# tbd

A small Clojure HTTP API built on [Ring](https://github.com/ring-clojure/ring) (Jetty) and
[reitit](https://github.com/metosin/reitit), with a ClojureScript
[re-frame](https://github.com/day8/re-frame) front end (`ui/`), Swagger UI docs, unit tests,
dockerized integration tests, and joint line coverage.

## Requirements

- Docker, for the integration tests and the `script/docker-*` tasks (all CI needs)
- For running tasks natively (optional): [Clojure CLI](https://clojure.org/guides/install_clojure) (tools.deps) with JDK 21+, [Node](https://nodejs.org/) 20+ (with a JDK) for the UI build, and [Babashka](https://babashka.org/) for `script/coverage-report`

## Running

```bash
script/ui-build        # compile the UI (once, and after UI changes)
script/server [port]
```

The server listens on port `3000` by default; pass a port argument or set `PORT` to change it
(the argument wins):

```bash
script/server 8080
PORT=8080 script/server
```

This is a thin wrapper around `clojure -X:run`, which also honors `PORT`. Then open
http://localhost:3000 for the UI. Without `script/ui-build` the server still starts, but `/`
shows a placeholder.

Or build and run the container:

```bash
docker build -t tbd .
docker run --rm -p 3000:3000 tbd
```

## API

| Method | Path | Description |
|--------|------|-------------|
| `GET` | `/` | The UI: an HTML shell that loads the compiled ClojureScript from `/js/main.js` |
| `GET` | `/api/ping` | Health check, returns `pong` |
| `GET` | `/api/add?x=2&y=3` | Adds two numbers: `{:result 5}` (EDN by default, see [Formats](#formats)) (400 if either is missing or not a number) |
| `POST`, `DELETE` | `/mcp` | The [MCP server](#mcp-server) (JSON-RPC over Streamable HTTP; `DELETE` ends a session; `GET` is `405`). **Needs an OAuth access token** (`401` without one) |
| `GET` | `/.well-known/oauth-protected-resource`, `/.well-known/oauth-authorization-server` | The [MCP OAuth](#connecting-an-mcp-client) discovery documents (RFC 9728 and 8414) |
| `POST` | `/oauth/register` | Dynamic client registration (RFC 7591) for MCP clients |
| `GET`, `POST` | `/oauth/authorize` | Where an MCP client sends the user's browser: Gitea login if needed, then a consent page |
| `POST` | `/oauth/token` | Trades an authorization code (with its PKCE verifier) or a refresh token for tokens |
| `GET` | `/api-docs` | Swagger UI |
| `GET` | `/swagger.json` | OpenAPI/Swagger spec |
| `GET` | `/auth/login` | Starts the Gitea OAuth login (redirects to Gitea) |
| `GET` | `/auth/callback` | OAuth redirect target: completes the login, sets the session cookie, redirects to `/` |
| `POST` | `/auth/logout` | Ends the session |
| `GET` | `/auth/me` | The logged-in user, `{:login "alice" :id 7 :admin? true}` (401 if not logged in) |
| `GET` | `/api/todos` | **Login required.** Your todos: `{:todos [{:id 1 :owner-id 7 :title "buy milk" :done false :created-at 1700000000000 :updated-at 1700000000000}]}` |
| `POST` | `/api/todos` | **Login required.** Body `{"title": "buy milk"}` creates a todo and returns it with `201` (400 if the title is blank or over 200 characters) |
| `GET` | `/api/todos/:id` | **Login required.** One todo (404 if it doesn't exist or isn't yours) |
| `PATCH` | `/api/todos/:id` | **Login required.** Body with `title` and/or `done` (`{"done": true}`) updates the todo and returns it (400 for an empty or invalid change, 404 as above) |
| `DELETE` | `/api/todos/:id` | **Login required.** Deletes the todo: `{:deleted true}` (404 as above) |
| `GET` | `/nrepl` | **Admin only.** Whether the nREPL debug server is on: `{:enabled false}`, or `{:enabled true :bind "127.0.0.1" :port 7888}` |
| `POST` | `/nrepl` | **Admin only.** Body `{"enabled": true}` (JSON or EDN) starts the nREPL debug server, `false` stops it; returns `{:enabled true :bind "127.0.0.1" :port 7888}` |

```bash
curl localhost:3000/api/ping           # pong
curl 'localhost:3000/api/add?x=2&y=3'  # {:result 5}
curl 'localhost:3000/api/add?x=2&y=3' -H 'Accept: application/json'  # {"result":5}
```

