# How to connect Cal.com to Hermes Agent (no API keys)

> Connect Cal.com to Hermes with ClawLink in one click — 168 tools your AI agent can call from chat via hosted OAuth. No API keys, no manual setup.

Web version: https://claw-link.dev/hermes/cal

Most guides for giving Hermes Agent Cal.com access start with registering your own OAuth app or pasting API keys into env files, then leave the token refresh and tool wiring to you. ClawLink gives Hermes a more practical Cal.com setup: pair once in the browser and your always-on Hermes agent can act on Cal.com for you, reading and doing real work on your behalf with no auth, token refresh, or tool wiring to build yourself.

**Start here — paste this into Hermes to set up ClawLink:**

> Set up ClawLink for Hermes and tell me when it's ready.
> 1. Install the plugin: `hermes plugins install ClawLink-HQ/hermes-plugin --enable`
> 2. Start pairing with `hermes clawlink begin`. It prints an approval link, so show me the link and stop, don't wait.
> 3. I'll approve it in my browser, then reply "approved".
> 4. When I say approved, finish setup: `hermes clawlink finish`
> 5. Then run `hermes clawlink test` and tell me whether ClawLink is ready.

## Setup

It takes three steps to connect Hermes to Cal.com.

1. **Install ClawLink** — add the plugin to Hermes Agent once.
2. **Connect Cal.com** — one-click OAuth in the ClawLink dashboard.
3. **Use it from chat** — ask Hermes Agent in plain English.

**Alternative for any agent (no plugin needed):** if the Hermes Agent plugin route isn't available or doesn't work, any AI agent with shell access can use the ClawLink CLI instead:

```bash
npx -y @useclawlink/cli login          # sign in via browser — no API key to paste
npx -y @useclawlink/cli connect cal  # connect Cal.com (browser OAuth)
npx -y @useclawlink/cli actions cal  # list available actions
npx -y @useclawlink/cli run cal <action> --input '<json>'  # execute (add --confirm for writes)
```

### Install by command

The prompt above walks Hermes through this. By hand, it is four commands and a browser approval:

```bash
hermes plugins install ClawLink-HQ/hermes-plugin --enable
hermes clawlink begin    # prints an approval link — open it and approve
hermes clawlink finish   # after approving in the browser
hermes clawlink test
```

Then connect Cal.com in the [ClawLink dashboard](https://claw-link.dev/dashboard) — a one-click OAuth approval, no API keys.

Verify the connection by asking Hermes:

> Use cal_fetch_all_bookings to show my bookings for this week: who, what event type, and whether each is confirmed.

### Using a different agent?

The Hermes plugin is one client of ClawLink's MCP server. Claude Code, Cursor, Codex, or any agent that can run a shell command pairs with the same ClawLink account through the CLI:

```bash
npx -y @useclawlink/cli login
```

`login` opens the same browser approval and stores a credential locally. Once Cal.com is connected in the dashboard, that agent calls the same 168 Cal.com tools over MCP. Full setup for MCP clients and shell agents: [connect apps to any AI agent](https://claw-link.dev/learn/connect-apps-to-any-ai-agent).

## Cal.com MCP for Hermes

Looking for a Cal.com MCP server for Hermes Agent? ClawLink connects Cal.com to Hermes Agent and exposes 168 Cal.com tools your agent can call over [MCP](https://claw-link.dev/learn/what-is-an-mcp-server), with [hosted auth](https://claw-link.dev/learn/oauth-for-ai-agents) and nothing to run or maintain yourself. Using OpenClaw instead? The [OpenClaw Cal.com integration](https://claw-link.dev/openclaw/cal) works the same way.

Search results answer "connect Cal.com to Hermes" with either an API key flow (Settings, Developer, API Keys, Add, "Never expires", plus an event-type ID) or a Composio Connect config block, and ChatGPT currently says it could not find an official Hermes-specific Cal.com connector at all. Both statements are about the gap this page fills. ClawLink connects Cal.com with hosted OAuth: you approve Cal.com's authorization screen once, and the 168 Cal.com tools below become callable from Hermes chat, with no API key generated, no `cal-api-version` header managed, and no config file edited. It is a Hermes connector, which Cal.com's own hosted MCP server (an excellent OAuth 2.1 MCP endpoint) is not: that one plugs into MCP clients generally, while this one pairs with Hermes Agent specifically and sits beside your other connected accounts with one place to revoke.

## What the Hermes Agent Cal.com integration can do

168 Cal.com tools are ready for Hermes Agent once the account is connected. The 30 below are the ones people reach for most; your agent can call all 168.

