Developers and AI agents

What an agent can do

Without a key, an agent with the KERF Agent Skill installed, or simply reading this site, can tell you whether we can cut a part, which of our materials and thicknesses suit it, how to prepare the file so it prices first time, what a warning or refusal on a part card means, and how ordering and delivery work. It cannot see a price; it hands you to kerf.au/quote, where you upload, confirm the measured size, choose the spec and pay.

With a key (below), through the API or the MCP server, it can also upload your file, read the measured geometry and any warnings, build a quote and read the price, return the checkout link, and follow the order. The prices it sees are the same ones the quote workspace shows, from the same price book, held for the same 14 days. What it still cannot do is pay: checkout returns a link, and you pay there.

The KERF Agent Skill

An Agent Skill is a small folder of plain-text instructions that a coding agent loads when a task matches. Ours covers file preparation, materials, ordering and the meaning of every check the workspace runs, all written from the same guides you are reading. It is built to work with no connection to KERF at all, so it never invents a tolerance, a thickness or a price: if a fact is not on this site, the skill says so and points to hello@kerf.au.

Install it in any agent that supports skills:

npx skills add kerf-au/kerf-plugin --skill kerf

The source is public and MIT licensed at github.com/kerf-au/kerf-plugin, so you can read exactly what the agent is told.

Rules an agent follows

These are written into the skill, into the MCP server's instructions and into every tool description. They are the same promises we make to a person.

• The agent never pays. Checkout is a link you open; payment stays with you.
• The agent never states a price. The live quote is the only price, in Australian dollars including GST, with delivery added at checkout.
• A suggestion is never chosen silently. A thickness read from a STEP file, or a nearby material when yours is not stocked, is shown to you and confirmed.
• A refusal is never waved through. If a part cannot be cut as drawn, the agent explains why in the workspace's own words and asks.
• Your file goes to KERF and nowhere else. The skill tells the agent not to paste design files into a conversation or send them to any other service.

llms.txt

kerf.au/llms.txt is a plain-text index of this site written for agents: what KERF is, where the guides are, and where to send someone for a price. Point an agent at it when you want it to read about KERF before helping you. It carries no numbers that could go stale; every fact links to the page that holds it.

The v1 API: early access

A small, key-authenticated JSON API is live for early access. With it, software or an agent can upload a file and get back the measured geometry and any warnings, build a quote and read the price, return the checkout link, and follow an order. The routes are /v1/materials (public), /v1/parts, /v1/quotes, /v1/quotes/{id}/checkout and /v1/orders. Prices come back in Australian dollars including GST; delivery is added at checkout.

Keys belong to an account: everything made through the API appears in that account's parts library, quotes and Order history here on kerf.au. To get one, sign in at kerf.au/quote, open your account (your name, top right) and create a key in the API keys section; it is shown once, with the Claude Code connect command beside it. For the full reference email hello@kerf.au. The agent still never pays: checkout returns a link, and the person pays.

The MCP server

The same API is available as MCP tools at https://kerf.au/mcp (streamable HTTP), so an agent can quote and order from a conversation with no code: find_materials, create_upload, list_parts, get_part, create_quote, get_quote, list_quotes, update_quote, checkout, list_orders and get_order. It signs in with the same API key, sent as a Bearer header. Files go to a signed upload URL, never through the agent's context. The tool descriptions and the server's instructions carry the rules above.

The commands that add it are at the top of this page; this section is about what happens afterwards. Each tool tells Claude Code whether it reads or writes, so the reads and the quote run without a prompt. The one tool it may pause on is checkout, because that call creates something outside the conversation: an unpaid draft in the shop, which expires on its own if nobody pays. Approve it when asked, or allow it for good by adding mcp__kerf__checkout to the allow list in your Claude Code permissions. Or install the plugin, which brings the MCP connection and the skill together:

npx plugins add kerf-au/kerf-plugin

With a key instead, for a machine with no browser: Claude Code takes --header "Authorization: Bearer $KERF_API_KEY" on the add command, Codex takes --bearer-token-env-var KERF_API_KEY, and Cursor an entry in mcp.json with a headers block.

Claude, ChatGPT and other apps that sign in

Apps that connect by signing in rather than by key, such as Claude's custom connectors and ChatGPT's, need only the address: add https://kerf.au/mcp as a custom connector, and you will be sent to kerf.au to sign in with your email and approve the connection. Nothing to copy. The connection appears in your account card as a connected app, where you can disconnect it at any time. Under the hood this is OAuth 2.1 with PKCE and short-lived tokens, the way the MCP specification describes it, with both ways an app can identify itself: a Client ID Metadata Document (the option Claude marks recommended) or dynamic client registration; the discovery documents are at /.well-known/oauth-authorization-server and /.well-known/oauth-protected-resource.

What goes in each box

KERF has no password, no client secret and no header to paste, so the boxes an app offers for them all stay empty. The one thing to get right is that KERF does ask every person to sign in. In Claude's Add custom connector dialog:

• Name: anything you like. MCP server URL: https://kerf.au/mcp. That is all step one needs.
• Authentication: Sign in now. No sign-in is the wrong answer here; it is for servers that are open to everyone or that take an API key, and KERF signs each person in before any tool runs.
• OAuth client: Use Claude's published identity, the one marked Recommended. Register automatically works as well. Pick Use your own OAuth client only if you registered a client with us yourself, which we do not ask anyone to do.
• Client secret and request headers: leave them blank. Filling them in is what stops a connection that would otherwise work.

Talk to us

Building something that should talk to KERF, or want early access when the API is ready? Email hello@kerf.au with "Developers" in the subject and a line about what you are making.