diff --git a/app/lib/workflows/runAgentStep.ts b/app/lib/workflows/runAgentStep.ts
index 33db6714..730b4e40 100644
--- a/app/lib/workflows/runAgentStep.ts
+++ b/app/lib/workflows/runAgentStep.ts
@@ -36,6 +36,10 @@ export type RunAgentStepInput = {
    * is added to `experimental_context` right before each model call.
    */
   agentContext: DurableAgentContext;
+  /** Active artist for the run — surfaced in the agent's system prompt (chat#1837). */
+  artistId?: string;
+  /** Owning account id — surfaced alongside the artist in the system prompt. */
+  accountId?: string;
   /**
    * Whether a user is present to answer `ask_user_question`. Interactive chat
    * sets true (default); headless runs (`/api/chat/runs`, `customer-prompt-task`)
@@ -135,6 +139,8 @@ export async function runAgentStep(input: RunAgentStepInput): Promise<RunAgentSt
   const systemPrompt = buildAgentSystemPrompt({
     cwd: input.agentContext.sandbox.workingDirectory,
     customInstructions: agentCustomInstructions,
+    artistId: input.artistId,
+    accountId: input.accountId,
   });
   const result = streamText({
     model: callModel,
diff --git a/app/lib/workflows/runAgentWorkflow.ts b/app/lib/workflows/runAgentWorkflow.ts
index 5a4d2717..b7335372 100644
--- a/app/lib/workflows/runAgentWorkflow.ts
+++ b/app/lib/workflows/runAgentWorkflow.ts
@@ -28,6 +28,8 @@ export type RunAgentWorkflowInput = {
    */
   accountId: string;
   modelId: string;
+  /** Active artist for the run — surfaced in the agent's system prompt (chat#1837). */
+  artistId?: string;
   /** Whether an interactive user is present (chat UI) to answer ask_user_question. */
   interactive?: boolean;
   /**
diff --git a/lib/chat/__tests__/buildAgentSystemPrompt.test.ts b/lib/chat/__tests__/buildAgentSystemPrompt.test.ts
index 0e99bbfc..491668f4 100644
--- a/lib/chat/__tests__/buildAgentSystemPrompt.test.ts
+++ b/lib/chat/__tests__/buildAgentSystemPrompt.test.ts
@@ -31,4 +31,17 @@ describe("buildAgentSystemPrompt", () => {
     expect(prompt).toMatch(/never fabricate/i);
     expect(prompt).toMatch(/sample|estimate|industry average/i);
   });
+  it("emits IMPORTANT CONTEXT VALUES when artistId/accountId are provided", () => {
+    const prompt = buildAgentSystemPrompt({
+      artistId: "ebae4bb9-e38f-4763-b3c8-ff30e99f5d01",
+      accountId: "fb678396-a68f-4294-ae50-b8cacf9ce77b",
+    });
+    expect(prompt).toMatch(/IMPORTANT CONTEXT VALUES/);
+    expect(prompt).toContain("artist_account_id: ebae4bb9-e38f-4763-b3c8-ff30e99f5d01");
+    expect(prompt).toContain("account_id: fb678396-a68f-4294-ae50-b8cacf9ce77b");
+  });
+
+  it("omits the context section when neither artistId nor accountId is provided", () => {
+    expect(buildAgentSystemPrompt({})).not.toMatch(/IMPORTANT CONTEXT VALUES/);
+  });
 });
diff --git a/lib/chat/buildAgentSystemPrompt.ts b/lib/chat/buildAgentSystemPrompt.ts
index c458b301..46f1e1a4 100644
--- a/lib/chat/buildAgentSystemPrompt.ts
+++ b/lib/chat/buildAgentSystemPrompt.ts
@@ -26,6 +26,10 @@ export type BuildAgentSystemPromptOptions = {
    * link prompt + recoup-api skill prompt).
    */
   customInstructions?: string;
+  /** Active artist for this run — injected so the agent never roster-guesses. */
+  artistId?: string;
+  /** Owning account id (the run's auth identity). */
+  accountId?: string;
 };
 
 /**
@@ -55,6 +59,22 @@ export function buildAgentSystemPrompt(options: BuildAgentSystemPromptOptions):
     parts.push(ENVIRONMENT_SECTION);
   }
 
+  if (options.artistId || options.accountId) {
+    // Mirrors the interactive chat's getSystemPrompt context block — without
+    // this, headless agents roster-guess and can land on the org-scoped
+    // artist list instead of the run's actual artist (recoupable/chat#1837).
+    const lines = ["# IMPORTANT CONTEXT VALUES (use these exact values in tools)"];
+    if (options.artistId) {
+      lines.push(
+        `- artist_account_id: ${options.artistId} (the active artist for this run — use for /api/artists/{id}/* and roster operations; do NOT search the roster for it)`,
+      );
+    }
+    if (options.accountId) {
+      lines.push(`- account_id: ${options.accountId}`);
+    }
+    parts.push(lines.join("\n"));
+  }
+
   if (options.customInstructions) {
     parts.push(options.customInstructions);
   }
diff --git a/lib/chat/buildRunAgentInput.ts b/lib/chat/buildRunAgentInput.ts
index cc487ddd..c644d400 100644
--- a/lib/chat/buildRunAgentInput.ts
+++ b/lib/chat/buildRunAgentInput.ts
@@ -11,6 +11,8 @@ export type BuildRunAgentInputParams = {
   sessionId: string;
   accountId: string;
   modelId: string;
+  /** Active artist for the run — surfaced in the agent's system prompt (chat#1837). */
+  artistId?: string;
   sessionTitle?: string;
   /** `session.clone_url` — the single source for repo ids + recoup org id. */
   cloneUrl: string | null;
@@ -44,6 +46,7 @@ export function buildRunAgentInput({
   sessionId,
   accountId,
   modelId,
+  artistId,
   sessionTitle,
   cloneUrl,
   sandboxState,
@@ -62,6 +65,7 @@ export function buildRunAgentInput({
     sessionId,
     accountId,
     modelId,
+    artistId,
     sessionTitle,
     interactive,
     repoOwner: repoIds?.owner,
diff --git a/lib/chat/handleChatWorkflowStream.ts b/lib/chat/handleChatWorkflowStream.ts
index fab562e1..568e546b 100644
--- a/lib/chat/handleChatWorkflowStream.ts
+++ b/lib/chat/handleChatWorkflowStream.ts
@@ -128,6 +128,7 @@ export async function handleChatWorkflowStream(request: NextRequest): Promise<Re
       sessionId: validated.sessionId,
       accountId: validated.accountId,
       modelId,
+      artistId: session.artist_id ?? undefined,
       sessionTitle: session.title ?? undefined,
       cloneUrl: session.clone_url,
       sandboxState: session.sandbox_state as VercelState,
diff --git a/lib/chat/runs/handleStartChatRun.ts b/lib/chat/runs/handleStartChatRun.ts
index b9d0125a..41b68d1c 100644
--- a/lib/chat/runs/handleStartChatRun.ts
+++ b/lib/chat/runs/handleStartChatRun.ts
@@ -57,6 +57,7 @@ export async function handleStartChatRun(request: NextRequest): Promise<Response
         sessionId: provisioned.session.id,
         accountId,
         modelId,
+        artistId,
         sessionTitle: provisioned.session.title ?? undefined,
         cloneUrl: provisioned.session.clone_url,
         sandboxState: provisioned.sandboxState,