### 30 of 168 Cal.com tools for Hermes

| Tool | What it does |
|---|---|
| **Add attendee** `cal_add_attendee` | Tool to create a new attendee for an existing booking in Cal.com. Use when you need to add an additional participant to a scheduled event. |
| **Add member to team using org and team ID** `cal_add_member_to_team_using_org_and_team_id` | Adds a new member to a specified team within an organization by creating a team membership. |
| **Add organization attribute option** `cal_add_organization_attribute_option` | Adds a new option to an organization's SINGLE_SELECT or MULTI_SELECT attribute. Use this action to extend the available choices for an existing attribute. |
| **Cancel booking via uid** `cal_cancel_booking_via_uid` | Cancels an existing and active Cal.com booking using its unique identifier (UID). |
| **Check calendar version2** `cal_check_calendar_version2` | Retrieves free/busy availability for a specified calendar to aid scheduling without revealing event details; requires an existing, accessible calendar, noting that data granularity can vary. |
| **Check gcal synchronization status** `cal_check_gcal_synchronization_status` | Call this read-only action to verify the connection and synchronization status of a user's Google Calendar integration with Cal. |
| **Check ics feed calendar endpoint** `cal_check_ics_feed_calendar_endpoint` | Checks an ICS feed URL (expected as a query parameter) to verify its validity, accessibility, and iCalendar data integrity. |
| **Check stripe status** `cal_check_stripe_status` | Verifies if Stripe is correctly connected to the Cal scheduling system and functional for processing payments, reporting only on the integration's status. |
| **Check team stripe integration status** `cal_check_team_stripe_integration_status` | Retrieves the Stripe integration status and related information for a team, primarily to verify account connection, subscription details, or payment setup; this is a read-only operation that does not modify Stripe settings. |
| **Confirm booking by uid** `cal_confirm_booking_by_uid` | Confirms an existing booking by `bookingUid` if the booking exists and is in a state allowing confirmation (e.g., not already cancelled or confirmed); this finalizes the booking, does not modify its details, and should typically be… |
| **Connect to calendar** `cal_connect_to_calendar` | Initiates or checks the external connection status for a specified calendar, possibly returning a redirect URL for user authorization to complete integration, without altering calendar data. |
| **Create membership for organization** `cal_create_membership_for_organization` | Creates a new membership for a user within a Cal.com organization. The caller must have admin/owner access to the organization, and the target user must already exist in the system. |
| **Fetch all bookings** `cal_fetch_all_bookings` | Fetches a list of bookings, optionally filtered by status, attendee, date range, or by |
| **Fetch event type details** `cal_fetch_event_type_details` | Fetches all configuration settings and characteristics for a single event type (identified by |
| **Fetch organization attribute by ID** `cal_fetch_organization_attribute_by_id` | Retrieves a specific attribute of an organization, useful for fetching a single data point |
| **Fetch provider access token** `cal_fetch_provider_access_token` | Fetches an OAuth access token for the specified `clientId` to authenticate API calls; this |
| **Fetch schedule by ID** `cal_fetch_schedule_by_id` | Fetches comprehensive details for a specific, existing schedule using its `scheduleId` |
| **Fetch user schedule by org ID** `cal_fetch_user_schedule_by_org_id` | Retrieves a specific user's schedule within an organization, returning availability windows |
| **Fetch webhook by event type ID** `cal_fetch_webhook_by_event_type_id` | Retrieves details for a single, specific webhook using its `webhookId` and associated |
| **Get all timezones** `cal_get_all_timezones` | Retrieves all supported time zone identifiers (e.g., 'America/New_York', 'Europe/London') and |
| **Get available slots info** `cal_get_available_slots_info` | Retrieves available time slots for scheduling by considering existing bookings and |
| **Get booking reference by ID** `cal_get_booking_reference_by_id` | Find a specific booking reference by its ID |
| **Get booking references** `cal_get_booking_references` | Retrieves external references for a specific booking within an organization's team |
| **Get conference oauth authorization URL** `cal_get_conference_oauth_authorization_url` | Generates an OAuth 2.0 authorization URL for a supported conferencing `app` to initiate or |
| **Get default schedule details** `cal_get_default_schedule_details` | Retrieves the Cal system's global default schedule configuration, not custom or user-specific |
| **Get destination calendars** `cal_get_destination_calendars` | Retrieve all destination calendars configured for the authenticated user |
| **Get event type by team ID** `cal_get_event_type_by_team_id` | Retrieves a specific event type by its ID, requiring that the event type is associated with the |
| **Get event type private links** `cal_get_event_type_private_links` | Retrieves all private booking links for a specific event type |
| **Get google calendar oauth authentication URL** `cal_get_google_calendar_oauth_authentication_url` | Generates the initial Google Calendar OAuth 2.0 authorization URL for user redirection to begin |
| **Get oauth clients user** `cal_get_oauth_clients_user` | Retrieves all managed users associated with a Platform OAuth client |

## Example prompts

**What's booked this week**

> Use cal_fetch_all_bookings to show my bookings for this week: who, what event type, and whether each is confirmed.

