diff --git a/docs/architecture/repository-boundaries.md b/docs/architecture/repository-boundaries.md
index fda4a95..a8c459d 100644
--- a/docs/architecture/repository-boundaries.md
+++ b/docs/architecture/repository-boundaries.md
@@ -41,7 +41,7 @@ These rules map platform ownership to filesystem and package boundaries. The exe
   general "browser-safe shared packages are fine" relaxation: `api-client`, `auth-client`,
   `surface-sdk`, and `module-ui-host` remain rejected inside a module. Both approved packages are
   browser-safe by construction — `design-tokens` has no dependencies at all and `ui` depends only on
-  it — so a module UI file that imports them still cannot typecheck `process.env`, proven by a real
+  it and React — so a module UI file that imports them still cannot typecheck `process.env`, proven by a real
   compile under the exact browser project a module uses. Both are also pinned at the bottom of the
   presentation stack by `design-packages-depend-downward-only`: neither may reach an implementation
   layer, an API/auth client, or the backend contracts barrel, because a design package that could
@@ -134,6 +134,14 @@ These rules map platform ownership to filesystem and package boundaries. The exe
 - Workspace package consumers use declared `exports`, not private subpaths.
 - Every internal dependency uses a `workspace:` range and every imported workspace package is
   declared by the consumer.
+- Code a workspace package ships (its `src/` and `bin/`, excluding tests and declaration files)
+  declares every runtime import in `dependencies` or `optionalDependencies`. A peer declaration may
+  stay beside it, but never replaces it: a workspace package is linked into its consumers as a
+  directory, so its imports resolve from its own `node_modules`, where a consumer never satisfies a
+  peer, and a production install (`pnpm install --prod`, as the production image runs) omits
+  development dependencies. Type-only imports are exempt; a `.tsx`/`.jsx` file counts as importing
+  `react`, because the automatic JSX runtime imports `react/jsx-runtime` implicitly
+  (`runtime-imports-are-production-dependencies`).
 - Workspace aliases are forbidden because they obscure package ownership in the dependency graph.
 - Workspace package names are unique and shared packages declare a recognized architectural role.
 - Circular source and workspace-package dependencies are rejected.
diff --git a/packages/module-sdk/package.json b/packages/module-sdk/package.json
index 7f26ab0..aeab99c 100644
--- a/packages/module-sdk/package.json
+++ b/packages/module-sdk/package.json
@@ -19,12 +19,12 @@
     "typecheck": "tsc --noEmit --project tsconfig.json"
   },
   "dependencies": {
-    "@ekklesia/contracts": "workspace:*"
+    "@ekklesia/contracts": "workspace:*",
+    "drizzle-orm": "0.45.2"
   },
   "devDependencies": {
     "@biomejs/biome": "2.5.3",
     "@types/node": "24.13.3",
-    "drizzle-orm": "0.45.2",
     "typescript": "7.0.2",
     "vitest": "4.1.10"
   },
diff --git a/packages/ui/package.json b/packages/ui/package.json
index c4e0e07..81a392c 100644
--- a/packages/ui/package.json
+++ b/packages/ui/package.json
@@ -19,7 +19,8 @@
     "typecheck": "tsc --noEmit --project tsconfig.json && tsc --noEmit --project tsconfig.test.json"
   },
   "dependencies": {
-    "@ekklesia/design-tokens": "workspace:*"
+    "@ekklesia/design-tokens": "workspace:*",
+    "react": "19.2.8"
   },
   "peerDependencies": {
     "react": "19.2.8"
@@ -31,7 +32,6 @@
     "@types/react": "19.2.18",
     "@types/react-dom": "19.2.4",
     "happy-dom": "20.0.11",
-    "react": "19.2.8",
     "react-dom": "19.2.8",
     "typescript": "7.0.2",
     "vitest": "4.1.10"
diff --git a/packages/ui/tests/tokens.test.ts b/packages/ui/tests/tokens.test.ts
index e3462ef..e4aa63d 100644
--- a/packages/ui/tests/tokens.test.ts
+++ b/packages/ui/tests/tokens.test.ts
@@ -67,7 +67,11 @@ describe("the shared elements consume design tokens, never hardcoded theme value
       await readFile(path.join(packageDirectory, "package.json"), "utf8"),
     ) as { dependencies?: Record<string, string>; peerDependencies?: Record<string, string> };
 
-    expect(Object.keys(manifest.dependencies ?? {})).toEqual(["@ekklesia/design-tokens"]);
+    // React is both a production dependency and a peer: the peer states that the consumer's React
+    // must be the same one, and the production declaration is what makes the package's own imports
+    // resolve, since a consumer never satisfies a linked workspace package's peer
+    // (`runtime-imports-are-production-dependencies`).
