How to connect Google Calendar to Hermes Agent

Pairing is a two-step handshake: run hermes clawlink begin, approve the link in your browser, then run hermes clawlink finish. If you ran finish before approving, or the approval link expired, run hermes clawlink begin again to get a fresh link. Confirm the plugin was installed with --enable, then verify with hermes clawlink test.

Reconnect Google Calendar from the dashboard, then start a fresh chat if the runtime still has the old tool catalog loaded.

Google Calendar tool schemas load on demand the first time a tool runs and are cached after that, so this error usually clears on its own: wait a few seconds and retry the same request. If every Google Calendar call keeps failing with it in a fresh chat, reconnect from the dashboard, and contact support if it still persists — that pattern points to a configuration problem on our side, not something you can fix by reconnecting again.

Two usual causes. The connected account may not have access to the specific workspace, inbox, store, or project in the request — check that first. If access looks right, the agent may have sent a placeholder value (like "YOUR_ID" or an example id from documentation) instead of a real one: ask it to run a list or search tool first, then retry the action with a real id from those results. Most failures at this stage are one of these two, not ClawLink bugs.

The connection is fine and the call succeeded; the agent just asked for everything. googlecalendar_events_list applies no time filter unless you give it one, and Google caps an unfiltered response at 250 events. On an account with a long history those 250 slots fill with the oldest events, so the agent receives a page of meetings from years back, finds nothing near today, and tells you the calendar is empty. We have a production call that returned 249 events dated 2015 to 2024 from the arguments \{"calendarId": "primary"\} alone. The fix is to bound the window rather than to reconnect anything.

Ask the agent to diagnose it:

Re-run the calendar lookup, but first call googlecalendar_get_current_date_time, then call googlecalendar_events_list with timeMin set to today, timeMax set to seven days out, singleEvents true and orderBy startTime. Show me the exact arguments before you send them.

The tool exists under a different name. ClawLink's Google Calendar tools read verb last, so it is googlecalendar_events_list, not list_events. This trips agents because every other Google Calendar MCP server uses the opposite order: list-events on @cocal/google-calendar-mcp and list_events on Google's own calendarmcp endpoint. The same applies to googlecalendar_patch_event rather than events_patch. One case is not the agent's fault at all: the description on googlecalendar_calendar_list_get says to "use GOOGLECALENDAR_CALENDAR_LIST_LIST instead" for listing calendars, and that tool is not exposed here, so following the instruction fails. The tool you want is googlecalendar_list_calendars. ClawLink returns a "Did you mean" line with the closest matches on every miss, so tell the agent to read that line instead of inventing another variant.

Ask the agent to diagnose it:

Run clawlink_list_tools for google-calendar and show me the exact tool names it returns. Then retry using a name from that list, not a guess.

The agent sent Google Calendar API's nested shape, \{"summary": "...", "start": \{"dateTime": "2026-08-14T13:00:00Z"\}, "end": \{"dateTime": "..."\}\}. That is exactly what Google's reference documents, so models write it from memory, but this tool takes flat arguments: the nested start is ignored and the required start_datetime really is missing. Retrying the same payload cannot fix it. The working form is start_datetime: "2026-08-14T13:00:00" with timezone set separately, and the length expressed as event_duration_hour and event_duration_minutes instead of an end time.

Ask the agent to diagnose it:

Retry the event creation and show me the arguments first. start_datetime must be a flat string like 2026-08-14T13:00:00, the zone goes in timezone, and the length goes in event_duration_hour and event_duration_minutes. Do not send a start or end object.

This one comes from googlecalendar_events_list_all_calendars, which takes snake_case time_min and time_max, while the single-calendar googlecalendar_events_list takes camelCase timeMin and timeMax. An agent that succeeded on one and then switched tools carries the wrong casing across and the required argument reads as absent. Give it the window in the casing the tool it is calling actually wants.

Ask the agent to diagnose it:

You are calling googlecalendar_events_list_all_calendars, which needs time_min and time_max in snake_case. Show me the arguments with that casing before sending.

