diff --git a/CHANGELOG.md b/CHANGELOG.md
index e4caf037dd4..686803c49d4 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -32,7 +32,7 @@ Docs: https://docs.openclaw.ai
 - Telegram: when `channels.telegram.commands.native` is `false`, exclude plugin commands from `setMyCommands` menu registration while keeping plugin slash handlers callable. (#15132) Thanks @Glucksberg.
 - Security/Agents: scope CLI process cleanup to owned child PIDs to avoid killing unrelated processes on shared hosts. Thanks @aether-ai-agent.
 - Security/Agents (macOS): prevent shell injection when writing Claude CLI keychain credentials. (#15924) Thanks @aether-ai-agent.
-- Security: fix Chutes manual OAuth login state validation (thanks @aether-ai-agent). (#16058)
+- Security: fix Chutes manual OAuth login state validation by requiring the full redirect URL (reject code-only pastes) (thanks @aether-ai-agent).
 - Security/Tlon: harden Urbit URL fetching against SSRF by blocking private/internal hosts by default (opt-in: `channels.tlon.allowPrivateNetwork`). Thanks @p80n-sec.
 - Security/Voice Call (Telnyx): require webhook signature verification when receiving inbound events; configs without `telnyx.publicKey` are now rejected unless `skipSignatureVerification` is enabled. Thanks @p80n-sec.
 - Security/Discovery: stop treating Bonjour TXT records as authoritative routing (prefer resolved service endpoints) and prevent discovery from overriding stored TLS pins; autoconnect now requires a previously trusted gateway. Thanks @simecek.
diff --git a/src/agents/chutes-oauth.test.ts b/src/agents/chutes-oauth.test.ts
index 26e99539d41..a9bc417f721 100644
--- a/src/agents/chutes-oauth.test.ts
+++ b/src/agents/chutes-oauth.test.ts
@@ -2,53 +2,51 @@ import { describe, expect, it } from "vitest";
 import { generateChutesPkce, parseOAuthCallbackInput } from "./chutes-oauth.js";
 
 describe("parseOAuthCallbackInput", () => {
-  const EXPECTED_STATE = "abc123def456";
+  it("rejects code-only input (state required)", () => {
+    const parsed = parseOAuthCallbackInput("abc123", "expected-state");
+    expect(parsed).toEqual({
+      error: "Paste the full redirect URL (must include code + state).",
+    });
+  });
 
-  it("returns code and state for valid URL with matching state", () => {
-    const result = parseOAuthCallbackInput(
-      `http://localhost/cb?code=authcode_xyz&state=${EXPECTED_STATE}`,
-      EXPECTED_STATE,
+  it("accepts full redirect URL when state matches", () => {
+    const parsed = parseOAuthCallbackInput(
+      "http://127.0.0.1:1456/oauth-callback?code=abc123&state=expected-state",
+      "expected-state",
     );
-    expect(result).toEqual({ code: "authcode_xyz", state: EXPECTED_STATE });
+    expect(parsed).toEqual({ code: "abc123", state: "expected-state" });
   });
 
-  it("rejects URL with mismatched state (CSRF protection)", () => {
-    const result = parseOAuthCallbackInput(
-      "http://localhost/cb?code=authcode_xyz&state=attacker_state",
-      EXPECTED_STATE,
+  it("accepts querystring-only input when state matches", () => {
+    const parsed = parseOAuthCallbackInput("code=abc123&state=expected-state", "expected-state");
+    expect(parsed).toEqual({ code: "abc123", state: "expected-state" });
+  });
+
+  it("rejects missing state", () => {
+    const parsed = parseOAuthCallbackInput(
+      "http://127.0.0.1:1456/oauth-callback?code=abc123",
+      "expected-state",
     );
-    expect(result).toHaveProperty("error");
-    expect((result as { error: string }).error).toMatch(/state mismatch/i);
+    expect(parsed).toEqual({
+      error: "Missing 'state' parameter. Paste the full redirect URL.",
+    });
   });
 
-  it("accepts bare code input for manual flow", () => {
-    const result = parseOAuthCallbackInput("bare_auth_code", EXPECTED_STATE);
-    expect(result).toEqual({ code: "bare_auth_code", state: EXPECTED_STATE });
-  });
-
-  it("rejects empty input", () => {
-    const result = parseOAuthCallbackInput("", EXPECTED_STATE);
-    expect(result).toEqual({ error: "No input provided" });
-  });
-
-  it("rejects URL missing code parameter", () => {
-    const result = parseOAuthCallbackInput(
-      `http://localhost/cb?state=${EXPECTED_STATE}`,
-      EXPECTED_STATE,
+  it("rejects state mismatch", () => {
+    const parsed = parseOAuthCallbackInput(
+      "http://127.0.0.1:1456/oauth-callback?code=abc123&state=evil",
+      "expected-state",
     );
-    expect(result).toHaveProperty("error");
-  });
-
-  it("rejects URL missing state parameter", () => {
-    const result = parseOAuthCallbackInput("http://localhost/cb?code=authcode_xyz", EXPECTED_STATE);
-    expect(result).toHaveProperty("error");
+    expect(parsed).toEqual({
+      error: "OAuth state mismatch - possible CSRF attack. Please retry login.",
+    });
   });
 });
 
 describe("generateChutesPkce", () => {
-  it("returns verifier and challenge strings", () => {
+  it("returns verifier and challenge", () => {
     const pkce = generateChutesPkce();
     expect(pkce.verifier).toMatch(/^[0-9a-f]{64}$/);
-    expect(pkce.challenge).toBeTruthy();
+    expect(pkce.challenge).toMatch(/^[A-Za-z0-9_-]+$/);
   });
 });
diff --git a/src/agents/chutes-oauth.ts b/src/agents/chutes-oauth.ts
index da36f7506a0..1b730593d22 100644
--- a/src/agents/chutes-oauth.ts
+++ b/src/agents/chutes-oauth.ts
@@ -42,28 +42,42 @@ export function parseOAuthCallbackInput(
     return { error: "No input provided" };
   }
 