+    expect(Object.keys(manifest.dependencies ?? {})).toEqual(["@ekklesia/design-tokens", "react"]);
     expect(Object.keys(manifest.peerDependencies ?? {})).toEqual(["react"]);
   });
 
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index 469eda1..ffd7375 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -201,6 +201,9 @@ importers:
       '@ekklesia/contracts':
         specifier: workspace:*
         version: link:../contracts
+      drizzle-orm:
+        specifier: 0.45.2
+        version: 0.45.2(@types/pg@8.20.0)(kysely@0.29.4)(pg@8.22.0)
     devDependencies:
       '@biomejs/biome':
         specifier: 2.5.3
@@ -208,9 +211,6 @@ importers:
       '@types/node':
         specifier: 24.13.3
         version: 24.13.3
-      drizzle-orm:
-        specifier: 0.45.2
-        version: 0.45.2(@types/pg@8.20.0)(kysely@0.29.4)(pg@8.22.0)
       typescript:
         specifier: 7.0.2
         version: 7.0.2
@@ -287,6 +287,9 @@ importers:
       '@ekklesia/design-tokens':
         specifier: workspace:*
         version: link:../design-tokens
+      react:
+        specifier: 19.2.8
+        version: 19.2.8
     devDependencies:
       '@biomejs/biome':
         specifier: 2.5.3
@@ -306,9 +309,6 @@ importers:
       happy-dom:
         specifier: 20.0.11
         version: 20.0.11
-      react:
-        specifier: 19.2.8
-        version: 19.2.8
       react-dom:
         specifier: 19.2.8
         version: 19.2.8(react@19.2.8)
diff --git a/scripts/check-boundaries.ts b/scripts/check-boundaries.ts
index be959e1..dd698b7 100644
--- a/scripts/check-boundaries.ts
+++ b/scripts/check-boundaries.ts
@@ -1,4 +1,5 @@
 import { readdir, readFile, stat } from "node:fs/promises";
+import { builtinModules } from "node:module";
 import path from "node:path";
 import { pathToFileURL } from "node:url";
 import { parse } from "yaml";
@@ -506,6 +507,82 @@ function collectImportSpecifiers(sourceText: string): string[] {
   return [...specifiers];
 }
 
+/**
+ * Whether a file is code a workspace package ships and executes: anything under its `src/` or
+ * `bin/`, except tests and declaration files. Build scripts, configuration files, and tests run with
+ * development dependencies installed, so they are outside this rule.
