diff --git a/src/gptscript.ts b/src/gptscript.ts
index 283169e..f139d17 100644
--- a/src/gptscript.ts
+++ b/src/gptscript.ts
@@ -1238,6 +1238,7 @@ export type Credential = {
     ephemeral: boolean
     expiresAt?: Date | undefined
     refreshToken?: string | undefined
+    checkParam?: string | undefined
 }
 
 // Types for OpenAI API-compatible models
@@ -1277,6 +1278,7 @@ type cred = {
     ephemeral: boolean
     expiresAt: string | undefined
     refreshToken: string | undefined
+    checkParam: string | undefined
 }
 
 export function credentialToJSON(c: Credential): string {
@@ -1289,7 +1291,8 @@ export function credentialToJSON(c: Credential): string {
         env: c.env,
         ephemeral: c.ephemeral,
         expiresAt: expiresAt,
-        refreshToken: c.refreshToken
+        refreshToken: c.refreshToken,
+        checkParam: c.checkParam
     } as cred)
 }
 
@@ -1302,7 +1305,8 @@ function jsonToCredential(cred: string): Credential {
         env: c.env,
         ephemeral: c.ephemeral,
         expiresAt: c.expiresAt ? new Date(c.expiresAt) : undefined,
-        refreshToken: c.refreshToken
+        refreshToken: c.refreshToken,
+        checkParam: c.checkParam
     }
 }
 
diff --git a/tests/gptscript.test.ts b/tests/gptscript.test.ts
index 83789e4..ea2f153 100644
--- a/tests/gptscript.test.ts
+++ b/tests/gptscript.test.ts
@@ -843,6 +843,7 @@ describe("gptscript module", () => {
                 ephemeral: false,
                 expiresAt: new Date(Date.now() + 5000), // 5 seconds from now
                 type: CredentialType.Tool,
+                checkParam: "my-check-param",
             })
         } catch (e) {
             throw new Error("failed to create credential: " + e)
@@ -856,6 +857,8 @@ describe("gptscript module", () => {
             const result = await g.revealCredential(["default"], name)
             expect(result.env["TEST"]).toEqual(value)
             expect(result.expiresAt!.valueOf()).toBeLessThan(new Date().valueOf())
+            expect(result.type).toEqual(CredentialType.Tool)
+            expect(result.checkParam).toEqual("my-check-param")
         } catch (e) {
             throw new Error("failed to reveal credential: " + e)
         }