From cbace8af70abcdddb374aa81bd6b500ea3dc1024 Mon Sep 17 00:00:00 2001
From: Aleksander Grygier <aleksander.grygier@gmail.com>
Date: Thu, 27 Aug 2026 09:51:08 +0200
Subject: [PATCH] ui: initialize only policy-enabled MCP servers for a flow

ensureInitialized accepts an optional server id set; the agentic
flow passes the servers its tool policy leaves usable, so servers
disabled for the conversation no longer get connected. Callers
without arguments keep the global behavior.

Assisted-by: pi
---
 .../ui/src/lib/stores/agentic/index.svelte.ts | 22 ++++++++++---------
 tools/ui/src/lib/stores/mcp/index.svelte.ts   | 17 +++++++++++---
 2 files changed, 26 insertions(+), 13 deletions(-)

diff --git a/tools/ui/src/lib/stores/agentic/index.svelte.ts b/tools/ui/src/lib/stores/agentic/index.svelte.ts
index bbf2526ce0..bf39b5e34f 100644
--- a/tools/ui/src/lib/stores/agentic/index.svelte.ts
+++ b/tools/ui/src/lib/stores/agentic/index.svelte.ts
@@ -329,18 +329,20 @@ class AgenticStore {
 		const disabledToolCategories = new Set(
 			toolPolicy?.disabledToolCategories ?? toolsStore.disabledToolCategories
 		);
-		// skip MCP init when the policy leaves no usable server: either the whole
-		// MCP category is off, or every globally-enabled server has its group key
-		// disabled for this flow
-		const hasMcpServers =
-			mcpStore.hasEnabledServers() &&
-			!disabledToolCategories.has(ToolSource.MCP) &&
-			mcpStore
-				.getServers()
-				.some((s) => s.enabled && !disabledTools.has(toolsStore.getMcpServerToolsKey(s.id)));
+		// servers usable under this flow's policy: globally enabled, category on,
+		// and their server-scoped group key not disabled
+		const policyEnabledServerIds = new Set(
+			disabledToolCategories.has(ToolSource.MCP)
+				? []
+				: mcpStore
+						.getServers()
+						.filter((s) => s.enabled && !disabledTools.has(toolsStore.getMcpServerToolsKey(s.id)))
+						.map((s) => s.id)
+		);
+		const hasMcpServers = policyEnabledServerIds.size > 0;
 
 		if (hasMcpServers) {
-			const initialized = await mcpStore.ensureInitialized();
+			const initialized = await mcpStore.ensureInitialized(policyEnabledServerIds);
 
 			if (!initialized) {
 				console.log('[AgenticStore] MCP not initialized');
diff --git a/tools/ui/src/lib/stores/mcp/index.svelte.ts b/tools/ui/src/lib/stores/mcp/index.svelte.ts
index 0b9eddf6bf..cb8be06c82 100644
--- a/tools/ui/src/lib/stores/mcp/index.svelte.ts
+++ b/tools/ui/src/lib/stores/mcp/index.svelte.ts
@@ -306,12 +306,18 @@ class MCPStore implements McpHealthHost {
 		return extras;
 	}
 
-	async ensureInitialized(): Promise<boolean> {
+	/**
+	 * Initialize connections. Callers can restrict which servers connect by
+	 * passing their ids (e.g. a conversation's tool policy); a different set
+	 * changes the config signature and re-initializes, same as a settings
+	 * change.
+	 */
+	async ensureInitialized(serverIds?: ReadonlySet<string>): Promise<boolean> {
 		if (!browser) {
 			return false;
 		}
 
-		const mcpConfig = this.buildMcpClientConfig(settingsStore.config);
+		const mcpConfig = this.buildMcpClientConfig(settingsStore.config, serverIds);
 		const signature = mcpConfig ? JSON.stringify(mcpConfig) : null;
 
 		if (!signature) {
@@ -1157,7 +1163,10 @@ class MCPStore implements McpHealthHost {
 	/**
 	 * Builds MCP client configuration from settings.
 	 */
-	private buildMcpClientConfig(cfg: SettingsConfigType): MCPClientConfig | undefined {
+	private buildMcpClientConfig(
+		cfg: SettingsConfigType,
+		serverIds?: ReadonlySet<string>
+	): MCPClientConfig | undefined {
 		const rawServers = parseMcpServerSettings(cfg.mcpServers);
 
 		if (!rawServers.length) {
@@ -1169,6 +1178,8 @@ class MCPStore implements McpHealthHost {
 		for (const [index, entry] of rawServers.entries()) {
 			if (!entry.enabled) continue;
 
+			if (serverIds && !serverIds.has(entry.id)) continue;
+
 			const normalized = this.buildServerConfig(entry);
 
 			if (normalized) servers[this.generateServerId(entry.id, index)] = normalized;