+ */
+function isRuntimeSourceFile(packageRelativePath: string): boolean {
+  const normalized = normalizePath(packageRelativePath);
+  if (!normalized.startsWith("src/") && !normalized.startsWith("bin/")) {
+    return false;
+  }
+  const segments = normalized.split("/");
+  if (segments.some((segment) => ["__tests__", "test", "tests"].includes(segment))) {
+    return false;
+  }
+  const fileName = segments.at(-1) ?? "";
+  return !/\.(?:test|spec)\.[cm]?[jt]sx?$/u.test(fileName) && !/\.d\.[cm]?ts$/u.test(fileName);
+}
+
+/** `import { type A, type B } from "x"` has no runtime binding: without `verbatimModuleSyntax`, the
+ * compiler erases it exactly like `import type`. A default or namespace binding, or any specifier
+ * without `type`, is a runtime import. */
+function importClauseIsTypeOnly(clause: string): boolean {
+  const trimmed = clause.trim();
+  if (!trimmed.startsWith("{") || !trimmed.endsWith("}")) {
+    return false;
+  }
+  const specifiers = trimmed
+    .slice(1, -1)
+    .split(",")
+    .map((specifier) => specifier.trim())
+    .filter((specifier) => specifier.length > 0);
+  return specifiers.length > 0 && specifiers.every((specifier) => /^type\s/u.test(specifier));
+}
+
+/**
+ * Bare specifiers a source file needs at run time: every static, side-effect, and dynamic import
+ * except type-only ones. A `.tsx`/`.jsx` file also needs `react`, because the platform compiles JSX
+ * with the automatic runtime (`"jsx": "react-jsx"`), which imports `react/jsx-runtime` without that
+ * import appearing in the source.
+ */
+function collectRuntimeImportSpecifiers(sourceText: string, extension: string): string[] {
+  const specifiers = new Set<string>();
+  const staticImport = /\b(?:import|export)\s+(type\s+)?([^;]*?)\bfrom\s*["']([^"'\n]+)["']/gu;
+  for (const match of sourceText.matchAll(staticImport)) {
+    const [, typeKeyword, clause = "", specifier] = match;
+    if (specifier && !typeKeyword && !importClauseIsTypeOnly(clause)) {
+      specifiers.add(specifier);
+    }
+  }
+  const sideEffectImport = /\bimport\s*["']([^"'\n]+)["']/gu;
+  const dynamicImport = /\b(?:import|require)\s*\(\s*["']([^"'\n]+)["']\s*\)/gu;
+  for (const pattern of [sideEffectImport, dynamicImport]) {
+    for (const match of sourceText.matchAll(pattern)) {
+      if (match[1]) {
+        specifiers.add(match[1]);
+      }
+    }
+  }
+  if (extension === ".tsx" || extension === ".jsx") {
+    specifiers.add("react/jsx-runtime");
+  }
+  return [...specifiers];
+}
+
+const NODE_BUILTIN_MODULES = new Set(builtinModules);
+
+function isBareSpecifier(specifier: string): boolean {
+  return !(
+    specifier.startsWith(".") ||
+    specifier.startsWith("/") ||
+    specifier.startsWith("#") ||
+    specifier.startsWith("node:") ||
+    /^[a-z][a-z0-9+.-]*:/u.test(specifier)
+  );
+}
+
 async function resolveSourceImport(
   fromFile: string,
   specifier: string,
@@ -906,6 +983,49 @@ export async function checkBoundaries(rootDirectory: string): Promise<BoundaryRe
     sourceGraph.set(relativeFile, new Set());
 
     const sourceText = await readFile(codeFile, "utf8");
+
+    // A workspace package is linked into its consumers as a directory, so Node resolves the
+    // package's own imports from the package's own `node_modules`. A peer dependency is never
+    // satisfied there by the consumer, and a production install (`pnpm install --prod`, as the
+    // production image runs) omits development dependencies. Code a package ships must therefore
+    // declare every runtime import as a production dependency. A peer declaration may stay beside it.