## Formats

The API speaks EDN, JSON and Transit (`application/transit+json`, `application/transit+msgpack`).
Responses follow the request's `Accept` header, and request bodies are read by their `Content-Type`.
**EDN is the default**: with no `Accept` (or `*/*`, or a type the API can't produce) you get EDN, and a
body sent with no `Content-Type` is read as EDN. Errors (400, 401, 403, ...) use the same format
as everything else. Two exceptions: `/api/ping` is always `text/plain`, and `/swagger.json` is always JSON.

Handlers return plain data (`(tbd.http/respond 200 {:result 5})`), and the muuntaja middleware in
`tbd.core` encodes it; don't `pr-str` a body yourself.

## Todos

Each logged-in user has their own todo list, keyed by their Gitea user id. Every query is
filtered by that id, so users can't see or change each other's todos; someone else's todo answers
`404`, exactly like a missing one. Without a login the todo routes answer `401`. The operations
themselves (ownership, validation, storage) live in `src/tbd/todo/service.clj`, which the HTTP routes
and the [MCP tools](#mcp-server) both call, so they behave the same and are tested once; a route or
tool only translates its request into a service call and the result into a response, and never
touches the database.

Todos are stored in a local [SQLite](https://www.sqlite.org/) file, `data/todo.db` by default
(git-ignored), which is created and migrated on the first todo request. Set `TODO_DB_PATH` to put it
elsewhere. In Docker, mount a volume at that path (e.g. `docker run -v tbd-data:/app/data ...`), or the
todos are lost with the container.

```bash
# after logging in in a browser, copy the `tbd-session` cookie value:
curl -XPOST localhost:3000/api/todos -H 'Cookie: tbd-session=...' \
     -H 'Content-Type: application/json' -d '{"title": "buy milk"}'
curl localhost:3000/api/todos -H 'Cookie: tbd-session=...'
```

## MCP server

The server also speaks [MCP](https://modelcontextprotocol.io/) (Model Context Protocol) at `/mcp`,
built on [PluMCP](https://github.com/plumce/plumcp) and running inside this same process; there is
nothing extra to start. It uses the Streamable HTTP transport, and, like the todo API, it acts **as
the logged-in user**: a client has to be approved by a user first (see below), and from then on
every tool call knows who is calling.

```bash
claude mcp add --transport http tbd https://tbd.example.com/mcp   # <BASE_URL>/mcp
```

The first time the client connects it gets a `401`, opens your browser, you log in with Gitea
as usual and approve the client, and the client keeps its tokens from then on. It needs the
[Gitea login](#authentication-and-the-admin-api) to be configured, including `BASE_URL` (which must
be the address the client uses; without them `/mcp` answers `503` rather than being open).

It offers these tools: `ping`, `add` (the same logic as `/api/add`), `whoami` (which user this
connection acts as, and whether they are an admin), and, on the caller's own todos (the same ones
as `/api/todos`), `list_todos`, `get_todo`, `create_todo`, `update_todo` and `delete_todo`. To add a
tool, add a `tool` to `src/tbd/mcp/tools.clj`; it should call the group's service (or pure `core`
functions), not a database, and if the group has no service yet, that is the thing to add, so the
HTTP routes can share it. Its arguments are described by the group's
[Malli](https://github.com/metosin/malli) schema in `src/tbd/<group>/schema.clj`, the same schema the
HTTP routes use for their parameters, so a shape of data is written down once: the tool's
input schema is generated from it, and the arguments a client sends are coerced and validated against
it (plumcp only checks that required ones are present). A tool that touches a user's data or does
something admin-only gets the caller from `current-user` there (`{:login :id :admin? :client-id}`),
and must not trust anything else about who is asking.

