---
title: "Karbon MCP server for AI agents - actionlake"
description: "Give Claude 74 Karbon actions through one MCP server: client groups, contacts, organizations. Your agent never holds the credential. 100,000 calls a month free."
canonical: https://actionlake.com/connectors/karbon
updated: 2026-10-23
---

Connectors · Accounting & finance

# Karbon MCP server for AI agents.

actionlake is an MCP gateway: one remote MCP server that connects Claude and other MCP clients to Karbon and the rest of your systems. It gives your agent 74 Karbon actions (41 reads, 27 writes and 6 that wait for a confirmation) and holds the Karbon credential itself, so the agent never does. It paces Karbon's limits and records every call.

[Connect Karbon free](https://actionlake.com/console?start=sandbox) [See pricing](https://actionlake.com/pricing)

100,000 free calls a month. No card, no email, no password: press Start a free sandbox on the next screen and keep the key it shows you.

`claude mcp add --transport http actionlake https://connect.actionlake.com/mcp`

the first call

```
do {
  action: "karbon.contacts.list",
  intent: "check which Karbon account is connected"
}
# List contacts · read · 1 upstream call
```

- 74 actions in one signed file
- 41 read look, never change
- 27 write create and update
- 6 wait for a yes destructive, confirmed first

Set up

## Connect Karbon in three steps.

1. 01
   ### Add actionlake to Claude.
   Run the command once in Claude Code; its consent page can create a free sandbox: 100,000 calls a month, no card. In the Claude app, add a custom connector with the URL below and paste your key on the consent page. Creating a new sandbox from the Claude app is not yet tested by us.
   `https://connect.actionlake.com/mcp`
2. 02
   ### Connect Karbon.
   Header credentials. No consent screen: your agent can connect it for you, but the key then passes through your chat. To keep it out of the model's context, paste it in the console instead. actionlake stores what you paste write-only, sealed under your tenant's key.
   - `application_id` Application ID (the 36-character GUID bearer token) from Karbon Settings > Connected Apps > API Applications
   - `access_key` Access Key (a JWT starting eyJ…) from the same API Application
   ```
   account { op: "connections.requirements", service: "karbon" }
   # free: exactly what to paste, and what is found for you
   ```
3. 03
   ### Make the first call. Check before a write.
   Ask in plain words; Claude picks the action. Before anything changes, `check` validates the call and prices it, for free.
   ```
   do    { action: "karbon.contacts.list" }
   # list contacts · read · 1 upstream call
   check { action: "karbon.contacts.create", input: { … } }
   # free: inputs, permissions, cost and confirmations, nothing sent
   ```

Karbon at a glance

**Sign-in**

Header credentials. No consent screen: your agent can connect it for you, but the key then passes through your chat. To keep it out of the model's context, paste it in the console instead.

**You provide**

`application_id` `access_key`

**Limits we pace to**

120 calls a minute, per connection

**API covered**

Karbon API v3 (v3, OpenAPI 3.1.0)`api.karbonhq.com`

**Built from**

Karbon's documentation, read 23 October 2026[karbonhq.github.io](https://karbonhq.github.io/karbon-api-reference/KarbonAPI.json) [developers.karbonhq.com](https://developers.karbonhq.com/)

**Service file**

Version 1.0.0, signed (Ed25519)

**Cached reads**

41 of 41 reads, for up to 5 minutes; a write clears what it affects

**Shared entities**

7, so ask can line Karbon up with your other systems

**Data**

Processed and stored in Sydney, Australia. No US region yet

Capabilities

## What an AI agent can do in Karbon.

74 actions in 26 areas. Every one carries its effect, so a key can allow the reads and hold the rest.

