diff --git a/lib/auth/__tests__/getApiKeyAccountId.test.ts b/lib/auth/__tests__/getApiKeyAccountId.test.ts
new file mode 100644
index 000000000..e2a9aa7cc
--- /dev/null
+++ b/lib/auth/__tests__/getApiKeyAccountId.test.ts
@@ -0,0 +1,54 @@
+import { describe, it, expect, vi, beforeEach } from "vitest";
+import { NextRequest } from "next/server";
+import { getApiKeyAccountId } from "@/lib/auth/getApiKeyAccountId";
+import { selectAccountApiKeys } from "@/lib/supabase/account_api_keys/selectAccountApiKeys";
+
+vi.mock("@/lib/networking/getCorsHeaders", () => ({ getCorsHeaders: () => ({}) }));
+vi.mock("@/lib/keys/hashApiKey", () => ({ hashApiKey: (k: string) => `hashed_${k}` }));
+vi.mock("@/lib/const", () => ({ PRIVY_PROJECT_SECRET: "test_secret" }));
+vi.mock("@/lib/supabase/account_api_keys/selectAccountApiKeys", () => ({
+  selectAccountApiKeys: vi.fn(),
+}));
+
+function req(apiKey?: string) {
+  const headers = new Headers();
+  if (apiKey) headers.set("x-api-key", apiKey);
+  return new NextRequest("https://x.test/api", { headers });
+}
+
+const baseRow = {
+  id: "k",
+  account: "acc-1",
+  key_hash: "hashed_recoup_sk_x",
+  name: "n",
+  last_used: null,
+  created_at: "2026-01-01T00:00:00Z",
+};
+
+describe("getApiKeyAccountId", () => {
+  beforeEach(() => vi.clearAllMocks());
+
+  it("returns accountId for a non-expiring key (expires_at null)", async () => {
+    vi.mocked(selectAccountApiKeys).mockResolvedValue([{ ...baseRow, expires_at: null }]);
+    expect(await getApiKeyAccountId(req("recoup_sk_x"))).toBe("acc-1");
+  });
+
+  it("returns accountId for a future expiry", async () => {
+    const future = new Date(Date.now() + 60_000).toISOString();
+    vi.mocked(selectAccountApiKeys).mockResolvedValue([{ ...baseRow, expires_at: future }]);
+    expect(await getApiKeyAccountId(req("recoup_sk_x"))).toBe("acc-1");
+  });
+
+  it("rejects an expired key with 401", async () => {
+    const past = new Date(Date.now() - 60_000).toISOString();
+    vi.mocked(selectAccountApiKeys).mockResolvedValue([{ ...baseRow, expires_at: past }]);
+    const res = await getApiKeyAccountId(req("recoup_sk_x"));
+    expect(res).toBeInstanceOf(Response);
+    expect((res as Response).status).toBe(401);
+  });
+
+  it("401 when no x-api-key header", async () => {
+    const res = await getApiKeyAccountId(req());
+    expect((res as Response).status).toBe(401);
+  });
+});
diff --git a/lib/auth/getApiKeyAccountId.ts b/lib/auth/getApiKeyAccountId.ts
index 49af4106a..a5dce9ed6 100644
--- a/lib/auth/getApiKeyAccountId.ts
+++ b/lib/auth/getApiKeyAccountId.ts
@@ -1,6 +1,7 @@
 import { NextRequest, NextResponse } from "next/server";
 import { getCorsHeaders } from "@/lib/networking/getCorsHeaders";
 import { hashApiKey } from "@/lib/keys/hashApiKey";
+import { isApiKeyExpired } from "@/lib/keys/isApiKeyExpired";
 import { PRIVY_PROJECT_SECRET } from "@/lib/const";
 import { selectAccountApiKeys } from "@/lib/supabase/account_api_keys/selectAccountApiKeys";
 
@@ -45,9 +46,11 @@ export async function getApiKeyAccountId(request: NextRequest): Promise<string |
       );
     }
 
-    const accountId = apiKeys[0]?.account ?? null;
+    const matched = apiKeys[0];
+    const accountId = matched?.account ?? null;
 
