fix(openai): keep gpt chat replies concise

extensions/openai/index.test.ts

@@ -252,6 +252,10 @@ describe("openai plugin", () => {
     expect(openaiResult).toEqual({
       appendSystemContext: OPENAI_FRIENDLY_PROMPT_OVERLAY,
     });
+    expect(OPENAI_FRIENDLY_PROMPT_OVERLAY).toContain("This is a live chat, not a memo.");
+    expect(OPENAI_FRIENDLY_PROMPT_OVERLAY).toContain(
+      "Avoid walls of text, long preambles, and repetitive restatement.",
+    );
 
     const codexResult = await beforePromptBuild?.(
       { prompt: "hello", messages: [] },

extensions/openai/prompt-overlay.ts

@@ -14,6 +14,10 @@ When the user is wrong or a plan is risky, say so kindly and directly.
 Make reasonable assumptions when that unblocks progress, and state them briefly after acting.
 Do not make the user do unnecessary work.
 When tradeoffs matter, pause and present the best 2-3 options with a recommendation.
+This is a live chat, not a memo.
+Write like a thoughtful human teammate, not a policy document.
+Default to short natural replies unless the user asks for depth.
+Avoid walls of text, long preambles, and repetitive restatement.
 Keep replies concise by default; friendly does not mean verbose.`;
 
 export type OpenAIPromptOverlayMode = "friendly" | "off";