feat(agent): route signal_report tasks to signals gateway product

packages/agent/src/server/agent-server.configure-environment.test.ts

@@ -2,13 +2,20 @@ import { afterEach, beforeEach, describe, expect, it } from "vitest";
 import { AgentServer } from "./agent-server";
 
 interface TestableServer {
-  configureEnvironment(args?: { isInternal?: boolean }): void;
+  configureEnvironment(args?: {
+    isInternal?: boolean;
+    originProduct?: string | null;
+    taskId?: string | null;
+    taskRunId?: string | null;
+    taskUserId?: number | null;
+  }): void;
 }
 
 const ENV_KEYS_UNDER_TEST = [
   "LLM_GATEWAY_URL",
   "ANTHROPIC_BASE_URL",
   "OPENAI_BASE_URL",
+  "ANTHROPIC_CUSTOM_HEADERS",
 ] as const;
 
 describe("AgentServer.configureEnvironment", () => {
@@ -85,6 +92,62 @@ describe("AgentServer.configureEnvironment", () => {
     expect(fromBackground).toBe("https://gateway.us.posthog.com/posthog_code");
   });
 
+  it("tags as signals when an internal task has origin_product 'signal_report'", () => {
+    buildServer("background").configureEnvironment({
+      isInternal: true,
+      originProduct: "signal_report",
+    });
+
+    expect(process.env.LLM_GATEWAY_URL).toBe(
+      "https://gateway.us.posthog.com/signals",
+    );
+    expect(process.env.ANTHROPIC_BASE_URL).toBe(
+      "https://gateway.us.posthog.com/signals",
+    );
+    expect(process.env.OPENAI_BASE_URL).toBe(
+      "https://gateway.us.posthog.com/signals/v1",
+    );
+  });
+
+  it("does not tag as signals when origin_product is 'signal_report' but the task is not internal", () => {
+    buildServer("background").configureEnvironment({
+      isInternal: false,
+      originProduct: "signal_report",
+    });
+
+    expect(process.env.LLM_GATEWAY_URL).toBe(
+      "https://gateway.us.posthog.com/posthog_code",
+    );
+  });
+
+  it("forwards task metadata as ANTHROPIC_CUSTOM_HEADERS", () => {
+    buildServer("background").configureEnvironment({
+      isInternal: true,
+      originProduct: "signal_report",
+      taskId: "task-abc",
+      taskRunId: "run-xyz",
+      taskUserId: 42,
+    });
+
+    expect(process.env.ANTHROPIC_CUSTOM_HEADERS).toBe(
+      [
+        "x-posthog-property-task_origin_product: signal_report",
+        "x-posthog-property-task_internal: true",
+        "x-posthog-property-task_id: task-abc",
+        "x-posthog-property-task_run_id: run-xyz",
+        "x-posthog-property-task_user_id: 42",
+      ].join("\n"),
+    );
+  });
+
+  it("omits optional task metadata from ANTHROPIC_CUSTOM_HEADERS when not provided", () => {
+    buildServer("background").configureEnvironment({ isInternal: false });
+
+    expect(process.env.ANTHROPIC_CUSTOM_HEADERS).toBe(
+      "x-posthog-property-task_internal: false",
+    );
+  });
+
   it("respects the LLM_GATEWAY_URL override regardless of internal flag", () => {
     process.env.LLM_GATEWAY_URL = "http://ngrok.test/proxy";
 

packages/agent/src/server/agent-server.ts

@@ -47,7 +47,11 @@ import type {
 } from "../types";
 import { resourceLink } from "../utils/acp-content";
 import { AsyncMutex } from "../utils/async-mutex";
-import { type GatewayProduct, getLlmGatewayUrl } from "../utils/gateway";
+import {
+  buildGatewayPropertyHeaders,
+  getLlmGatewayUrl,
+  resolveGatewayProduct,
+} from "../utils/gateway";
 import { Logger } from "../utils/logger";
 import { logAgentshRuntimeInfo } from "./agentsh-runtime";
 import {
@@ -844,7 +848,13 @@ export class AgentServer {
       }),
     ]);
 
-    this.configureEnvironment({ isInternal: preTask?.internal === true });
+    this.configureEnvironment({
+      isInternal: preTask?.internal === true,
+      originProduct: preTask?.origin_product,
+      taskId: payload.task_id,
+      taskRunId: payload.run_id,
+      taskUserId: payload.user_id,
+    });
 
     const prUrl = getTaskRunStateString(preTaskRun, "slack_notified_pr_url");
 
@@ -1804,18 +1814,35 @@ ${attributionInstructions}
 
   private configureEnvironment({
     isInternal = false,
+    originProduct,
+    taskId,
+    taskRunId,
+    taskUserId,
   }: {
     isInternal?: boolean;
+    originProduct?: string | null;
+    taskId?: string | null;
+    taskRunId?: string | null;
+    taskUserId?: number | null;
   } = {}): void {
     const { apiKey, apiUrl, projectId } = this.config;
-    const product: GatewayProduct = isInternal
-      ? "background_agents"
-      : "posthog_code";
+    const product = resolveGatewayProduct({ isInternal, originProduct });
     const gatewayUrl =
       process.env.LLM_GATEWAY_URL || getLlmGatewayUrl(apiUrl, product);
     const openaiBaseUrl = gatewayUrl.endsWith("/v1")
       ? gatewayUrl
       : `${gatewayUrl}/v1`;
+    // Forward task metadata as `x-posthog-property-*` headers so the gateway
+    // lifts them onto the $ai_generation event. Routes through the Anthropic
+    // SDK's ANTHROPIC_CUSTOM_HEADERS env var; the OpenAI/codex path has no
+    // equivalent today.
+    const customHeaders = buildGatewayPropertyHeaders({
+      task_origin_product: originProduct,
+      task_internal: isInternal,
+      task_id: taskId,
+      task_run_id: taskRunId,
+      task_user_id: taskUserId,
+    });
 
