diff --git a/bun.lock b/bun.lock
index 740abb79909b..4f64137224c5 100644
--- a/bun.lock
+++ b/bun.lock
@@ -351,6 +351,7 @@
         "mime-types": "3.0.2",
         "minimatch": "10.2.5",
         "npm-package-arg": "13.0.2",
+        "resolve.exports": "2.0.3",
         "semver": "^7.6.3",
         "turndown": "7.2.0",
         "venice-ai-sdk-provider": "2.1.1",
@@ -4957,6 +4958,8 @@
 
     "resolve-pkg-maps": ["resolve-pkg-maps@1.0.0", "", {}, "sha512-seS2Tj26TBVOC2NIc2rOe2y2ZO7efxITtLZcGSOnHHNOQ7CkiUBfw0Iw2ck6xkIhPwLhKNLS8BO+hEpngQlqzw=="],
 
+    "resolve.exports": ["resolve.exports@2.0.3", "", {}, "sha512-OcXjMsGdhL4XnbShKpAcSqPMzQoYkYyhbEaeSko47MjRP9NfEQMhZkXL1DoFlt9LWQn4YttrdnV6X2OiyzBi+A=="],
+
     "responselike": ["responselike@2.0.1", "", { "dependencies": { "lowercase-keys": "^2.0.0" } }, "sha512-4gl03wn3hj1HP3yzgdI7d3lCkF95F21Pz4BPGvKHinyQzALR5CapwC8yIi0Rh58DEMQ/SguC03wFj2k0M/mHhw=="],
 
     "restructure": ["restructure@3.0.2", "", {}, "sha512-gSfoiOEA0VPE6Tukkrr7I0RBdE0s7H1eFCDBk05l1KIQT1UIKNc5JZy6jdyW6eYH3aR3g5b3PuL77rq0hvwtAw=="],
diff --git a/packages/core/package.json b/packages/core/package.json
index ba3653df8ae1..d42d59b52805 100644
--- a/packages/core/package.json
+++ b/packages/core/package.json
@@ -9,7 +9,8 @@
     "db": "bun drizzle-kit",
     "migration": "bun run script/migration.ts",
     "fix-node-pty": "bun run script/fix-node-pty.ts",
-    "test": "bun test --only-failures",
+    "test": "bun test --only-failures && bun run test:node-npm",
+    "test:node-npm": "node --conditions=fixture-provider --test test/npm.node.ts",
     "typecheck": "tsgo --noEmit"
   },
   "bin": {
@@ -23,6 +24,11 @@
     "./*": "./src/*.ts"
   },
   "imports": {
+    "#npm-resolve": {
+      "bun": "./src/npm/resolve.bun.ts",
+      "node": "./src/npm/resolve.node.ts",
+      "default": "./src/npm/resolve.bun.ts"
+    },
     "#sqlite": {
       "bun": "./src/database/sqlite.bun.ts",
       "node": "./src/database/sqlite.node.ts",
@@ -119,6 +125,7 @@
     "mime-types": "3.0.2",
     "minimatch": "10.2.5",
     "npm-package-arg": "13.0.2",
+    "resolve.exports": "2.0.3",
     "semver": "^7.6.3",
     "turndown": "7.2.0",
     "venice-ai-sdk-provider": "2.1.1",
diff --git a/packages/core/src/npm.ts b/packages/core/src/npm.ts
index 30e12cff1206..20fa13bfd75a 100644
--- a/packages/core/src/npm.ts
+++ b/packages/core/src/npm.ts
@@ -12,6 +12,7 @@ import { filesystem } from "./effect/app-node-platform"
 import { LayerNode } from "./effect/layer-node"
 import { makeRuntime } from "./effect/runtime"
 import { NpmConfig } from "./npm-config"
+import { resolveModule } from "#npm-resolve"
 
