Showcase
Each example shows real output produced by TypedLM itself, from files in the project repository. Input on the left, output on the right.
Classification
crates/typedlm/examples/classification.rsDetail: Classification →//! Classify support tickets into enums.
//!
//! ```sh
//! TYPEDLM_MODEL=qwen3:32b cargo run --example classification
//! ```
mod common;
use schemars::JsonSchema;
use serde::{Deserialize, Serialize};
use typedlm::prelude::*;
#[derive(Debug, Serialize, Deserialize, JsonSchema)]
enum Urgency {
Low,
Medium,
High,
}
#[derive(Debug, Serialize, Deserialize, JsonSchema)]
enum Category {
Billing,
Technical,
Shipping,
/// Anything that fits none of the other categories.
Other,
}
#[derive(Debug, Serialize, Deserialize, JsonSchema)]
struct TicketClassification {
urgency: Urgency,
category: Category,
}
/// Classify a customer support ticket by urgency and category.
#[derive(TypedLm, Serialize)]
#[lm(output = TicketClassification)]
struct ClassifyTicket {
/// The ticket as written by the customer.
text: String,
}
#[tokio::main(flavor = "current_thread")]
async fn main() -> Result<(), Error> {
let classify = Program::<ClassifyTicket, _>::new(common::provider()).temperature(0.0);
// `run` returns the typed output; a single `String` field lets it take text.
let ticket = classify
.run("Production database is down since 9:00")
.await?;
match ticket.urgency {
Urgency::High => println!("escalate: {ticket:?}"),
Urgency::Medium | Urgency::Low => println!("queue: {ticket:?}"),
}
// `execute` also reports what the call cost.
let execution = classify.execute("I was charged twice this month").await?;
println!(
"{:?} — {} attempt(s), {} tokens, model {}",
execution.output,
execution.attempts,
execution.usage.input_tokens + execution.usage.output_tokens,
execution.model
);
Ok(())
}escalate: TicketClassification { urgency: High, category: Technical }
TicketClassification { urgency: High, category: Billing } — 1 attempt(s), 318 tokens, model qwen3:32bInvoice extraction
crates/typedlm/examples/extraction.rsDetail: Invoice extraction →//! Extract a nested invoice structure and check it against domain rules.
//!
//! ```sh
//! TYPEDLM_MODEL=qwen3:32b cargo run --example extraction
//! ```
mod common;
use schemars::JsonSchema;
use serde::{Deserialize, Serialize};
use typedlm::prelude::*;
#[derive(Debug, Serialize, Deserialize, JsonSchema)]
struct LineItem {
description: String,
quantity: u32,
/// Net unit price in cents.
unit_price_cents: u64,
}
#[derive(Debug, Serialize, Deserialize, JsonSchema)]
struct Invoice {
number: String,
/// Issue date as YYYY-MM-DD.
date: String,
items: Vec<LineItem>,
/// Net total in cents, before tax.
net_cents: u64,
/// Grand total in cents, including tax.
total_cents: u64,
/// Anything unusual about the invoice, if mentioned.
note: Option<String>,
}
/// Extract the invoice data from the text. Amounts are in cents.
#[derive(TypedLm, Serialize)]
#[lm(output = Invoice, validate = items_add_up)]
struct ExtractInvoice {
text: String,
}
/// Rules the schema cannot express. Failing ones are sent back to the model,
/// so each message says what to fix.
fn items_add_up(invoice: &Invoice) -> Result<(), Vec<String>> {
let items: u64 = invoice
.items
.iter()
.map(|item| u64::from(item.quantity) * item.unit_price_cents)
.sum();
let mut errors = Vec::new();
if items != invoice.net_cents {
errors.push(format!(
"the line items add up to {items} cents but net_cents is {}; check quantities and unit prices",
invoice.net_cents
));
}
if invoice.total_cents < invoice.net_cents {
errors.push("total_cents must not be smaller than net_cents".into());
}
if errors.is_empty() {
Ok(())
} else {
Err(errors)
}
}
const TEXT: &str = "Invoice no. RE-2026-0042, issued 14 September 2026.
2 x Server maintenance at 150.00 EUR each
1 x Emergency call-out at 89.50 EUR
Subtotal 389.50 EUR, VAT 19 % 74.01 EUR, total 463.51 EUR.
Payable within 14 days.";
#[tokio::main(flavor = "current_thread")]
async fn main() -> Result<(), Error> {
let extract = Program::<ExtractInvoice, _>::new(common::provider()).temperature(0.0);
let invoice = extract.run(TEXT).await?;
println!("{} from {}", invoice.number, invoice.date);
for item in &invoice.items {
println!(
" {} x {} à {:.2}",
item.quantity,
item.description,
item.unit_price_cents as f64 / 100.0
);
}
println!(
"net {:.2}, total {:.2}",
invoice.net_cents as f64 / 100.0,
invoice.total_cents as f64 / 100.0
);
if let Some(note) = invoice.note {
println!("note: {note}");
}
Ok(())
}RE-2026-0042 from 2026-09-14 2 x Server maintenance à 150.00 1 x Emergency call-out à 89.50 net 389.50, total 463.51 note: Payable within 14 days.
Evaluation report
crates/typedlm/examples/evaluation.rsDetail: Evaluation report →//! Measure a classifier on a labelled dataset.
//!
//! ```sh
//! TYPEDLM_MODEL=qwen3:32b cargo run --example evaluation
//! ```
//!
//! `examples/data/tickets.jsonl` labels only some fields per ticket; each line is
//! checked against the output type when loading. Keep datasets much larger than
//! this one: the report's confidence interval shows how little 8 examples say.
mod common;
use schemars::JsonSchema;
use serde::{Deserialize, Serialize};
use typedlm::eval::{Dataset, ExactMatch, evaluate};
use typedlm::prelude::*;
#[derive(Debug, Serialize, Deserialize, JsonSchema)]
enum Urgency {
Low,
Medium,
High,
}
#[derive(Debug, Serialize, Deserialize, JsonSchema)]
enum Category {
Billing,
Technical,
Shipping,
/// Anything that fits none of the other categories.
Other,
}
#[derive(Debug, Serialize, Deserialize, JsonSchema)]
struct TicketClassification {
urgency: Urgency,
category: Category,
}
/// Classify a customer support ticket by urgency and category.
#[derive(TypedLm, Serialize, Deserialize, Clone, Debug)]
#[lm(output = TicketClassification)]
struct ClassifyTicket {
/// The ticket as written by the customer.
text: String,
}
#[tokio::main(flavor = "current_thread")]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
let path = concat!(env!("CARGO_MANIFEST_DIR"), "/examples/data/tickets.jsonl");
let dataset = Dataset::<ClassifyTicket>::from_jsonl(path)?;
let classify = Program::<ClassifyTicket, _>::new(common::provider()).temperature(0.0);
let report = evaluate(&classify, &dataset, &ExactMatch, 4).await;
println!("{report}");
for (index, error) in &report.failures {
println!("example {index} failed: {error}");
}
// The report is plain data, e.g. for storing next to the dataset.
println!("{}", serde_json::to_string(&report)?);
Ok(())
}ClassifyTicket model qwen3:32b examples 8 exact match 87.5 % (95 % CI 52.9 % – 97.8 %) category 85.7 % (6/7) urgency 100.0 % (5/5) valid 100.0 % repaired 0.0 % failed 0.0 % latency p50 96248 ms latency p95 121426 ms tokens 1099 in / 1925 out