diff --git a/bun.lockb b/bun.lockb
index 7f4b8658..291418d4 100755
Binary files a/bun.lockb and b/bun.lockb differ
diff --git a/packages/openauth/package.json b/packages/openauth/package.json
index a5e3276b..a2ac5351 100644
--- a/packages/openauth/package.json
+++ b/packages/openauth/package.json
@@ -1,6 +1,7 @@
 {
   "name": "@openauthjs/openauth",
   "version": "0.4.3",
+  "license": "MIT",
   "type": "module",
   "scripts": {
     "build": "bun run script/build.ts",
diff --git a/packages/openauth/src/issuer.ts b/packages/openauth/src/issuer.ts
index f4c1f277..931c7f2c 100644
--- a/packages/openauth/src/issuer.ts
+++ b/packages/openauth/src/issuer.ts
@@ -405,6 +405,38 @@ export interface IssuerInput<
     input: Result,
     req: Request,
   ): Promise<Response>
+  /**
+   * Optional callback that's called when a refresh token is used to get new access tokens.
+   *
+   * This allows you to update dynamic user attributes (permissions, roles, etc.) during
+   * token refresh without requiring the user to re-authenticate.
+   *
+   * If not provided, the original properties from the initial authentication will be reused.
+   *
+   * @example
+   * ```ts
+   * {
+   *   refresh: async (ctx, value) => {
+   *     // Fetch updated permissions from database
+   *     const permissions = await db.getPermissions(value.properties.userId)
+   *     return ctx.subject("user", {
+   *       ...value.properties,
+   *       permissions // Updated value
+   *     })
+   *   }
+   * }
+   * ```
+   */
+  refresh?(
+    response: OnSuccessResponder<SubjectPayload<Subjects>>,
+    input: {
+      type: string
+      properties: any
+      subject: string
+      clientID: string
+    },
+    req: Request,
+  ): Promise<Response>
   /**
    * @internal
    */
@@ -944,6 +976,44 @@ export function issuer<
             400,
           )
         }
+
+        // If refresh callback is provided, call it to allow updating properties
+        if (input.refresh) {
+          return input.refresh(
+            {
+              async subject(type, properties, opts) {
+                const tokens = await generateTokens(
+                  c,
+                  {
+                    type: type as string,
+                    subject: opts?.subject || payload.subject,
+                    properties,
+                    clientID: payload.clientID,
+                    ttl: {
+                      access: opts?.ttl?.access ?? ttlAccess,
+                      refresh: opts?.ttl?.refresh ?? ttlRefresh,
+                    },
+                  },
+                  { generateRefreshToken },
+                )
+                return c.json({
+                  access_token: tokens.access,
+                  refresh_token: tokens.refresh,
+                  expires_in: tokens.expiresIn,
+                })
+              },
+            },
+            {
+              type: payload.type,
+              properties: payload.properties,
+              subject: payload.subject,
+              clientID: payload.clientID,
+            },
+            c.req.raw,
+          )
+        }
+
+        // Fallback: use existing cached properties
         const tokens = await generateTokens(c, payload, {
           generateRefreshToken,
         })
diff --git a/packages/openauth/test/issuer.test.ts b/packages/openauth/test/issuer.test.ts
index be303d77..b3384d9f 100644
--- a/packages/openauth/test/issuer.test.ts
+++ b/packages/openauth/test/issuer.test.ts
@@ -6,7 +6,7 @@ import {
   beforeEach,
   afterEach,
 } from "bun:test"
-import { object, string } from "valibot"
+import { object, string, array, optional } from "valibot"
 import { issuer } from "../src/issuer.js"
 import { createClient } from "../src/client.js"
 import { createSubjects } from "../src/subject.js"
@@ -16,6 +16,7 @@ import { Provider } from "../src/provider/provider.js"
 const subjects = createSubjects({
   user: object({
     userID: string(),
+    permissions: optional(array(string()))
   }),
 })
 
@@ -339,6 +340,106 @@ describe("refresh token", () => {
     const reused = await response.json()
     expect(reused.error).toBe("invalid_request")
   })
+
+  test("refresh callback updates properties", async () => {
+    let refreshCallCount = 0
+    const refreshedSubjects = createSubjects({
+      user: object({
+        userID: string(),
+        permissions: optional(array(string())),
+      }),
+    })
+    const issuerWithRefresh = issuer({
+      ...issuerConfig,
+      subjects: refreshedSubjects,
+      refresh: async (ctx, value) => {
+        refreshCallCount++
+        expect(value.type).toBe("user")
+        expect(value.properties).toStrictEqual({ userID: "123" })
+        expect(value.subject).toMatch(/^user:[a-f0-9]+$/)
+        expect(value.clientID).toBe("123")
+
+        return ctx.subject("user", {
+          userID: "123",
+          permissions: ["read", "write"],
+        })
+      },
+    })
+
+    const client = createClient({
+      issuer: "https://auth.example.com",
+      clientID: "123",
+      fetch: (a, b) => Promise.resolve(issuerWithRefresh.request(a, b)),
+    })
+
+    // Generate initial tokens
+    const { challenge, url } = await client.authorize(
+      "https://client.example.com/callback",
+      "code",
+      { pkce: true },
+    )
+    let response = await issuerWithRefresh.request(url)
+    response = await issuerWithRefresh.request(response.headers.get("location")!, {
+      headers: {
+        cookie: response.headers.get("set-cookie")!,
+      },
+    })
+    const location = new URL(response.headers.get("location")!)
+    const code = location.searchParams.get("code")
+    const exchanged = await client.exchange(
+      code!,
+      "https://client.example.com/callback",
+      challenge.verifier,
+    )
+    if (exchanged.err) throw exchanged.err
+    const initialTokens = exchanged.tokens
+
+    // Verify initial token doesn't have permissions (just has userID)
+    const initialVerified = await client.verify(refreshedSubjects, initialTokens.access)
+    if (initialVerified.err) throw initialVerified.err
+    expect(initialVerified.subject.type).toBe("user")
+    expect(initialVerified.subject.properties.userID).toBe("123")
+    expect(initialVerified.subject.properties.permissions).toBeUndefined()
+    expect(refreshCallCount).toBe(0)
+
+    // Refresh the token
+    setSystemTime(Date.now() + 1000 * 60 + 1000)
+    response = await issuerWithRefresh.request("https://auth.example.com/token", {
+      method: "POST",
+      headers: {
+        "Content-Type": "application/x-www-form-urlencoded",
+      },
+      body: new URLSearchParams({
+        grant_type: "refresh_token",
+        refresh_token: initialTokens.refresh,
+      }).toString(),
+    })
+    expect(response.status).toBe(200)
+    const refreshed = await response.json()
+    expect(refreshCallCount).toBe(1)
+
+    // Verify refreshed token has updated properties including permissions
+    const refreshedVerified = await client.verify(
+      refreshedSubjects,
+      refreshed.access_token,
+    )
+    expect(refreshedVerified).toStrictEqual({
+      aud: "123",
+      subject: {
+        type: "user",
+        properties: {
+          userID: "123",
+          permissions: ["read", "write"],
+        },
+      },
+    })
+    if (refreshedVerified.err) throw refreshedVerified.err
+    // Explicitly verify permissions were added by the refresh callback
+    expect(refreshedVerified.subject.properties.permissions).toStrictEqual([
+      "read",
+      "write",
+    ])
+  })
 })
 
 describe("user info", () => {