Otis

com.otisbasePublished by otisbase.comOfficial publisherv0.1.0Updated Oct 27, 2026

Free client billing for AI assistants: hours, expenses, timers, invoices and payments.

VerifiedStreamable HTTPWeb executableProductivity & WorkflowFinanceBusiness & Commerce

Overview

AI-generated overview

Otis is a hosted MCP server for freelance and small-agency client billing: an assistant records clients, time, expenses and payments and issues invoices you…

What you can do
  • Record clients and their billing details, plus business details, tax settings and invoice numbering
  • Log billable time, services, reported AI usage and expenses
  • Create draft invoices with discounts and tax, then issue them once you confirm the exact total
  • Record full and partial payments with references that prevent duplicates
  • Export the complete business records
When to use it
Useful for consultants and small agencies that want to bill clients conversationally from an AI assistant instead of a separate app or dashboard, including tracking hours and expenses and turning them into invoices.
Requirements
Remote MCP endpoint added to the assistant; sign-in uses OAuth with an email code, so no API key is needed. Records are stored in the EU. Self-hosting requires a Cloudflare account, Node 24 or newer, a KV namespace and email sending configuration.
Before you install
The assistant writes real billing records and can issue invoices, which are immutable once issued; Otis requires your exact total before issuing. It holds client billing details and business tax settings, and sign-in codes and security notices are sent by email. Records are stored in the EU on the hosted service.

Installation

In SourceWeft

  1. Open Otis in the dashboard and add it to a workspace.
  2. Connect the required credentials. They are stored privately and never shown on public pages.
  3. Enable the server for the chats that should use its tools.

Web executable via Streamable HTTP. Remote servers run from the web runtime once configured in a workspace.

Use with an agent

Paste this prompt into Claude Code, Codex, Cursor or another agent — or into SourceWeft chat. The agent reads this server's install guide, shows you its publisher, endpoint and sign-in, and adds it to your client once you agree. Keys never go into a command.

Read https://sourceweft.com/mcp/com.otisbase%2Fotis/install.md and connect the MCP server it describes to my client. Before changing any config, show me its publisher, endpoint and sign-in method and wait for my OK. Never put an API key in a command or in a file I would commit; ask me where it should come from.

Read the install guide the agent follows

Other MCP clients

Add this to your client's mcpServers config. The client completes OAuth sign-in on first connect.

{
  "mcpServers": {
    "otis": {
      "type": "http",
      "url": "https://mcp.otisbase.com/mcp"
    }
  }
}

README

Otis MCP

The source code of Otisbase, a free MCP server for client billing, built for consultants and small agencies.

Otis has no app or dashboard. Your AI assistant is the interface: it records clients, work, expenses and payments in Otis, and issues the invoices you approve. Otis stores the records and enforces the rules. It numbers invoices, calculates totals, requires your exact total before it issues an invoice, and never rewrites an issued invoice. Otis runs no AI model; every result comes from the records and the rules in this repository.

This repository is the complete service that runs at mcp.otisbase.com: the MCP server, email sign-in and the storage layer. It runs on Cloudflare Workers. The otisbase.com website is maintained separately.

Use the hosted service

Add this URL as a remote MCP server in your assistant:

https://mcp.otisbase.com/mcp

Sign-in uses OAuth with an email code, so there is no API key. How to install has a guide for Claude, ChatGPT, Claude Code, Codex, Cursor, Muse, Grok Bot and Mistral Vibe. The hosted service is free. Records are stored in the EU.