-    if (!accountId) {
+    // Reject an unknown key, or an ephemeral key past its TTL (chat#1813).
+    if (!accountId || isApiKeyExpired(matched?.expires_at)) {
       return NextResponse.json(
         {
           status: "error",
diff --git a/lib/chat/__tests__/buildRunAgentInput.test.ts b/lib/chat/__tests__/buildRunAgentInput.test.ts
new file mode 100644
index 000000000..45af4f7cc
--- /dev/null
+++ b/lib/chat/__tests__/buildRunAgentInput.test.ts
@@ -0,0 +1,61 @@
+import { describe, it, expect, vi, beforeEach } from "vitest";
+import { buildRunAgentInput } from "@/lib/chat/buildRunAgentInput";
+import { parseGitHubRepoIdentifiers } from "@/lib/github/parseGitHubRepoIdentifiers";
+import { extractOrgId } from "@/lib/recoupable/extractOrgId";
+
+vi.mock("@/lib/github/parseGitHubRepoIdentifiers", () => ({
+  parseGitHubRepoIdentifiers: vi.fn(() => ({ owner: "o", repo: "r" })),
+}));
+vi.mock("@/lib/recoupable/extractOrgId", () => ({
+  extractOrgId: vi.fn(() => "org-1"),
+}));
+
+const base = {
+  messages: [{ id: "m1", role: "user", parts: [] }] as never,
+  chatId: "chat-1",
+  sessionId: "sess-1",
+  accountId: "acc-1",
+  modelId: "anthropic/claude-haiku-4.5",
+  sessionTitle: "Weekly report",
+  cloneUrl: "https://github.com/o/r.git",
+  sandboxState: { type: "vercel", sandboxName: "sb-1" } as never,
+  workingDirectory: "/work",
+  skills: [] as never,
+};
+
+describe("buildRunAgentInput", () => {
+  beforeEach(() => vi.clearAllMocks());
+
+  it("assembles the workflow input, deriving repo ids + org id from cloneUrl", () => {
+    const input = buildRunAgentInput(base);
+    expect(input.chatId).toBe("chat-1");
+    expect(input.sessionId).toBe("sess-1");
+    expect(input.accountId).toBe("acc-1");
+    expect(input.modelId).toBe("anthropic/claude-haiku-4.5");
+    expect(input.sessionTitle).toBe("Weekly report");
+    expect(input.repoOwner).toBe("o");
+    expect(input.repoName).toBe("r");
+    expect(input.agentContext.recoupOrgId).toBe("org-1");
+    expect(input.agentContext.sandbox).toEqual({
+      state: { type: "vercel", sandboxName: "sb-1" },
+      workingDirectory: "/work",
+    });
+  });
+
+  it("includes recoupAccessToken when provided", () => {
+    const input = buildRunAgentInput({ ...base, recoupAccessToken: "tok-123" });
+    expect(input.agentContext.recoupAccessToken).toBe("tok-123");
+  });
+
+  it("omits recoupAccessToken entirely when absent", () => {
+    const input = buildRunAgentInput(base);
+    expect("recoupAccessToken" in input.agentContext).toBe(false);
+  });
+
+  it("leaves recoupOrgId undefined when cloneUrl is null (no org derivation)", () => {
+    const input = buildRunAgentInput({ ...base, cloneUrl: null });
+    expect(input.agentContext.recoupOrgId).toBeUndefined();
+    expect(extractOrgId).not.toHaveBeenCalled();
+    expect(parseGitHubRepoIdentifiers).toHaveBeenCalledWith(null);
+  });
+});
diff --git a/lib/chat/buildRunAgentInput.ts b/lib/chat/buildRunAgentInput.ts
new file mode 100644
index 000000000..95b0df423
--- /dev/null
+++ b/lib/chat/buildRunAgentInput.ts
@@ -0,0 +1,66 @@
+import type { UIMessage } from "ai";
+import type { RunAgentWorkflowInput } from "@/app/lib/workflows/runAgentWorkflow";