**Find a free slot**

> Call cal_get_available_slots_info for the event type \<event type> over the next five working days and tell me the three earliest slots after 9am.

**Audit before touching**

> List my event types and their booking limits. Do not change anything; I want to know which ones are fully booked or close to it.

**Reschedule with approval**

> Find my next booking with \<name> via cal_fetch_all_bookings, check slots for the alternative time, and show me the cancellation and new-booking plan before you execute anything.

## How the Cal.com tools behave

Details that decide whether a Cal.com prompt is a quick slot check or a booking nobody approved.

- **Bookings are addressed by uid.** `cal_fetch_all_bookings` and `cal_get_booking_reference_by_id` are where booking uids come from; `cal_cancel_booking_via_uid` and `cal_confirm_booking_by_uid` take exactly those values, and an invented one fails like a permissions error.
- **Writes notify humans.** Confirming sends confirmation, cancelling notifies the invitee. The show-before-write prompt is not ceremony, it is the difference between an email going out or not.
- **Slot checks are the safe surface.** `cal_get_available_slots_info` and schedule reads answer most scheduling questions without any side effects.
- **Event types carry the rules.** Required fields, booking limits, and locations live on the event type, so a failed create is usually diagnosable by fetching the type's details.
- **Team and org tools sit apart.** Team membership, org attributes, and webhooks are separate tool families with org-scoped access; personal accounts hit 403 on them by design.
- **120 requests per minute.** Cal.com's documented default; fine for real work, fatal for a polling loop, and the response headers tell the agent its standing.

## ClawLink vs. building it yourself

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 Cal.com working from chat.

| | Manual | ClawLink |
|---|---|---|
| **Connection flow** | Register a Cal.com app, configure redirect URLs, manage consent details, and reconnect users when auth settings drift. | Users connect Cal.com through the hosted browser flow and ClawLink keeps the token lifecycle out of your app code. |
| **Ongoing maintenance** | You own refresh logic, permission debugging, environment config, and every provider-specific edge case for Cal.com. | ClawLink handles the repetitive integration plumbing so your team can focus on the workflow instead of the infrastructure. |
| **Agent usability** | You still need to expose the right Cal.com actions to the runtime in a format your agent can reliably use. | 168 tools for Cal.com are already exposed through ClawLink, so the agent can read and act from chat immediately. |

## ClawLink vs. Composio

Composio also exposes Cal.com to AI agents. It is developer infrastructure: Python and TypeScript SDKs, an MCP server, and a catalog past 1,000 apps, aimed at teams shipping agent products. ClawLink is built for Hermes Agent users instead. You install the plugin once, connect Cal.com in the browser, and the 168 tools above work from chat. There is no SDK, no config file, and no API key handling. Choosing between them? Read the full [Composio alternatives](https://claw-link.dev/hub/composio-alternatives) comparison.

### Hermes paired but still can't use Cal.com
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`.

### Connection succeeds but no tools appear
Reconnect Cal.com from the dashboard, then start a fresh chat if the runtime still has the old tool catalog loaded.

### "Tool schema not loaded yet" error when calling Cal.com tools
Cal.com 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 Cal.com 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.

### Cal.com returns 403 or "permission denied" on one action while others work
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.

### Cal.com returns 403 on booking tools but reads work fine
Reads succeeding and writes 403ing is the signature of a scope or role boundary, not a broken connection. The engines' taught causes are the map: missing OAuth scopes (booking writes need the `BOOKING_WRITE`-class scope, which the connection carries or not), organization-only endpoints that a personal account cannot reach no matter what, and user booking limits on the specific event type. Our two hosted causes still apply on top: workspace or project access (an event type in an org the connected account does not manage) and the placeholder trap (a booking uid the agent invented instead of one from `cal_fetch_all_bookings`). Have the agent quote the error, name the endpoint, and confirm which account authorized the connection before reconnecting, because a reconnect will not fix an org boundary.

Ask the agent to diagnose it:

```text
Call cal_fetch_all_bookings and show me which bookings exist. Then quote the exact 403 from the failing write and which endpoint it hit. Do not retry the write yet.
```

### Cal.com starts returning rate-limit errors mid-task
Cal.com documents a 120-requests-per-minute default limit for API-key and unauthenticated calls, which is the figure the AI Overviews quote, and responses carry rate-limit headers the agent can read. An agent walking a schedule, then event types, then a slot search, one call at a time, is unlikely to trip it, but a loop re-checking availability every few seconds will. The fix is to stop polling: ask for the slots you need once, work from `cal_get_available_slots_info` results, and have the agent report the rate-limit header it saw rather than retrying blindly.