What Otis records

AreaRecords
BusinessBusiness details, tax settings and invoice numbering, used by its owner
ClientsClients and their billing details
WorkBillable time, services, reported AI usage and expenses
InvoicesDrafts, issued invoices with immutable contents, discounts and tax
PaymentsFull and partial payments, with references that prevent duplicates
ExportA complete export of the business records

How it works

PartImplementation
RuntimeOne Cloudflare Worker (src/index.ts)
MCP server@modelcontextprotocol/server over Streamable HTTP at /mcp (src/mcp.ts)
Sign-in@cloudflare/workers-oauth-provider with an email code (src/auth.ts)
Business recordsSQLite in one Durable Object per business (src/business-store.ts)
Accounts and sign-insDurable Objects (src/account-store.ts, src/sign-in-store.ts)
OAuth stateWorkers KV
EmailCloudflare Email Sending, for sign-in codes and security notices
Data locationDurable Objects in the EU jurisdiction (src/regions.ts)
Sign-in pagesServer-rendered HTML with its own small stylesheet (src/html.ts, src/shell.ts)

Every business operation checks the caller's current membership. Amounts are integers in minor units. Writes take a request ID, so a retried call does not record the same fact twice.

Repository layout

PathContents
src/Worker, MCP tools, sign-in, storage, billing rules and public docs
test/Integration tests in Cloudflare's local runtime
scripts/Live endpoint checks and the plugin generator

Read the MCP docs before you change behavior. The rules agents follow are in src/docs.ts, src/descriptions.ts and src/workflows.ts, and the tests in test/ show the rules the server enforces.

Develop

You need Node 24 or newer.

bash
npm cinpm run checknpm test

Tests run in Cloudflare's local runtime. Email delivery is simulated in tests.

To run the Worker locally:

bash
npm run dev -- --local --ip 127.0.0.1 --port 8788

Then open http://127.0.0.1:8788/health. The local runtime uses local storage only.

The plugins for each assistant are generated from src/workflows.ts in the private project and published as their own repositories; Skills links them.

Self-host

You can run your own copy on a Cloudflare account. Edit wrangler.jsonc before you deploy:

  1. Set account_id to your Cloudflare account.
  2. Create a KV namespace for OAuth state and put its ID in kv_namespaces. For EU storage, create it in the EU jurisdiction.
  3. Replace the two routes with your own domains.
  4. Set the vars:
    • ORIGIN: the URL of the MCP host.
    • SITE_ORIGIN: the URL of your website. Website pages opened on the MCP host redirect there, and the sign-in pages link to its Terms and Privacy Policy.
    • EMAIL_FROM: the sender for sign-in codes. The domain must be set up for Cloudflare Email Sending.
    • FEEDBACK_TO: the address that receives feedback sent through the feedback_send tool.
    • DO_JURISDICTION: eu keeps Durable Objects in the EU. Remove it to let Cloudflare choose.
    • SIGN_IN_ENABLED: true to allow sign-in.
  5. Set ratelimits.namespace_id to an ID that is unique in your account.

Then deploy:

bash
npx wrangler loginnpm run deploy

The sign-in pages and emails name Otisbase. Change them in src/html.ts, src/auth.ts and src/notify.ts, and publish your own terms and privacy policy, before you offer your copy to other people.

Contribute

Bug reports, fixes and ideas are welcome. See CONTRIBUTING.md. To report a security problem, see SECURITY.md. You can also send feedback from your assistant: ask it to send feedback to Otis.

License

The code is released under the MIT License.

These items are not covered by the MIT License:

The copy and check icons in src/html.ts come from Phosphor Icons (MIT).

Source: README.md at commit 32570dd

Tools

0
This server asks you to sign in, so SourceWeft could not read its tools without an account and has not indexed them. What a connected account sees can depend on that account and its permissions.

Version history

1
  1. v0.1.0LatestOct 23, 2026

Score

85% of the applicable checks met

How complete this listing is, computed from the registry entry, the endpoint and public sources. Not a rating of the server and not a statement that it is safe or working today: reachability is a dated check, and no installs or reviews go into the score.

  • Reached in the last 30 daysRequired25 pts
  • Auth declaredRequired10 pts
  • Tools listed15 pts

    Answer tools/list without a credential, or ship a package that starts in a sandbox without one.

  • DescriptionRequired15 pts
  • Logo10 pts
  • Documentation15 pts
  • License10 pts