- **41** read look, never change
- **27** write create and update
- **6** destructive wait for a confirmation

1. ### Client groups
   6
   3 read · 3 write · 0 destructive
   Create a client group · List client groups · Get a client group · Get a client group by its user-defined identifier
2. ### Contacts
   6
   3 read · 3 write · 0 destructive
   List contacts · Create a contact · Get a contact · Replace a contact
3. ### Organizations
   6
   3 read · 3 write · 0 destructive
   List organizations · Create an organization · Get an organization · Replace an organization
4. ### Webhook subscriptions
   5
   1 read · 2 write · 2 destructive
   Create a webhook subscription · Get the webhook subscription for a webhook type · Delete the webhook subscription for a webhook type · Delete all webhook subscriptions
5. ### Work items
   5
   2 read · 3 write · 0 destructive
   List work items · Create a work item · Get a work item · Replace a work item
6. ### Teams
   4
   2 read · 1 write · 1 destructive
   List teams · Get a team · Add members to a team · Remove a member from a team
7. ### Work schedules
   4
   1 read · 3 write · 0 destructive
   Create a work schedule · Get a work schedule · Replace a work schedule · End a work schedule
8. ### Custom fields
   3
   1 read · 1 write · 1 destructive
   Create a custom field definition · List custom field definitions · Delete a custom field definition

**18 more areas · 35 actions**

- Estimate summaries **3**
- Integration tasks **3**
- Manual payments **3**
- Users **3**
- Business cards **2**
- Custom field values **2**
- Files **2**
- Invoices **2**
- Notes **2**
- Payments **2**
- Time entries **2**
- Timesheets **2**
- Work templates **2**
- Comments **1**
- Expenses **1**
- Integration task definitions **1**
- Roles **1**
- Tenant settings **1**

Top actions

## The Karbon API, shaped for agents.

The ids your agent types, what each does, and the one name it shares with other systems. 32 of Karbon's 32 action names are shared with at least one other connector, so an agent learns them once.

| Action | What it does | Effect | Same name in |
| --- | --- | --- | --- |
| `karbon.contacts.list` List contacts | List contacts. | read | `crm.contact.list` 177 connectors |
| `karbon.organizations.list` List organizations | List organizations. | read | `crm.company.list` 162 connectors |
| `karbon.users.list` List users | List users. | read | `identity.user.list` 474 connectors |
| `karbon.contacts.create` Create a contact | Create a contact. | write | `crm.contact.create` 161 connectors |
| `karbon.invoices.list` List invoices | List invoices. | read | `finance.invoice.list` 101 connectors |
| `karbon.organizations.create` Create an organization | Create an organization. | write | `crm.company.create` 142 connectors |
| `karbon.payments.list` List payments | List payments. | read | `finance.payment.list` 75 connectors |
| `karbon.work_items.list` List work items | List work items. | read | `work.task.list` 122 connectors |
| `karbon.time_entries.list` List individual time entries | List individual time entries. | read | `work.time_entry.list` 59 connectors |
| `karbon.manual_payments.create` Record a manual payment against an invoice | Record a manual payment against an invoice. | write | `finance.payment.create` 67 connectors |
| `karbon.users.create` Invite a user | Invite a user. | write | `identity.user.create` 262 connectors |
| `karbon.manual_payments.delete` Delete a manual payment | Delete a manual payment. | destructive | `finance.payment.delete` 37 connectors |

Try it

## Prompts to paste into Claude.

Each one names the Karbon actions it will call, so you know what it reads and what it changes before you send it.

1. Read read
   Which Karbon invoices are more than 30 days overdue? Group them by customer with the total owed.
   calls `karbon.invoices.list`
2. Write write
   Create a contact in Karbon. Show me exactly what you will send before you save it.
   calls `karbon.contacts.create`
3. Across systems read
   Which Karbon companies have invoices in ConnectWise PSA, and how many each?
   calls `karbon.organizations.list` `connectwise_manage.invoices.list`

Across your systems

## Karbon, joined to the rest of your business.

One `ask` fetches from Karbon and another system, joins the rows on the same customer on our side, and hands your agent the answer, not every row.

