fix(mcp): keep pre-snake_case tool names as deprecated aliases

apps/mcp/e2e/discovery.test.ts

@@ -10,9 +10,13 @@ import {
 const EXPECTED_TOOLS = [
 	"add_memory",
 	"fetch-graph-data",
+	"getDocument",
 	"get_document",
 	"get_profile",
 	"guided-save",
+	"listDocuments",
+	"listMemories",
+	"listSpaces",
 	"list_documents",
 	"list_memories",
 	"list_spaces",
@@ -23,6 +27,7 @@ const EXPECTED_TOOLS = [
 	"select-space",
 	"set-active-tag",
 	"upload-file",
+	"whoAmI",
 	"who_am_i",
 ]
 const describeWithAuth = describe.skipIf(!OAUTH_CREDENTIALS_AVAILABLE)

apps/mcp/src/server/tools/index.ts

@@ -16,7 +16,46 @@ import type { ToolDeps } from "./types"
 import * as uploadFile from "./upload-file"
 import * as whoAmI from "./who-am-i"
 
-export function registerAllTools(deps: ToolDeps) {
+// Renamed to snake_case in #1665; clients with a cached tool list still call the old names.
+// Remove once PostHog shows ~0 $mcp_tool_call events for these names for 2 weeks.
+const LEGACY_TOOL_NAMES: Record<string, string> = {
+	get_document: "getDocument",
+	list_spaces: "listSpaces",
+	list_documents: "listDocuments",
+	list_memories: "listMemories",
+	who_am_i: "whoAmI",
+}
+
+type LooseRegisterTool = (
+	name: string,
+	config: { title?: string; description?: string },
+	cb: unknown,
+) => ReturnType<ToolDeps["server"]["registerTool"]>
+
+// Aliases must stay listed: ChatGPT rejects calls to tools missing from tools/list.
+function withLegacyToolNames(server: ToolDeps["server"]): ToolDeps["server"] {
+	const register = server.registerTool.bind(server) as LooseRegisterTool
+	const registerTool: LooseRegisterTool = (name, config, cb) => {
+		const tool = register(name, config, cb)
+		const legacyName = LEGACY_TOOL_NAMES[name]
+		if (legacyName) {
+			register(
+				legacyName,
+				{
+					...config,
+					...(config.title ? { title: `${config.title} (deprecated)` } : {}),
+					description: `Deprecated: use ${name}.`,
+				},
+				cb,
+			)
+		}
+		return tool
+	}
+	return { registerTool: registerTool as ToolDeps["server"]["registerTool"] }
+}
+
+export function registerAllTools(toolDeps: ToolDeps) {
+	const deps = { ...toolDeps, server: withLegacyToolNames(toolDeps.server) }
 	searchMemory.register(deps)
 	getProfile.register(deps)
 	listDocuments.register(deps)