fix(collab): treated guest prompts as user interjections

Converted user-attributed collab prompt frames to prioritized user messages only on the model-facing path, preserving guest details in persisted transcript frames.

Added regression coverage for the provider role, steering envelope, and retained guest attribution.

Fixes #7288

packages/coding-agent/CHANGELOG.md

@@ -2,6 +2,10 @@
 
 ## [Unreleased]
 
+### Fixed
+
+- Fixed collab guest prompts being sent to models as unframed developer context, so guest messages now retain their transcript attribution while reaching the model as prioritized user interjections ([#7288](https://github.com/can1357/oh-my-pi/issues/7288)).
+
 ## [17.2.3] - 2026-08-01
 
 ### Changed

packages/coding-agent/src/session/messages.ts

@@ -24,6 +24,7 @@ import type {
 } from "@oh-my-pi/pi-ai";
 import * as AIError from "@oh-my-pi/pi-ai/error";
 import { isRecord, logger, prompt } from "@oh-my-pi/pi-utils";
+import { COLLAB_PROMPT_MESSAGE_TYPE } from "@oh-my-pi/pi-wire";
 import userInterjectionTemplate from "../prompts/steering/user-interjection.md" with { type: "text" };
 import { formatTitleConversationContext, type TitleConversationTurn } from "../tiny/message-preproc";
 
@@ -614,8 +615,18 @@ export function normalizeCustomMessagePayload<T = unknown>(
 	};
 }
 
-function isSteeringUserMessage(message: AgentMessage | undefined): message is UserMessage & { steering: true } {
-	return message?.role === "user" && message.steering === true;
+type SteeringUserMessage =
+	| (UserMessage & { steering: true })
+	| (CustomMessage & {
+			customType: typeof COLLAB_PROMPT_MESSAGE_TYPE;
+			attribution: "user";
+	  });
+
+function isSteeringUserMessage(message: AgentMessage | undefined): message is SteeringUserMessage {
+	if (message?.role === "user") return message.steering === true;
+	return (
+		message?.role === "custom" && message.customType === COLLAB_PROMPT_MESSAGE_TYPE && message.attribution === "user"
+	);
 }
 
 function userMessageWithoutSteering(message: UserMessage): UserMessage {
@@ -655,17 +666,26 @@ function getArrayContentImages(content: (TextContent | ImageContent)[]): ImageCo
 	return images ?? [];
 }
 
-function wrapSteeringUserMessage(message: UserMessage): UserMessage {
+function wrapSteeringUserMessage(message: SteeringUserMessage): UserMessage {
+	const userMessage: UserMessage =
+		message.role === "user"
+			? userMessageWithoutSteering(message)
+			: {
+					role: "user",
+					content: message.content,
+					attribution: "user",
+					timestamp: message.timestamp,
+				};
 	if (typeof message.content === "string") {
-		if (message.content.length === 0) return message;
-		return { ...userMessageWithoutSteering(message), content: renderSteeringEnvelope(message.content) };
+		if (message.content.length === 0) return message.role === "user" ? message : userMessage;
+		return { ...userMessage, content: renderSteeringEnvelope(message.content) };
 	}
 
 	const text = getArrayContentText(message.content);
-	if (text.length === 0) return message;
+	if (text.length === 0) return message.role === "user" ? message : userMessage;
 	const content: (TextContent | ImageContent)[] = [{ type: "text", text: renderSteeringEnvelope(text) }];
 	content.push(...getArrayContentImages(message.content));
-	return { ...userMessageWithoutSteering(message), content };
+	return { ...userMessage, content };
 }
 
 export function wrapSteeringForModel(messages: AgentMessage[]): AgentMessage[] {

packages/coding-agent/test/session-messages.test.ts

@@ -7,6 +7,7 @@ import {
 	SKILL_PROMPT_MESSAGE_TYPE,
 	wrapSteeringForModel,
 } from "@oh-my-pi/pi-coding-agent/session/messages";
+import { COLLAB_PROMPT_MESSAGE_TYPE } from "@oh-my-pi/pi-wire";
 
 function expectAttribution(message: Message | undefined, expected: "user" | "agent" | undefined): void {
 	expect(message).toBeDefined();
@@ -382,6 +383,31 @@ describe("wrapSteeringForModel", () => {
 		expect(wrappedText).not.toContain("&");
 	});
 
+	it("presents user-attributed collab prompts as wrapped user turns", () => {
+		const message: AgentMessage = {
+			role: "custom",
+			customType: COLLAB_PROMPT_MESSAGE_TYPE,
+			content: "Reply with exactly PONG",
+			display: true,
+			details: { from: "guest" },
+			attribution: "user",
+			timestamp: 1,
+		};
+
+		const wrapped = wrapSteeringForModel([message]);
+		const providerMessages = convertToLlm(wrapped);
+
+		expect(wrapped[0]?.role).toBe("user");
+		expect(getUserText(wrapped[0])).toContain("<system-notice>");
+		expect(getUserText(wrapped[0])).toContain("Reply with exactly PONG");
+		expect(providerMessages).toHaveLength(1);
+		expect(providerMessages[0]?.role).toBe("user");
+		expect(message).toMatchObject({
+			role: "custom",
+			details: { from: "guest" },
+		});
+	});
+
 	it("wraps buried steering messages too so wire bytes stay stable across turns", () => {
 		const buried: AgentMessage = {
 			role: "user",