+    const runtimePackage = findContainingPackage(codeFile, packagesByDepth);
+    if (runtimePackage && isRuntimeSourceFile(path.relative(runtimePackage.directory, codeFile))) {
+      const reported = new Set<string>();
+      for (const specifier of collectRuntimeImportSpecifiers(
+        sourceText,
+        path.extname(codeFile).toLowerCase(),
+      )) {
+        if (!isBareSpecifier(specifier)) {
+          continue;
+        }
+        const dependencyName = packageNameFromSpecifier(specifier);
+        const manifest = runtimePackage.manifest;
+        if (
+          reported.has(dependencyName) ||
+          dependencyName === runtimePackage.name ||
+          NODE_BUILTIN_MODULES.has(dependencyName) ||
+          manifest.dependencies?.[dependencyName] !== undefined ||
+          manifest.optionalDependencies?.[dependencyName] !== undefined
+        ) {
+          continue;
+        }
+        reported.add(dependencyName);
+        const declaredAs =
+          manifest.peerDependencies?.[dependencyName] !== undefined
+            ? "only as a peer dependency"
+            : manifest.devDependencies?.[dependencyName] !== undefined
+              ? "only as a development dependency"
+              : "not at all";
+        violations.push({
+          from: relativeFile,
+          message: `${runtimePackage.name} imports ${dependencyName} at run time but declares it ${declaredAs}; a runtime import must be in dependencies.`,
+          rule: "runtime-imports-are-production-dependencies",
+          to: dependencyName,
+        });
+      }
+    }
+
     for (const specifier of collectImportSpecifiers(sourceText)) {
       const dependencyName = packageNameFromSpecifier(specifier);
       if (from.layer === "module" && isModuleUiPackage(dependencyName)) {
diff --git a/tests/boundaries.test.ts b/tests/boundaries.test.ts
index a762e94..60f6601 100644
--- a/tests/boundaries.test.ts
+++ b/tests/boundaries.test.ts
@@ -56,6 +56,10 @@ describe("repository dependency boundaries", () => {
     ["design-package-depends-upward", "design-packages-depend-downward-only"],
     ["cross-package-relative", "workspace-imports-use-public-exports"],
     ["cycle", "no-circular-source-dependencies"],
+    ["runtime-peer-only-dependency", "runtime-imports-are-production-dependencies"],
+    ["runtime-dev-only-dependency", "runtime-imports-are-production-dependencies"],
+    ["runtime-jsx-implies-react", "runtime-imports-are-production-dependencies"],
+    ["runtime-undeclared-dependency", "runtime-imports-are-production-dependencies"],
   ])("rejects %s", async (fixture, expectedRule) => {
     const result = await checkBoundaries(path.join(fixtures, fixture));
     expect(result.violations.map((violation) => violation.rule)).toContain(expectedRule);
@@ -106,6 +110,57 @@ describe("repository dependency boundaries", () => {
     expect(uiViolations.map((violation) => violation.message).join(" ")).not.toContain("compat");
   });
 
+  it("accepts runtime imports declared as production dependencies, and everything that is not shipped runtime code", async () => {
+    // Production and optional dependencies, a peer kept beside its production declaration, Node
+    // built-ins, the package's own exports, type-only imports of development dependencies, and
+    // tests or build scripts that run with development dependencies installed.
+    const result = await checkBoundaries(path.join(fixtures, "legal-runtime-dependencies"));
+
+    expect(result.violations).toEqual([]);
+  });
+
+  it.each([
+    [
+      "runtime-peer-only-dependency",
+      "packages/sdk/src/index.ts",
+      "drizzle-orm",
+      "only as a peer dependency",
+    ],
+    [
+      "runtime-dev-only-dependency",
+      "packages/sdk/src/index.ts",
+      "zod",
+      "only as a development dependency",
+    ],
+    // The automatic JSX runtime imports `react/jsx-runtime` without that import appearing in source.
+    [
+      "runtime-jsx-implies-react",
+      "packages/ui/src/index.tsx",
+      "react",
+      "only as a peer dependency",
+    ],
+    [
+      "runtime-undeclared-dependency",
+      "modules/calendar/src/server/index.ts",
+      "sharp",
+      "not at all",
+    ],
+  ])("reports %s once, naming the file, the package, and how it is declared", async (fixture, from, to, declaredAs) => {
+    // A workspace package's imports resolve from its own node_modules: a peer is never satisfied
+    // there by the consumer, and a production install omits development dependencies, so each of
+    // these imports fails at run time in the production image even though development works.
