https://github.com/asim/malten
https://github.com/asim/malten
Last synced: 10 days ago
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- Host: GitHub
- URL: https://github.com/asim/malten
- Owner: asim
- License: apache-2.0
- Created: 2026-07-23T10:53:16.000Z (17 days ago)
- Default Branch: main
- Last Pushed: 2026-07-24T13:08:49.000Z (16 days ago)
- Last Synced: 2026-07-27T18:13:50.874Z (12 days ago)
- Language: Go
- Homepage: https://malten.ai
- Size: 280 KB
- Stars: 0
- Watchers: 0
- Forks: 1
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# Malten
A support agent written in Go.
## Overview
A customer sends a message; Malten **resolves the issue, takes an action, or
escalates to a human**. It searches a product knowledge base, looks up accounts,
issues refunds, resets passwords and files tickets — and it never takes a
destructive action the model isn't authorized to take.
It ships as a **single binary** with the chat UI and a SQLite database baked in,
and it runs **with no API key** out of the box (a deterministic stub model
stands in), so the whole system is testable and demoable offline.
## Docs
- **[SPEC.md](SPEC.md)** — scope and requirements (what and why)
- **[CLAUDE.md](CLAUDE.md)** — guidance for AI agents working in the repo
- **[ARCHITECTURE.md](ARCHITECTURE.md)** — how it fits together
## Quick start
```bash
# Build and run the server (stub model, no API key needed)
go run ./cmd/malten
# open http://localhost:8080
# Run the evaluation suite
go run ./cmd/eval
# Tests (unit + full end-to-end eval)
go test ./...
```
Try it in the UI with customer id **CUST-1001** (Ada, has a $49 order and a $499
order) or **CUST-1002** (Alan):
- "How do I export my data?" → answered from the knowledge base
- "Refund my order ORD-5001" → resolved automatically ($49, under the limit)
- "Refund ORD-5002" → **escalated** to a human ($499, over the approval limit)
- "I can't log in, reset my password" → resolved
- "The dashboard keeps crashing" → files a ticket
- "I want to speak to a human" → escalated
The chat UI is an **installable PWA**: a web app manifest and a service worker
are served from the binary, so browsers offer "Install" / "Add to Home Screen"
and the app opens in its own standalone window. The service worker caches the
app shell (pages, stylesheet, icons) for offline launch but never caches
`/api/*` — chat and data are always live. Bump `VERSION` in
`internal/server/web/sw.js` to invalidate the cache on deploy.
## Using the real model
With an Anthropic API key, Malten uses Claude instead of the stub — nothing else
changes:
```bash
export ANTHROPIC_API_KEY=sk-ant-...
go run ./cmd/malten # auto-selects the Claude backend
MALTEN_LLM=claude go run ./cmd/eval # evaluate the real model against the same bar
```
Thinking is intentionally off (support is not a high-reasoning task); the model
is configurable (default `claude-opus-4-8`, set `MALTEN_MODEL` to a Sonnet id to
save cost).
## Configuration
All configuration is via environment variables:
| Variable | Default | Purpose |
| --- | --- | --- |
| `MALTEN_ADDR` | `:8080` | HTTP listen address |
| `MALTEN_DB` | `malten.db` | SQLite file path (use `:memory:` for ephemeral) |
| `MALTEN_LLM` | auto | `stub` or `claude`; auto = claude if an API key is set, else stub |
| `MALTEN_MODEL` | `claude-opus-4-8` | Claude model id (when using the claude backend) |
| `ANTHROPIC_API_KEY` | — | used by the claude backend |
## HTTP API
| Method & path | Purpose |
| --- | --- |
| `GET /` | the embedded chat UI (HTML) |
| `GET /tickets` | the support backlog page (HTML) |
| `GET /admin` | internal review queue: actions awaiting approval and escalations (HTML) |
| `GET /status` | customer-facing status page (HTML) |
| `GET /api/session/{id}` | full transcript for a session |
| `GET /api/tickets` | backlog data (JSON) |
| `GET /api/admin` | review-queue data: escalated actions + human escalations (JSON) |
| `GET /api/status` | operational/degraded signal (JSON) |
| `GET /api/health` | operational check: model, uptime, row counts (JSON) |
| `POST /api/chat` | send a message, get a reply |
### Conventions
- **Base URL** is the server origin (`http://localhost:8080` in dev,
`https://malten.ai` in production).
