diff --git a/build.zig.zon b/build.zig.zon
index 5132dc046..1c11debc0 100644
--- a/build.zig.zon
+++ b/build.zig.zon
@@ -27,6 +27,11 @@
         .fizzy_sdk = .{
             .path = "sdk/",
         },
+        // A plugin that imports `tape` and `replay`, linked into the test build as an app would.
+        .tape_fixture = .{
+            .path = "tests/fixtures/tape-plugin",
+            .lazy = true,
+        },
         // Fizzy's native backend (SDL3, its GPU renderer, the platform pieces), with SDL,
         // zig-objc and zigwin32 pinned there. App-only: plugins never link it.
         .fizzy_backend = .{
diff --git a/build/app.zig b/build/app.zig
index ad5f442ff..49e4e8e45 100644
--- a/build/app.zig
+++ b/build/app.zig
@@ -1513,6 +1513,39 @@ fn addTests(
         const fixture_test = b.addTest(.{ .name = "rehome-fixture", .root_module = module });
         test_step.dependOn(&b.addRunArtifact(fixture_test).step);
     }
+    // What a plugin does with `tape` and `replay` (`tests/fixtures/tape-plugin/play.zig`), through
+    // the path an application's plugin takes: its own `staticModule`, then `rehome` onto this
+    // executable's framework. The fixture's own build tests the same file as a dylib.
+    // Fizzy's own build only: the fixture is not in `.paths`, so an app fetching fizzy lacks it.
+    if (cfg.app_is_fizzy) if (b.lazyDependency("tape_fixture", .{})) |fixture_dep| {
+        const source = b.lazyImport(@This(), "tape_fixture").?.staticModule(fixture_dep.builder, .{
+            .target = target,
+            .optimize = optimize,
+            .dvui = dvui_testing_dep.module("dvui_testing"),
+            .core = core_module_test,
+            .sdk = sdk_module_test,
+            .icons = icons_test,
+        });
+        const consumer = b.createModule(.{ .target = target, .optimize = optimize, .link_libc = true });
+        const module = @import("plugins.zig").rehome(b, .{
+            .target = target,
+            .optimize = optimize,
+            .dvui = dvui_testing_dep.module("dvui_testing"),
+            .core = core_module_test,
+            .sdk = sdk_module_test,
+            .icons = icons_test,
+            .backend = null,
+            .workbench_opts = workbench_opts,
+            .consumer = consumer,
+        }, "tape_fixture", source);
+        const play_tests = b.addTest(.{
+            .name = "fizzy-tape-plugin-bundled-tests",
+            .root_module = module,
+            .filters = test_filters,
+        });
+        test_integration_step.dependOn(&b.addRunArtifact(play_tests).step);
+        check_integration_step.dependOn(&play_tests.step);
+    };
     const workbench_module_test = workbench_plugin.addStaticModule(b, target, optimize, .{
         .dvui = dvui_testing_dep.module("dvui_testing"),
         .core = core_module_test,
diff --git a/build/sdk.zig b/build/sdk.zig
index e40bdee49..ca4ce5d39 100644
--- a/build/sdk.zig
+++ b/build/sdk.zig
@@ -59,6 +59,9 @@ pub fn wireSdkModule(
     sdk_module.addImport("dvui", dvui_module);
     sdk_module.addImport("proxy_bridge", proxy_bridge_module);
     sdk_module.addImport("core", core_module);
+    // Their data types are on the plugin boundary (`sdk/src/dylib.zig`).