+    const result = await checkBoundaries(path.join(fixtures, fixture));
+
+    expect(result.violations).toEqual([
+      {
+        from,
+        message: expect.stringContaining(`declares it ${declaredAs}`),
+        rule: "runtime-imports-are-production-dependencies",
+        to,
+      },
+    ]);
+  });
+
   it("still rejects module UI source that reaches into Core internals", async () => {
     // Allowing `.tsx` inside a module changed which *formats* a module may contain. It did not
     // change which layers a module may import: module UI is subject to the identical layer rules
diff --git a/tests/fixtures/boundaries/legal-runtime-dependencies/packages/sdk/package.json b/tests/fixtures/boundaries/legal-runtime-dependencies/packages/sdk/package.json
new file mode 100644
index 0000000..431a815
--- /dev/null
+++ b/tests/fixtures/boundaries/legal-runtime-dependencies/packages/sdk/package.json
@@ -0,0 +1,29 @@
+{
+  "name": "@ekklesia/sdk",
+  "version": "0.0.0",
+  "type": "module",
+  "dependencies": {
+    "drizzle-orm": "0.45.2",
+    "react": "19.2.8",
+    "polyfill": "1.0.0"
+  },
+  "peerDependencies": {
+    "drizzle-orm": "0.45.2",
+    "react": "19.2.8"
+  },
+  "optionalDependencies": {
+    "fsevents": "2.3.3"
+  },
+  "devDependencies": {
+    "esbuild": "0.28.1",
+    "type-only": "1.0.0",
+    "vitest": "4.1.10"
+  },
+  "exports": {
+    ".": "./src/index.ts",
+    "./schema": "./src/index.ts"
+  },
+  "ekklesia": {
+    "layer": "module-sdk"
+  }
+}
diff --git a/tests/fixtures/boundaries/legal-runtime-dependencies/packages/sdk/scripts/build.mjs b/tests/fixtures/boundaries/legal-runtime-dependencies/packages/sdk/scripts/build.mjs
new file mode 100644
index 0000000..0099779
--- /dev/null
+++ b/tests/fixtures/boundaries/legal-runtime-dependencies/packages/sdk/scripts/build.mjs
@@ -0,0 +1,3 @@
+import { build } from "esbuild";
+
+await build({ entryPoints: ["src/index.ts"] });
diff --git a/tests/fixtures/boundaries/legal-runtime-dependencies/packages/sdk/src/index.test.ts b/tests/fixtures/boundaries/legal-runtime-dependencies/packages/sdk/src/index.test.ts
new file mode 100644
index 0000000..4564e86
--- /dev/null
+++ b/tests/fixtures/boundaries/legal-runtime-dependencies/packages/sdk/src/index.test.ts
@@ -0,0 +1,5 @@
+import { describe, it } from "vitest";
+
+describe("sdk", () => {
+  it("runs with development dependencies installed", () => undefined);
+});
diff --git a/tests/fixtures/boundaries/legal-runtime-dependencies/packages/sdk/src/index.ts b/tests/fixtures/boundaries/legal-runtime-dependencies/packages/sdk/src/index.ts
new file mode 100644
index 0000000..0f72329
--- /dev/null
+++ b/tests/fixtures/boundaries/legal-runtime-dependencies/packages/sdk/src/index.ts
@@ -0,0 +1,13 @@
+import { readFile } from "fs/promises";
+import path from "node:path";
+import "polyfill";
+import { pgTableCreator } from "drizzle-orm/pg-core";
+import type { Config } from "type-only";
+import { type Options, type Settings } from "type-only/settings";
+export type { Shape } from "type-only/shape";
+export { createSchema } from "@ekklesia/sdk/schema";
+
