fix(vscode): sync mode picker with agent mode changes from backend

[kirillk]

Problem

When the agent switched modes automatically — for example from plan to code after a plan follow-up — the VS Code mode picker stayed stuck on the old value (e.g. ask). This was confusing because the agent was already operating in a different mode while the UI still showed the previous one.

The root cause: agentSelections in the session store was only written on explicit user picker actions. It was never updated from incoming backend message events.

What this PR fixes

Demo

Screen.Recording.2026-04-06.at.12.02.59.PM.mp4

Every backend agent/mode change manifests as a user message with the agent field set, followed by a message.updated SSE event. The fix intercepts those messages in two places to keep the picker in sync.

Scenario	Mechanism	Fixed?
User sends a message with a non-default agent	createUserMessage() sets agent on user msg → message.updated SSE	✅ via handleMessageCreated
Plan follow-up "Continue here" (plan → code)	PlanFollowup.inject() writes synthetic user msg with agent: "code" → SSE	✅ via handleMessageCreated
Plan follow-up custom answer	PlanFollowup.inject() writes synthetic user msg with agent: "plan" → SSE	✅ via handleMessageCreated
Shell command	shell() creates user msg with agent: input.agent → SSE	✅ via handleMessageCreated
Command execution	command() → createUserMessage() with resolved agent → SSE	✅ via handleMessageCreated
Session reload / switch	Extension calls loadMessages → history batch load	✅ via handleMessagesLoaded
Question option with mode field clicked	QuestionDock.pick() detects option.mode	✅ optimistic update via selectAgent()

Changes

• session-agent.ts — new pure helper resolveSessionAgent(messages, names) that finds the latest valid user-message agent from a message list, ignoring assistant messages and unrecognized names
• session.tsx — handleMessagesLoaded now calls resolveSessionAgent and writes result to agentSelections; handleMessageCreated updates agentSelections when a user message with a changed agent arrives
• types/messages.ts — added mode?: string to QuestionOption so the VS Code webview preserves the same question option metadata the backend and shared app already support
• question-dock-utils.ts — new resolveQuestionMode(options, answer) helper
• QuestionDock.tsx — calls session.selectAgent(mode) on pick when the selected option carries a mode, giving instant feedback before the next user message arrives

Tests

• packages/kilo-vscode/tests/unit/session-agent.test.ts — 5 unit tests for the reconciliation helper
• packages/kilo-vscode/tests/unit/question-dock-utils.test.ts — 3 new cases for resolveQuestionMode
• packages/kilo-vscode/tests/unit/kilo-provider-utils.test.ts — extended question.asked test to assert option.mode survives SSE mapping

[kilo-code-bot]

Code Review Summary

Status: 3 Issues Found | Recommendation: Address before merge

Overview

Severity	Count
CRITICAL	0
WARNING	3
SUGGESTION	0

Fix these issues in Kilo Cloud

Issue Details (click to expand)

WARNING

File	Line	Issue
packages/kilo-vscode/webview-ui/src/context/session.tsx	819	messagesLoaded can still run before agentsLoaded, so the picker misses the restored agent until a later rescan or message arrives.
packages/kilo-vscode/webview-ui/src/components/chat/QuestionDock.tsx	107	The optimistic mode change is only rolled back on questionError, so failed replies can leave the picker and model selection mutated.
packages/kilo-vscode/webview-ui/src/components/chat/QuestionDock.tsx	105	Switching from a mode-carrying option to a plain/custom answer before submit leaves the earlier optimistic mode selected and can send later prompts with the wrong defaults.

Other Observations (not in diff)

No additional observations outside the diff.

Files Reviewed (9 files)

• packages/kilo-docs/pages/code-with-ai/platforms/vscode/whats-new.md - 0 issues
• packages/kilo-vscode/tests/unit/kilo-provider-utils.test.ts - 0 issues
• packages/kilo-vscode/tests/unit/question-dock-utils.test.ts - 0 issues
• packages/kilo-vscode/tests/unit/session-agent.test.ts - 0 issues
• packages/kilo-vscode/webview-ui/src/components/chat/QuestionDock.tsx - 2 issues
• packages/kilo-vscode/webview-ui/src/components/chat/question-dock-utils.ts - 0 issues
• packages/kilo-vscode/webview-ui/src/context/session-agent.ts - 0 issues
• packages/kilo-vscode/webview-ui/src/context/session.tsx - 1 issue
• packages/kilo-vscode/webview-ui/src/types/messages.ts - 0 issues

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_{Reviewed by gpt-5.4-20260305 · 603,405 tokens}