diff --git a/packages/prompts-core/src/loader.test.ts b/packages/prompts-core/src/loader.test.ts
index 2842ab640..12fb333fc 100644
--- a/packages/prompts-core/src/loader.test.ts
+++ b/packages/prompts-core/src/loader.test.ts
@@ -1,13 +1,19 @@
 import { describe, expect, test } from "bun:test"
 import { dirname, join } from "node:path"
 import { fileURLToPath } from "node:url"
-import { loadPrompt, PromptFileNotFoundError, PromptPathTraversalError } from "./loader"
-import type { PromptSource } from "./types"
+import { loadPrompt, loadPromptSync, PromptFileNotFoundError, PromptPathTraversalError } from "./loader"
+import type { BundledPromptSource, PromptSource } from "./types"
 
 const fixtureSource: PromptSource = {
   baseDir: join(dirname(fileURLToPath(import.meta.url)), "__test_fixtures__"),
 }
 
+const bundledSource: BundledPromptSource = {
+  kind: "bundled",
+  content: "Bundled prompt body with {A}, {B}, and {C}.\n",
+  filePath: "packages/prompts-core/prompts/test/default.md",
+}
+
 class ResolverFailureError extends Error {
   readonly name = "ResolverFailureError"
 }
@@ -92,6 +98,34 @@ describe("loadPrompt", () => {
     expect(prompt.body).toBe("GPT prompt body with Alpha and Beta.\n")
   })
 
+  test("#given bundled prompt source #then returns synchronously with multiple injections", () => {
+    const prompt = loadPrompt({
+      source: bundledSource,
+      name: "test-prompt",
+      variant: "default",
+      inject: [
+        { placeholder: "{A}", resolver: () => "Alpha" },
+        { placeholder: "{B}", resolver: () => "Beta" },
+        { placeholder: "{C}", resolver: () => "Gamma" },
+      ],
+    })
+
+    expect(prompt.body).toBe("Bundled prompt body with Alpha, Beta, and Gamma.\n")
+    expect(prompt.filePath).toBe("packages/prompts-core/prompts/test/default.md")
+  })
+
+  test("#given bundled prompt source #when using sync loader #then returns synchronously", () => {
+    const prompt = loadPromptSync({
+      source: bundledSource,
+      name: "test-prompt",
+      variant: "default",
+      inject: [{ placeholder: "{A}", resolver: () => "Alpha" }],
+    })
+
+    expect(prompt.body).toBe("Bundled prompt body with Alpha, {B}, and {C}.\n")
+    expect(prompt.filePath).toBe("packages/prompts-core/prompts/test/default.md")
+  })
+
   test("#given injection resolver throws #then propagates the error", async () => {
     const error = await captureError(() =>
       loadPrompt({
diff --git a/packages/prompts-core/src/loader.ts b/packages/prompts-core/src/loader.ts
index df01b4579..6f9e34e56 100644
--- a/packages/prompts-core/src/loader.ts
+++ b/packages/prompts-core/src/loader.ts
@@ -1,7 +1,14 @@
 import { parseFrontmatter } from "@oh-my-opencode/utils"
 import { readFile } from "node:fs/promises"
 import { isAbsolute, relative, resolve } from "node:path"
-import type { LoadedPrompt, LoadPromptInput, RuntimeInjection } from "./types"
+import type {
+  LoadedPrompt,
+  LoadBundledPromptInput,
+  LoadFilesystemPromptInput,
+  LoadPromptInput,
+  RuntimeInjection,
+  SyncRuntimeInjection,
+} from "./types"
 
 export class PromptFileNotFoundError extends Error {
   readonly name = "PromptFileNotFoundError"
@@ -27,8 +34,31 @@ export class PromptPathTraversalError extends Error {
   }
 }
 