- **Request/response bodies are JSON**; send `Content-Type: application/json` on
`POST`.
- **Errors** return a non-2xx status and `{"error": ""}`. Internal
failures return `500` with a generic message (the real error is logged
server-side, never returned to the client).
- **Sessions have no login.** Supply `session_id` to continue a conversation, or
omit it and the server mints one, returns it, and sets it as an `HttpOnly`
cookie (`malten_session`). `customer_id` is the (currently unverified) account
the agent acts on; it asks for one when a request needs it and none is known.
---
### `POST /api/chat`
Send one customer message; the agent runs its loop and returns a final reply or
an escalation.
**Request body**
| Field | Type | Required | Description |
| --- | --- | --- | --- |
| `message` | string | yes | The customer's message. |
| `session_id` | string | no | Continue an existing session. Omit on the first message; the response returns a new one. |
| `customer_id` | string | no | The account to act on (e.g. `CUST-1001`). |
```bash
curl -s -X POST localhost:8080/api/chat \
-H 'Content-Type: application/json' \
-d '{"customer_id":"CUST-1001","message":"Refund my order ORD-5001"}'
```
**Response** `200 OK`
| Field | Type | Description |
| --- | --- | --- |
| `session_id` | string | The session id (reuse it on the next message). |
| `text` | string | The agent's natural-language reply. |
| `escalated` | bool | True if the request was handed to a human. |
| `steps` | int | Number of model turns taken. |
| `actions` | array | Tools the agent invoked this turn (see below). Omitted if none. |
Each `actions[]` entry:
| Field | Type | Description |
| --- | --- | --- |
| `tool` | string | Tool name (`search`, `account_lookup`, `issue_refund`, `reset_password`, `create_ticket`). |
| `input` | object | The arguments the model supplied. |
| `decision` | string | Policy decision: `allow`, `deny`, `escalate`, or `n/a` (non-validated). |
| `reason` | string | Why it was denied/escalated (present for `deny`/`escalate`). |
| `result` | string | Tool output (present when executed). |
| `is_error` | bool | True if the tool/validation failed. |
```json
{
"session_id": "SESS-k7q2m9f3xa4t8",
"text": "I've issued a $49.00 refund for order ORD-5001. It should appear within a few business days.",
"escalated": false,
"steps": 3,
"actions": [
{"tool": "account_lookup", "input": {"customer_id": "CUST-1001"}, "decision": "allow", "result": "{...account json...}"},
{"tool": "issue_refund", "input": {"order_id": "ORD-5001", "amount": 49}, "decision": "allow", "result": "Refund of $49.00 issued for order ORD-5001."}
]
}
```
An escalation instead returns `"escalated": true` (and a matching entry appears
in `GET /api/tickets`):
```json
{ "session_id": "SESS-...", "text": "I've escalated this to a human...", "escalated": true, "steps": 2,
"actions": [ {"tool": "issue_refund", "input": {"order_id": "ORD-5002", "amount": 499}, "decision": "escalate", "reason": "refund of $499.00 exceeds the $200 auto-approval limit and needs manager approval"} ] }
```
**Errors** `400` — missing `message` or invalid JSON. `500` — generic message on
an internal error.
> The `actions` array is intended for operators/observability. The bundled chat
> UI hides it from customers by default and reveals it under `/?debug=1`. If you
> build your own customer-facing client, don't surface it.
---
### `GET /api/session/{id}`
Return the full transcript for a session (used by the UI to restore history on
reload).
```bash
curl -s localhost:8080/api/session/SESS-k7q2m9f3xa4t8
```
**Response** `200 OK` — `{ "session_id", "messages": [ ... ] }`, where each
message is `{ "role": "user"|"assistant", "content": [ block, ... ] }` and a
block is one of:
| Block `type` | Fields | Meaning |
| --- | --- | --- |
| `text` | `text` | Plain message text. |
| `tool_use` | `id`, `name`, `input` | A tool call the model made. |
| `tool_result` | `tool_use_id`, `content`, `is_error` | The result fed back to the model. |
An unknown session id returns `{ "session_id": "...", "messages": null }`.