+export async function load(config: Config, options: Options, settings: Settings) {
+  const watcher = await import("fsevents");
+  return { config, options, path, readFile, settings, table: pgTableCreator, watcher };
+}
diff --git a/tests/fixtures/boundaries/legal-runtime-dependencies/packages/sdk/src/view.tsx b/tests/fixtures/boundaries/legal-runtime-dependencies/packages/sdk/src/view.tsx
new file mode 100644
index 0000000..2e16e72
--- /dev/null
+++ b/tests/fixtures/boundaries/legal-runtime-dependencies/packages/sdk/src/view.tsx
@@ -0,0 +1,3 @@
+export function View() {
+  return <div />;
+}
diff --git a/tests/fixtures/boundaries/legal-runtime-dependencies/packages/sdk/tests/fixture.ts b/tests/fixtures/boundaries/legal-runtime-dependencies/packages/sdk/tests/fixture.ts
new file mode 100644
index 0000000..4fd9cab
--- /dev/null
+++ b/tests/fixtures/boundaries/legal-runtime-dependencies/packages/sdk/tests/fixture.ts
@@ -0,0 +1,3 @@
+import { build } from "esbuild";
+
+export const builder = build;
diff --git a/tests/fixtures/boundaries/module-imports-ui-host/modules/calendar/package.json b/tests/fixtures/boundaries/module-imports-ui-host/modules/calendar/package.json
index cbfac02..7ed3057 100644
--- a/tests/fixtures/boundaries/module-imports-ui-host/modules/calendar/package.json
+++ b/tests/fixtures/boundaries/module-imports-ui-host/modules/calendar/package.json
@@ -3,7 +3,8 @@
   "version": "0.0.0",
   "type": "module",
   "dependencies": {
-    "@ekklesia/module-ui-host": "workspace:*"
+    "@ekklesia/module-ui-host": "workspace:*",
+    "react": "19.2.8"
   },
   "exports": {
     ".": "./src/index.ts"
diff --git a/tests/fixtures/boundaries/module-ui-imports-core/modules/announcements/package.json b/tests/fixtures/boundaries/module-ui-imports-core/modules/announcements/package.json
index dd9096a..e222e24 100644
--- a/tests/fixtures/boundaries/module-ui-imports-core/modules/announcements/package.json
+++ b/tests/fixtures/boundaries/module-ui-imports-core/modules/announcements/package.json
@@ -2,6 +2,9 @@
   "name": "@ekklesia/module-announcements",
   "version": "0.0.0",
   "type": "module",
+  "dependencies": {
+    "react": "19.2.8"
+  },
   "exports": {
     ".": "./src/index.ts"
   },
diff --git a/tests/fixtures/boundaries/runtime-dev-only-dependency/packages/sdk/package.json b/tests/fixtures/boundaries/runtime-dev-only-dependency/packages/sdk/package.json
new file mode 100644
index 0000000..97f2e88
--- /dev/null
+++ b/tests/fixtures/boundaries/runtime-dev-only-dependency/packages/sdk/package.json
@@ -0,0 +1,12 @@
+{
+  "name": "@ekklesia/sdk",
+  "version": "0.0.0",
+  "type": "module",
+  "devDependencies": { "zod": "4.0.0" },
+  "exports": {
+    ".": "./src/index.ts"
+  },
+  "ekklesia": {
+    "layer": "module-sdk"
+  }
+}
diff --git a/tests/fixtures/boundaries/runtime-dev-only-dependency/packages/sdk/src/index.ts b/tests/fixtures/boundaries/runtime-dev-only-dependency/packages/sdk/src/index.ts
new file mode 100644
index 0000000..69291ab
--- /dev/null
+++ b/tests/fixtures/boundaries/runtime-dev-only-dependency/packages/sdk/src/index.ts
@@ -0,0 +1,3 @@
+import { z } from "zod";
