refactor(runtime): consolidate followup, gateway, and provider dedupe paths

src/agents/pi-embedded-runner/run/attempt.test.ts

@@ -60,8 +60,8 @@ describe("injectHistoryImagesIntoMessages", () => {
 });
 
 describe("resolvePromptBuildHookResult", () => {
-  it("reuses precomputed legacy before_agent_start result without invoking hook again", async () => {
-    const hookRunner = {
+  function createLegacyOnlyHookRunner() {
+    return {
       hasHooks: vi.fn(
         (hookName: "before_prompt_build" | "before_agent_start") =>
           hookName === "before_agent_start",
@@ -69,6 +69,10 @@ describe("resolvePromptBuildHookResult", () => {
       runBeforePromptBuild: vi.fn(async () => undefined),
       runBeforeAgentStart: vi.fn(async () => ({ prependContext: "from-hook" })),
     };
+  }
+
+  it("reuses precomputed legacy before_agent_start result without invoking hook again", async () => {
+    const hookRunner = createLegacyOnlyHookRunner();
     const result = await resolvePromptBuildHookResult({
       prompt: "hello",
       messages: [],
@@ -85,14 +89,7 @@ describe("resolvePromptBuildHookResult", () => {
   });
 
   it("calls legacy hook when precomputed result is absent", async () => {
-    const hookRunner = {
-      hasHooks: vi.fn(
-        (hookName: "before_prompt_build" | "before_agent_start") =>
-          hookName === "before_agent_start",
-      ),
-      runBeforePromptBuild: vi.fn(async () => undefined),
-      runBeforeAgentStart: vi.fn(async () => ({ prependContext: "from-hook" })),
-    };
+    const hookRunner = createLegacyOnlyHookRunner();
     const messages = [{ role: "user", content: "ctx" }];
     const result = await resolvePromptBuildHookResult({
       prompt: "hello",

src/agents/pi-embedded-runner/run/payloads.errors.test.ts

@@ -2,9 +2,15 @@ import type { AssistantMessage } from "@mariozechner/pi-ai";
 import { describe, expect, it } from "vitest";
 import { formatBillingErrorMessage } from "../../pi-embedded-helpers.js";
 import { makeAssistantMessageFixture } from "../../test-helpers/assistant-message-fixtures.js";
-import { buildEmbeddedRunPayloads } from "./payloads.js";
+import {
+  buildPayloads,
+  expectSinglePayloadText,
+  expectSingleToolErrorPayload,
+} from "./payloads.test-helpers.js";
 
 describe("buildEmbeddedRunPayloads", () => {
+  const OVERLOADED_FALLBACK_TEXT =
+    "The AI service is temporarily overloaded. Please try again in a moment.";
   const errorJson =
     '{"type":"error","error":{"details":null,"type":"overloaded_error","message":"Overloaded"},"request_id":"req_011CX7DwS7tSvggaNHmefwWg"}';
   const errorJsonPretty = `{
@@ -22,31 +28,25 @@ describe("buildEmbeddedRunPayloads", () => {
       content: [{ type: "text", text: errorJson }],
       ...overrides,
     });
-
-  type BuildPayloadParams = Parameters<typeof buildEmbeddedRunPayloads>[0];
-  const buildPayloads = (overrides: Partial<BuildPayloadParams> = {}) =>
-    buildEmbeddedRunPayloads({
-      assistantTexts: [],
-      toolMetas: [],
-      lastAssistant: undefined,
-      sessionKey: "session:telegram",
-      inlineToolResultsAllowed: false,
-      verboseLevel: "off",
-      reasoningLevel: "off",
-      toolResultFormat: "plain",
-      ...overrides,
+  const makeStoppedAssistant = () =>
+    makeAssistant({
+      stopReason: "stop",
+      errorMessage: undefined,
+      content: [],
     });
 
+  const expectOverloadedFallback = (payloads: ReturnType<typeof buildPayloads>) => {
+    expect(payloads).toHaveLength(1);
+    expect(payloads[0]?.text).toBe(OVERLOADED_FALLBACK_TEXT);
+  };
+
   it("suppresses raw API error JSON when the assistant errored", () => {
     const payloads = buildPayloads({
       assistantTexts: [errorJson],
       lastAssistant: makeAssistant({}),
     });
 
-    expect(payloads).toHaveLength(1);
-    expect(payloads[0]?.text).toBe(
-      "The AI service is temporarily overloaded. Please try again in a moment.",
-    );
+    expectOverloadedFallback(payloads);
     expect(payloads[0]?.isError).toBe(true);
     expect(payloads.some((payload) => payload.text === errorJson)).toBe(false);
   });
@@ -59,10 +59,7 @@ describe("buildEmbeddedRunPayloads", () => {
       verboseLevel: "on",
     });
 