+import type { DurableAgentContext } from "@/lib/agent/tools/AgentContext";
+import type { VercelState } from "@/lib/sandbox/vercel/state";
+import { parseGitHubRepoIdentifiers } from "@/lib/github/parseGitHubRepoIdentifiers";
+import { extractOrgId } from "@/lib/recoupable/extractOrgId";
+
+export type BuildRunAgentInputParams = {
+  messages: UIMessage[];
+  chatId: string;
+  sessionId: string;
+  accountId: string;
+  modelId: string;
+  sessionTitle?: string;
+  /** `session.clone_url` — the single source for repo ids + recoup org id. */
+  cloneUrl: string | null;
+  sandboxState: VercelState;
+  workingDirectory: string;
+  skills: DurableAgentContext["skills"];
+  /**
+   * Short-lived bearer for in-sandbox recoup-api calls: the user's Privy JWT
+   * (interactive `/api/chat/workflow`) or an ephemeral account key (headless
+   * `/api/chat/generate`). Omitted when absent so the service key never leaks.
+   */
+  recoupAccessToken?: string;
+};
+
+/**
+ * Build the durable `RunAgentWorkflowInput` shared by the interactive and
+ * headless callers, so both construct workflow input identically
+ * (recoupable/chat#1813). Repo identifiers and the recoup org id are both
+ * derived from `cloneUrl` here — one source of truth, no caller duplication.
+ */
+export function buildRunAgentInput({
+  messages,
+  chatId,
+  sessionId,
+  accountId,
+  modelId,
+  sessionTitle,
+  cloneUrl,
+  sandboxState,
+  workingDirectory,
+  skills,
+  recoupAccessToken,
+}: BuildRunAgentInputParams): RunAgentWorkflowInput {
+  const repoIds = parseGitHubRepoIdentifiers(cloneUrl);
+  const recoupOrgId = cloneUrl ? (extractOrgId(cloneUrl) ?? undefined) : undefined;
+
+  return {
+    messages,
+    chatId,
+    sessionId,
+    accountId,
+    modelId,
+    sessionTitle,
+    repoOwner: repoIds?.owner,
+    repoName: repoIds?.repo,
+    agentContext: {
+      sandbox: { state: sandboxState, workingDirectory },
+      recoupOrgId,
+      skills,
+      ...(recoupAccessToken ? { recoupAccessToken } : {}),
+    },
+  };
+}
diff --git a/lib/chat/handleChatWorkflowStream.ts b/lib/chat/handleChatWorkflowStream.ts
index 8d61ce96e..fab562e1c 100644
--- a/lib/chat/handleChatWorkflowStream.ts
+++ b/lib/chat/handleChatWorkflowStream.ts
@@ -14,8 +14,7 @@ import { persistLatestUserMessage } from "@/lib/chat/persistLatestUserMessage";
 import { errorResponse } from "@/lib/networking/errorResponse";
 import { getCorsHeaders } from "@/lib/networking/getCorsHeaders";
 import { runAgentWorkflow } from "@/app/lib/workflows/runAgentWorkflow";
-import { extractOrgId } from "@/lib/recoupable/extractOrgId";
-import { parseGitHubRepoIdentifiers } from "@/lib/github/parseGitHubRepoIdentifiers";
+import { buildRunAgentInput } from "@/lib/chat/buildRunAgentInput";
 import { DEFAULT_WORKING_DIRECTORY } from "@/lib/sandbox/vercel/sandbox/constants";
 import { connectVercel } from "@/lib/sandbox/vercel/connect/connectVercel";
 import type { VercelState } from "@/lib/sandbox/vercel/state";
@@ -92,9 +91,6 @@ export async function handleChatWorkflowStream(request: NextRequest): Promise<Re
   void persistLatestUserMessage(validated.chatId, validated.messages as never);
 
