v1.15.0-mcp-multi: multi-server MCP client + stdio transport + config file + tool globs

Generalizes the v1.14.1 single-server Context7 PoC into a multi-server MCP
client registry with per-server graceful degradation. JSON config at
/data/mcp.json (bind-mounted alongside AGENTS.md) matches opencode's
mcpServers schema shape. Config file missing = no MCP (opt-in by presence).

Two transports: Streamable HTTP (remote servers like Context7) and stdio
(local subprocess servers like codecontext). Stdio spawns a persistent child
via the SDK's StdioClientTransport; shutdown hook closes all transports.

Tool prefix generalized from context7_<name> to <serverName>_<toolName> with
a toolToServer reverse map for dispatch routing. AGENTS.md tools: field now
supports glob patterns (context7_*, !web_*) via matchToolGlob — last-match-
wins with ! deny prefix. Replaces exact-match .includes() in stream-phase.ts.

refreshToolNames() in agents.ts rebuilds the DEFAULT_TOOLS snapshot after
appendMcpTools so agents without explicit tools: lists see MCP tools —
reviewer caught that the module-load-time snapshot would permanently exclude
late-registered tools.

Read-only invariant: readOnlyHint === false rejected at discovery. Result
size capped at 5MB. v1.14.1 env vars removed — superseded by config file.
Default data/mcp.json ships with Context7 disabled.

363/363 server tests passing. No schema changes, no frontend changes.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

apps/server/src/services/mcp-config.ts

@@ -0,0 +1,78 @@
+/**
+ * v1.15.0-mcp-multi: MCP config file schema + loader.
+ *
+ * Reads a JSON config file (default `/data/mcp.json`) that declares MCP
+ * servers — their transport type, connection parameters, and enabled state.
+ * Schema shape matches opencode's `mcpServers` key for copy-paste compat.
+ */
+import { readFileSync } from 'node:fs';
+import { z } from 'zod';
+import type { FastifyBaseLogger } from 'fastify';
+
+// ---- Zod schema ----
+
+const McpServerConfigSchema = z.discriminatedUnion('type', [
+  z.object({
+    type: z.literal('streamableHttp'),
+    url: z.string().url(),
+    headers: z.record(z.string()).optional(),
+    enabled: z.boolean().default(true),
+  }),
+  z.object({
+    type: z.literal('stdio'),
+    command: z.string().min(1),
+    args: z.array(z.string()).default([]),
+    env: z.record(z.string()).optional(),
+    enabled: z.boolean().default(true),
+  }),
+]);
+
+const McpConfigSchema = z.object({
+  mcpServers: z.record(z.string(), McpServerConfigSchema).default({}),
+});
+
+export type McpServerConfig = z.infer<typeof McpServerConfigSchema>;
+
+export interface McpServerEntry {
+  name: string;
+  config: McpServerConfig;
+}
+
+// ---- Loader ----
+
+/**
+ * Read and validate the MCP config file. Returns enabled servers only.
+ * File missing → log info, return []. Parse/validation error → log warn, return [].
+ */
+export function loadMcpConfig(configPath: string, log: FastifyBaseLogger): McpServerEntry[] {
+  let raw: string;
+  try {
+    raw = readFileSync(configPath, 'utf8');
+  } catch {
+    log.info(`mcp: config not found at ${configPath}, skipping`);
+    return [];
+  }
+
+  let json: unknown;
+  try {
+    json = JSON.parse(raw);
+  } catch (err) {
+    log.warn({ err }, `mcp: failed to parse ${configPath} as JSON`);
+    return [];
+  }
+
+  const result = McpConfigSchema.safeParse(json);
+  if (!result.success) {
+    log.warn({ errors: result.error.flatten().fieldErrors }, `mcp: invalid config at ${configPath}`);
+    return [];
+  }
+
+  const entries: McpServerEntry[] = [];
+  for (const [name, config] of Object.entries(result.data.mcpServers)) {
+    if (config.enabled) {
+      entries.push({ name, config });
+    }
+  }
+
+  return entries;
+}