Claude + Karbon: What It Can (and Can't) Do in 2026
Karbon now runs an official MCP server, and it connects to Claude. It lives at mcp.karbonhq.com/mcp, Karbon’s developer docs link to it, and you add it in Claude as a custom connector and sign in with your normal Karbon login. No API key, no server to host, no developer.
Karbon’s REST API is a separate thing, and it’s plan-gated: Business and Enterprise only. Here’s how to set up the connector, what the API needs, the limits of both, and what to use if you want Karbon work to happen without you.
Connecting Karbon’s MCP server to Claude
- In Claude, open Customize → Connectors and add a custom connector.
- Paste
https://mcp.karbonhq.com/mcpas the server URL. - When Karbon’s sign-in page opens, log in with your Karbon account and approve access.
The server asks for read and write access, so Claude can look up clients and work items and update records from the chat.
Karbon’s API: Business and Enterprise only
Unlike TaxDome (no public API) and Canopy (approval-gated), Karbon lets you create API credentials yourself, as long as your firm is on the right plan:
- Plan-gated. The REST API comes with the Business and Enterprise plans; the Team plan doesn’t include it. Each firm gets one API application.
- Where the keys live. In Karbon, go to Settings → Connected Apps → API Applications to create it. It issues an application ID and an access key together.
- A broad API. Karbon’s public API reaches contacts and organizations, work items (including from templates), invoices and payments, notes, teams, and webhooks — the actual work, not just the client list.
- It’s a key-and-header login. The API authenticates with the application ID as a bearer token plus the access key in a header. That’s what a developer or an automation tool uses. For chatting with Karbon in Claude, the MCP server’s sign-in replaces all of it.
Community connectors and Zapier
Before the official server went live, developers built small community connectors for Karbon on top of the API. A few exist on GitHub, but they’re early, lightly maintained, and need your API keys, so with Karbon’s own server available there’s little reason to run one.
There’s also Zapier: Karbon is on it (connect via your access key under Settings → Connected Apps → Zapier), but it’s in early access and thin — the triggers and actions are contacts-only (person and organization records), with no work-item or invoice events. So Zapier reaches the client shell, not the workflow.
What Karbon ships on its own
Worth separating from any Claude integration: Karbon has its own AI. Karbon AI (email drafting, thread and timeline summaries, client briefs) runs on Microsoft’s Azure OpenAI service, and Karbon launched Kai, an “AI coworker,” in June 2026 for data entry, follow-ups, and onboarding. Those run inside Karbon; they don’t connect to your Claude account. They’re the vendor’s own features, not a Claude bridge.
The limit that matters: nothing in Karbon can start Claude
Here’s the catch even the best connector doesn’t fix: everything Claude does starts with you asking or with a clock.
- It never notices anything. A connector can expose Karbon’s data, but there’s nothing on the Claude side catching “a work item hit ready-for-review” or “a client just replied” and acting on it.
- Scheduled, but not triggered. Claude’s scheduled tasks do run unattended — remotely, on a clock you set, app closed. They fire at 8am because you said 8am, not when a work item moves or a client replies.
- The gap is where practice work slips. A review that clears at 4pm gets its handoff tomorrow morning, and a client email lands in a batch instead of an answer.
And email? Claude’s Gmail connector asks you to approve every send, and its Outlook add-in doesn’t send at all. You could pay a developer to build sending in too, but it’s one more thing to maintain, and nothing in Karbon can be what sets it off.
So Claude with a Karbon connector is good for “pull the Delgado engagement and summarize where it stands,” and not built for “every time a work item hits review, tell the manager and update the client.”
If you want Karbon work to happen on its own: Carly
The moment you want something to happen in Karbon without you in the chat — a note logged the instant a client emails, the manager pinged when a job hits review, a client updated when their work moves — you’ve crossed past what Claude is for.
That’s where Carly fits. Add Karbon’s MCP server under Connect an API at carlyassistant.com/integrations, or on Business or Enterprise paste your API application keys there, and Carly works the events and schedules for you, 24/7 in the cloud, starting from what happened rather than what time it is:
- When a work item hits “ready for review” → Carly notifies the manager and updates the client on timing.
- When a client replies to an email → Carly logs the note on the work item and creates the follow-up task.
- When a job is completed → Carly sends the client the wrap-up note and the invoice reminder.
- When a deadline is a week out and work is still open → Carly chases the missing pieces so nothing slips past filing day.
Carly connects to thousands of apps, Karbon included, and it drafts and sends email across Gmail and Outlook, manages your calendar, and handles tasks. Free Zapier-style workflows; AI agents from $35/month. For more options, see the best AI automation tools for Karbon.
Claude vs Carly for Karbon
| Claude (Karbon’s MCP server) | Carly | |
|---|---|---|
| Look up work items, contacts & notes | Yes | Yes |
| Create/update records | Yes (in chat) | Yes |
| Acts the moment something happens (job moves, client replies) | No | Yes |
| Chases open work before deadlines on its own | No | Yes |
| Has its own inbox for work to land in | No | Yes |
| Sends the emails itself, not just drafts | No, every send waits on your approval | Yes |
| What it takes to set up | Add Karbon’s MCP server as a custom connector, sign in | Add Karbon’s MCP server, or paste your API keys (Business/Enterprise) |
| Pricing | Claude Pro $20 / Max $100–$200 | AI agents from $35/mo |
Claude with Karbon’s MCP server is a Karbon lookup and edit inside a chat. Carly is a teammate that acts on your workflow — reviews, replies, deadlines — the moment each one happens.
Frequently Asked Questions
Does Claude work with Karbon?
Yes. Karbon runs an official MCP server at mcp.karbonhq.com/mcp. In Claude, go to Customize → Connectors, add it as a custom connector, and sign in with your Karbon login. Like every Claude connector, it works inside a conversation you start.
Is Karbon’s official MCP server live?
Yes. It’s live at mcp.karbonhq.com/mcp and linked from Karbon’s developer docs. You sign in with your Karbon login, so it doesn’t need API keys. Community connectors and Zapier still exist, but the official server is the simpler path.
How do I get a Karbon API key?
API access comes with Karbon’s Business and Enterprise plans, not Team. In Karbon, go to Settings → Connected Apps → API Applications to create your firm’s one API application, which gives you an application ID and an access key. You don’t need either to use Karbon’s MCP server.
What if I want Karbon to act on its own — log notes, notify managers, chase deadlines?
That’s outside what Claude does; a scheduled task can sweep your job list on a timer, but nothing acts on Karbon’s events. Carly fires on Karbon events and schedules 24/7 in the cloud and can log notes, create tasks, notify your team, and send email through Karbon’s MCP server or your API keys. AI agents start at $35/month.
More: Claude connectors · Claude + Canopy · Claude + TaxDome · Claude + QuickBooks · Can Claude send emails · Claude vs Carly
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