How to Connect Harvest to Claude (and What It Can't Do)
Harvest is one of the few time trackers that now ships its own official MCP server. As of mid-2026 you won’t find a Harvest tile in Claude’s connectors directory, but Harvest publishes a first-party Harvest MCP that you add to Claude as a custom connector and authorize with a normal Harvest sign-in. Two catches before you get excited: custom connectors require a paid Claude plan, and the connection only does anything inside a chat you open. Claude never touches your Harvest account between conversations.
What the official Harvest MCP covers
Harvest kept the scope tight and practical. Once authorized, Claude can:
- Run timers — start one on any project and task (with a note), stop whatever’s running, and check whether the clock is going at all.
- Review tracked time — logged hours by project or client, billable versus non-billable, and how a project is tracking against its budget.
- Handle expenses — log a new expense, edit an existing one, and browse your expense categories.
- Submit timesheets — send a date range off for approval without opening the Harvest app.
Access mirrors your Harvest role: you can edit your own entries but not a teammate’s, and whether you can see other people’s hours depends on your permissions. Notably absent from the tool list: invoices. Turning tracked billables into an invoice — the reason many freelancers pay for Harvest in the first place — still happens in the Harvest app. Community servers like southleft/harvest-mcp wrap more of the Harvest v2 API if you need broader reach and don’t mind self-hosting.
Connecting it
Open Settings → Connectors in Claude, add a custom connector, and paste the server address from Harvest’s help article. Claude hands you off to Harvest’s OAuth screen; approve it and you’re done — no API tokens to copy around. Since it’s Harvest’s own server, the trust question is simpler than with a random community repo, but the paid-plan requirement for custom connectors still applies.
What a Harvest user would actually type
The connector earns its keep in the small, frequent moments of a billing week:
“Start a timer on the Meridian retainer under Design QA — note that I’m reviewing homepage comps.”
“How many billable hours have we logged against Brightline this month, and how close is that to the 40-hour retainer?”
“Log a $84 client dinner to the Atlas project and submit my timesheet for June 22–28.”
Claude executes each of these, confirms what it did, and can reason across the results — which client ate your week, whether a fixed-fee project is quietly going underwater.
The invoicing gap, and the bigger one behind it
The missing invoice tools are an annoyance. The structural limit is bigger: nothing happens unless you’re in the chat asking. Claude can tell you the Brightline retainer is 92% burned if you think to ask on the right day. It cannot invoice the client when the retainer runs out, nudge a contractor who hasn’t submitted hours by Thursday, or email you when a fixed-fee project crosses 90% of budget — there are no schedules and no event triggers on any Claude connector, official or not. For a solo consultant who bills monthly, that means the month-end scramble stays a scramble.
Handing the billing loop to Carly
Carly is an AI executive assistant designed around exactly the part Claude leaves out: acting on triggers. Instead of you asking about retainer burn, Carly watches for it. A few Harvest-shaped workflows people run on it:
- When a project’s tracked hours cross a threshold, get an alert — or have Carly draft the client email before you’ve noticed.
- At month end, pull each client’s billables, assemble the summary, and send it (Gmail and Outlook, attachments included), not just draft it.
- After every calendar meeting with a client, log the time to the right Harvest project automatically.
You describe the workflow in plain English — “when the Meridian retainer hits 90%, email me the hours breakdown” — and Carly interviews you, then builds it. It runs in the cloud around the clock, so nothing depends on your laptop or your memory. AI agents start at $35/month, and steps in a workflow that don’t use AI run free and unlimited. See integrations and the Harvest integration page.
Side by side
| Claude + Harvest MCP | Carly | |
|---|---|---|
| Start/stop timers, log expenses | Yes (when you ask in chat) | Yes (on triggers or schedule) |
| Billable-hours and budget questions | Yes | Yes |
| Creates and sends the client invoice | No (MCP exposes no invoice tools) | Yes — drafts and sends via Gmail/Outlook |
| Acts when a retainer or budget runs low | No | Yes |
| Chases unsubmitted timesheets before payroll | No | Yes |
| Runs while your laptop is closed | No | Yes (cloud) |
| Cost of entry | Paid Claude plan | AI agents from $35/mo |
One is a very capable Harvest keyboard replacement. The other keeps the billing loop turning whether or not you show up.
Frequently Asked Questions
Does Claude integrate with Harvest?
Yes — and unusually, through an official server. Harvest publishes its own Harvest MCP, which you add to Claude as a custom connector (paid Claude plan required) and authorize via Harvest sign-in. It handles timers, time review, expenses, and timesheet submission inside a chat.
Can Claude create or send Harvest invoices?
Not through the official MCP — as of mid-2026 its tools stop at timers, expenses, and timesheets. Some community servers reach the invoice endpoints of Harvest’s v2 API, but even then Claude only acts when prompted in a chat, and sending the invoice to your client is still on you.
Is the Harvest MCP free to use?
Harvest doesn’t charge for the MCP itself, but connecting it to Claude requires a paid Claude plan, since custom connectors aren’t available on the free tier.
Can Claude invoice a client automatically when a retainer runs out?
No. No Claude connector fires on events or schedules — someone has to be in the conversation asking. Trigger-driven billing is what an agent platform like Carly is for.
What does Carly do with Harvest that Claude can’t?
Carly acts without being prompted: retainer-burn alerts, month-end billing summaries emailed to you or the client, time logged after meetings, timesheet chasing before payroll. AI agents start at $35/month.
More: Claude connectors · Can Claude send emails · Claude vs Carly · Claude Cowork alternatives · Best AI tools for consultants · Claude + Toggl · Claude + TickTick · Claude + Clockify
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