- Which Karbon companies have invoices in ConnectWise PSA, and how many each?
  `karbon.organizations.list` + `connectwise_manage.invoices.list`, on `crm.company` · [ConnectWise PSA](https://actionlake.com/connectors/connectwise-psa)
- Which Karbon companies have tickets in HubSpot CRM, and how many each?
  `karbon.organizations.list` + `hubspot_crm.tickets.list`, on `crm.company` · [HubSpot CRM](https://actionlake.com/connectors/hubspot-crm)

Also mapped by other connectors `identity.user` **517** `crm.company` **227** `crm.contact` **192** `work.task` **105** `finance.invoice` **91** `finance.payment` **53** `work.time_entry` **40**

ask

```
ask {
  intent: "which Karbon companies have invoices in ConnectWise PSA, and how many each",
  steps: [
    { action: "karbon.organizations.list", as: "co", input: {}, limit: 100, max_pages: 5 },
    { action: "connectwise_manage.invoices.list", as: "inv", input: {}, limit: 100, max_pages: 5 },
    { join: {
        left: "co",
        right: "inv",
        on: "crm.company",
        group_by: "co.name",
        select: ["co.name", "count(inv.id) as invoices"]
    } }
  ]
}
```

Example. Run it through check first: it validates the steps and prices them, and it is free.

Governance for Karbon

## Destructive actions wait for a yes.

6 Karbon actions are destructive. These are all of them:

- Delete a manual payment `karbon.manual_payments.delete`
- Reverse a manual payment `karbon.manual_payments.reverse`
- Remove a member from a team `karbon.teams.remove_member`
- Delete a custom field definition `karbon.custom_fields.delete`
- Delete the webhook subscription for a webhook type `karbon.webhook_subscriptions.delete`
- Delete all webhook subscriptions `karbon.webhook_subscriptions.delete_all`

A destructive action runs only with `confirm: true`. Under the `human` policy the agent cannot confirm for itself: the run stops until a named person approves, in the console or from a signed link in an email. The cap on a key is refused before the call is sent, never after.

do karbon.manual_payments.delete confirm_policy: **human**

Delete a manual payment?

**intent:** the user asked me to delete a manual payment

run suspended · waiting for a named person · key _karbon-agent_ cannot confirm itself

In the console, or from an emailed signed link.

a key for this connector

```
account {
  op: "keys.create", name: "karbon-agent",
  allowed_actions: ["karbon.*"], cap_calls: 2000,
  confirm_policy: "human_for_writes",
  approval_rules: [
    { match: "karbon.manual_payments.delete", approver: "lead@example.com" },
    { match: "karbon.manual_payments.reverse", approver: "lead@example.com" },
    { match: "karbon.teams.remove_member", approver: "lead@example.com" }
  ]
}
```

Illustrative. Scoped to Karbon only, capped at 2,000 upstream calls, every write confirmed, and the destructive ones approved by a named person.

Cost

## What Karbon costs on actionlake.

Every Karbon action is one upstream call, the only thing actionlake bills. Searching, `check`, `cost`, `account` and any call Karbon refused with 401, 403, 429 or a 5xx are free. Paid plans start at US$49 a month for 250,000 calls, with overage from US$0.30 down to US$0.18 per 1,000.

- 1 upstream call per action all 74 Karbon actions
- 74 actions page each page of a long list is one call
- 41 reads can be cached a cache hit costs nothing
- 100,000 calls a month, free paid plans from US$49 a month for 250,000

[See pricing](https://actionlake.com/pricing)

Action index

## Every Karbon action.

74 actions by area: the id your agent calls, what it does, and its effect.

**Client groups 6**

- `karbon.client_groups.create` Create a client group write
- `karbon.client_groups.get` Get a client group read
- `karbon.client_groups.get_by_user_defined_identifier` Get a client group by its user-defined identifier read
- `karbon.client_groups.list` List client groups read
- `karbon.client_groups.patch` Update a client group's name write
- `karbon.client_groups.update` Replace a client group write

**Contacts 6**

- `karbon.contacts.create` Create a contact write
- `karbon.contacts.get` Get a contact read
- `karbon.contacts.get_by_user_defined_identifier` Get a contact by its user-defined identifier read
- `karbon.contacts.list` List contacts read
- `karbon.contacts.patch` Update selected fields of a contact write
- `karbon.contacts.update` Replace a contact write

**Organizations 6**

- `karbon.organizations.create` Create an organization write
- `karbon.organizations.get` Get an organization read
- `karbon.organizations.get_by_user_defined_identifier` Get an organization by its user-defined identifier read
- `karbon.organizations.list` List organizations read
- `karbon.organizations.patch` Update an organization's name write
- `karbon.organizations.update` Replace an organization write

