=$(1) .cache/bin/aego edit $(SHOTS_TMP)/project --hidden
+
+shots: cli
+	rm -rf docs/shots
+	$(call SHOTS_RUN,$(CURDIR)/docs/shots)
+
+shots-check: cli
+	rm -rf $(SHOTS_TMP)/out
+	$(call SHOTS_RUN,$(SHOTS_TMP)/out)
+	go run ./tools/shotdiff -want docs/shots -got $(SHOTS_TMP)/out
 
 runtime: bootstrap
 	go build -tags aego_runtime -o .cache/bin/aego-runtime ./cmd/aego-runtime

app/agent/cli_test.go

@@ -0,0 +1,85 @@
+package agent
+
+import (
+	"bytes"
+	"encoding/json"
+	"testing"
+)
+
+func mustFind(t *testing.T, name string) *Command {
+	t.Helper()
+	c, ok := Find(name)
+	if !ok {
+		t.Fatalf("no command %s", name)
+	}
+	return c
+}
+
+func TestParseArgs(t *testing.T) {
+	set := mustFind(t, "scene.set")
+	a, f, err := parseArgs(set, []string{"s.aescene", "--json", "Player", "--dry-run", "Body2D.mass", "-3"})
+	if err != nil || !f.json || a.Str("value") != "-3" || a.Str("node") != "Player" || !a.Bool("dry-run") {
+		t.Fatalf("flags after positionals: %v %+v %v", a, f, err)
+	}
+	add := mustFind(t, "scene.add-node")
+	for _, toks := range [][]string{{"s", "N", "--index=1"}, {"s", "N", "--index", "1"}} {
+		a, _, err := parseArgs(add, toks)
+		if n, _ := a.Int("index", -1); err != nil || n != 1 {
+			t.Fatalf("%v: %v %v", toks, a, err)
+		}
+	}
+	a, _, err = parseArgs(set, []string{"s", "--", "Player", "Body2D.mass", "--odd"})
+	if err != nil || a.Str("value") != "--odd" {
+		t.Fatalf("after --: %v %v", a, err)
+	}
+	if _, _, err := parseArgs(set, []string{"s", "--nope"}); err == nil {
+		t.Fatal("an unknown flag was accepted")
+	}
+	if _, _, err := parseArgs(set, []string{"s", "a", "b", "c", "d"}); err == nil {
+		t.Fatal("an extra positional was accepted")
+	}
+	var out, errw bytes.Buffer
+	if code := Main(nil, []string{"scene", "set", "s", "--nope"}, &out, &errw, Options{}); code != 2 {
+		t.Fatalf("unknown flag exit %d", code)
+	}
+	if code := Main(nil, []string{"scene", "set", "a", "b", "c", "d", "e"}, &out, &errw, Options{}); code != 2 {
+		t.Fatalf("extra positional exit %d", code)
+	}
+	if code := Main(nil, []string{"scene", "help"}, &out, &errw, Options{}); code != 0 {
+		t.Fatalf("help exit %d", code)
+	}
+}
+
+func TestSchemasAndToolNames(t *testing.T) {
+	seen := map[string]bool{}
+	for _, c := range Commands() {
+		if seen[c.Tool()] {
+			t.Fatalf("tool name %s is used twice", c.Tool())
+		}
+		seen[c.Tool()] = true
+		b, err := json.Marshal(c.Schema())
+		if err != nil {
+			t.Fatal(err)
+		}
+		var sch struct {
+			Type       string                    `json:"type"`
+			Properties map[string]map[string]any `json:"properties"`
+			Required   []string                  `json:"required"`
+		}
+		if err := json.Unmarshal(b, &sch); err != nil || sch.Type != "object" {
+			t.Fatalf("%s: %s", c.Name, b)
+		}
+		var want []string
+		for _, x := range c.AllArgs() {
+			if x.Required {
+				want = append(want, x.Name)
+			}
+			if _, ok := sch.Properties[x.Name]; !ok {
+				t.Fatalf("%s: no property %s", c.Name, x.Name)
+			}
+		}
+		if len(want) != len(sch.Required) {
+			t.Fatalf("%s: required %v, want %v", c.Name, sch.Required, want)
+		}
+	}
+}

app/agent/project.go

@@ -0,0 +1,66 @@
+package agent
+
+import (
+	"strconv"
+
+	"aego/asset"
+	"aego/project/refs"
+	"aego/scene/mutate"
+)
+
+func projectCommands() []*Command {
+	return []*Command{
+		{Name: "project.validate", Doc: "missing assets and nodes, import errors, prefabs and scenes that do not load", Run: (*Session).projectValidate},
+	}
+}
+
+func (s *Session) projectValidate(Args) (*Output, error) {
+	out := &Output{}
+	add := func(err bool, node, msg string) {
+		out.Problems = append(out.Problems, mutate.Problem{Error: err, Node: node, Message: msg})
+	}
+	for _, m := range refs.MissingAssets(s.Project, s.Pipeline) {
+		add(true, "", "missing asset "+m.Label())
+	}
+	for _, m := range refs.MissingNodes(s.Pipeline) {
+		add(true, m.Scene+" "+m.Path, m.Owner+"."+m.Field+" references a node that is not in the scene")
+	}
+	if s.scriptErr != nil {
+		add(true, "", "script types: "+s.scriptErr.Error())
+	}
+	for _, e := range s.libErrs {
+		add(true, "", e.Error())
+	}
+	for _, x := range s.Pipeline.Assets() {
+		if x.Error != "" {
+			add(true, x.Path, x.Error)
+			continue
+		}
+		if x.Kind != asset.ArtScene && x.Kind != asset.ArtPrefab {
+			continue
+		}
+		src, err := s.read(x.Path)
+		if err != nil {
+			add(true, x.Path, err.Error())
+			continue
+		}
+		doc, err := mutate.Load(src, x.Path, s.env())
+		if err != nil {
+			add(true, x.Path, err.Error())
+			continue
+		}
+		for _, p := range doc.Problems {
+			add(p.Error, x.Path+" "+p.Node, p.Message)
+		}
+	}
+	errs, warns := 0, 0
+	for _, p := range out.Problems {
+		if p.Error {
+			errs++
+		} else {
+			warns++
+		}
+	}
+	out.Notes = []string{"project: " + strconv.Itoa(errs) + " error(s), " + strconv.Itoa(warns) + " warning(s)"}
+	return out, nil
+}

app/assembly/builtin/builtin.go

@@ -6,6 +6,7 @@ import (
 	"aego/engine/module"
 	"aego/modules/accessibility"
 	"aego/modules/audio"
+	"aego/modules/camera"
 	"aego/modules/dataasset"
 	"aego/modules/debug"
 	"aego/modules/display"
@@ -71,6 +72,10 @@ func tweenEntry() assembly.Entry {
 	return assembly.Entry{ID: tween.ID, Requires: []string{scripting.ID}, New: func(assembly.Options) module.Module { return tween.New() }}
 }
 
