fix(cli): keep json preflight stdout machine-readable

src/cli/program/preaction.ts

@@ -3,7 +3,7 @@ import { setVerbose } from "../../globals.js";
 import { isTruthyEnvValue } from "../../infra/env.js";
 import type { LogLevel } from "../../logging/levels.js";
 import { defaultRuntime } from "../../runtime.js";
-import { getCommandPath, getVerboseFlag, hasHelpOrVersion } from "../argv.js";
+import { getCommandPath, getVerboseFlag, hasFlag, hasHelpOrVersion } from "../argv.js";
 import { emitCliBanner } from "../banner.js";
 import { resolveCliName } from "../cli-name.js";
 
@@ -30,6 +30,7 @@ const PLUGIN_REQUIRED_COMMANDS = new Set([
   "onboard",
 ]);
 const CONFIG_GUARD_BYPASS_COMMANDS = new Set(["doctor", "completion", "secrets"]);
+const JSON_PARSE_ONLY_COMMANDS = new Set(["config set"]);
 
 function getRootCommand(command: Command): Command {
   let current = command;
@@ -51,6 +52,17 @@ function getCliLogLevel(actionCommand: Command): LogLevel | undefined {
   return typeof logLevel === "string" ? (logLevel as LogLevel) : undefined;
 }
 
+function isJsonOutputMode(commandPath: string[], argv: string[]): boolean {
+  if (!hasFlag(argv, "--json")) {
+    return false;
+  }
+  const key = `${commandPath[0] ?? ""} ${commandPath[1] ?? ""}`.trim();
+  if (JSON_PARSE_ONLY_COMMANDS.has(key)) {
+    return false;
+  }
+  return true;
+}
+
 export function registerPreActionHooks(program: Command, programVersion: string) {
   program.hook("preAction", async (_thisCommand, actionCommand) => {
     setProcessTitleForCommand(actionCommand);
@@ -79,8 +91,13 @@ export function registerPreActionHooks(program: Command, programVersion: string)
     if (CONFIG_GUARD_BYPASS_COMMANDS.has(commandPath[0])) {
       return;
     }
+    const suppressDoctorStdout = isJsonOutputMode(commandPath, argv);
     const { ensureConfigReady } = await import("./config-guard.js");
-    await ensureConfigReady({ runtime: defaultRuntime, commandPath });
+    await ensureConfigReady({
+      runtime: defaultRuntime,
+      commandPath,
+      ...(suppressDoctorStdout ? { suppressDoctorStdout: true } : {}),
+    });
     // Load plugins for commands that need channel access
     if (PLUGIN_REQUIRED_COMMANDS.has(commandPath[0])) {
       const { ensurePluginRegistryLoaded } = await import("../plugin-registry.js");