How to connect Plain to Hermes Agent (paste one key, 22 tools)

Most guides for giving Hermes Agent Plain 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 Plain setup: pair once in the browser and your always-on Hermes agent can act on Plain for you, reading and doing real work on your behalf with no auth, token refresh, or tool wiring to build yourself.

Setup

It takes three steps to connect Hermes to Plain.

1
Install and pair
Install the ClawLink plugin, then pair Hermes with a one-time browser approval:
hermes plugins install ClawLink-HQ/hermes-plugin --enable
2
Connect Plain
Paste your API key in the dashboard.
3
Use it from chat
Ask Hermes Agent: "What can you do with Plain?"

Install by command

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

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 Plain in the ClawLink dashboard — paste your Plain API key once.

Verify the connection by asking Hermes:

Pull the relevant data from Plain, summarize it in plain English, and point out anything that needs attention.

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:

npx -y @useclawlink/cli login

login opens the same browser approval and stores a credential locally. Once Plain is connected in the dashboard, that agent calls the same 22 Plain tools over MCP. Full setup for MCP clients and shell agents: connect apps to any AI agent.

Plain MCP for Hermes

Looking for a Plain MCP server for Hermes Agent? ClawLink connects Plain to Hermes Agent and exposes 22 Plain tools your agent can call over MCP, with hosted auth and nothing to run or maintain yourself. Using OpenClaw instead? The OpenClaw Plain integration works the same way.

What the Hermes Agent Plain integration can do

22 Plain tools are ready for Hermes Agent once the account is connected. The 20 below are the ones people reach for most; your agent can call all 22.

20 of 22 Plain tools for Hermes

Tool	What it does
Fetch company `plain_fetch_company`	Fetch company details by ID
Fetch issues `plain_fetch_issues`	Fetches external issue tracker links (Jira, Linear, GitHub, etc.) associated with a customer's
Fetch tier `plain_fetch_tier`	Fetch a tier by its ID
Get customer by email `plain_get_customer_by_email`	Fetch customer details by email address
Get customer by ID `plain_get_customer_by_id`	Retrieve details of a specific customer by their unique ID
Get customers `plain_get_customers`	Fetch a list of customers
Get thread by ID `plain_get_thread_by_id`	Fetches comprehensive details of a specific thread by ID, including customer info, status
Get user by ID `plain_get_user_by_id`	Fetch workspace user/team member by ID
List customer groups `plain_list_customer_groups`	List all customer groups
List tiers `plain_list_tiers`	Retrieve a list of tiers with pagination
Query threads `plain_query_threads`	Retrieve a paginated list of threads
Add customer to group `plain_add_customer_to_group`	Add a customer to one or more customer groups
Create customer group `plain_create_customer_group`	Creates a new customer group in Plain for organizing and segmenting customers
Create thread `plain_create_thread`	Create a new thread
Run graphql query `plain_run_graphql_query`	Execute any GraphQL query or mutation against Plain API
Send message `plain_send_message`	Send a new message within a thread
Update company `plain_update_company`	Upserts (creates or updates) a company in Plain
Update thread `plain_update_thread`	Update a thread's title
Upsert customer `plain_upsert_customer`	Upsert (create or update) a customer
Remove customer from group `plain_remove_customer_from_group`	Removes a customer from one or more customer groups in Plain

Try it: find the Plain tool you need

Browse the 20 Plain tools

Click any tool to see exactly what Hermes can do and copy a ready-to-use prompt.

Example prompts

Pull the relevant data from Plain, summarize it in plain English, and point out anything that needs attention.

ClawLink vs. building it yourself

The alternative to ClawLink is usually manual API key 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 Plain working from chat.

	Manual	ClawLink
Credential handling	Collect, validate, store, and rotate the Plain API key yourself, then make sure every tool call uses the right account.	Users complete the hosted ClawLink setup once and the connected Plain account becomes available to the agent without you building credential management.
Ongoing maintenance	You own refresh logic, permission debugging, environment config, and every provider-specific edge case for Plain.	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 Plain actions to the runtime in a format your agent can reliably use.	22 tools for Plain are already exposed through ClawLink, so the agent can read and act from chat immediately.

ClawLink vs. Composio

Composio also exposes Plain 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 Plain in the browser, and the 22 tools above work from chat. There is no SDK and no config file, and the Plain key you paste at setup is stored server-side rather than kept in your environment. Choosing between them? Read the full Composio alternatives comparison.

Troubleshooting

Hermes paired but still can't use Plain

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 Plain 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 Plain tools

Plain 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 Plain 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.

Plain 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.

API key setup works but results look incomplete

Double-check that the API key for Plain has the right scopes or account access. A valid key can still be too limited for some reads or writes.

FAQ

Is there a Hermes Agent Plain integration?

Yes. ClawLink is the fastest way to connect Hermes to Plain: link your Plain account once in the browser and Hermes Agent can call the Plain API through 22 ready-made tools — no custom code or token handling.

How do I connect Plain 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 Plain in the dashboard and Hermes can use it from the next message — no config files, and the Plain key you paste is stored server-side instead of in your environment.

How long does it take to connect Plain to Hermes Agent?

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

Why use ClawLink instead of wiring Plain up myself?

Hermes paired but still can't use Plain

How to connect Plain to Hermes Agent

Setup

Install and pair

Connect Plain

Use it from chat