**Webhook subscriptions 5**

- `karbon.webhook_subscriptions.create` Create a webhook subscription write
- `karbon.webhook_subscriptions.delete` Delete the webhook subscription for a webhook type destructive
- `karbon.webhook_subscriptions.delete_all` Delete all webhook subscriptions destructive
- `karbon.webhook_subscriptions.get` Get the webhook subscription for a webhook type read
- `karbon.webhook_subscriptions.update` Update a webhook subscription write

**Work items 5**

- `karbon.work_items.create` Create a work item write
- `karbon.work_items.get` Get a work item read
- `karbon.work_items.list` List work items read
- `karbon.work_items.patch` Update selected fields of a work item write
- `karbon.work_items.update` Replace a work item write

**Teams 4**

- `karbon.teams.add_members` Add members to a team write
- `karbon.teams.get` Get a team read
- `karbon.teams.list` List teams read
- `karbon.teams.remove_member` Remove a member from a team destructive

**Work schedules 4**

- `karbon.work_schedules.create` Create a work schedule write
- `karbon.work_schedules.end` End a work schedule write
- `karbon.work_schedules.get` Get a work schedule read
- `karbon.work_schedules.update` Replace a work schedule write

**Custom fields 3**

- `karbon.custom_fields.create` Create a custom field definition write
- `karbon.custom_fields.delete` Delete a custom field definition destructive
- `karbon.custom_fields.list` List custom field definitions read

**Estimate summaries 3**

- `karbon.estimate_summaries.get` Get an estimate summary read
- `karbon.estimate_summaries.list` List estimate summaries for a work item read
- `karbon.estimate_summaries.update` Update an estimate summary write

**Integration tasks 3**

- `karbon.integration_tasks.get` Get an integration task read
- `karbon.integration_tasks.list` List integration tasks read
- `karbon.integration_tasks.update` Update an integration task write

**Manual payments 3**

- `karbon.manual_payments.create` Record a manual payment against an invoice write
- `karbon.manual_payments.delete` Delete a manual payment destructive
- `karbon.manual_payments.reverse` Reverse a manual payment destructive

**Users 3**

- `karbon.users.create` Invite a user write
- `karbon.users.get` Get a user read
- `karbon.users.list` List users read

**Business cards 2**

- `karbon.business_cards.get` Get a business card read
- `karbon.business_cards.update` Update a business card write

**Custom field values 2**

- `karbon.custom_field_values.get` Get custom field values for a contact or organization read
- `karbon.custom_field_values.update` Set custom field values for a contact or organization write

**Files 2**

- `karbon.files.get` Get file details and a download link read
- `karbon.files.list` List files attached to an entity read

**Invoices 2**

- `karbon.invoices.get` Get an invoice read
- `karbon.invoices.list` List invoices read

**Notes 2**

- `karbon.notes.create` Create a note write
- `karbon.notes.get` Get a note read

**Payments 2**

- `karbon.payments.get` Get a payment read
- `karbon.payments.list` List payments read

**Time entries 2**

- `karbon.time_entries.get` Get an individual time entry read
- `karbon.time_entries.list` List individual time entries read

**Timesheets 2**

- `karbon.timesheets.get` Get a timesheet read
- `karbon.timesheets.list` List timesheets read

**Work templates 2**

- `karbon.work_templates.get` Get a work template read
- `karbon.work_templates.list` List work templates read

**Comments 1**

- `karbon.comments.get` Get a comment read

**Expenses 1**

- `karbon.expenses.create` Create an expense write

**Integration task definitions 1**

- `karbon.integration_task_definitions.list` List integration task definitions read

**Roles 1**

- `karbon.roles.list` List roles read

**Tenant settings 1**

- `karbon.tenant_settings.get` Get tenant settings (work types, statuses, contact types) read

Questions

## The Karbon MCP server, answered.

**Is there a Karbon MCP server for Claude?**

Yes. actionlake is an MCP gateway: a remote MCP server that gives Claude, or another MCP client, 74 Karbon actions across client groups, contacts, organizations and webhook subscriptions, through the same eight tools it uses for every other connector. actionlake is independent; it is not made or endorsed by Karbon.