+func cameraEntry() assembly.Entry {
+	return assembly.Entry{ID: camera.ID, Requires: []string{scripting.ID}, New: func(assembly.Options) module.Module { return camera.New() }}
+}
+
 func dataEntry() assembly.Entry {
 	return assembly.Entry{ID: dataasset.ID, New: func(assembly.Options) module.Module { return dataasset.New() }}
 }
@@ -85,5 +90,5 @@ func savegameEntry() assembly.Entry {
 
 func Default() assembly.Catalog {
 	return assembly.Catalog{core(), dataEntry(), inputEntry(), render2dEntry(), render3dEntry(), scriptEntry(), physicsEntry(), debugEntry(),
-		displayEntry(), audioEntry(), accessibilityEntry(), settingsEntry(), tweenEntry(), spawnEntry(), savegameEntry()}
+		displayEntry(), audioEntry(), accessibilityEntry(), settingsEntry(), tweenEntry(), cameraEntry(), spawnEntry(), savegameEntry()}
 }

app/assembly/builtin/headless.go

@@ -3,5 +3,5 @@ package builtin
 import "aego/app/assembly"
 
 func Headless() assembly.Catalog {
-	return assembly.Catalog{core(), dataEntry(), inputEntry(), scriptEntry(), physicsEntry(), debugEntry(), displayEntry(), audioEntry(), accessibilityEntry(), settingsEntry(), tweenEntry(), spawnEntry(), savegameEntry()}
+	return assembly.Catalog{core(), dataEntry(), inputEntry(), scriptEntry(), physicsEntry(), debugEntry(), displayEntry(), audioEntry(), accessibilityEntry(), settingsEntry(), tweenEntry(), cameraEntry(), spawnEntry(), savegameEntry()}
 }

app/assembly/editors/editors.go

@@ -2,6 +2,8 @@ package editors
 
 import (
 	"aego/app/assembly"
+	"aego/modules/camera"
+	cameraeditor "aego/modules/camera/editor"
 	"aego/modules/debug"
 	debugeditor "aego/modules/debug/editor"
 	inputmod "aego/modules/input"
@@ -20,5 +22,6 @@ func With(c assembly.Catalog) assembly.Catalog {
 		With(render2d.ID, render2deditor.Hook).
 		With(render3d.ID, render3deditor.Hook).
 		With(physics.ID, physicseditor.Hook).
+		With(camera.ID, cameraeditor.Hook).
 		With(debug.ID, debugeditor.Hook)
 }

app/assembly/playground/playground.go

@@ -4,11 +4,16 @@ import (
 	"aego/app/assembly"
 	"aego/engine/base"
 	"aego/engine/module"
+	"aego/modules/camera"
 	"aego/modules/debug"
 	inputmod "aego/modules/input"
 	"aego/modules/physics"
 	"aego/modules/render2d"
+	"aego/modules/render3d"
+	"aego/modules/savegame"
 	"aego/modules/scripting"
+	"aego/modules/spawn"
+	"aego/modules/tween"
 	"aego/script/stdlib"
 	"aego/script/vm"
 )
@@ -23,6 +28,11 @@ func Catalog() assembly.Catalog {
 		}},
 		{ID: physics.ID, New: func(assembly.Options) module.Module { return physics.New() }},
 		{ID: debug.ID, New: func(assembly.Options) module.Module { return debug.New() }},
+		{ID: tween.ID, Requires: []string{scripting.ID}, New: func(assembly.Options) module.Module { return tween.New() }},
+		{ID: camera.ID, Requires: []string{scripting.ID}, New: func(assembly.Options) module.Module { return camera.New() }},
+		{ID: render3d.ID, New: func(assembly.Options) module.Module { return render3d.New() }},
+		{ID: spawn.ID, New: func(assembly.Options) module.Module { return spawn.New() }},
+		{ID: savegame.ID, Requires: []string{scripting.ID, spawn.ID}, New: func(assembly.Options) module.Module { return savegame.New() }},
 	}
 }
 

app/assembly/playground/saves.go

@@ -0,0 +1,61 @@
+package playground
+
+import (
+	"io/fs"
+	"path"
+	"sort"
+	"strings"
+	"time"
+
+	"aego/contracts/persistence"
+	"aego/engine"
+	"aego/platform"
+	"aego/save"
+)
+
+// UseMemorySaves gives e a save store kept in memory, for runs in a browser page that must not touch the visitor's storage.
+func UseMemorySaves(e *engine.Engine) {
+	e.SetService(persistence.StoreID, save.NewStoreFS("saves", &memUser{files: map[string][]byte{}}))
+}
+
+type memUser struct {
+	files map[string][]byte
+}
+
+func (m *memUser) ReadFile(p string) ([]byte, error) {
+	data, ok := m.files[path.Clean(p)]
+	if !ok {
+		return nil, fs.ErrNotExist
+	}
+	return append([]byte(nil), data...), nil
+}
+
+func (m *memUser) WriteFile(p string, data []byte) error {
+	m.files[path.Clean(p)] = append([]byte(nil), data...)
+	return nil
+}
+
+func (m *memUser) Remove(p string) error {
+	delete(m.files, path.Clean(p))
+	return nil
+}
+
+func (m *memUser) Stat(p string) (platform.UserEntry, error) {
+	data, ok := m.files[path.Clean(p)]
+	if !ok {
+		return platform.UserEntry{}, fs.ErrNotExist
+	}
+	return platform.UserEntry{Name: path.Base(p), Size: int64(len(data)), Mod: time.Time{}}, nil
+}
+
+func (m *memUser) List(dir string) ([]platform.UserEntry, error) {
+	prefix := path.Clean(dir) + "/"
+	var out []platform.UserEntry
+	for p, data := range m.files {
+		if rest, ok := strings.CutPrefix(p, prefix); ok && !strings.Contains(rest, "/") {
+			out = append(out, platform.UserEntry{Name: rest, Size: int64(len(data))})
+		}
+	}
+	sort.Slice(out, func(i, j int) bool { return out[i].Name < out[j].Name })
+	return out, nil
+}