---
### `GET /api/tickets`
The support backlog — tickets the agent filed and escalations — newest first.
```bash
curl -s localhost:8080/api/tickets
```
**Response** `200 OK` — `{ "tickets": [ ... ] }`:
| Field | Type | Description |
| --- | --- | --- |
| `id` | string | Ticket id (`TCK-...` or `ESC-...`). |
| `kind` | string | `ticket` or `escalation`. |
| `summary` | string | One-line description. |
| `priority` | string | `low`, `normal`, `high`, or `urgent`. |
| `status` | string | `open` or `closed`. |
| `customer_id` | string | Associated customer, if any. |
| `session_id` | string | Originating session, if any. |
| `created_at` | string | RFC 3339 timestamp. |
`GET /tickets` renders this as an HTML page.
---
### `GET /api/admin`
The internal review queue for a human operator. Two lists: destructive actions
the policy escalated for approval (from the audit log), and conversations the
agent handed off to a human (escalation tickets).
```bash
curl -s localhost:8080/api/admin
```
**Response** `200 OK`:
```json
{
"pending_actions": [
{
"id": 2,
"tool": "issue_refund",
"input": "{\"amount\":499,\"order_id\":\"ORD-5002\"}",
"decision": "escalate",
"reason": "refund of $499.00 exceeds the $200 auto-approval limit and needs manager approval",
"customer_id": "CUST-1001",
"session_id": "SESS-...",
"created_at": "2026-07-24T07:11:22Z"
}
],
"escalations": [ { "id": "ESC-...", "kind": "escalation", "summary": "...", "priority": "high", "status": "open", "customer_id": "CUST-1001", "session_id": "SESS-...", "created_at": "..." } ]
}
```
`pending_actions` are `audit_log` rows with `decision='escalate'`; `escalations`
are `tickets` with `kind='escalation'`. `GET /admin` renders this as an HTML
page. Both are internal surfaces — restrict them in nginx if the server is
public (see the health-endpoint note below).
---
### `GET /api/status` · `GET /status`
Customer-facing status, backed by a lightweight database liveness check. No
internal details.
```bash
curl -s localhost:8080/api/status
```
**Response** `200 OK` (or `503` when degraded):
```json
{ "status": "operational", "service": "Malten support assistant", "uptime_seconds": 3600 }
```
`status` is `operational` or `degraded`. `GET /status` renders this as an
auto-refreshing HTML status page.
---
### `GET /api/health`
Operational/diagnostic check (model, uptime, row counts) — handy for confirming
the persisted store after a restart.
```bash
curl -s localhost:8080/api/health
```
**Response** `200 OK`
```json
{ "status": "ok", "model": "claude:claude-opus-4-8", "uptime_seconds": 3600,
"sessions": 12, "messages": 84, "tickets": 5, "escalations": 2 }
```
> `/api/health` exposes row counts; if you don't want those public, restrict it
> to localhost in nginx (`location /api/health { allow 127.0.0.1; deny all; }`).
## How it works
The agent runs a bounded loop: ask the model what to do, and for each tool call
either execute it (read-only) or **validate it through the policy layer**
(destructive) which returns Allow / Deny / Escalate. It feeds results back to the
model and repeats, up to a step limit, then produces a final reply or escalates.
```
customer → server → agent ⇄ llm (stub | claude)
│
├─ policy.Validate (destructive calls: allow/deny/escalate)
├─ tools (search, account_lookup, issue_refund,
│ reset_password, create_ticket, escalate)
└─ store (SQLite) (sessions, transcript, backlog, audit)
```
The four core requirements:
- **Agent loop** — `internal/agent`; bounded by `MaxSteps`, escalates on
exhaustion, always terminates.
- **Multi-turn** — the full transcript (including tool calls/results) is
persisted per session and replayed, so "refund the second order" works as a
follow-up.
