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 See 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

74actionsin one signed file
41readlook, never change
27writecreate and update
6wait for a yesdestructive, confirmed first

Set up

Connect Karbon in three steps.

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
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_idApplication ID (the 36-character GUID bearer token) from Karbon Settings > Connected Apps > API Applications
- access_keyAccess 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
```

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 callcheck { 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_idaccess_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 2026karbonhq.github.io 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.

41readlook, never change
27writecreate and update
6destructivewait for a confirmation

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
Contacts
6
3 read · 3 write · 0 destructive
List contacts · Create a contact · Get a contact · Replace a contact
Organizations
6
3 read · 3 write · 0 destructive
List organizations · Create an organization · Get an organization · Replace an organization
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
Work items
5
2 read · 3 write · 0 destructive
List work items · Create a work item · Get a work item · Replace a work item
Teams
4
2 read · 1 write · 1 destructive
List teams · Get a team · Add members to a team · Remove a member from a team
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
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.

Readread
Which Karbon invoices are more than 30 days overdue? Group them by customer with the total owed.
callskarbon.invoices.list
Writewrite
Create a contact in Karbon. Show me exactly what you will send before you save it.
callskarbon.contacts.create
Across systemsread
Which Karbon companies have invoices in ConnectWise PSA, and how many each?
callskarbon.organizations.listconnectwise_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
Which Karbon companies have tickets in HubSpot CRM, and how many each?
karbon.organizations.list + hubspot_crm.tickets.list, on crm.company · HubSpot CRM

Also mapped by other connectorsidentity.user 517crm.company 227crm.contact 192work.task 105finance.invoice 91finance.payment 53work.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 paymentkarbon.manual_payments.delete
Reverse a manual paymentkarbon.manual_payments.reverse
Remove a member from a teamkarbon.teams.remove_member
Delete a custom field definitionkarbon.custom_fields.delete
Delete the webhook subscription for a webhook typekarbon.webhook_subscriptions.delete
Delete all webhook subscriptionskarbon.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.

dokarbon.manual_payments.deleteconfirm_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: "[email protected]" },    { match: "karbon.manual_payments.reverse", approver: "[email protected]" },    { match: "karbon.teams.remove_member", approver: "[email protected]" }  ]}

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.

1upstream call per actionall 74 Karbon actions
74actions pageeach page of a long list is one call
41reads can be cacheda cache hit costs nothing
100,000calls a month, freepaid plans from US$49 a month for 250,000

See pricing

Action index

Every Karbon action.

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

Client groups6

karbon.client_groups.createCreate a client groupwrite
karbon.client_groups.getGet a client groupread
karbon.client_groups.get_by_user_defined_identifierGet a client group by its user-defined identifierread
karbon.client_groups.listList client groupsread
karbon.client_groups.patchUpdate a client group's namewrite
karbon.client_groups.updateReplace a client groupwrite

Contacts6

karbon.contacts.createCreate a contactwrite
karbon.contacts.getGet a contactread
karbon.contacts.get_by_user_defined_identifierGet a contact by its user-defined identifierread
karbon.contacts.listList contactsread
karbon.contacts.patchUpdate selected fields of a contactwrite
karbon.contacts.updateReplace a contactwrite

Organizations6

karbon.organizations.createCreate an organizationwrite
karbon.organizations.getGet an organizationread
karbon.organizations.get_by_user_defined_identifierGet an organization by its user-defined identifierread
karbon.organizations.listList organizationsread
karbon.organizations.patchUpdate an organization's namewrite
karbon.organizations.updateReplace an organizationwrite

Webhook subscriptions5

karbon.webhook_subscriptions.createCreate a webhook subscriptionwrite
karbon.webhook_subscriptions.deleteDelete the webhook subscription for a webhook typedestructive
karbon.webhook_subscriptions.delete_allDelete all webhook subscriptionsdestructive
karbon.webhook_subscriptions.getGet the webhook subscription for a webhook typeread
karbon.webhook_subscriptions.updateUpdate a webhook subscriptionwrite

Work items5

karbon.work_items.createCreate a work itemwrite
karbon.work_items.getGet a work itemread
karbon.work_items.listList work itemsread
karbon.work_items.patchUpdate selected fields of a work itemwrite
karbon.work_items.updateReplace a work itemwrite

Teams4

karbon.teams.add_membersAdd members to a teamwrite
karbon.teams.getGet a teamread
karbon.teams.listList teamsread
karbon.teams.remove_memberRemove a member from a teamdestructive

Work schedules4

karbon.work_schedules.createCreate a work schedulewrite
karbon.work_schedules.endEnd a work schedulewrite
karbon.work_schedules.getGet a work scheduleread
karbon.work_schedules.updateReplace a work schedulewrite

Custom fields3

karbon.custom_fields.createCreate a custom field definitionwrite
karbon.custom_fields.deleteDelete a custom field definitiondestructive
karbon.custom_fields.listList custom field definitionsread

Estimate summaries3

karbon.estimate_summaries.getGet an estimate summaryread
karbon.estimate_summaries.listList estimate summaries for a work itemread
karbon.estimate_summaries.updateUpdate an estimate summarywrite

Integration tasks3

karbon.integration_tasks.getGet an integration taskread
karbon.integration_tasks.listList integration tasksread
karbon.integration_tasks.updateUpdate an integration taskwrite

Manual payments3

karbon.manual_payments.createRecord a manual payment against an invoicewrite
karbon.manual_payments.deleteDelete a manual paymentdestructive
karbon.manual_payments.reverseReverse a manual paymentdestructive

Users3

karbon.users.createInvite a userwrite
karbon.users.getGet a userread
karbon.users.listList usersread

Business cards2

karbon.business_cards.getGet a business cardread
karbon.business_cards.updateUpdate a business cardwrite

Custom field values2

karbon.custom_field_values.getGet custom field values for a contact or organizationread
karbon.custom_field_values.updateSet custom field values for a contact or organizationwrite

Files2

karbon.files.getGet file details and a download linkread
karbon.files.listList files attached to an entityread

Invoices2

karbon.invoices.getGet an invoiceread
karbon.invoices.listList invoicesread

Notes2

karbon.notes.createCreate a notewrite
karbon.notes.getGet a noteread

Payments2

karbon.payments.getGet a paymentread
karbon.payments.listList paymentsread

Time entries2

karbon.time_entries.getGet an individual time entryread
karbon.time_entries.listList individual time entriesread

Timesheets2

karbon.timesheets.getGet a timesheetread
karbon.timesheets.listList timesheetsread

Work templates2

karbon.work_templates.getGet a work templateread
karbon.work_templates.listList work templatesread

Comments1

karbon.comments.getGet a commentread

Expenses1

karbon.expenses.createCreate an expensewrite

Integration task definitions1

karbon.integration_task_definitions.listList integration task definitionsread

Roles1

karbon.roles.listList rolesread

Tenant settings1

karbon.tenant_settings.getGet 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.

Give your agent Karbon today.

Connect Karbon free See pricing

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

Karbon MCP server for AI agents.

Connect Karbon in three steps.

Add actionlake to Claude.

Connect Karbon.

Make the first call. Check before a write.

What an AI agent can do in Karbon.

Client groups

Contacts

Organizations

Webhook subscriptions

Work items

Teams

Work schedules

Custom fields