+    sdk_module.addImport("tape", core_module.import_table.get("tape").?);
+    sdk_module.addImport("replay", core_module.import_table.get("replay").?);
     // `sdk_version` as a *named* module rather than a relative `@import`: `sdk/sdk_version.zig`
     // is the single edit site for the triplet, but it sits outside this module's root
     // (`sdk/src/`), and Zig confines a module's relative imports to its own root — a named
diff --git a/scripts/check-examples.sh b/scripts/check-examples.sh
index f866248e8..1b580daba 100755
--- a/scripts/check-examples.sh
+++ b/scripts/check-examples.sh
@@ -127,6 +127,11 @@ if [[ -n $builds ]]; then
   printf '%s\n' $builds | xargs -P "${EXAMPLES_JOBS:-3}" -n 1 bash -c 'build_one "$1"' _
 fi
 
+# A plugin that imports `tape` and `replay` builds and plays a tape as a dylib too
+# (tests/fixtures/tape-plugin; the same file is tested linked into the app by `test-integration`).
+echo "== tape-plugin fixture, as a dylib"
+(cd "$root/tests/fixtures/tape-plugin" && zig build test --cache-dir "$work/tape-plugin-cache" --prefix "$work/tape-plugin-out")
+
 # An app's list is exact: one naming none of fizzy's, workbench included, fails while build.zig
 # configures, which compiles nothing. The build must fail and say which plugin is missing.
 echo "== app-only fixture, expected to fail naming fizzy.plugins.workbench"
diff --git a/sdk/AGENTS.md b/sdk/AGENTS.md
index e0ad42b7a..e0b41e0ee 100644
--- a/sdk/AGENTS.md
+++ b/sdk/AGENTS.md
@@ -9,6 +9,10 @@ file is the rules for changing it.
   `sdk_version.zig` outside a release PR (`CONTRIBUTING.md`, "Changing the SDK").
 - **A new boundary type goes in `sdk_boundary_types`** (`src/dylib.zig`), or the fingerprint never
   sees it change.
+- **`tape` and `replay` are boundary too.** `tape.binary.version` is folded into the shape
+  fingerprint and the tape data types are in `tape_boundary_types` (`src/dylib.zig`): bump the version or
+  change one, and the fingerprint moves. A store plugin imports both, as a bundled one does
+  (`plugin.create`; `tests/fixtures/tape-plugin`).
 - **This directory ships on its own** as `fizzy-sdk-v*.tar.gz` (`scripts/pack-sdk.sh`), holding
   only what `build.zig.zon`'s `.paths` lists. A new top-level file here goes in that list too;
   `scripts/check-examples.sh` builds the example plugin from the packed tarball and catches it.
diff --git a/sdk/plugin_sdk.zig b/sdk/plugin_sdk.zig
index 287cdc616..787a0f6d1 100644
--- a/sdk/plugin_sdk.zig
+++ b/sdk/plugin_sdk.zig
@@ -43,6 +43,9 @@ pub const Modules = struct {
     sdk: *std.Build.Module,
     dvui: *std.Build.Module,
     proxy_bridge: *std.Build.Module,
+    /// `core`'s own `tape` and `replay`, the instances a statically linked plugin imports.
+    tape: *std.Build.Module,
+    replay: *std.Build.Module,
 };
 
 pub const ModulesOptions = struct {
@@ -164,6 +167,8 @@ fn modulesFromDep(fizzy_dep: *std.Build.Dependency) Modules {
         .sdk = fizzy_dep.module("fizzy_sdk"),
         .dvui = fizzy_dep.module("dvui"),
         .proxy_bridge = fizzy_dep.module("proxy_bridge"),
+        .tape = fizzy_dep.module("tape"),
+        .replay = fizzy_dep.module("replay"),
     };
 }
 
@@ -176,6 +181,8 @@ pub fn addImports(mod: *std.Build.Module, plugin_modules: Modules) void {
     mod.addImport("fizzy_sdk", plugin_modules.sdk);
     mod.addImport("dvui", plugin_modules.dvui);
     mod.addImport("proxy_bridge", plugin_modules.proxy_bridge);
+    mod.addImport("tape", plugin_modules.tape);
+    mod.addImport("replay", plugin_modules.replay);
 }
 
 fn module(
@@ -662,6 +669,9 @@ pub fn exportModules(
     sdk_mod.addImport("dvui", dvui_proxy_mod);
     sdk_mod.addImport("proxy_bridge", proxy_bridge_mod);
     sdk_mod.addImport("core", core_mod);
+    // The fingerprint hashes `tape`'s and `replay`'s data types (`dylib.zig`).