(The UI has tools of its own for a browser agent, [see below](#browser-mcp-tools-webmcp); they are not part of this server.)

Sessions are kept in memory, so they end when the server restarts (clients just re-initialize; their
tokens are in the database and keep working). Server-to-client streaming (`GET /mcp`) is deliberately
off: nothing here pushes messages, and the response would hang under Jetty. PluMCP needs JDK 21+.

### Connecting an MCP client

tbd is its own OAuth 2.1 authorization server for `/mcp` (in `src/tbd/oauth/`), with the Gitea login
as the way a user proves who they are. Gitea's own tokens never reach an MCP client, and the tokens
tbd issues are worth nothing anywhere else. The flow is the one the
[MCP authorization spec](https://modelcontextprotocol.io/specification/2025-06-18/basic/authorization)
describes, so any compliant client does it by itself:

1. `POST /mcp` with no token gets `401` and `WWW-Authenticate: Bearer resource_metadata="<BASE_URL>/.well-known/oauth-protected-resource/mcp"`.
2. The client reads that document, then `/.well-known/oauth-authorization-server`, and registers itself at
   `/oauth/register` (dynamic client registration, public clients only).
3. It opens `/oauth/authorize` in the browser (authorization-code flow, PKCE `S256` required). If you aren't
   logged in you go through the Gitea login first and come back; then a consent page names the client and
   the address you'll be sent back to, and asks you to **Approve** or **Deny**.
4. The client trades the code at `/oauth/token` for an access token (1 hour) and a refresh token (30 days,
   rotated on every use), and sends `Authorization: Bearer ...` on every `/mcp` request.

The consent page is what stops a stranger's client (anyone can register one) from getting a token by
sending you a link: nothing is issued without your click. Redirect URIs must be `https`, `http` on
`localhost`/`127.0.0.1`/`[::1]` (the port may vary), or an app's own scheme (`cursor://...`).

What's stored is in `OAUTH_DB_PATH`: registered clients, and for each approval the user and a *hash* of the
current access and refresh tokens. To cut a client off, delete its row from `grants`. Admin-ness isn't in
the token: it is looked up in `ADMIN_USERS` on every request, so removing someone from the list takes
effect at once. A Gitea account that is disabled keeps working until its refresh token expires (up to 30
days without use) or its grant is deleted, since Gitea isn't asked again after the login.

## Authentication and the admin API

Login is OAuth2 (authorization-code flow) against a [Gitea](https://about.gitea.com/) instance.
Anyone with a Gitea account can log in, but routes marked `:admin? true` (currently
`GET` and `POST /nrepl`) also require the user to be on the `ADMIN_USERS` allowlist: **401** without a
login, **403** for a logged-in non-admin. With no allowlist, nobody is an admin.

1. In Gitea (Settings > Applications) create an OAuth2 application, a confidential client, with
   the redirect URI `<BASE_URL>/auth/callback`.
2. `cp .env-template .env` and fill it in. `script/server` loads `.env`; for Docker use
   `docker run --env-file .env`. `.env` is git-ignored and kept out of the image.

| Variable | Purpose |
|----------|---------|
| `GITEA_URL`, `GITEA_CLIENT_ID`, `GITEA_CLIENT_SECRET` | The Gitea OAuth2 application. Without all three (and `BASE_URL`), `/auth/login` answers 503 |
| `BASE_URL` | Public URL of this app; an `https://` one also marks the session cookie `Secure`. It is also the address of the MCP server: the OAuth issuer, and what MCP clients are told to use (`<BASE_URL>/mcp`) |
| `ADMIN_USERS` | Comma-separated Gitea usernames (case-insensitive) allowed to use the admin API |
| `SESSION_SECRET` | Signs and encrypts session cookies. Unset = a random key per start, so logins don't survive a restart |
| `TODO_DB_PATH` | SQLite file for the todo group (default `data/todo.db`) |
| `OAUTH_DB_PATH` | SQLite file for the MCP OAuth server: registered clients, codes and tokens (default `data/oauth.db`). Mount a volume for it in Docker too, or every MCP client has to be approved again after each restart |
| `NREPL_PORT`, `NREPL_BIND` | Where the debug nREPL listens (default `7888` on `127.0.0.1`) |