app/assembly/playground/try.go

@@ -0,0 +1,62 @@
+package playground
+
+import (
+	"encoding/base64"
+	"strings"
+
+	"aego/asset"
+	"aego/asset/loader"
+	"aego/core/ids"
+	"aego/script/bytecode"
+	"aego/vfs"
+	"aego/vfs/memfs"
+)
+
+// EncodeTry packs the compiled script of a try scene for a docs page: base64 modules joined by commas.
+func EncodeTry(mods []*bytecode.Module) string {
+	parts := make([]string, len(mods))
+	for i, m := range mods {
+		parts[i] = base64.StdEncoding.EncodeToString(bytecode.Encode(m))
+	}
+	return strings.Join(parts, ",")
+}
+
+func DecodeTry(code string) ([]*bytecode.Module, error) {
+	if code == "" {
+		return nil, nil
+	}
+	var mods []*bytecode.Module
+	for _, part := range strings.Split(code, ",") {
+		b, err := base64.StdEncoding.DecodeString(part)
+		if err != nil {
+			return nil, err
+		}
+		m, err := bytecode.Decode(b)
+		if err != nil {
+			return nil, err
+		}
+		mods = append(mods, m)
+	}
+	return mods, nil
+}
+
+// MountTry gives the loader the prefabs of a try scene, keyed by asset id; none unmounts them.
+func MountTry(l *loader.Loader, prefabs map[string]string) error {
+	idx := asset.NewIndex()
+	files := map[string][]byte{}
+	for key, text := range prefabs {
+		id, err := ids.ParseAssetID(key)
+		if err != nil {
+			return err
+		}
+		p := id.String() + ".aeprefab"
+		files[p] = []byte(text)
+		idx.Put(asset.Entry{ID: id, Kind: asset.ArtPrefab, Name: p, Source: p,
+			Artifacts: []asset.Artifact{{Kind: asset.ArtPrefab, Path: "try://" + p}}})
+	}
+	fs, err := vfs.New(vfs.Mount{Scheme: "try", ReadOnly: true, Source: memfs.New(files)})
+	if err != nil {
+		return err
+	}
+	return l.Mount(idx, fs)
+}

app/docstool/diagnostics.go

@@ -0,0 +1,33 @@
+package docstool
+
+import (
+	"aego/app/playground"
+	"aego/engine/docs"
+	"aego/script/diag"
+)
+
+func diagnoser(pg *playground.Playground) func(string, *docs.DiagInfo) {
+	return func(code string, d *docs.DiagInfo) {
+		got, err := pg.Reproduce(code)
+		if err != nil || got.Code == "" {
+			return
+		}
+		d.Severity, d.At, d.Message = got.Severity, got.File, got.Message
+		d.Line, d.Col, d.EndLine, d.EndCol = got.Line, got.Col, got.EndLine, got.EndCol
+	}
+}
+
+// DiagnosticProblems lists codes whose example is missing or no longer produces the code.
+func DiagnosticProblems() []docs.Problem {
+	pg, err := playground.New()
+	if err != nil {
+		return []docs.Problem{{ID: docs.DiagnosticsID, Error: true, Message: "cannot start the docs runtime: " + err.Error()}}
+	}
+	var out []docs.Problem
+	for _, c := range diag.Codes() {
+		if _, err := pg.Reproduce(c); err != nil {
+			out = append(out, docs.Problem{ID: c, Error: true, Message: err.Error()})
+		}
+	}
+	return out
+}

app/docstool/docstool_test.go

@@ -138,7 +138,7 @@ func TestF1Refs(t *testing.T) {
 	if err := os.WriteFile(path, []byte(probe), 0o644); err != nil {
 		t.Fatal(err)
 	}
-	reg, ws, err := build(p, nil)
+	reg, ws, err := build(p, nil, nil)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -169,3 +169,17 @@ func TestF1Refs(t *testing.T) {
 		}
 	}
 }
+
+func TestDiagnosticExamplesExported(t *testing.T) {
+	if ps := DiagnosticProblems(); len(ps) > 0 {
+		t.Fatalf("diagnostics examples: %v", ps)
+	}
+	reg, err := ExportRegistry(nil, nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+	e, ok := reg.Get("AES2001")
+	if !ok || e.Diag == nil || e.Diag.Line == 0 || e.Diag.Severity != "error" || !strings.Contains(e.Diag.Message, "heigth") {
+		t.Fatalf("AES2001 example was not diagnosed: %+v", e.Diag)
+	}
+}

app/docstool/registry.go

@@ -9,6 +9,7 @@ import (
 
 	"aego/app/assembly"
 	"aego/app/assembly/builtin"
+	"aego/app/playground"
 	"aego/engine/docs"
 	"aego/engine/module"
 	scriptsystems "aego/modules/scripting/systems"
@@ -20,7 +21,8 @@ import (
 	"aego/script/workspace"
 )
 
-func build(p *project.Project, mods []module.Module) (*docs.Registry, *workspace.Workspace, error) {
+// build assembles the registry; with pg it also compiles the diagnostics examples and the try scripts.
+func build(p *project.Project, mods []module.Module, pg *playground.Playground) (*docs.Registry, *workspace.Workspace, error) {
 	types, err := assembly.NewTypes()
 	if err != nil {
 		return nil, nil, err
@@ -41,6 +43,10 @@ func build(p *project.Project, mods []module.Module) (*docs.Registry, *workspace
 		return nil, nil, err
 	}
 	src := docs.SourcesOf(bm, types.Schema(), man)
+	if pg != nil {
+		src.Diagnose = diagnoser(pg)
+		src.CompileTry = pg.TryCode
+	}
 	var ws *workspace.Workspace
 	if p != nil {
 		ws, err = workspace.Open(workspace.Config{Root: p.Root, Module: p.Module, Scripts: p.ScriptsDir(), Bindings: reg.Table(), Docs: bm})
@@ -61,7 +67,17 @@ func build(p *project.Project, mods []module.Module) (*docs.Registry, *workspace
 }
 
 func Registry(p *project.Project, mods []module.Module) (*docs.Registry, error) {
-	r, _, err := build(p, mods)
+	r, _, err := build(p, mods, nil)
+	return r, err
+}
+
+// ExportRegistry is Registry with the diagnostics examples compiled for their messages and positions, and the try scripts compiled.
+func ExportRegistry(p *project.Project, mods []module.Module) (*docs.Registry, error) {
+	pg, err := playground.New()
+	if err != nil {
+		return nil, err
+	}
+	r, _, err := build(p, mods, pg)
 	return r, err
 }
 
@@ -84,9 +100,9 @@ func WriteExport(reg *docs.Registry, title, path string, w io.Writer) error {
 	return os.WriteFile(path, data, 0o644)
 }
 
-func Check(reg *docs.Registry, strict bool, w io.Writer) int {
+func Check(reg *docs.Registry, strict bool, w io.Writer, extra ...docs.Problem) int {
 	errs, warns := 0, 0
-	for _, p := range reg.Check(strict) {
+	for _, p := range append(reg.Check(strict), extra...) {
 		level := "warn "
 		if p.Error {
 			level = "error"

app/docstool/site.go

@@ -16,6 +16,7 @@ import (
 	"strings"
 	"time"
 
