Install Jentic One Beta

Connect the Harpoon API to your agent

Jentic One is a self-hosted execution layer for AI agents. It lets your agent call the Harpoon API, or any other public or private API you need. You set the rules, the agent never sees your credentials, and every call is logged.

Two steps, two machines. Install the instance in a safe environment, then register your agent from wherever it runs.

Step 1: Jentic One Host machine

# On the machine that will host your Jentic One instance:
curl -fsSL "https://jentic.com/install.sh?src=apis&api=%2Fapis%2Fharpoonapp.com%2Fharpoonapp" | sh

Step 2: Agent machine

# On the machine where your agent runs (keep this separate from the instance):
curl -fsSL "https://jentic.com/install.sh?src=apis&api=%2Fapis%2Fharpoonapp.com%2Fharpoonapp" | sh
jentic register       # connects your agent to your Jentic One instance

Jentic One is in public beta. The setup above keeps your agent separate from the instance, which is what you want before using real credentials: an agent running as the same OS user as Jentic One can read its stored keys directly. Just evaluating? A single local install is fine to start. See the secure deployment guide for the tiers.

Capabilities

What an agent can do with Harpoon API.

Create, list, fetch, update, and delete clients in a Harpoon workspace

Manage contacts attached to a client

Issue and look up client credits

Generate estimates with auto-incrementing document IDs

Track expected revenue records for forecasting

GET STARTED

Start building with Harpoon API

Explore with Jentic One

View OpenAPI Document

Use Cases

Patterns agents use Harpoon API for, with concrete tasks.

★ Freelance Invoicing Automation

Automate invoice creation when a freelancer marks a project complete by calling POST /estimates to draft an estimate and converting it to an invoice via the Invoices endpoints. The Harpoon API auto-allocates document IDs through GET /estimates/next-document-id so numbering stays consistent. Most freelancers integrate this with a time-tracker to capture billable hours.

Fetch the next estimate ID from GET /estimates/next-document-id, then POST /estimates with the line items for project 'Brand Refresh'.

Revenue Forecasting Dashboard

Pipe expected revenue records into a forecasting dashboard by calling GET /expected-revenue and listing forecasted amounts by client. The endpoint returns expected revenue items with amounts, dates, and clientIds that a BI tool can roll up into monthly run-rate. Freelancers use this to project cash flow.

List all expected revenue via GET /expected-revenue and group by month and clientId for a 90-day forecast.

Client and Contact Sync

Keep the freelancer's CRM and accounting workspace in sync by mirroring clients and their contacts via /clients and /contacts. The API supports list, get, create, update, and delete on both resources, enabling two-way reconciliation. Pair this with a CRM webhook to trigger on every contact change.

When a new contact is added in HubSpot, call POST /contacts in Harpoon with the same email, name, and clientId.

AI Agent Billing Assistant

Wire a billing assistant that responds to 'create an invoice for client X for project Y' by chaining the estimate, invoice, and expense endpoints through Jentic. The Bearer token sits in your Jentic One instance and is injected per call. Harpoon does not include payment capture, so the agent ends at invoice issuance, not collection.

When asked 'invoice Acme for 12 hours of strategy work at $200/hr', create an estimate with the line items, convert to invoice, and return the invoice ID.

Key Endpoints

36 endpoints — harpoon is a financial planning and management platform built for freelancers and small agencies, focused on revenue forecasting, invoicing, and expense tracking.

METHOD

PATH

DESCRIPTION

GET

/clients

List clients

POST

/clients

Create a client

POST

/contacts

Create a contact

GET

/estimates/next-document-id

Get the next estimate document ID

POST

/estimates

Create an estimate

GET

/expected-revenue

List expected revenue records

POST

/credits

Issue a client credit

GET

/clients

List clients

POST

/clients

Create a client

POST

/contacts

Create a contact

GET

/estimates/next-document-id

Get the next estimate document ID

POST

/estimates

Create an estimate

GET

/expected-revenue

List expected revenue records

POST

/credits

Issue a client credit

Why Jentic?