 export class InstallFailedError extends Schema.TaggedErrorClass<InstallFailedError>()("NpmInstallFailedError", {
   add: Schema.Array(Schema.String).pipe(Schema.optional),
@@ -50,7 +51,7 @@ export function sanitize(pkg: string) {
 const resolveEntryPoint = (name: string, dir: string): EntryPoint => {
   let entrypoint: string | undefined
   try {
-    entrypoint = typeof Bun !== "undefined" ? import.meta.resolve(name, dir) : import.meta.resolve(dir)
+    entrypoint = resolveModule(name, dir)
   } catch {
     entrypoint = undefined
   }
diff --git a/packages/core/src/npm/resolve.bun.ts b/packages/core/src/npm/resolve.bun.ts
new file mode 100644
index 000000000000..db27b9528c74
--- /dev/null
+++ b/packages/core/src/npm/resolve.bun.ts
@@ -0,0 +1,3 @@
+export function resolveModule(name: string, directory: string) {
+  return import.meta.resolve(name, directory)
+}
diff --git a/packages/core/src/npm/resolve.node.ts b/packages/core/src/npm/resolve.node.ts
new file mode 100644
index 000000000000..aba58108f21e
--- /dev/null
+++ b/packages/core/src/npm/resolve.node.ts
@@ -0,0 +1,26 @@
+import { Script, constants } from "node:vm"
+import { createRequire, registerHooks } from "node:module"
+import path from "node:path"
+import { pathToFileURL } from "node:url"
+import { resolve, type Package } from "resolve.exports"
+
+// Capture import conditions from the runtime, including custom conditions and module-sync.
+let conditions: readonly string[] = []
+const hooks = registerHooks({
+  resolve(specifier, context, nextResolve) {
+    // Concurrent startup requires must not overwrite the import probe's conditions.
+    if (specifier === "node:module" && context.conditions.includes("import")) conditions = context.conditions
+    return nextResolve(specifier, context)
+  },
+})
+await new Script('import("node:module")', {
+  importModuleDynamically: constants.USE_MAIN_CONTEXT_DEFAULT_LOADER,
+}).runInThisContext()
+hooks.deregister()
+
+export function resolveModule(_name: string, directory: string) {
+  const pkg = createRequire(import.meta.url)(path.join(directory, "package.json")) as Package
+  const target = resolve(pkg, ".", { conditions, unsafe: true })?.[0]
+  if (target) return pathToFileURL(path.resolve(directory, target)).href
+  return pathToFileURL(createRequire(path.join(directory, "package.json")).resolve(directory)).href
+}
diff --git a/packages/core/test/fixture/npm-require.node.ts b/packages/core/test/fixture/npm-require.node.ts
new file mode 100644
index 000000000000..af064b2e2625
--- /dev/null
+++ b/packages/core/test/fixture/npm-require.node.ts
@@ -0,0 +1,4 @@
+import { createRequire } from "node:module"
+
+// Other modules can require dependencies while the resolver awaits its import probe.
+createRequire(import.meta.url)("node:path")
diff --git a/packages/core/test/npm.node.ts b/packages/core/test/npm.node.ts
new file mode 100644
index 000000000000..d7c0d81e8cfc
--- /dev/null
+++ b/packages/core/test/npm.node.ts
@@ -0,0 +1,77 @@
+import assert from "node:assert/strict"
+import { mkdtemp, mkdir, writeFile, rm } from "node:fs/promises"
+import { tmpdir } from "node:os"
+import path from "node:path"
+import { test } from "node:test"
+import { pathToFileURL } from "node:url"
+import { resolveModule } from "#npm-resolve"
+import "./fixture/npm-require.node.ts"
+
+const cases = [
+  { title: "string exports", manifest: { exports: "./entry.mjs" }, file: "entry.mjs" },
+  {
+    title: "npm alias with a different manifest name",
+    manifest: { name: "@fixture/original", exports: "./entry.mjs" },
+    file: "entry.mjs",
+  },
+  {
+    title: "nested import conditions",
+    manifest: { exports: { ".": { node: { import: "./entry.mjs", require: "./wrong.cjs" } } } },
+    file: "entry.mjs",
+  },
+  {
+    title: "export condition key order",
+    manifest: { exports: { ".": { default: "./entry.mjs", import: "./wrong.mjs" } } },
+    file: "entry.mjs",
+  },
+  {
+    title: "runtime module-sync condition",
+    manifest: { exports: { ".": { "module-sync": "./entry.mjs", import: "./wrong.mjs" } } },
+    file: "entry.mjs",
+  },
+  {
+    title: "custom runtime condition",
+    manifest: { exports: { ".": { "fixture-provider": "./entry.mjs", default: "./wrong.mjs" } } },
+    file: "entry.mjs",
+  },
+  { title: "legacy main", manifest: { main: "./entry.cjs" }, file: "entry.cjs" },
+  { title: "legacy index", manifest: {}, file: "index.js" },
+]
+
+for (const fixture of cases) {
+  test(fixture.title, async (t) => {
+    const root = await mkdtemp(path.join(tmpdir(), "opencode-npm-node-"))
+    t.after(() => rm(root, { recursive: true, force: true }))
+    const directory = path.join(root, "node_modules", "@fixture", "provider")
+    await mkdir(directory, { recursive: true })
+    await writeFile(
+      path.join(directory, "package.json"),
+      JSON.stringify({ name: "@fixture/provider", ...fixture.manifest }),
+    )
+    await writeFile(
+      path.join(directory, fixture.file),
+      fixture.file.endsWith(".mjs")
+        ? 'export const createFixture = () => "loaded"'
+        : 'exports.createFixture = () => "loaded"',
+    )
+
+    // The previous Node branch returned this directory URL instead of an entry file.
+    await assert.rejects(import(pathToFileURL(directory).href), { code: "ERR_UNSUPPORTED_DIR_IMPORT" })
+    const entrypoint = resolveModule("@fixture/provider", directory)
+    assert.equal(entrypoint, pathToFileURL(path.join(directory, fixture.file)).href)
+    assert.equal((await import(entrypoint)).createFixture(), "loaded")
+  })
+}
+
+for (const exports of [{ ".": { require: "./index.js" } }, { "./other": "./index.js" }, { ".": null }]) {
+  test(`does not bypass unavailable root exports: ${JSON.stringify(exports)}`, async (t) => {
+    const directory = await mkdtemp(path.join(tmpdir(), "opencode-npm-node-"))
+    t.after(() => rm(directory, { recursive: true, force: true }))
+    await writeFile(
+      path.join(directory, "package.json"),
+      JSON.stringify({ name: "fixture", exports, main: "index.js" }),
+    )
+    await writeFile(path.join(directory, "index.js"), "exports.fixture = true")
+    assert.throws(() => resolveModule("fixture", directory))
+  })
+}
diff --git a/packages/core/test/npm.test.ts b/packages/core/test/npm.test.ts
index 7e4a5763bf08..d808149c1dbf 100644
--- a/packages/core/test/npm.test.ts
+++ b/packages/core/test/npm.test.ts
@@ -54,6 +54,7 @@ describe("Npm.add", () => {
     }).pipe(Effect.scoped, Effect.provide(npmLayer(path.join(tmp.path, "cache"))), Effect.runPromise)
 
     expect(entry.entrypoint).toBeDefined()
+    expect((await import(entry.entrypoint!)).fixture).toBe(true)
   })
 })