+	"aego/app/assembly/builtin"
 	"aego/engine"
 	"aego/engine/module"
 	"aego/project"
@@ -40,7 +41,7 @@ func (e *Env) export(path string) error {
 		}
 		return e.Native(args...)
 	}
-	reg, err := Registry(e.Project, e.Modules)
+	reg, err := ExportRegistry(e.Project, e.Modules)
 	if err != nil {
 		return err
 	}
@@ -71,7 +72,7 @@ func (e *Env) Check(strict bool) int {
 		fmt.Fprintln(e.Stderr, "aego:", err)
 		return 1
 	}
-	code := Check(reg, strict, e.Stdout)
+	code := Check(reg, strict, e.Stdout, DiagnosticProblems()...)
 	if CheckTry(reg, e.Stdout) > 0 && code == 0 {
 		code = 1
 	}
@@ -98,7 +99,10 @@ func (e *Env) git(args ...string) string {
 }
 
 func (e *Env) commit() string {
-	return e.git("rev-parse", "--short", "HEAD")
+	if c := e.git("rev-parse", "--short", "HEAD"); c != "" {
+		return c
+	}
+	return os.Getenv("AEGO_COMMIT")
 }
 
 func (e *Env) branch() string {
@@ -150,6 +154,14 @@ func (e *Env) Build(out string, play bool) error {
 	if c := e.commit(); c != "" {
 		args = append(args, "-commit", c)
 	}
+	var icons []string
+	for _, d := range builtin.IconSources() {
+		icons = append(icons, filepath.Join(e.Engine, filepath.FromSlash(d)))
+	}
+	args = append(args, "-icons", strings.Join(icons, ","))
+	if shots := filepath.Join(e.Engine, "docs", "shots"); fileExists(filepath.Join(shots, "demo.png")) {
+		args = append(args, "-poster", filepath.Join(shots, "demo.png"), "-shots", shots)
+	}
 	if hero := filepath.Join(e.Engine, "docs", "hero.png"); fileExists(hero) {
 		args = append(args, "-hero", hero)
 	}

app/docstool/tool.go

@@ -21,7 +21,11 @@ func Tool(p *project.Project, args []string, stdout, stderr io.Writer, mods ...m
 	if err := fs.Parse(args[1:]); err != nil {
 		return 2
 	}
-	reg, err := Registry(p, mods)
+	build := Registry
+	if args[0] == "export" {
+		build = ExportRegistry
+	}
+	reg, err := build(p, mods)
 	if err != nil {
 		fmt.Fprintln(stderr, "aego:", err)
 		return 1
@@ -34,7 +38,7 @@ func Tool(p *project.Project, args []string, stdout, stderr io.Writer, mods ...m
 		}
 		return 0
 	case "check":
-		return Check(reg, *strict, stdout)
+		return Check(reg, *strict, stdout, DiagnosticProblems()...)
 	}
 	fmt.Fprintf(stderr, "unknown docs command %q\n", args[0])
 	return 2

app/docstool/try.go

@@ -41,9 +41,16 @@ func CheckTry(reg *docs.Registry, w io.Writer) int {
 			}
 			msgs = append(msgs, msg)
 		}
-		switch res := pg.PlayScene(e.ID, []byte(e.Try)); {
+		var code string
+		var err error
+		if e.TryScript != "" {
+			code, err = pg.TryCode(e.TryScript)
+		}
+		switch res := pg.PlayScene(e.ID, []byte(e.Try), code, e.TryPrefabs); {
 		case !sandbox[e.ID]:
 			add("belongs to a module the docs runtime does not include")
+		case err != nil:
+			add("script does not compile: " + err.Error())
 		case !res.Started:
 			add("does not load: " + res.Error)
 		default:

app/docsview/app.go

@@ -7,6 +7,7 @@ import (
 	playmods "aego/app/assembly/playground"
 	"aego/asset"
 	"aego/asset/loader"
+	"aego/contracts/debugdraw"
 	"aego/core/log"
 	"aego/core/mathx"
 	edclip "aego/editor/core/clipboard"
@@ -20,6 +21,7 @@ import (
 	"aego/engine/base"
 	"aego/engine/module"
 	"aego/format/aetext"
+	"aego/modules/physics"
 	scriptsystems "aego/modules/scripting/systems"
 	"aego/platform"
 	"aego/render"
@@ -41,9 +43,11 @@ const (
 	maxSprites = 16384
 	gameShare  = 0.6
 	stackBelow = 640
-	maxLines   = 200
-	defaultW   = 960
-	defaultH   = 440
+	// inspectorMin keeps field names and values readable in narrow embeds.
+	inspectorMin = 400
+	maxLines     = 200
+	defaultW     = 960
+	defaultH     = 440
 )
 
 var coreBlocks = []string{"window", "defaults"}
@@ -71,12 +75,14 @@ type App struct {
 	ui       *core.Context
 	clip     *docsession.Clipboard
 	session  *docsession.Session
+	scripts  *scriptHost
 	insp     *inspector.Panel
 	game     *gameview.Panel
 	list     *draw.List
 	log      *log.Logger
 	lines    []Line
 	textOn   bool
+	shown    *engine.World
 	closed   bool
 }
 
@@ -138,15 +144,17 @@ func New(opt Options) (*App, error) {
 		return nil, err
 	}
 	a.e.SetService(loader.ServiceID, a.loader)
+	playmods.UseMemorySaves(a.e)
 	a.e.SetService(renderhost.ServiceID, a.renderer)
 	if err := a.man.Init(&module.InitContext{Engine: a.e, Assets: a.loader, Log: a.log, Editor: true, Sections: sections}); err != nil {
 		a.Close()
 		return nil, err
 	}
 	a.initUI()
+	a.scripts = &scriptHost{reg: reg, types: a.types, man: a.man, log: a.log}
 	a.session = docsession.New(docsession.Options{
 		Engine: a.e, Renderer: a.renderer, Loader: a.loader, Types: a.types, Sections: sections,
-		Scripts:   &scriptHost{reg: reg, types: a.types, man: a.man, log: a.log},
+		Scripts:   a.scripts,
 		UI:        a.ui,
 		Clipboard: a.clip,
 		Log:       a.log,
@@ -270,7 +278,7 @@ func layout(body mathx.Rect, gap float32) (game, insp mathx.Rect) {
 		return mathx.Rect{X: body.X, Y: body.Y, W: body.W, H: h},
 			mathx.Rect{X: body.X, Y: body.Y + h + gap, W: body.W, H: max(0, body.H-h-gap)}
 	}
-	w := body.W * gameShare
+	w := min(body.W*gameShare, body.W-inspectorMin)
 	return mathx.Rect{X: body.X, Y: body.Y, W: w, H: body.H},
 		mathx.Rect{X: body.X + w + gap, Y: body.Y, W: max(0, body.W-w-gap), H: body.H}
 }
@@ -308,10 +316,24 @@ func (a *App) toolbar(r mathx.Rect) {
 	}
 }
 