Sessions live in an encrypted, signed, `HttpOnly`, `SameSite=Lax` cookie and expire after 8 hours
(enforced server-side). The cookie is stateless, so `POST /auth/logout` clears it in the browser but
can't revoke a copy someone already captured; it just expires on its own.

### The nREPL endpoint

```bash
# after logging in in a browser, copy the `tbd-session` cookie value:
curl -XPOST localhost:3000/nrepl -H 'Cookie: tbd-session=...' \
     -H 'Content-Type: application/json' -d '{"enabled": true}'
clj -Sdeps '{:deps {nrepl/nrepl {:mvn/version "1.2.0"}}}' -M -m nrepl.cmdline --connect --host 127.0.0.1 --port 7888
```

nREPL has no authentication and evaluates arbitrary code, so enabling it is effectively remote code
execution for whoever can reach the port. It therefore binds to loopback by default; reach it through
an SSH tunnel (or `docker exec`) rather than setting `NREPL_BIND=0.0.0.0`. Each enable/disable is
logged with the admin's Gitea username. It stays on until an admin disables it (or the server
restarts), so switch it off when you're done.

## UI

`ui/` is a [re-frame](https://github.com/day8/re-frame) app (ClojureScript, React 19 via
[Reagent](https://reagent-project.github.io/)) built with [shadow-cljs](https://github.com/thheller/shadow-cljs).
It's a small calculator form that calls `GET /api/add` and shows the sum (or the server's
validation error). Below it, once you're logged in, is a todo list (add, tick off, delete) backed by
`/api/todos`; it stays hidden when you're not. At the bottom is a section with the
`claude mcp add ...` command to copy (with this page's own address in it) and the steps to sign in, for
adding the [MCP server](#mcp-server) to Claude Code. A "Log in" / "Log out" link sits in the footer row
next to the API docs links.

shadow-cljs compiles it into `resources/public/js/` (git-ignored). The server serves that
directory at `/js`, and serves `resources/public/index.html`, the shell that mounts the app, at `/`.

| Task | What it does |
|------|--------------|
| `script/ui-build` | Optimized release build into `resources/public/js` |
| `script/ui-watch` | Rebuilds on every change, with hot reload; run `script/server` alongside and refresh the page |

The Docker image builds the UI in its own stage, so `docker build` needs no local Node.

### Browser MCP tools (WebMCP)

The page also offers tools of its own to your MCP client (Claude), through [WebMCP](https://webmcp.dev):
a small library that adds a widget to the page and lets the page register tools with it. They are the browser-side twin of the
[server's MCP tools](#mcp-server): those work on your data on the server, these work *the page*, doing
what you could do with the mouse and keyboard, so you see it happen. They are in `ui/src/tbd/ui/webmcp.cljs`,
registered with `registerTool` on a `WebMCP` instance (the `@jason.today/webmcp` npm package):

| Tool | What it does |
|------|--------------|
| `ping`, `whoami` | Health check; who is logged in on the page, if anyone |
| `get_calculator` | What the calculator form holds: its two fields and the result it shows |
| `add` | Types `x` and `y` into the calculator, presses Add, and returns the sum the page shows |
| `list_todos`, `get_todo` | The todos the page shows (login required, like the todo list itself) |
| `create_todo` | Types a `title` into the new-todo field, presses Add, returns the new todo |
| `set_todo_done` | Ticks or unticks a todo's checkbox (`id`, `done`) |
| `delete_todo` | Presses a todo's Delete button |

Each tool dispatches the same re-frame events the views do and waits for the result to show up in
the app-db, so what the agent sees is what the page shows, server errors included. There is no
`update_todo` with a title as on the server, because the page can't edit one.

