refactor: rebuild agent system prompt

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

@@ -1,14 +1,11 @@
 import type { AgentMessage, AgentTool } from "@mariozechner/pi-agent-core";
-import {
-  buildSystemPrompt,
-  SessionManager,
-} from "@mariozechner/pi-coding-agent";
+import { SessionManager } from "@mariozechner/pi-coding-agent";
 import { Type } from "@sinclair/typebox";
 import { describe, expect, it, vi } from "vitest";
 import {
   applyGoogleTurnOrderingFix,
   buildEmbeddedSandboxInfo,
-  createSystemPromptAppender,
+  createSystemPromptOverride,
   splitSdkTools,
 } from "./pi-embedded-runner.js";
 import type { SandboxContext } from "./sandbox.js";
@@ -109,27 +106,15 @@ describe("splitSdkTools", () => {
   });
 });
 
-describe("createSystemPromptAppender", () => {
-  it("appends without duplicating context files", () => {
-    const sentinel = "CONTEXT_SENTINEL_42";
-    const defaultPrompt = buildSystemPrompt({
-      cwd: "/tmp",
-      contextFiles: [{ path: "/tmp/AGENTS.md", content: sentinel }],
-    });
-    const appender = createSystemPromptAppender("APPEND_SECTION");
-    const finalPrompt = appender(defaultPrompt);
-    const occurrences = finalPrompt.split(sentinel).length - 1;
-    const contextHeaders = finalPrompt.split("# Project Context").length - 1;
-    expect(typeof appender).toBe("function");
-    expect(occurrences).toBe(1);
-    expect(contextHeaders).toBe(1);
-    expect(finalPrompt).toContain("APPEND_SECTION");
+describe("createSystemPromptOverride", () => {
+  it("returns the override prompt regardless of default prompt", () => {
+    const override = createSystemPromptOverride("OVERRIDE");
+    expect(override("DEFAULT")).toBe("OVERRIDE");
   });
 
-  it("returns the default prompt when append text is empty", () => {
-    const defaultPrompt = buildSystemPrompt({ cwd: "/tmp" });
-    const appender = createSystemPromptAppender("  \n  ");
-    expect(appender(defaultPrompt)).toBe(defaultPrompt);
+  it("returns an empty string for blank overrides", () => {
+    const override = createSystemPromptOverride("  \n  ");
+    expect(override("DEFAULT")).toBe("");
   });
 });