+// showPhysics draws collider and joint outlines in the game view, since docs scenes have no art for them.
+func (a *App) showPhysics() {
+	w := a.session.Controller().World()
+	if w == nil || w == a.shown {
+		return
+	}
+	if d, ok := engine.ServiceOf[debugdraw.Draw](w, debugdraw.ServiceID); ok {
+		d.Hide(physics.ChannelShapes, false)
+		d.Hide(physics.ChannelJoints, false)
+		a.shown = w
+	}
+}
+
 func (a *App) Update(dt float64) {
 	e := a.e
 	now := e.Platform().Now()
 	a.session.Tick(dt)
+	a.showPhysics()
 	ui := a.ui
 	ui.Time = now
 	m := e.Metrics()

app/docsview/app_test.go

@@ -3,6 +3,7 @@
 package docsview
 
 import (
+	"encoding/json"
 	"strings"
 	"testing"
 
@@ -27,7 +28,7 @@ func tries(t *testing.T) []docs.Entry {
 		t.Fatal(err)
 	}
 	out := p.TryScenes()
-	if len(out) < 4 {
+	if len(out) < 10 {
 		t.Fatalf("only %d try scenes; does the module embed res/docs/try?", len(out))
 	}
 	return out
@@ -46,11 +47,22 @@ func errorsOf(a *App) []string {
 
 func TestTryScenesRun(t *testing.T) {
 	a := newHeadless(t)
+	p, err := playground.New()
+	if err != nil {
+		t.Fatal(err)
+	}
 	for _, e := range tries(t) {
-		if err := a.session.Load([]byte(e.Try), e.TrySelect); err != nil {
-			t.Fatalf("%s: %v", e.ID, err)
+		var code string
+		if e.TryScript != "" {
+			if code, err = p.TryCode(e.TryScript); err != nil {
+				t.Fatalf("%s: %v", e.ID, err)
+			}
 		}
-		if err := a.Step(60); err != nil {
+		req, _ := json.Marshal(map[string]any{"scene": e.Try, "select": e.TrySelect, "code": code, "prefabs": e.TryPrefabs})
+		if r := a.Call("load", req); r.Error != "" {
+			t.Fatalf("%s: %s", e.ID, r.Error)
+		}
+		if err := a.Step(400); err != nil {
 			t.Fatalf("%s: %v", e.ID, err)
 		}
 		st := a.session.State()

app/docsview/bridge.go

@@ -6,22 +6,27 @@ import (
 	"encoding/json"
 	"strconv"
 
+	playmods "aego/app/assembly/playground"
 	"aego/editor/core/docsession"
+	"aego/scene/sceneio"
 )
 
 type request struct {
-	Scene     string  `json:"scene"`
-	Select    string  `json:"select"`
-	Component string  `json:"component"`
-	Field     string  `json:"field"`
-	Value     float64 `json:"value"`
+	Scene     string            `json:"scene"`
+	Select    string            `json:"select"`
+	Code      string            `json:"code"`
+	Prefabs   map[string]string `json:"prefabs"`
+	Component string            `json:"component"`
+	Field     string            `json:"field"`
+	Value     float64           `json:"value"`
 }
 
 type Reply struct {
-	Text  string            `json:"text,omitempty"`
-	Error string            `json:"error,omitempty"`
-	State *docsession.State `json:"state,omitempty"`
-	Log   []Line            `json:"log,omitempty"`
+	Text   string            `json:"text,omitempty"`
+	Values map[string]string `json:"values,omitempty"`
+	Error  string            `json:"error,omitempty"`
+	State  *docsession.State `json:"state,omitempty"`
+	Log    []Line            `json:"log,omitempty"`
 }
 
 func (a *App) Call(method string, payload []byte) Reply {
@@ -35,7 +40,16 @@ func (a *App) Call(method string, payload []byte) Reply {
 	var err error
 	switch method {
 	case "load":
-		err = s.Load([]byte(req.Scene), req.Select)
+		mods, derr := playmods.DecodeTry(req.Code)
+		if err = derr; err == nil {
+			err = a.scripts.use(mods)
+		}
+		if err == nil {
+			err = playmods.MountTry(a.loader, req.Prefabs)
+		}
+		if err == nil {
+			err = s.Load([]byte(req.Scene), req.Select)
+		}
 	case "reset":
 		err = s.Reset()
 	case "text":
@@ -61,7 +75,16 @@ func (a *App) Call(method string, payload []byte) Reply {
 		return Reply{Error: err.Error()}
 	}
 	st := s.State()
-	return Reply{Text: string(s.Text()), State: &st}
+	return Reply{Text: string(s.Text()), Values: Values(s.Text()), State: &st}
+}
+
+// Values flattens a scene file into the field keys the docs scene tree uses.
+func Values(text []byte) map[string]string {
+	nodes, err := sceneio.Outline(text)
+	if err != nil {
+		return nil
+	}
+	return sceneio.OutlineValues(nodes)
 }
 
 func (a *App) Reply(method, payload string) string {

app/docsview/scripts.go

@@ -22,6 +22,15 @@ type scriptHost struct {
 	mods  []*bytecode.Module
 }
 
+// use makes mods the scripts of the next scene and publishes their types, so the scene keeps their fields.
+func (h *scriptHost) use(mods []*bytecode.Module) error {
+	if err := scriptruntime.Publish(h.types.Schema(), mods, h.reg.Surface()); err != nil {
+		return err
+	}
+	h.mods = mods
+	return nil
+}
+
 func (h *scriptHost) Errors() int {
 	return 0
 }

app/edit/edit.go

@@ -154,6 +154,9 @@ func Run(p *project.Project, cfg Config, mods ...sdk.Module) error {
 			panic(rec)
 		}
 	}()
+	if dir := os.Getenv(EnvShots); dir != "" {
+		return s.shots(dir)
+	}
 	if err := s.Run(); err != nil {
 		return err
 	}

app/edit/edit_test.go

@@ -116,12 +116,8 @@ func TestPlayLeavesEditSceneByteIdentical(t *testing.T) {
 		t.Fatal("Spin is not registered")
 	}
 	speed, _ := td.Field("speed")
-	add := &commands.AddComponent{
-		Node:   spinner,
-		Type:   td.ID,
-		Name:   td.FullName,
-		Values: []commands.FieldValue{{Field: speed.ID, Value: schema.Float32(3)}},
-	}
+	add := commands.NewMutation("Add "+td.FullName, commands.EnvFor(es),
+		commands.AddComp(es, spinner, td, []commands.FieldValue{{Field: speed.ID, Value: schema.Float32(3)}}))
 	if err := d.History.Exec(add); err != nil {
 		t.Fatal(err)
 	}