-    expect(payloads).toHaveLength(1);
-    expect(payloads[0]?.text).toBe(
-      "The AI service is temporarily overloaded. Please try again in a moment.",
-    );
+    expectOverloadedFallback(payloads);
     expect(payloads.some((payload) => payload.text === errorJsonPretty)).toBe(false);
   });
 
@@ -71,10 +68,7 @@ describe("buildEmbeddedRunPayloads", () => {
       lastAssistant: makeAssistant({ content: [{ type: "text", text: errorJsonPretty }] }),
     });
 
-    expect(payloads).toHaveLength(1);
-    expect(payloads[0]?.text).toBe(
-      "The AI service is temporarily overloaded. Please try again in a moment.",
-    );
+    expectOverloadedFallback(payloads);
     expect(payloads.some((payload) => payload.text?.includes("request_id"))).toBe(false);
   });
 
@@ -108,15 +102,10 @@ describe("buildEmbeddedRunPayloads", () => {
   it("does not suppress error-shaped JSON when the assistant did not error", () => {
     const payloads = buildPayloads({
       assistantTexts: [errorJsonPretty],
-      lastAssistant: makeAssistant({
-        stopReason: "stop",
-        errorMessage: undefined,
-        content: [],
-      }),
+      lastAssistant: makeStoppedAssistant(),
     });
 
-    expect(payloads).toHaveLength(1);
-    expect(payloads[0]?.text).toBe(errorJsonPretty.trim());
+    expectSinglePayloadText(payloads, errorJsonPretty.trim());
   });
 
   it("adds a fallback error when a tool fails and no assistant output exists", () => {
@@ -133,31 +122,21 @@ describe("buildEmbeddedRunPayloads", () => {
   it("does not add tool error fallback when assistant output exists", () => {
     const payloads = buildPayloads({
       assistantTexts: ["All good"],
-      lastAssistant: makeAssistant({
-        stopReason: "stop",
-        errorMessage: undefined,
-        content: [],
-      }),
+      lastAssistant: makeStoppedAssistant(),
       lastToolError: { toolName: "browser", error: "tab not found" },
     });
 
-    expect(payloads).toHaveLength(1);
-    expect(payloads[0]?.text).toBe("All good");
+    expectSinglePayloadText(payloads, "All good");
   });
 
   it("adds completion fallback when tools run successfully without final assistant text", () => {
     const payloads = buildPayloads({
       toolMetas: [{ toolName: "write", meta: "/tmp/out.md" }],
-      lastAssistant: makeAssistant({
-        stopReason: "stop",
-        errorMessage: undefined,
-        content: [],
-      }),
+      lastAssistant: makeStoppedAssistant(),
     });
 
-    expect(payloads).toHaveLength(1);
+    expectSinglePayloadText(payloads, "✅ Done.");
     expect(payloads[0]?.isError).toBeUndefined();
-    expect(payloads[0]?.text).toBe("✅ Done.");
   });
 
   it("does not add completion fallback when the run still has a tool error", () => {
@@ -171,11 +150,7 @@ describe("buildEmbeddedRunPayloads", () => {
 
   it("does not add completion fallback when no tools ran", () => {
     const payloads = buildPayloads({
-      lastAssistant: makeAssistant({
-        stopReason: "stop",
-        errorMessage: undefined,
-        content: [],
-      }),
+      lastAssistant: makeStoppedAssistant(),
     });
 
     expect(payloads).toHaveLength(0);
@@ -199,10 +174,10 @@ describe("buildEmbeddedRunPayloads", () => {
       verboseLevel: "on",
     });
 
-    expect(payloads).toHaveLength(1);
-    expect(payloads[0]?.isError).toBe(true);
-    expect(payloads[0]?.text).toContain("Exec");
-    expect(payloads[0]?.text).toContain("code 1");
+    expectSingleToolErrorPayload(payloads, {
+      title: "Exec",
+      detail: "code 1",
+    });
   });
 
   it("does not add tool error fallback when assistant text exists after tool calls", () => {