+    sdk_mod.addImport("tape", core_mod.import_table.get("tape").?);
+    sdk_mod.addImport("replay", core_mod.import_table.get("replay").?);
     // See the matching comment in `build/sdk.zig`. `sdk_version.zig` needs no `repoPath` hop:
     // unlike `src/…`, it lives at this package's root in *both* layouts (in-repo `fizzy/sdk/`
     // and the release tarball, whose root is that same directory).
diff --git a/sdk/src/dylib.zig b/sdk/src/dylib.zig
index 2ac1adc19..216d5259d 100644
--- a/sdk/src/dylib.zig
+++ b/sdk/src/dylib.zig
@@ -13,6 +13,8 @@ const builtin = @import("builtin");
 const dvui = @import("dvui");
 const proxy_bridge = @import("proxy_bridge");
 const core = @import("core");
+const tape = @import("tape");
+const replay = @import("replay");
 const fingerprint = @import("fingerprint.zig");
 const dvui_context = @import("dvui_context.zig");
 const runtime = @import("runtime.zig");
@@ -189,6 +191,36 @@ const sdk_boundary_types = .{
     VersionTriplet,
 };
 
+/// A plugin's demo crosses the boundary as bytes (`Demo.tape`), so these are shared by what they
+/// spell, not by pointer: `tape.binary.version` is folded in `sdk_shape_fingerprint`, and the
+/// data types a tape is made of are hashed here. `Stage` is the seam a plugin's app fills in.
+const tape_boundary_types = .{
+    tape.Tape,
+    tape.Tape.Op,
+    tape.Tape.Action,
+    tape.Tape.Button,
+    tape.Tape.Command,
+    tape.Tape.Step,
+    tape.Tape.Scroll,
+    tape.Tape.Target,
+    tape.Tape.Wait,
+    tape.Tape.Skip,
+    tape.Tape.Until,
+    tape.Tape.Caption,
+    tape.Tape.Chapter,
+    tape.Tape.Keyframe,
+    tape.Tape.Setting,
+    tape.Tape.File,
+    tape.Tape.Check,
+    tape.Sequencer.Point,
+    tape.Sequencer.Failure,
+    tape.Sequencer.Sink,
+    tape.Sequencer.Sink.VTable,
+    replay.Player,
+    replay.Stage,
+    replay.Stage.VTable,
+};
+
 const entry_symbol_types = .{
     RegisterFn,
     SetGlobalsFn,
@@ -280,6 +312,8 @@ pub const sdk_shape_fingerprint: u64 = blk: {
     h = fingerprint.hashAllShape(h, sdk_boundary_types, 6);
     h = fingerprint.hashAllShape(h, entry_symbol_types, 3);
     h = fingerprint.hashAllShape(h, dvui_shared_state_types, 6);
+    h = fingerprint.hashAllShape(h, tape_boundary_types, 6);
+    h = fingerprint.foldString(h, std.mem.asBytes(&tape.binary.version));
     break :blk h;
 };
 
diff --git a/sdk/src/version.zig b/sdk/src/version.zig
index dd33bb112..565c00fc6 100644
--- a/sdk/src/version.zig
+++ b/sdk/src/version.zig
@@ -75,7 +75,7 @@ pub const sdk_version = @import("sdk_version").sdk_version;
 /// why it is a single target/mode-invariant literal rather than a per-target table. Update this
 /// value from the `@compileError` it triggers whenever it changes; leave `sdk_version` to the
 /// next SDK release.