     Object.assign(process.env, {
       // PostHog
@@ -1828,6 +1855,7 @@ ${attributionInstructions}
       ANTHROPIC_API_KEY: apiKey,
       ANTHROPIC_AUTH_TOKEN: apiKey,
       ANTHROPIC_BASE_URL: gatewayUrl,
+      ANTHROPIC_CUSTOM_HEADERS: customHeaders,
       // OpenAI (for models like GPT-4, o1, etc.)
       OPENAI_API_KEY: apiKey,
       OPENAI_BASE_URL: openaiBaseUrl,

packages/agent/src/types.ts

@@ -37,7 +37,8 @@ export interface Task {
     | "eval_clusters"
     | "user_created"
     | "support_queue"
-    | "session_summaries";
+    | "session_summaries"
+    | "signal_report";
   github_integration?: number | null;
   repository: string; // Format: "organization/repository" (e.g., "posthog/posthog-js")
   json_schema?: Record<string, unknown> | null; // JSON schema for task output validation

packages/agent/src/utils/gateway.test.ts

@@ -0,0 +1,70 @@
+import { describe, expect, it } from "vitest";
+import { buildGatewayPropertyHeaders, resolveGatewayProduct } from "./gateway";
+
+describe("resolveGatewayProduct", () => {
+  it.each([
+    { isInternal: false, originProduct: undefined, expected: "posthog_code" },
+    {
+      isInternal: undefined,
+      originProduct: undefined,
+      expected: "posthog_code",
+    },
+    {
+      isInternal: false,
+      originProduct: "signal_report",
+      expected: "posthog_code",
+    },
+    {
+      isInternal: true,
+      originProduct: undefined,
+      expected: "background_agents",
+    },
+    {
+      isInternal: true,
+      originProduct: "session_summaries",
+      expected: "background_agents",
+    },
+    { isInternal: true, originProduct: "signal_report", expected: "signals" },
+  ] as const)(
+    "isInternal=$isInternal originProduct=$originProduct -> $expected",
+    ({ isInternal, originProduct, expected }) => {
+      expect(resolveGatewayProduct({ isInternal, originProduct })).toBe(
+        expected,
+      );
+    },
+  );
+});
+
+describe("buildGatewayPropertyHeaders", () => {
+  it("renders each property as an x-posthog-property header line", () => {
+    expect(
+      buildGatewayPropertyHeaders({
+        task_origin_product: "signal_report",
+        task_internal: true,
+      }),
+    ).toBe(
+      "x-posthog-property-task_origin_product: signal_report\nx-posthog-property-task_internal: true",
+    );
+  });
+
+  it("drops null and undefined values but keeps falsy primitives", () => {
+    expect(
+      buildGatewayPropertyHeaders({
+        task_origin_product: null,
+        task_internal: false,
+        task_count: 0,
+      }),
+    ).toBe(
+      "x-posthog-property-task_internal: false\nx-posthog-property-task_count: 0",
+    );
+  });
+
+  it("returns an empty string when no usable properties remain", () => {
+    expect(
+      buildGatewayPropertyHeaders({
+        task_origin_product: null,
+        task_internal: undefined,
+      }),
+    ).toBe("");
+  });
+});

packages/agent/src/utils/gateway.ts

@@ -1,4 +1,34 @@
-export type GatewayProduct = "posthog_code" | "background_agents";
+export type GatewayProduct = "posthog_code" | "background_agents" | "signals";
+
+export function resolveGatewayProduct({
+  isInternal,
+  originProduct,
+}: {
+  isInternal?: boolean;
+  originProduct?: string | null;
+} = {}): GatewayProduct {
+  if (isInternal) {
+    return originProduct === "signal_report" ? "signals" : "background_agents";
+  }
+  return "posthog_code";
+}
+
+/**
+ * Build `x-posthog-property-<name>: <value>` header lines that the LLM
+ * gateway lifts onto the `$ai_generation` event it captures for each call
+ * (see `services/llm-gateway/src/llm_gateway/request_context.py`).
+ *
+ * Returns a newline-joined string ready for `ANTHROPIC_CUSTOM_HEADERS`.
+ * `null`/`undefined` property values are dropped.
+ */
+export function buildGatewayPropertyHeaders(
+  properties: Record<string, string | number | boolean | null | undefined>,
+): string {
+  return Object.entries(properties)
+    .filter(([, value]) => value !== null && value !== undefined)
+    .map(([key, value]) => `x-posthog-property-${key}: ${value}`)
+    .join("\n");
+}
 
 function getGatewayBaseUrl(posthogHost: string): string {
   const url = new URL(posthogHost);