src/agents/pi-embedded-runner/run/payloads.test-helpers.ts

@@ -0,0 +1,41 @@
+import { expect } from "vitest";
+import { buildEmbeddedRunPayloads } from "./payloads.js";
+
+export type BuildPayloadParams = Parameters<typeof buildEmbeddedRunPayloads>[0];
+type RunPayloads = ReturnType<typeof buildEmbeddedRunPayloads>;
+
+export function buildPayloads(overrides: Partial<BuildPayloadParams> = {}) {
+  return buildEmbeddedRunPayloads({
+    assistantTexts: [],
+    toolMetas: [],
+    lastAssistant: undefined,
+    sessionKey: "session:telegram",
+    inlineToolResultsAllowed: false,
+    verboseLevel: "off",
+    reasoningLevel: "off",
+    toolResultFormat: "plain",
+    ...overrides,
+  });
+}
+
+export function expectSinglePayloadText(
+  payloads: RunPayloads,
+  text: string,
+  expectedError?: boolean,
+): void {
+  expect(payloads).toHaveLength(1);
+  expect(payloads[0]?.text).toBe(text);
+  if (typeof expectedError === "boolean") {
+    expect(payloads[0]?.isError).toBe(expectedError);
+  }
+}
+
+export function expectSingleToolErrorPayload(
+  payloads: RunPayloads,
+  params: { title: string; detail: string },
+): void {
+  expect(payloads).toHaveLength(1);
+  expect(payloads[0]?.isError).toBe(true);
+  expect(payloads[0]?.text).toContain(params.title);
+  expect(payloads[0]?.text).toContain(params.detail);
+}

src/agents/pi-embedded-runner/run/payloads.test.ts

@@ -1,21 +1,5 @@
 import { describe, expect, it } from "vitest";
-import { buildEmbeddedRunPayloads } from "./payloads.js";
-
-type BuildPayloadParams = Parameters<typeof buildEmbeddedRunPayloads>[0];
-
-function buildPayloads(overrides: Partial<BuildPayloadParams> = {}) {
-  return buildEmbeddedRunPayloads({
-    assistantTexts: [],
-    toolMetas: [],
-    lastAssistant: undefined,
-    sessionKey: "session:telegram",
-    inlineToolResultsAllowed: false,
-    verboseLevel: "off",
-    reasoningLevel: "off",
-    toolResultFormat: "plain",
-    ...overrides,
-  });
-}
+import { buildPayloads, expectSingleToolErrorPayload } from "./payloads.test-helpers.js";
 
 describe("buildEmbeddedRunPayloads tool-error warnings", () => {
   it("suppresses exec tool errors when verbose mode is off", () => {
@@ -33,10 +17,10 @@ describe("buildEmbeddedRunPayloads tool-error warnings", () => {
       verboseLevel: "on",
     });
 
-    expect(payloads).toHaveLength(1);
-    expect(payloads[0]?.isError).toBe(true);
-    expect(payloads[0]?.text).toContain("Exec");
-    expect(payloads[0]?.text).toContain("command failed");
+    expectSingleToolErrorPayload(payloads, {
+      title: "Exec",
+      detail: "command failed",
+    });
   });
 
   it("keeps non-exec mutating tool failures visible", () => {

src/agents/pi-extensions/context-pruning/pruner.ts

@@ -96,22 +96,26 @@ function hasImageBlocks(content: ReadonlyArray<TextContent | ImageContent>): boo
   return false;
 }
 
+function estimateTextAndImageChars(content: ReadonlyArray<TextContent | ImageContent>): number {
+  let chars = 0;
+  for (const block of content) {
+    if (block.type === "text") {
+      chars += block.text.length;
+    }
+    if (block.type === "image") {
+      chars += IMAGE_CHAR_ESTIMATE;
+    }
+  }
+  return chars;
+}
+
 function estimateMessageChars(message: AgentMessage): number {
   if (message.role === "user") {
     const content = message.content;
     if (typeof content === "string") {
       return content.length;
     }
-    let chars = 0;
-    for (const b of content) {
-      if (b.type === "text") {
-        chars += b.text.length;
-      }
-      if (b.type === "image") {
-        chars += IMAGE_CHAR_ESTIMATE;
-      }
-    }
-    return chars;
+    return estimateTextAndImageChars(content);
   }
 
   if (message.role === "assistant") {
@@ -135,16 +139,7 @@ function estimateMessageChars(message: AgentMessage): number {
   }
 
   if (message.role === "toolResult") {
-    let chars = 0;
-    for (const b of message.content) {
-      if (b.type === "text") {
-        chars += b.text.length;
-      }
-      if (b.type === "image") {
-        chars += IMAGE_CHAR_ESTIMATE;
-      }
-    }
-    return chars;
+    return estimateTextAndImageChars(message.content);
   }
 
   return 256;