app/edit/onadd_test.go

@@ -42,7 +42,7 @@ func TestColliderFitsSprite(t *testing.T) {
 	}
 	for _, name := range []string{"Crate", "Bare"} {
 		id := es.ID(es.Find(es.Root(), name))
-		if err := d.History.Exec(&commands.AddComponent{Node: id, Type: td.ID, Name: td.FullName, OnAdd: ctx.OnAdd(td)}); err != nil {
+		if err := d.History.Exec(commands.NewMutation("Add "+td.FullName, commands.WithOnAdd(commands.EnvFor(es), ctx.OnAdd), commands.AddComp(es, id, td, nil))); err != nil {
 			t.Fatal(err)
 		}
 	}

app/edit/play_test.go

@@ -51,12 +51,8 @@ func openSpinner(t *testing.T) *spinFixture {
 	}
 	fd, _ := td.Field("speed")
 	f.typ, f.speed = td.ID, fd.ID
-	add := &commands.AddComponent{
-		Node:   f.spinner,
-		Type:   td.ID,
-		Name:   td.FullName,
-		Values: []commands.FieldValue{{Field: fd.ID, Value: schema.Float32(3)}},
-	}
+	add := commands.NewMutation("Add "+td.FullName, commands.EnvFor(es),
+		commands.AddComp(es, f.spinner, td, []commands.FieldValue{{Field: fd.ID, Value: schema.Float32(3)}}))
 	if err := d.History.Exec(add); err != nil {
 		t.Fatal(err)
 	}

app/export/web/index.html

@@ -21,6 +21,7 @@ canvas { display: block; width: 100%; height: 100%; outline: none; touch-action:
 #fullscreen { position: fixed; top: 10px; right: 10px; width: 36px; height: 36px; border: 0; border-radius: 6px; background: rgba(0, 0, 0, 0.45); color: #fff; font-size: 18px; cursor: pointer; opacity: 0.5; }
 #fullscreen:hover { opacity: 1; }
 </style>
+<link rel="preload" href="game.wasm?v={{.Build}}" as="fetch" type="application/wasm" crossorigin>
 </head>
 <body>
 <canvas id="game" data-aego tabindex="0" aria-label="{{.Title}}"></canvas>

app/playground/check_test.go

@@ -0,0 +1,31 @@
+package playground
+
+import (
+	"testing"
+
+	"aego/app/assembly/builtin"
+)
+
+func TestCheckSnippetsCompile(t *testing.T) {
+	p, err := NewWith(builtin.Default())
+	if err != nil {
+		t.Fatal(err)
+	}
+	n := 0
+	for _, e := range p.docs.All() {
+		for _, s := range e.Snippets {
+			if !s.Check || s.Lang != "aes" {
+				continue
+			}
+			n++
+			for _, d := range p.Compile(map[string]string{"main.aes": s.Code}) {
+				if d.Severity == "error" {
+					t.Errorf("%s (line %d of its page): %d:%d %s %s", e.ID, s.Line, d.Line, d.Col, d.Code, d.Message)
+				}
+			}
+		}
+	}
+	if n == 0 {
+		t.Fatal("no aes check blocks in the documentation")
+	}
+}

app/playground/diagnose.go

@@ -0,0 +1,65 @@
+package playground
+
+import (
+	"errors"
+	"fmt"
+	"strings"
+
+	"aego/script/diag"
+)
+
+const exampleFrames = 3
+
+// Reproduce runs the diagnostics example of code and returns what its broken version reports.
+func (p *Playground) Reproduce(code string) (Diagnostic, error) {
+	ex, ok := diag.Example(code)
+	if !ok {
+		return Diagnostic{}, errors.New("no example in script/diag/examples.go")
+	}
+	if ex.Why != "" {
+		return Diagnostic{}, nil
+	}
+	if ex.Bad == "" || ex.Good == "" {
+		return Diagnostic{}, errors.New("the example needs both a broken and a fixed version")
+	}
+	bad := reports(p.Run(ex.Sources(false), exampleFrames))
+	var found *Diagnostic
+	for i := range bad {
+		if bad[i].Code == code {
+			found = &bad[i]
+			break
+		}
+	}
+	if found == nil {
+		return Diagnostic{}, fmt.Errorf("the broken example does not report %s, it reports %s", code, list(bad))
+	}
+	var wrong []Diagnostic
+	for _, d := range reports(p.Run(ex.Sources(true), exampleFrames)) {
+		if d.Code == code || d.Severity == "error" {
+			wrong = append(wrong, d)
+		}
+	}
+	if len(wrong) > 0 {
+		return *found, fmt.Errorf("the fixed example still reports %s", list(wrong))
+	}
+	return *found, nil
+}
+
+func reports(res Result) []Diagnostic {
+	out := append([]Diagnostic(nil), res.Diagnostics...)
+	for _, f := range res.Faults {
+		out = append(out, Diagnostic{File: f.File, Line: f.Line, Code: f.Code, Severity: "error", Message: f.Message})
+	}
+	return out
+}
+
+func list(ds []Diagnostic) string {
+	if len(ds) == 0 {
+		return "nothing"
+	}
+	parts := make([]string, len(ds))
+	for i, d := range ds {
+		parts[i] = strings.TrimSpace(d.Code + " " + d.Message)
+	}
+	return strings.Join(parts, "; ")
+}

app/playground/diagnose_test.go

@@ -0,0 +1,27 @@
+package playground
+
+import (
+	"testing"
+
+	"aego/script/diag"
+)
+
+func TestDiagnosticExamples(t *testing.T) {
+	p := open(t)
+	var skipped []string
+	for _, code := range diag.Codes() {
+		d, err := p.Reproduce(code)
+		if err != nil {
+			t.Errorf("%s: %v", code, err)
+			continue
+		}
+		if d.Code == "" {
+			skipped = append(skipped, code)
+			continue
+		}
+		t.Logf("%s %s:%d:%d-%d:%d %s %s", code, d.File, d.Line, d.Col, d.EndLine, d.EndCol, d.Severity, d.Message)
+	}
+	if len(skipped) > 10 {
+		t.Errorf("%d codes are not reproducible: %v", len(skipped), skipped)
+	}
+}

app/playground/game.go

@@ -152,6 +152,7 @@ func newGame(cfg GameConfig, types *scene.Types, reg *bind.Registry, man *module
 		return nil, err
 	}
 	e.SetService(loader.ServiceID, g.loader)
+	playmods.UseMemorySaves(e)
 	e.SetService(renderhost.ServiceID, g.renderer)
 	e.SetView(frame.ServiceID, g.runner)
 	e.MainWorld().Recorder = recorder.New(recordDepth)

app/playground/play.go

@@ -1,10 +1,13 @@
 package playground
 
 import (
+	"errors"
+	"fmt"
 	"path"
 	"sort"
 	"strings"
 