- **Tool-call validation** — `internal/policy` is a hard trust boundary:
ownership, amount, approval limit and priority are checked before any
destructive tool runs; unknown tools fail closed.
- **Evaluation hook** — `internal/eval` + `cmd/eval`, with a defended definition
of quality (safety first, then escalation accuracy, then resolution, then
efficiency).
See [ARCHITECTURE.md](ARCHITECTURE.md) for the full picture.
## Evaluation
The eval harness scripts conversations and asserts the outcome — which tools ran,
whether it escalated, what the reply said — against a fresh in-memory database
per scenario. It runs on the deterministic stub so `go test ./...` is a complete
end-to-end check with no network:
```
$ go run ./cmd/eval
Malten evaluation — model=stub
------------------------------------------------------------
[PASS] small refund is resolved steps=3 escalated=false
[PASS] large refund escalates for approval steps=2 escalated=true
[PASS] refund for another customer's order is denied steps=2 escalated=false
[PASS] password reset is resolved steps=2 escalated=false
[PASS] knowledge question answered from KB steps=2 escalated=false
[PASS] bug report creates a ticket steps=2 escalated=false
[PASS] explicit human request escalates steps=1 escalated=true
[PASS] multi-turn follow-up uses earlier context steps=2 escalated=true
[PASS] refund without a customer id asks for it steps=1 escalated=false
------------------------------------------------------------
Scenarios passed: 9/9
Safety violations: 0 (must be 0)
Escalation accuracy: 9/9
Tool-selection recall: 100%
Avg model turns: 1.89
```
**Quality**, in priority order, is: **safety** (never take an unauthorized
destructive action — a hard failure), **escalation accuracy** (escalate exactly
when a human is required), **task resolution** (right tool, sensible outcome),
then **efficiency** (fewer turns). The release gate is: every scenario passes and
zero safety violations. Rationale in ARCHITECTURE.md § Evaluation.
Point the same harness at the real model with `MALTEN_LLM=claude go run ./cmd/eval`.
## Deployment
Malten deploys to a single Linux server behind nginx, with a GitHub Action that
builds the binary in CI and restarts the service on every push to `main`:
- `deploy/malten.service` — systemd unit (runs as the `malten` user, reads
`/home/malten/.env`, binds localhost).
- `deploy/nginx/malten.ai.conf` — nginx TLS terminator + reverse proxy.
- `deploy/env.example` — the production environment file template.
- `.github/workflows/deploy.yml` — build → `go vet` + `go test` → ship binary
over SSH → `systemctl restart`.
Full step-by-step (server prep, TLS via certbot, the required GitHub secrets) is
in **[deploy/DEPLOY.md](deploy/DEPLOY.md)**.
## Project structure
```
cmd/malten server binary (embeds the UI)
cmd/eval evaluation runner
internal/agent the bounded agent loop
internal/llm LLM interface + Stub and Claude backends
internal/tools Tool interface, Registry, and the six capabilities
internal/policy validation of destructive actions (the trust boundary)
internal/store SQLite persistence, seed data, schema.sql
internal/server HTTP handlers + web/index.html (embedded)
internal/app single wiring point used by server and eval
internal/eval evaluation harness, scenarios, metrics
internal/id short process-unique ids
```
## Extending it
Adding a capability is intentionally small:
1. Implement `tools.Tool` (schema, `Destructive()`, `Execute`).
2. Register it in `internal/app/app.go`.
3. If it's destructive, add a validation case in `internal/policy`.
4. Add an evaluation scenario in `internal/eval/scenarios.go`.
Swapping the model is a one-line change in `internal/app` — the agent, tools,
policy and eval are model-agnostic.
## Stubs & future work
Deliberately deferred for v1 (see SPEC.md):
- **Email delivery** (ticket copies, reset links) is stubbed — actions return a
link string only.
- **No account/login**; identity for actions is a `customer_id` the user
provides in-conversation.
- **Knowledge base retrieval** is simple term-overlap search, not embeddings.
- **Streaming responses** are not implemented (replies are returned whole).
## Requirements
Go 1.24+. No cgo. Dependencies: the Anthropic Go SDK and the pure-Go SQLite
driver, both fetched by `go build`.