-pub const recorded_sdk_shape_fingerprint: u64 = 0x68bbdb31985c4555;
+pub const recorded_sdk_shape_fingerprint: u64 = 0x9bf131098b2d283c;
 
 comptime {
     if (dylib.sdk_shape_fingerprint != recorded_sdk_shape_fingerprint) {
diff --git a/tests/fixtures/tape-plugin/build.zig b/tests/fixtures/tape-plugin/build.zig
new file mode 100644
index 000000000..67a6ed6e0
--- /dev/null
+++ b/tests/fixtures/tape-plugin/build.zig
@@ -0,0 +1,22 @@
+const std = @import("std");
+const fizzy = @import("fizzy");
+
+/// The plugin as an application links it (`build/app.zig` builds it this way and plays its tests).
+// anytype: the app's framework struct, whose type `fizzy.plugin.staticModule` owns.
+pub fn staticModule(b: *std.Build, framework: anytype) *std.Build.Module {
+    return fizzy.plugin.staticModule(b, framework, .{});
+}
+
+pub fn build(b: *std.Build) void {
+    const target = b.standardTargetOptions(.{});
+    const optimize = b.standardOptimizeOption(.{});
+
+    const plugin = fizzy.plugin.create(b, .{ .target = target, .optimize = optimize });
+
+    // The plugin's module as the dylib sees it, tested: `tape` and `replay` resolve in a store
+    // plugin as they do in a bundled one (`build/app.zig` tests `play.zig` the other way).
+    const tests = b.addTest(.{ .name = "tape-fixture-tests", .root_module = plugin.module });
+    const test_step = b.step("test", "Run the fixture's tests as a dylib plugin sees its imports");
+    test_step.dependOn(&b.addRunArtifact(tests).step);
+    test_step.dependOn(&plugin.lib.step);
+}
diff --git a/tests/fixtures/tape-plugin/build.zig.zon b/tests/fixtures/tape-plugin/build.zig.zon
new file mode 100644
index 000000000..759cf5868
--- /dev/null
+++ b/tests/fixtures/tape-plugin/build.zig.zon
@@ -0,0 +1,18 @@
+.{
+    .name = .tape_fixture,
+    .version = "0.1.0",
+    .minimum_zig_version = "0.17.0",
+    .paths = .{
+        "build.zig",
+        "build.zig.zon",
+        "plugin.zig",
+        "plugin.zig.zon",
+        "play.zig",
+    },
+    .fingerprint = 0x39f10a95729a0ebe,
+    .dependencies = .{
+        .fizzy = .{
+            .path = "../../../sdk",
+        },
+    },
+}
diff --git a/tests/fixtures/tape-plugin/play.zig b/tests/fixtures/tape-plugin/play.zig
new file mode 100644
index 000000000..ca6d89696
--- /dev/null
+++ b/tests/fixtures/tape-plugin/play.zig
@@ -0,0 +1,74 @@
+//! A plugin's use of `tape` and `replay`: write a demo with `Script`, ship it as bytes, load it and
+//! play it. The same file is tested twice: linked into an app (`build/app.zig`, the imports
+//! `plugins.staticModule` gives) and built as a plugin dylib (this directory's `build.zig`, the
+//! imports `plugin.create` gives), which is how a plugin's one source builds both ways.