ClawLink asks Google for https://www.googleapis.com/auth/calendar and https://www.googleapis.com/auth/calendar.events, which covers every tool on this page. A 403 with this message means the token you actually granted is narrower than what was requested, which happens when a permission checkbox is cleared on Google's consent screen or the flow is completed against a different account partway through. Note that the usual advice for this error does not apply here: there is no token.json or local token cache to delete, because ClawLink holds the grant server side. Reconnect Google Calendar from the dashboard and approve every permission Google asks for. It is rare, four occurrences across 8,567 production Google Calendar calls, so check the calendar id first if events are simply missing.

Ask the agent to diagnose it:

Tell me which Google account is connected and which calendar id you are calling. If the account is right, I will reconnect Google Calendar and approve every checkbox on the consent screen.

The Google grant was withdrawn on Google's side, not on ours, so the credential is gone rather than expired. This happens when someone removes ClawLink at myaccount.google.com/permissions, when a Workspace admin revokes third-party access, or when the password changes on an account with that policy. Nothing retries its way out of it. Reconnect Google Calendar in the dashboard and the same tools resume; if the status reads INITIALIZING instead, an OAuth flow was started and never finished, so complete the consent screen in one browser session.

Ask the agent to diagnose it:

Stop retrying. Tell me the connection status you are seeing for google-calendar and wait; I need to reconnect the account in the ClawLink dashboard before this can work.

Try reconnecting Google Calendar and complete the consent flow in the same browser session. Partial OAuth approvals or switching accounts mid-flow can leave the connection incomplete.

Yes. ClawLink is the fastest way to connect Hermes to Google Calendar: link your Google Calendar account once in the browser and Hermes Agent can call the Google Calendar API through 44 ready-made tools — no custom code or token handling.

Install the plugin with hermes plugins install ClawLink-HQ/hermes-plugin --enable, then pair once: run hermes clawlink begin, approve the link in your browser, and run hermes clawlink finish. Connect Google Calendar in the dashboard and Hermes can use it from the next message — no config files or API keys to manage.

About two minutes. Sign in, click Connect next to Google Calendar in the dashboard, authenticate, and Hermes Agent can use it from the next chat message.

The alternative to ClawLink is usually manual OAuth app setup plus your own token handling, permission troubleshooting, and tool plumbing for Hermes Agent. That is fine if you want to build and maintain the integration yourself. Most teams just want Google Calendar working from chat.

Not with ClawLink. The official Hermes Google Workspace skill and the third-party guides all start by creating a Google Cloud project, enabling the Calendar API, creating a Desktop OAuth client and downloading a client secret JSON. ClawLink runs that OAuth application for you, so you approve Google's own consent screen in the browser and Hermes can call Google Calendar from the next message. No Cloud project, no client secret on your machine, and nothing to keep running.

Two scopes: https://www.googleapis.com/auth/calendar and https://www.googleapis.com/auth/calendar.events. That is enough to read, create, edit and delete events on the calendars the connected account can reach, and we would rather name it than describe it as narrower than it is. What it avoids is a standing credential: there is no client secret or token file on your machine, the grant appears under Third-party apps and services in your Google account, and one click at myaccount.google.com/permissions ends it. If that reach is more than you want on a personal calendar, connect a secondary Google account and share into it only the calendars Hermes should see.

Two causes, and neither is the connection. If the answer is about events from years ago or Hermes claims the calendar is empty, the listing call went out with no time window, and Google returns the calendar's history capped at 250 events rather than what is coming up. If the answer is off by a few days, the agent worked out "next Tuesday" from the date it assumed rather than today's. Ask it to call googlecalendar_get_current_date_time first, then list events with an explicit timeMin and timeMax.

Pairing is a two-step handshake: run hermes clawlink begin, approve the link in your browser, then run hermes clawlink finish. If you ran finish before approving, or the approval link expired, run hermes clawlink begin again to get a fresh link. Confirm the plugin was installed with --enable, then verify with hermes clawlink test.