Ask the agent to diagnose it:

```text
Tell me how many Cal.com calls you made in the last minute and whether any were polling in a loop. Quote the exact rate-limit response. Do not call Cal.com again until I reply.
```

### Cal.com tools are missing, or one tool name is not found
The engines' answer to this symptom is self-hosted MCP mechanics: a missing API key, an incorrect JSON config, or an outdated package, fixed with `npx -y @calcom/cal-mcp@latest` and a `CAL_API_KEY`. None of that exists in this flow. The hosted causes are the two real ones: the connection or pairing is incomplete (confirm the plugin installed with `--enable`, both pairing commands ran, and Cal.com shows as connected), or schemas load on demand, so the first Cal.com call in a fresh session can arrive before the catalog and needs one retry. If most tools work and one name fails, that name is wrong rather than missing.

Ask the agent to diagnose it:

```text
List the Cal.com tools you actually have access to. If there are none, say so plainly. If there are, tell me which one fetches bookings and use that exact name.
```

### The agent can see slots but cannot create a booking
Slot availability and booking creation are different gates. Seeing free slots means the read surface works; failing to create a booking means one of the write gates is closed: the event type requires a field the agent did not supply (location, time zone, or a custom question the type enforces), the attendee email fails validation, or the event type's booking limits are exhausted. The engines' p3 answers add the org/team role dimension: a connection that can read org data can still be blocked from writing. Have the agent show you the exact error from `cal_confirm_booking_by_uid` or the create call, then check the event type's requirements rather than reconnecting.

Ask the agent to diagnose it:

```text
Show me the exact error from the failed booking create, then fetch the event type's details and tell me which required fields it declares. Do not retry the create yet.
```

### OAuth finished in the browser but the account is still missing
Try reconnecting Cal.com and complete the consent flow in the same browser session. Partial OAuth approvals or switching accounts mid-flow can leave the connection incomplete.

### Is there a Hermes Agent Cal.com integration?
Yes. ClawLink is the fastest way to connect Hermes to Cal.com: link your Cal.com account once in the browser and Hermes Agent can call the Cal.com API through 168 ready-made tools — no custom code or token handling.

### How do I connect Cal.com to Hermes with ClawLink?
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 Cal.com in the dashboard and Hermes can use it from the next message — no config files or API keys to manage.

### How long does it take to connect Cal.com to Hermes Agent?
About two minutes. Sign in, click Connect next to Cal.com in the dashboard, authenticate, and Hermes Agent can use it from the next chat message.

### Why use ClawLink instead of wiring Cal.com up myself?
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 Cal.com working from chat.

### How is this different from Cal.com's own hosted MCP server?
Cal.com ships a hosted MCP server at mcp.cal.com, OAuth 2.1, no API key, and it is the best-of answer everywhere; there is no beating it at its own game. The difference is the client it serves. That MCP endpoint connects to generic MCP clients through their config files. ClawLink is the Hermes-specific route: you pair Hermes once with `hermes clawlink begin` and `hermes clawlink finish`, connect Cal.com in the dashboard, and the 168 tools appear in chat with no MCP endpoint configured anywhere. If you live in an MCP client and like its config, Cal.com's own server is the right tool. If you run Hermes Agent and want the connection to be a one-time browser approval, this page is it.

### What can the agent do in Cal.com?
The full booking surface: fetch bookings and references, confirm and cancel bookings by uid, get available slots, add attendees, and manage event types, schedules, and teams. The answer ChatGPT gives as "what you generally cannot do", an autonomous agent that reads and modifies bookings, is exactly the set of 168 tools. The writes to be deliberate about are the user-visible ones: confirming a booking sends confirmation, cancelling one notifies the invitee, and adding an attendee changes a live meeting. Slot checking and schedule reads are the safe, high-value surface.

### What permissions does the connection carry?
Your Cal.com account's access, through OAuth. The scopes the engines teach for Cal.com API v2 are the useful map: `PROFILE_READ` and `PROFILE_WRITE` for profile data and `BOOKING_WRITE` for creating and managing bookings. Some endpoints are organization-only, so a personal-account connection cannot reach org-level routes no matter how the prompt is phrased, and booking limits on an event type cap what the agent can create. If a call fails with a permissions error, the first questions are which Cal.com account authorized the connection and whether the endpoint is org-scoped.

### Is it safe to connect Cal.com to an agent through ClawLink?
The engines' answer is yes, with least privilege, and the specifics are worth following: scoped OAuth instead of long-lived keys, human confirmation before booking changes, and care about what the agent does with attendee data. This setup gives you the scoped OAuth (the token is held server-side, never written to a local config, and revocable from the dashboard) and the rest is prompt discipline: have the agent check slots and fetch bookings before it writes, and make it confirm the exact booking before cancel or confirm. A booking is a promise to another human's calendar, which is why the read-first pattern is the safe one.

### Hermes paired but still can't use Cal.com
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`.

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