What agents get from Jentic-routed access to this vendor.

Setup

Wiring the Harpoon API by hand means setting its Authorization Bearer token on every call and building each client, estimate, invoice, and revenue request yourself. Through Jentic you install once, import the Harpoon API from the API Directory, store the token once, and your agent calls it.

Permission scoping

The Harpoon API carries its targets in the request body against collection endpoints like /clients and /estimates, so scope your agent to the operations it needs, such as reading clients or expected revenue. You choose what it may call, so creating clients, estimates, or credits are not included unless you add them.

Credential isolation

Your Harpoon personal access token is stored once, encrypted, by your own Jentic One instance and injected as the Authorization Bearer header at execution time. It never enters the agent's prompt, logs, or context.

Intent-based discovery

Agents search Jentic by intent such as 'create a freelance invoice' or 'check expected revenue', and Jentic returns the matching Harpoon operation with its input schema so the agent calls the right endpoint without reading the developer docs.

FAQs

Specific to using Harpoon API through Jentic.

What authentication does the Harpoon API use?

Harpoon uses HTTP Bearer authentication. Generate a personal access token in the Harpoon dashboard and include it as Authorization: Bearer <token>. Through Jentic the token is stored in the encrypted vault and injected per call so it never enters the agent's prompt context.

Can I create estimates with auto-incrementing IDs in Harpoon?

Yes. Call GET /estimates/next-document-id to retrieve the next document ID, then include it in the POST /estimates body. This keeps estimate numbering consistent without race conditions across multiple integrations.

What are the rate limits for the Harpoon API?

Harpoon does not publish a public per-second rate limit in the OpenAPI spec; the API is intended for individual freelancer and small agency volumes. Build clients to back off on HTTP 429, and contact Harpoon support if a high-volume integration is planned.

How do I create an invoice through Jentic?

Search Jentic for 'create a harpoon invoice', load the schema for the invoice creation operation, and execute with clientId and line items. Run pip install jentic and use the async client.search, client.load, and client.execute pattern.

Does the Harpoon API include payment processing?

No. Harpoon focuses on invoicing, estimates, expenses, and revenue forecasting. Payment capture (credit card or ACH) is handled by external processors; the API records that an invoice is paid but does not charge cards itself.

Can I limit what my agent is allowed to do with the Harpoon API?

Yes. Because you run Jentic One yourself, your own rules decide which Harpoon operations and credentials the agent may use. The Harpoon API carries its targets in the request body against collection endpoints like /clients and /estimates, so you can scope the agent to only the operations it needs, such as reading clients with GET /clients or listing forecasts with GET /expected-revenue. Write operations like POST /estimates, POST /clients, or POST /credits stay off limits unless you explicitly grant them.

Harpoonapp Harpoon API

Name: Harpoon API
Brand: Harpoon API
Availability: InStock

Official vendor OpenAPI document · agent-readyFinanceAccountingbearer36 EndpointsREST

For Agents

Manage Harpoon clients, contacts, estimates, invoices, expenses, and expected revenue with a Bearer token.

Use for: Create a new client in Harpoon, List all open invoices for the agency, Add a contact to an existing Harpoon client, Generate an estimate with the next available document ID

Not supported: Does not handle payment capture, payroll, or bank feed reconciliation - use for freelance and agency financial records (clients, estimates, invoices, expenses, revenue forecasts) only.

Harpoon is a financial planning and management platform built for freelancers and small agencies, focused on revenue forecasting, invoicing, and expense tracking. The API exposes 36 endpoints to manage clients, contacts, credits, estimates, invoices, expenses, and expected revenue records. Authentication is HTTP Bearer using a personal access token issued from the Harpoon dashboard. The API focuses on financial records - it does not run payroll or sync directly to external bank feeds.

Jentic One on Github View OpenAPI Document

Connect the Harpoon API to your agent

Capabilities

Start building with Harpoon API

Use Cases

Key Endpoints

Why Jentic?

Related APIs

FAQs

Harpoonapp Harpoon API