+const std = @import("std");
+const tape = @import("tape");
+const replay = @import("replay");
+
+const Played = struct {
+    commands: usize = 0,
+
+    fn sink(self: *Played) tape.Sequencer.Sink {
+        return .{ .ctx = self, .vtable = &.{
+            .locate = locate,
+            .moveTo = moveTo,
+            .button = button,
+            .scroll = scroll,
+            .key = key,
+            .text = text,
+            .command = command,
+            .keyframe = keyframe,
+            .holds = holds,
+            .failed = failed,
+        } };
+    }
+    fn locate(_: *anyopaque, _: tape.Tape.Target) ?tape.Sequencer.Point {
+        return null;
+    }
+    fn moveTo(_: *anyopaque, _: tape.Sequencer.Point) void {}
+    fn button(_: *anyopaque, _: tape.Tape.Button, _: bool) void {}
+    fn scroll(_: *anyopaque, _: tape.Tape.Scroll) void {}
+    fn key(_: *anyopaque, _: []const u8) void {}
+    fn text(_: *anyopaque, _: []const u8) void {}
+    fn command(ctx: *anyopaque, cmd: tape.Tape.Command) void {
+        const self: *Played = @ptrCast(@alignCast(ctx));
+        if (std.mem.eql(u8, cmd.id, "fixture.hello")) self.commands += 1;
+    }
+    fn keyframe(_: *anyopaque, _: *const tape.Tape.Keyframe) void {}
+    fn holds(_: *anyopaque, _: tape.Tape.Until) bool {
+        return true;
+    }
+    fn failed(_: *anyopaque, _: tape.Sequencer.Failure) void {}
+};
+
+test "a plugin writes a demo, ships it as bytes, and plays it back" {
+    const gpa = std.testing.allocator;
+    var owned = owned: {
+        // `finish` hands the arena to `owned`, so `script` owns it only until then.
+        var script: tape.Script = .init(gpa, "fixture", "Fixture");
+        errdefer script.deinit();
+        try script.keyframe(.{ .root = "demo://fixture" });
+        try script.command("fixture.hello");
+        break :owned try script.finish();
+    };
+    defer owned.deinit();
+
+    const bytes = try tape.binary.encode(gpa, owned.tape, .{});
+    defer gpa.free(bytes);
+    var loaded = try tape.Tape.load(gpa, bytes, .{});
+    defer loaded.deinit();
+
+    var played: Played = .{};
+    var seq: tape.Sequencer = .init(&loaded.tape);
+    var frames: usize = 0;
+    while (!seq.done() and frames < 1_000) : (frames += 1) {
+        _ = seq.advance(seq.now + 16, 16, played.sink());
+    }
+    try std.testing.expectEqual(@as(usize, 1), played.commands);
+}
+
+test "replay is the module that drives a window with a tape" {
+    // The player takes the tape `tape` made: one `Tape` type on both sides of the import.
+    try std.testing.expect(@hasDecl(replay.Player, "play"));
+}
diff --git a/tests/fixtures/tape-plugin/plugin.zig b/tests/fixtures/tape-plugin/plugin.zig
new file mode 100644
index 000000000..4f3389782
--- /dev/null
+++ b/tests/fixtures/tape-plugin/plugin.zig
@@ -0,0 +1,22 @@
+//! Fixture: a plugin that imports `tape` and `replay`, built as a dylib to show a store plugin gets
+//! both (`play.zig` holds what it does with them). Registers nothing but itself.
+const sdk = @import("fizzy_sdk");
+
+pub const plugin_options = @import("fizzy_plugin_options");
+
+var plugin: sdk.Plugin = .{
+    .state = undefined,
+    .vtable = &vtable,
+    .id = plugin_options.id,
+    .display_name = plugin_options.name,
+};
+
+const vtable: sdk.Plugin.VTable = .{};
+
+pub fn register(host: *sdk.Host) !void {
+    try host.registerPlugin(&plugin);
+}
+
+test {
+    _ = @import("play.zig");
+}
diff --git a/tests/fixtures/tape-plugin/plugin.zig.zon b/tests/fixtures/tape-plugin/plugin.zig.zon
new file mode 100644
index 000000000..f0f6d5e85
--- /dev/null
+++ b/tests/fixtures/tape-plugin/plugin.zig.zon
@@ -0,0 +1,8 @@
+.{
+    .id = "tape_fixture",
+    .name = "Tape fixture",
+    .version = "0.1.0",
+    .min_sdk_version = "",
+    .description = "Imports tape and replay, as a dylib.",
+    .tags = .{"fixture"},
+}