+
+export const identifier = z.string();
diff --git a/tests/fixtures/boundaries/runtime-jsx-implies-react/packages/ui/package.json b/tests/fixtures/boundaries/runtime-jsx-implies-react/packages/ui/package.json
new file mode 100644
index 0000000..54b9e7b
--- /dev/null
+++ b/tests/fixtures/boundaries/runtime-jsx-implies-react/packages/ui/package.json
@@ -0,0 +1,13 @@
+{
+  "name": "@ekklesia/ui",
+  "version": "0.0.0",
+  "type": "module",
+  "peerDependencies": { "react": "19.2.8" },
+  "devDependencies": { "react": "19.2.8" },
+  "exports": {
+    ".": "./src/index.ts"
+  },
+  "ekklesia": {
+    "layer": "ui"
+  }
+}
diff --git a/tests/fixtures/boundaries/runtime-jsx-implies-react/packages/ui/src/index.tsx b/tests/fixtures/boundaries/runtime-jsx-implies-react/packages/ui/src/index.tsx
new file mode 100644
index 0000000..1fea126
--- /dev/null
+++ b/tests/fixtures/boundaries/runtime-jsx-implies-react/packages/ui/src/index.tsx
@@ -0,0 +1,3 @@
+export function Badge(props: { readonly label: string }) {
+  return <span>{props.label}</span>;
+}
diff --git a/tests/fixtures/boundaries/runtime-peer-only-dependency/packages/sdk/package.json b/tests/fixtures/boundaries/runtime-peer-only-dependency/packages/sdk/package.json
new file mode 100644
index 0000000..9d64412
--- /dev/null
+++ b/tests/fixtures/boundaries/runtime-peer-only-dependency/packages/sdk/package.json
@@ -0,0 +1,13 @@
+{
+  "name": "@ekklesia/sdk",
+  "version": "0.0.0",
+  "type": "module",
+  "peerDependencies": { "drizzle-orm": "0.45.2" },
+  "devDependencies": { "drizzle-orm": "0.45.2" },
+  "exports": {
+    ".": "./src/index.ts"
+  },
+  "ekklesia": {
+    "layer": "module-sdk"
+  }
+}
diff --git a/tests/fixtures/boundaries/runtime-peer-only-dependency/packages/sdk/src/index.ts b/tests/fixtures/boundaries/runtime-peer-only-dependency/packages/sdk/src/index.ts
new file mode 100644
index 0000000..3e2e0f5
--- /dev/null
+++ b/tests/fixtures/boundaries/runtime-peer-only-dependency/packages/sdk/src/index.ts
@@ -0,0 +1,3 @@
+import { pgTableCreator } from "drizzle-orm/pg-core";
+
+export const createTable = pgTableCreator((name) => name);
diff --git a/tests/fixtures/boundaries/runtime-undeclared-dependency/modules/calendar/package.json b/tests/fixtures/boundaries/runtime-undeclared-dependency/modules/calendar/package.json
new file mode 100644
index 0000000..6e5e91d
--- /dev/null
+++ b/tests/fixtures/boundaries/runtime-undeclared-dependency/modules/calendar/package.json
@@ -0,0 +1,12 @@
+{
+  "name": "@ekklesia/module-calendar",
+  "version": "0.0.0",
+  "type": "module",
+
+  "exports": {
+    ".": "./src/index.ts"
+  },
+  "ekklesia": {
+    "layer": "module"
+  }
+}
diff --git a/tests/fixtures/boundaries/runtime-undeclared-dependency/modules/calendar/src/server/index.ts b/tests/fixtures/boundaries/runtime-undeclared-dependency/modules/calendar/src/server/index.ts
new file mode 100644
index 0000000..16d2dd5
--- /dev/null
+++ b/tests/fixtures/boundaries/runtime-undeclared-dependency/modules/calendar/src/server/index.ts
@@ -0,0 +1,3 @@
+export async function loadSharp() {
+  return await import("sharp");
+}