**What do I need to connect Karbon?**

Application ID (the 36-character GUID bearer token) from Karbon Settings > Connected Apps > API Applications and Access Key (a JWT starting eyJ…) from the same API Application. The free call account { op: "connections.requirements", service: "karbon" } lists exactly what to paste.

**Can an AI agent delete or change things in Karbon?**

Only if its key allows it, and only with an explicit confirmation. 6 Karbon actions are destructive, including delete a manual payment, reverse a manual payment and remove a member from a team. Each runs only with confirm: true. Under the human confirm policy, or an approval rule on the key, the run waits until a named person approves it.

**Will an AI agent use up my Karbon API limit?**

actionlake paces every call to the limits in the Karbon service file: 120 calls a minute per connection. Repeated reads are answered from cache (41 Karbon actions can be), which never reaches Karbon.

**What does a Karbon action cost?**

One upstream call, the only unit actionlake bills. A list that pages bills one call per page (74 Karbon actions page). Cache hits, searches, dry runs and calls Karbon refused with 401, 403, 429 or a 5xx are free. The Free plan includes 100,000 calls a month with no card. Paid plans start at US$49 a month for 250,000 calls, with overage from US$0.30 down to US$0.18 per 1,000.

**Which Karbon API does it cover?**

The Karbon API v3 (v3, OpenAPI 3.1.0) at api.karbonhq.com. It is built from Karbon's documentation as read on 23 October 2026. 74 actions in 26 areas, each one in the signed service file (version 1.0.0).

**Can I combine Karbon with my other systems?**

Yes. ask joins Karbon to ConnectWise PSA or HubSpot CRM on the same customer and returns the answer rather than every row. Karbon maps crm.company, which 227 other connectors also map.

**Does actionlake keep my Karbon data, and where?**

actionlake processes and stores data in Sydney, Australia; there is no US region yet. Reads may be cached for up to 5 minutes, and a write clears the reads it affects. Each run's request and response is kept, sealed, for your plan's trace window: 1 day on Free, 3 days on Starter, 7 days on Pro, 14 days on Team, 30 days on Business and 30 days on Enterprise. Your Karbon credential is sealed under your tenant's key, never logged and never returned. Your traffic is not used to train models.

**Which AI clients can use it?**

Claude Code, tested by us end to end, and the Claude app as a custom connector, tested by us with an existing key. Other MCP clients that support remote servers over Streamable HTTP (MCP revisions 2025-06-18 and 2025-11-25) and OAuth dynamic client registration, or a bearer header, should connect the same way; we have not tested them. Or plain REST, under the same action names.

## More connectors like Karbon

Shares the most action names with

- [Harvest 24](https://actionlake.com/connectors/harvest)
- [Smokeball 20](https://actionlake.com/connectors/smokeball)
- [Hubstaff 17](https://actionlake.com/connectors/hubstaff)
- [ChartMogul 17](https://actionlake.com/connectors/chartmogul)
- [DoorLoop 17](https://actionlake.com/connectors/doorloop)
- [Open Dental 14](https://actionlake.com/connectors/open-dental)

Joins with, on shared entities

- [HaloPSA 6](https://actionlake.com/connectors/halopsa)
- [Productive.io 6](https://actionlake.com/connectors/productive-io)
- [Kaseya BMS 6](https://actionlake.com/connectors/kaseya-bms)
- [Rev.io 6](https://actionlake.com/connectors/rev-io)
- [Planhat 6](https://actionlake.com/connectors/planhat)
- [Fergus 6](https://actionlake.com/connectors/fergus)

Browse

- [All Accounting & finance connectors](https://actionlake.com/connectors/category/accounting-and-finance)
- [All connectors](https://actionlake.com/connectors)
- [How actionlake compares](https://actionlake.com/compare)

actionlake is independent. It is not made or endorsed by Karbon; the name is the vendor's own. Counts are from the Karbon service file, version 1.0.0.

## Give your agent Karbon today.

[Connect Karbon free](https://actionlake.com/console?start=sandbox) [See pricing](https://actionlake.com/pricing)

Start free - 100,000 calls/month, no card. No signup. Hard caps on every key. Cached answers are free.

---

Source: https://actionlake.com/connectors/karbon
More: https://actionlake.com/llms.txt