+	playmods "aego/app/assembly/playground"
 	"aego/script/bytecode"
 	"aego/script/diag"
 )
@@ -110,13 +113,39 @@ func (p *Playground) LoseContext(lose bool) bool {
 	return p.game != nil && p.game.LoseContext(lose)
 }
 
-func (p *Playground) PlayScene(name string, src []byte) PlayResult {
+func (p *Playground) PlayScene(name string, src []byte, code string, prefabs map[string]string) PlayResult {
+	mods, err := playmods.DecodeTry(code)
+	if err != nil {
+		return PlayResult{Error: err.Error()}
+	}
 	g, err := p.host()
 	if err != nil {
 		return PlayResult{Error: err.Error()}
 	}
-	if err := g.Play(name, src, nil); err != nil {
+	if err := playmods.MountTry(g.loader, prefabs); err != nil {
+		return PlayResult{Error: err.Error()}
+	}
+	if err := g.Play(name, src, mods); err != nil {
 		return PlayResult{Error: err.Error()}
 	}
 	return PlayResult{Started: true}
 }
+
+// TryCode compiles the script of a try scene into the form DecodeTry reads.
+func (p *Playground) TryCode(script string) (string, error) {
+	placed, err := place(map[string]string{"main.aes": script})
+	if err != nil {
+		return "", err
+	}
+	p.ws.Sync(placed)
+	gen, ds := p.ws.Build()
+	if len(gen.Failed) > 0 || diag.HasErrors(ds) {
+		for _, d := range diagnostics(gen.Sources, ds) {
+			if d.Severity == "error" {
+				return "", fmt.Errorf("%s:%d:%d: %s", d.File, d.Line, d.Col, d.Message)
+			}
+		}
+		return "", errors.New("the script does not build")
+	}
+	return playmods.EncodeTry(ordered(gen.Modules)), nil
+}

app/playground/playground.go

@@ -101,9 +101,16 @@ type Playground struct {
 	proj     *exampleProject
 	gameCfg  GameConfig
 	game     *Game
+
+	simEngine *engine.Engine
 }
 
 func New() (*Playground, error) {
+	return NewWith(playmods.Catalog())
+}
+
+// NewWith builds a playground over another module catalog, for checks that need every module's types.
+func NewWith(cat assembly.Catalog) (*Playground, error) {
 	proj, err := loadProject()
 	if err != nil {
 		return nil, err
@@ -113,7 +120,7 @@ func New() (*Playground, error) {
 		return nil, err
 	}
 	reg := bind.New()
-	man, err := playmods.Catalog().Load(types, reg, assembly.Options{Seed: 1, Testing: true})
+	man, err := cat.Load(types, reg, assembly.Options{Seed: 1, Testing: true})
 	if err != nil {
 		return nil, err
 	}
@@ -205,6 +212,23 @@ func diagnostics(sm *source.Manager, ds []diag.Diagnostic) []Diagnostic {
 	return out
 }
 
+func blocked(failed map[string][]diag.Diagnostic) []Diagnostic {
+	pkgs := make([]string, 0, len(failed))
+	for pkg := range failed {
+		pkgs = append(pkgs, pkg)
+	}
+	sort.Strings(pkgs)
+	var out []Diagnostic
+	for _, pkg := range pkgs {
+		for _, d := range failed[pkg] {
+			if d.Code == diag.CompileBlocked {
+				out = append(out, Diagnostic{Code: d.Code, Message: d.Message, Severity: severity(d)})
+			}
+		}
+	}
+	return out
+}
+
 func failed(err error) []Diagnostic {
 	return []Diagnostic{{Severity: "error", Message: err.Error()}}
 }
@@ -263,6 +287,7 @@ func (p *Playground) Run(files map[string]string, frames int) Result {
 	gen, ds := p.ws.Build()
 	res := Result{Diagnostics: diagnostics(gen.Sources, ds)}
 	if len(gen.Failed) > 0 || diag.HasErrors(ds) {
+		res.Diagnostics = append(res.Diagnostics, blocked(gen.Failed)...)
 		return res
 	}
 	pkgs := make([]string, 0, len(gen.Modules))
@@ -295,16 +320,17 @@ func (p *Playground) Run(files map[string]string, frames int) Result {
 	}
 	w := engine.NewWorld("playground")
 	w.Input = &input.State{}
-	ctx := engine.Context{World: w, Dt: 1.0 / 60}
+	w.SetService(scene.ServiceID, s)
+	w.SetService(runtime.ServiceID, rt)
+	e, detach, err := p.attach(w, s, lg)
+	if err != nil {
+		res.Diagnostics = append(res.Diagnostics, failed(err)...)
+		return res
+	}
+	defer detach()
 	for i := 0; i < frames; i++ {
-		ctx.Frame++
-		frame = ctx.Frame
-		rt.RunDeferred()
-		rt.FixedUpdate(&ctx)
-		rt.Update(&ctx)
-		rt.Coroutines(&ctx)
-		s.Flush()
-		s.UpdateTransforms()
+		frame = uint64(i + 1)
+		e.TickWorld(w, engine.ScopePlay, 1.0/60)
 	}
 	res.Frames = frames
 	for _, f := range rt.Faults() {

app/playground/sandbox_test.go

@@ -75,12 +75,18 @@ func TestSandboxHeapLimit(t *testing.T) {
 	}
 }
 
-func TestSandboxHasNoSaves(t *testing.T) {
+// The sandbox has aego/save for the Persist demo; its saves stay in memory, never in the visitor's storage.
+func TestSandboxSavesStayInMemory(t *testing.T) {
 	p := newHeadless(t)
-	for _, d := range p.Compile(map[string]string{"main.aes": saveScript}) {
+	res := p.Run(map[string]string{"main.aes": saveScript}, 10)
+	for _, d := range res.Diagnostics {
 		if d.Severity == "error" {
-			return
+			t.Fatalf("aego/save does not compile in the sandbox: %s", d.Message)
+		}
+	}
+	for _, l := range res.Log {
+		if strings.Contains(l.Text, "saves are not available") {
+			t.Fatal("the sandbox has no save store")
 		}
 	}
-	t.Fatal("aego/save compiled in the sandbox")
 }