+  // Manual flow must validate CSRF state; require URL (or querystring) that includes `state`.
+  let url: URL;
   try {
-    const url = new URL(trimmed);
-    const code = url.searchParams.get("code");
-    const state = url.searchParams.get("state");
-    if (!code) {
-      return { error: "Missing 'code' parameter in URL" };
-    }
-    if (!state) {
-      return { error: "Missing 'state' parameter. Paste the full URL (or just the code)." };
-    }
-    if (state !== expectedState) {
-      return { error: "OAuth state mismatch - possible CSRF attack. Please retry login." };
-    }
-    return { code, state };
+    url = new URL(trimmed);
   } catch {
-    // Manual flow: users often paste only the authorization code.
-    // In that case we can't validate state, but the user is explicitly opting in by pasting it.
-    if (!/\s/.test(trimmed) && !trimmed.includes("://") && trimmed.length > 0) {
-      return { code: trimmed, state: expectedState };
+    // Code-only paste (common) is no longer accepted because it defeats state validation.
+    if (
+      !/\s/.test(trimmed) &&
+      !trimmed.includes("://") &&
+      !trimmed.includes("?") &&
+      !trimmed.includes("=")
+    ) {
+      return { error: "Paste the full redirect URL (must include code + state)." };
+    }
+
+    // Users sometimes paste only the query string: `?code=...&state=...` or `code=...&state=...`
+    const qs = trimmed.startsWith("?") ? trimmed : `?${trimmed}`;
+    try {
+      url = new URL(`http://localhost/${qs}`);
+    } catch {
+      return { error: "Paste the full redirect URL (must include code + state)." };
     }
-    return { error: "Paste the redirect URL (or authorization code)." };
   }
+
+  const code = url.searchParams.get("code")?.trim();
+  const state = url.searchParams.get("state")?.trim();
+  if (!code) {
+    return { error: "Missing 'code' parameter in URL" };
+  }
+  if (!state) {
+    return { error: "Missing 'state' parameter. Paste the full redirect URL." };
+  }
+  if (state !== expectedState) {
+    return { error: "OAuth state mismatch - possible CSRF attack. Please retry login." };
+  }
+  return { code, state };
 }
 
 function coerceExpiresAt(expiresInSeconds: number, now: number): number {
diff --git a/src/commands/auth-choice.e2e.test.ts b/src/commands/auth-choice.e2e.test.ts
index 9bdf233f526..ede6ce190dc 100644
--- a/src/commands/auth-choice.e2e.test.ts
+++ b/src/commands/auth-choice.e2e.test.ts
@@ -1127,7 +1127,7 @@ describe("applyAuthChoice", () => {
 
     expect(text).toHaveBeenCalledWith(
       expect.objectContaining({
-        message: "Paste the redirect URL (or authorization code)",
+        message: "Paste the redirect URL",
       }),
     );
     expect(result.config.auth?.profiles?.["chutes:remote-user"]).toMatchObject({
diff --git a/src/commands/chutes-oauth.ts b/src/commands/chutes-oauth.ts
index 1925649bb4a..161ae621db0 100644
--- a/src/commands/chutes-oauth.ts
+++ b/src/commands/chutes-oauth.ts
@@ -156,7 +156,7 @@ export async function loginChutes(params: {
     await params.onAuth({ url });
     params.onProgress?.("Waiting for redirect URL…");
     const input = await params.onPrompt({
-      message: "Paste the redirect URL (or authorization code)",
+      message: "Paste the redirect URL",
       placeholder: `${params.app.redirectUri}?code=...&state=...`,
     });
     const parsed = parseOAuthCallbackInput(String(input), state);
@@ -176,7 +176,7 @@ export async function loginChutes(params: {
     }).catch(async () => {
       params.onProgress?.("OAuth callback not detected; paste redirect URL…");
       const input = await params.onPrompt({
-        message: "Paste the redirect URL (or authorization code)",
+        message: "Paste the redirect URL",
         placeholder: `${params.app.redirectUri}?code=...&state=...`,
       });
       const parsed = parseOAuthCallbackInput(String(input), state);
diff --git a/src/commands/oauth-flow.ts b/src/commands/oauth-flow.ts
index 77ea367c9ab..1b0eba3b4f8 100644
--- a/src/commands/oauth-flow.ts
+++ b/src/commands/oauth-flow.ts
@@ -17,8 +17,7 @@ export function createVpsAwareOAuthHandlers(params: {
   onAuth: (event: { url: string }) => Promise<void>;
   onPrompt: (prompt: OAuthPrompt) => Promise<string>;
 } {
-  const manualPromptMessage =
-    params.manualPromptMessage ?? "Paste the redirect URL (or authorization code)";
+  const manualPromptMessage = params.manualPromptMessage ?? "Paste the redirect URL";
   let manualCodePromise: Promise<string> | undefined;
 
   return {