   const modelId = chat.model_id ?? DEFAULT_MODEL_ID;
-  const recoupOrgId = session.clone_url
-    ? (extractOrgId(session.clone_url) ?? undefined)
-    : undefined;
 
   // Connect the sandbox up-front so we can (a) read the real working
   // directory and (b) discover project-level skills. The connected
@@ -119,40 +115,26 @@ export async function handleChatWorkflowStream(request: NextRequest): Promise<Re
     );
   }
 
-  // Derive repo identifiers from `session.clone_url` so we have a
-  // single source of truth. The `sessions.repo_owner/repo_name`
-  // columns exist in the schema but were never populated; treating
-  // `clone_url` as canonical avoids a denormalization where the
-  // columns could drift from the URL.
-  const repoIds = parseGitHubRepoIdentifiers(session.clone_url);
-
+  // Build the durable workflow input via the shared builder so the
+  // interactive and headless (/api/chat/generate) callers stay in lockstep
+  // (chat#1813). Repo ids + recoup org id are derived from `clone_url` inside
+  // the builder — the single source of truth. The short-lived Privy JWT from
+  // the chat UI is forwarded as `recoupAccessToken`; x-api-key callers don't
+  // send it, so the long-lived service key never enters model-issued bash.
   const run = await start(runAgentWorkflow, [
-    {
+    buildRunAgentInput({
       messages: validated.messages,
       chatId: validated.chatId,
       sessionId: validated.sessionId,
       accountId: validated.accountId,
       modelId,
       sessionTitle: session.title ?? undefined,
-      repoOwner: repoIds?.owner,
-      repoName: repoIds?.repo,
-      agentContext: {
-        sandbox: {
-          state: session.sandbox_state as VercelState,
-          workingDirectory,
-        },
-        recoupOrgId,
-        skills,
-        // Forward the short-lived Privy JWT from the chat UI when
-        // present. The `recoup-api` skill's curl examples authenticate
-        // against recoup-api with this as a Bearer header (via the
-        // `$RECOUP_ACCESS_TOKEN` env var injected by buildRecoupExecEnv).
-        // x-api-key auth callers don't send this field — the long-lived
-        // recoup_sk_ key is deliberately NOT forwarded (exfiltration
-        // risk from model-issued bash).
-        ...(validated.recoupAccessToken ? { recoupAccessToken: validated.recoupAccessToken } : {}),
-      },
-    },
+      cloneUrl: session.clone_url,
+      sandboxState: session.sandbox_state as VercelState,
+      workingDirectory,
+      skills,
+      recoupAccessToken: validated.recoupAccessToken,
+    }),
   ]);
 
   // Promote placeholder → real run id via CAS. If something asynchronously
diff --git a/lib/keys/__tests__/isApiKeyExpired.test.ts b/lib/keys/__tests__/isApiKeyExpired.test.ts
new file mode 100644
index 000000000..87ac88f3b
--- /dev/null
+++ b/lib/keys/__tests__/isApiKeyExpired.test.ts
@@ -0,0 +1,24 @@
+import { describe, it, expect } from "vitest";
+import { isApiKeyExpired } from "@/lib/keys/isApiKeyExpired";
+
+describe("isApiKeyExpired", () => {
+  const now = Date.parse("2026-06-23T00:00:00Z");
+
+  it("treats null/undefined expiry as never-expiring", () => {
+    expect(isApiKeyExpired(null, now)).toBe(false);
+    expect(isApiKeyExpired(undefined, now)).toBe(false);
+  });
+
+  it("is false for a future expiry", () => {
+    expect(isApiKeyExpired("2026-06-23T01:00:00Z", now)).toBe(false);
+  });
+
+  it("is true at or past the expiry", () => {
+    expect(isApiKeyExpired("2026-06-22T23:59:59Z", now)).toBe(true);
+    expect(isApiKeyExpired("2026-06-23T00:00:00Z", now)).toBe(true);
+  });
+
+  it("treats an unparseable expiry as non-expiring (never lock out)", () => {
+    expect(isApiKeyExpired("not-a-date", now)).toBe(false);
+  });
+});
diff --git a/lib/keys/isApiKeyExpired.ts b/lib/keys/isApiKeyExpired.ts
new file mode 100644
index 000000000..57e7632ec
--- /dev/null
+++ b/lib/keys/isApiKeyExpired.ts
@@ -0,0 +1,15 @@
+/**
+ * Whether an api key's `expires_at` has passed. NULL/undefined = never expires.
+ * An unparseable value is treated as non-expiring so a bad row can't lock a
+ * caller out. Used by api auth to reject ephemeral keys past their TTL
+ * (recoupable/chat#1813).
+ */
+export function isApiKeyExpired(
+  expiresAt: string | null | undefined,
+  now: number = Date.now(),
+): boolean {
+  if (!expiresAt) return false;
+  const exp = Date.parse(expiresAt);
+  if (Number.isNaN(exp)) return false;
+  return exp <= now;
+}
diff --git a/types/database.types.ts b/types/database.types.ts
index 1771da89f..872750b72 100644
--- a/types/database.types.ts
+++ b/types/database.types.ts
@@ -12,6 +12,7 @@ export type Database = {
         Row: {
           account: string | null;
           created_at: string;
+          expires_at: string | null;
           id: string;
           key_hash: string | null;
           last_used: string | null;
@@ -20,6 +21,7 @@ export type Database = {
         Insert: {
           account?: string | null;
           created_at?: string;
+          expires_at?: string | null;
           id?: string;
           key_hash?: string | null;
           last_used?: string | null;
@@ -28,6 +30,7 @@ export type Database = {
         Update: {
           account?: string | null;
           created_at?: string;
+          expires_at?: string | null;
           id?: string;
           key_hash?: string | null;
           last_used?: string | null;