app/playground/sim.go

@@ -0,0 +1,43 @@
+package playground
+
+import (
+	"aego/core/log"
+	"aego/engine"
+	"aego/engine/module"
+	"aego/scene"
+	"aego/scene/frame"
+)
+
+// sim is a windowless engine that steps the module systems of a console run, so tweens, timers and physics work there as in Play.
+func (p *Playground) sim() (*engine.Engine, error) {
+	if p.simEngine != nil {
+		return p.simEngine, nil
+	}
+	b := engine.NewBuilder(engine.Config{Headless: true, HeadlessFrameTime: 1.0 / 60, Seed: 1, AppID: "aego-playground-console"}).WithLogger(log.Nop())
+	if err := frame.Register(b.Registry()); err != nil {
+		return nil, err
+	}
+	e, err := b.Use(p.man.Engine()).Build()
+	if err != nil {
+		return nil, err
+	}
+	if err := p.man.Init(&module.InitContext{Engine: e, Log: log.Nop(), Sections: p.sections}); err != nil {
+		e.Close()
+		return nil, err
+	}
+	p.simEngine = e
+	return e, nil
+}
+
+func (p *Playground) attach(w *engine.World, s *scene.Scene, lg *log.Logger) (*engine.Engine, func(), error) {
+	e, err := p.sim()
+	if err != nil {
+		return nil, nil, err
+	}
+	w.Time.Configure(e.TimeConfig())
+	detach, err := p.man.Attach(&module.AttachContext{World: w, Scene: s, Log: lg, Play: true})
+	if err != nil {
+		return nil, nil, err
+	}
+	return e, detach, nil
+}

app/run/agent.go

@@ -0,0 +1,65 @@
+package run
+
+import (
+	"bytes"
+	"encoding/hex"
+	"strconv"
+	"strings"
+
+	"aego/app/agent"
+	"aego/core/log"
+	"aego/core/rewind"
+	"aego/project"
+	"aego/sdk"
+)
+
+const maxRunLog = 200
+
+func AgentRunner(mods ...sdk.Module) agent.Runner {
+	return func(p *project.Project, r agent.RunRequest) (agent.RunReport, error) {
+		var buf bytes.Buffer
+		lg := log.New(log.NewTextSink(&buf))
+		lg.SetLevel(log.Warn)
+		frames, seed := r.Frames, r.Seed
+		if frames <= 0 {
+			frames = 120
+		}
+		if seed == 0 {
+			seed = 1
+		}
+		a, err := Open(p, Config{Headless: true, FrameTime: defaultDetStep, Seed: seed, ScenePath: r.Scene, Logger: lg, NoProfile: true}, mods...)
+		if err != nil {
+			return agent.RunReport{Log: logLines(buf.String())}, err
+		}
+		rep := agent.RunReport{}
+		driver := a.Driver()
+		for rep.Frames < frames {
+			if !a.Engine.Step(driver) {
+				rep.Error = "the game stopped at frame " + strconv.Itoa(rep.Frames+1)
+				if err := a.Engine.Err(); err != nil {
+					rep.Error += ": " + err.Error()
+				}
+				break
+			}
+			rep.Frames++
+		}
+		sum, _, _ := WorldHash(a.Engine.MainWorld(), rewind.NewHasher())
+		rep.Hash = hex.EncodeToString(sum[:])
+		a.Close()
+		rep.Log = logLines(buf.String())
+		return rep, nil
+	}
+}
+
+func logLines(s string) []string {
+	var out []string
+	for _, l := range strings.Split(strings.TrimSpace(s), "\n") {
+		if l = strings.TrimSpace(l); l != "" {
+			out = append(out, l)
+		}
+	}
+	if len(out) > maxRunLog {
+		out = append(out[:maxRunLog], "…")
+	}
+	return out
+}

app/run/determinism.go

@@ -78,7 +78,7 @@ func WorldHash(w *engine.World, h *rewind.Hasher) (sum [32]byte, covered, skippe
 }
 
 func determinismPass(p *project.Project, o DeterminismOptions, mods []sdk.Module) ([]checkpoint, []string, []string, error) {
-	a, err := Open(p, Config{Headless: true, FrameTime: o.FrameTime, Seed: o.Seed, ScenePath: o.ScenePath, Logger: log.Nop()}, mods...)
+	a, err := Open(p, Config{Headless: true, FrameTime: o.FrameTime, Seed: o.Seed, ScenePath: o.ScenePath, Logger: log.Nop(), NoProfile: true}, mods...)
 	if err != nil {
 		return nil, nil, nil, err
 	}

app/run/run.go

@@ -43,6 +43,7 @@ type Config struct {
 	Profile    string
 	Logger     *log.Logger
 	Seed       uint64
+	NoProfile  bool
 }
 
 type App struct {
@@ -138,6 +139,7 @@ func Open(p *project.Project, cfg Config, mods ...sdk.Module) (*App, error) {
 		Debug:              cfg.Debug,
 		FailOnScriptErrors: true,
 		Profile:            cfg.Profile,
+		NoProfile:          cfg.NoProfile,
 	}, sdk.AdaptAll(mods)...)
 	if err != nil {
 		return nil, err

app/run/tool.go

@@ -1,10 +1,13 @@
 package run
 
 import (
+	"aego/app/agent"
+	"aego/app/agent/mcp"
 	"bytes"
 	"flag"
 	"fmt"
 	"io"
+	"os"
 	"sort"
 	"strings"
 
@@ -39,6 +42,10 @@ func Tool(p *project.Project, args []string, stdout, stderr io.Writer, mods ...s
 		return toolTest(p, args[1:], stdout, stderr, mods)
 	case "docs":
 		return docstool.Tool(p, args[1:], stdout, stderr, sdk.AdaptAll(mods)...)
+	case "agent":
+		return agent.Main(p, args[1:], stdout, stderr, agent.Options{Mods: mods, Run: AgentRunner(mods...)})
+	case "mcp":
+		return mcp.Main(p, args[1:], os.Stdin, stdout, stderr, agent.Options{Mods: mods, Run: AgentRunner(mods...)})
 	}
 	fmt.Fprintf(stderr, "unknown tool %q\n", args[0])
 	return 2

cmd/aego-playground/web/index.html

@@ -4,6 +4,11 @@
 <meta charset="utf-8">
 <meta name="viewport" content="width=device-width, initial-scale=1">
 <title>Aego Playground</title>
+<meta name="description" content="Write Aego Script in the browser and run it: console examples and small scenes, with problems and output next to the code.">
+<meta property="og:type" content="website">
+<meta property="og:site_name" content="Aego">
+<meta property="og:title" content="Aego Playground">
+<meta property="og:description" content="Write Aego Script in the browser and run it: console examples and small scenes, with problems and output next to the code.">
 <link rel="icon" href="data:,">
 <link rel="stylesheet" href="play.css?v=dev">
 </head>