To connect (the page's "Browser tools (WebMCP)" section says the same):

1. Add the WebMCP server to your MCP client, once: `npx -y @jason.today/webmcp@latest --config claude`
   (restart Claude Desktop afterwards).
2. Ask the client to *make a webmcp token*.
3. Click the blue square in the bottom right corner of the page, paste the token, and press Connect.
   The token works once, and the page has no field for it: the widget is where it goes.
4. The tools show up in the client, prefixed with the page's host.

## Development

Every task is a bash script in `script/`. Start an nREPL server (with CIDER middleware) on the port in `.nrepl-port`, or `3000` if that
file doesn't exist:

```bash
script/repl
```

### Tests

| Task | What it does |
|------|--------------|
| `script/unit-test` | Runs the Clojure tests in `test/` |
| `script/ui-test` | Runs the ClojureScript tests in `ui/test/` under Node (needs Node and a JDK; CI doesn't run it yet) |
| `script/integration-test` | Builds the app image, starts it on a random port, runs the [integration suite](integration-test/README.md) against it, then tears it down |
| `script/test` | Unit tests, then integration tests (stops at the first failure) |
| `script/docker-unit-test` | Same as `script/unit-test`, but inside the app image (Docker only) |

### Coverage

Line coverage via [Cloverage](https://github.com/cloverage/cloverage):

| Task | Output |
|------|--------|
| `script/unit-coverage` | `target/coverage/unit/` |
| `script/integration-coverage` | `target/coverage/integration/` |
| `script/coverage` | Runs both, then writes the merged report to `target/coverage/merged/` |
| `script/docker-unit-coverage`, `script/docker-coverage-report` | Dockerized versions of the unit run and the merge step, so `script/docker-unit-coverage`, `script/integration-coverage`, `script/docker-coverage-report` is `script/coverage` with no local Clojure or Babashka (this is what CI runs) |

Each report directory has an `index.html` and an `lcov.info`. See
[integration-test/README.md](integration-test/README.md) for how integration coverage is
collected.


## Project layout

```
src/tbd/
  core.clj            Router, Ring app, and server startup
  <group>/routes.clj  Each route group (health, math, ...) owns its route subtree
  <group>/core.clj    Business logic for the group, with no HTTP concerns
  <group>/schema.clj  Malli schemas of the group's input, shared by its routes and the MCP tools
  auth/               Gitea OAuth (core), session + admin middleware (middleware), /auth routes
  mcp/                MCP server (PluMCP) mounted at `/mcp`: tools (tools.clj), Malli-to-tool glue (schema.clj) and the Ring handler (routes.clj)
  oauth/              tbd as the OAuth authorization server for MCP clients: rules (core), SQLite storage (db), `/oauth` + discovery routes, and the bearer-token middleware guarding `/mcp` (middleware)
  nrepl/              On-demand nREPL server (core) and the admin-only `/nrepl` routes
  todo/               Per-user todos: pure rules (core), Malli schemas of the input (schema), SQLite storage (db), `/api/todos` routes
ui/                   ClojureScript re-frame app (shadow-cljs project); ui/src/tbd/ui/{db,events,subs,views,webmcp,core}.cljs, tests in ui/test/
.env-template         Settings the server reads from the environment; copy to .env (git-ignored)
resources/public/     index.html (the shell served at /) and js/ (compiled UI output, git-ignored)
test/                 Unit tests
integration-test/     Dockerized integration tests and coverage harness
script/               Bash entry points (server, ui-build, test, coverage, repl, ...) and coverage helpers
```

To add a new group, create `tbd.<group>.routes` with a `routes` fn that returns a reitit route
vector, then add it to the router in `src/tbd/core.clj`. To make a route admin-only, put
`:admin? true` in its route data (admin allowlist), or `:login? true` (any logged-in user; the user is
passed to the handler as `:user`). A group with storage keeps it in its own `tbd.<group>.db`, apart
from its business logic in `core.clj`.