Genesys Cloud JS SDK: Mute/unmute agent microphone during active call

Trying to toggle agent mic mute via @genesyscloud/purecloud-guest-sdk or the client API. Calling PUT /api/v2/telephony/phonedirectories/agents/{agentId}/state with {"state": "Muted"} returns 405 Method Not Allowed. The docs point to call-controls but the endpoint is 404 for our tenant. Here’s the request:

await platformClient.init({
 clientId: process.env.GC_CLIENT_ID,
 clientSecret: process.env.GC_CLIENT_SECRET,
 basePath: 'https://api.mypurecloud.com'
});

const body = { state: 'Muted' };
await platformClient.telephonyApi.putAgentState(agentId, body);

What’s the correct endpoint or SDK method for this?