-export async function loadPrompt<TFrontmatter = Record<string, unknown>>(
+export function loadPrompt<TFrontmatter = Record<string, unknown>>(
+  input: LoadBundledPromptInput
+): LoadedPrompt<TFrontmatter>
+export function loadPrompt<TFrontmatter = Record<string, unknown>>(
+  input: LoadFilesystemPromptInput
+): Promise<LoadedPrompt<TFrontmatter>>
+export function loadPrompt<TFrontmatter = Record<string, unknown>>(
   input: LoadPromptInput
+): LoadedPrompt<TFrontmatter> | Promise<LoadedPrompt<TFrontmatter>> {
+  if (isLoadBundledPromptInput(input)) return loadBundledPrompt(input)
+  return loadFilesystemPrompt(input)
+}
+
+export function loadPromptSync<TFrontmatter = Record<string, unknown>>(
+  input: LoadBundledPromptInput
+): LoadedPrompt<TFrontmatter> {
+  return loadBundledPrompt(input)
+}
+
+function isLoadBundledPromptInput(input: LoadPromptInput): input is LoadBundledPromptInput {
+  return input.source.kind === "bundled"
+}
+
+async function loadFilesystemPrompt<TFrontmatter = Record<string, unknown>>(
+  input: LoadFilesystemPromptInput
 ): Promise<LoadedPrompt<TFrontmatter>> {
   const filePath = resolvePromptFilePath(input.source.baseDir, input.name, input.variant)
   const content = await readPromptFile(input.name, input.variant, filePath)
@@ -44,6 +74,21 @@ export async function loadPrompt<TFrontmatter = Record<string, unknown>>(
   }
 }
 
+function loadBundledPrompt<TFrontmatter = Record<string, unknown>>(
+  input: LoadBundledPromptInput
+): LoadedPrompt<TFrontmatter> {
+  const parsed = parseFrontmatter<TFrontmatter>(input.source.content)
+  const body = applyRuntimeInjectionsSync(parsed.body, input.inject ?? [])
+
+  return {
+    frontmatter: parsed.data,
+    body,
+    hadFrontmatter: parsed.hadFrontmatter,
+    parseError: parsed.parseError,
+    filePath: input.source.filePath,
+  }
+}
+
 function resolvePromptFilePath(baseDir: string, promptName: string, variant: string): string {
   const resolvedBaseDir = resolve(baseDir)
   const filePath = resolve(resolvedBaseDir, promptName, `${variant}.md`)
@@ -76,6 +121,17 @@ async function applyRuntimeInjections(
   return renderedBody
 }
 
+function applyRuntimeInjectionsSync(
+  body: string,
+  injections: readonly SyncRuntimeInjection[]
+): string {
+  let renderedBody = body
+  for (const injection of injections) {
+    renderedBody = renderedBody.replaceAll(injection.placeholder, injection.resolver())
+  }
+  return renderedBody
+}
+
 function getErrorCode(error: Error): string | undefined {
   if (!("code" in error)) return undefined
   return typeof error.code === "string" ? error.code : undefined
diff --git a/packages/prompts-core/src/types.ts b/packages/prompts-core/src/types.ts
index c70351455..1fb30be23 100644
--- a/packages/prompts-core/src/types.ts
+++ b/packages/prompts-core/src/types.ts
@@ -8,22 +8,45 @@ export type ModelVariant =
   | "opus-4-7"
   | "minimax"
 
-export type PromptSource = {
+export type FilesystemPromptSource = {
+  readonly kind?: "filesystem"
   readonly baseDir: string
 }
 
+export type BundledPromptSource = {
+  readonly kind: "bundled"
+  readonly content: string
+  readonly filePath: string
+}
+
+export type PromptSource = FilesystemPromptSource | BundledPromptSource
+
 export type RuntimeInjection = {
   readonly placeholder: string
   readonly resolver: () => string | Promise<string>
 }
 
-export type LoadPromptInput = {
-  readonly source: PromptSource
+export type SyncRuntimeInjection = {
+  readonly placeholder: string
+  readonly resolver: () => string
+}
+
+export type LoadFilesystemPromptInput = {
+  readonly source: FilesystemPromptSource
   readonly name: string
   readonly variant: string
   readonly inject?: readonly RuntimeInjection[]
 }
 
+export type LoadBundledPromptInput = {
+  readonly source: BundledPromptSource
+  readonly name: string
+  readonly variant: string
+  readonly inject?: readonly SyncRuntimeInjection[]
+}
+
+export type LoadPromptInput = LoadFilesystemPromptInput | LoadBundledPromptInput
+
 export type LoadedPrompt<TFrontmatter = Record<string, unknown>> = {
   readonly frontmatter: TFrontmatter
   readonly body: string