Structured content with consistent schemas

You maintain a conference listing site. A contributor submits this PR:

---
name: "PyData NYC"
startDate: 2026-09-18
endDate: September 20, 2026
timezone: US/Eastern
city: New York
ticketCost: 350
tags:
  - Python
  - Data Science
---

Three days of talks and workshops.

Four things are wrong: endDate is in a different format than startDate. timezone is US/Eastern, not a valid IANA zone. city is an invented field — your schema uses location. ticketCost is ticket_price misspelled. Your query that filters by ticket_price silently excludes this event. The timezone string fails your date library. You find out when the site renders.

The fix is not a style guide in a README. It’s a template that enforces the schema at the point of entry.

Set up the template

Create a directory for the event template:

templates/
  event/
    diecut.toml
    template/
      event.md.die

Write the config

Create templates/event/diecut.toml:

[template]
name = "event"

[variables.name]
type = "string"
prompt = "Event name"

[variables.start_date]
type = "string"
prompt = "Start date (ISO 8601, e.g. 2026-04-15T00:00:00.000Z)"

[variables.end_date]
type = "string"
prompt = "End date (ISO 8601, e.g. 2026-04-17T23:59:59.000Z)"

[variables.timezone]
type = "select"
prompt = "Timezone"
choices = [
  "America/New_York",
  "America/Chicago",
  "America/Denver",
  "America/Los_Angeles",
  "America/Toronto",
  "Europe/London",
  "Europe/Berlin",
  "Asia/Tokyo",
  "UTC",
]
default = "America/New_York"

[variables.location]
type = "string"
prompt = "Location (city, state or country)"

[variables.online]
type = "bool"
prompt = "Online event?"
default = false

[variables.website]
type = "string"
prompt = "Event website URL"

[variables.free]
type = "bool"
prompt = "Free to attend?"
default = false

[variables.ticket_price]
type = "int"
prompt = "Ticket price (USD, whole dollars)"
when = "not free"

[variables.tags]
type = "multiselect"
prompt = "Tags"
choices = [
  "Web Development",
  "Tech",
  "Unconference",
  "Open Source",
  "Design",
  "DevOps",
  "AI/ML",
  "Security",
  "Data",
  "Leadership",
]

[variables.featured]
type = "bool"
prompt = "Feature this event?"
default = false

[variables.description]
type = "string"
prompt = "Short description (one or two sentences)"

A few things to note:

timezone is a select. The user can only pick from the list. No invented timezone strings.
ticket_price is conditional — only shown when free is false.
tags is a multiselect. The user picks from a fixed list of choices. No freeform strings.

These constraints are not documentation. They are enforced at generation time. A contributor who types a timezone not in the list sees:

Timezone [America/New_York]: US/Eastern
Error: "US/Eastern" is not a valid choice. Select a value from the list.

The file is not written. The invalid value never reaches the content directory.

Write the template file

Create templates/event/template/event.md.die:

---
name: "{{ name }}"
startDate: {{ start_date }}
endDate: {{ end_date }}
timezone: "{{ timezone }}"
location: "{{ location }}"
online: {{ online }}
website: "{{ website }}"
{% if not free %}ticketPrice: {{ ticket_price }}
{% endif %}tags:
{% for tag in tags %}  - "{{ tag }}"
{% endfor %}featured: {{ featured }}
verified: false
---

{{ description }}

The verified field is always false on creation — a human reviewer sets it later. It doesn’t need to be a variable.

The human workflow

Someone needs to add Grok Conf. They run:

diecut new ./templates/event -o content/events/grok-2026.md

diecut reads the config and prompts for each variable:

Event name: Grok Conf
Start date (ISO 8601, e.g. 2026-04-15T00:00:00.000Z): 2026-04-15T00:00:00.000Z
End date (ISO 8601, e.g. 2026-04-17T23:59:59.000Z): 2026-04-17T23:59:59.000Z
Timezone [America/New_York]:
  1. America/New_York
  2. America/Chicago
  3. America/Denver
  4. America/Los_Angeles
  5. America/Toronto
  6. Europe/London
  7. Europe/Berlin
  8. Asia/Tokyo
  9. UTC
Location (city, state or country): Greenville, SC
Online event? [no]: no
Event website URL: https://atlaslocal.com/grok-26
Free to attend? [no]: no
Ticket price (USD, whole dollars): 279
Tags:
  1. Web Development
  2. Tech
  3. Unconference
  4. Open Source
  5. Design
  6. DevOps
  7. AI/ML
  8. Security
  9. Data
  10. Leadership
Feature this event? [no]: no
Short description (one or two sentences): Grok Conf is an attendee-driven unconference for web folks.

The output at content/events/grok-2026.md:

---
name: "Grok Conf"
startDate: 2026-04-15T00:00:00.000Z
endDate: 2026-04-17T23:59:59.000Z
timezone: "America/New_York"
location: "Greenville, SC"
online: false
website: "https://atlaslocal.com/grok-26"
ticketPrice: 279
tags:
  - "Web Development"
  - "Tech"
  - "Unconference"
featured: false
verified: false
---

Grok Conf is an attendee-driven unconference for web folks.

Only fields declared in diecut.toml appear. ticketPrice is present because the event is not free. The tags are from the approved list.

The LLM workflow

An LLM can generate the same entry without interactive prompts.

Without a schema, an LLM asked to “add Grok Conf as a conference entry” might produce:

---
title: "Grok Conf"
date: "April 15–17, 2026"
location: "Greenville, South Carolina"
price: "$279"
categories:
  - web
  - javascript
  - unconference
isFeatured: false
---

title instead of name. date instead of startDate/endDate. price as a string with a dollar sign instead of ticket_price as an integer. categories instead of tags, with freeform strings instead of approved choices. Your content layer ignores the entry silently.

With diecut, the LLM reads diecut.toml to understand the schema, then calls:

diecut new ./templates/event --defaults \
  -d name="Grok Conf" \
  -d start_date="2026-04-15T00:00:00.000Z" \
  -d end_date="2026-04-17T23:59:59.000Z" \
  -d timezone="America/New_York" \
  -d location="Greenville, SC" \
  -d online=false \
  -d website="https://atlaslocal.com/grok-26" \
  -d free=false \
  -d ticket_price=279 \
  -d tags="Web Development,Tech,Unconference" \
  -d featured=false \
  -d description="Grok Conf is an attendee-driven unconference for web folks." \
  -o content/events/grok-2026.md

--defaults suppresses all prompts. Each -d key=value flag overrides one variable. The result is the same file as the human workflow produced.

The schema constrains what the LLM can do:

It cannot pass a field that doesn’t exist in the template. Unknown -d keys are ignored.
It can only use tag values from the choices list. Passing "JavaScript" for tags would fail validation — that value is not in the list.
It cannot set ticket_price when free=true — the conditional makes that field inactive.

The LLM reads the diecut.toml directly to know what fields exist and what values are valid.

Compare this to the alternative: a CONTRIBUTING.md documenting the required fields and valid tag values. Three months later someone adds Rust to the approved tags — in diecut.toml and in the multiselect choices, but not in the README. The LLM reads the README and generates entries without Rust, or reads a cached version and generates Rust when the template no longer accepts it.

The diecut.toml the LLM reads is the same file that enforces constraints at generation time. They cannot drift from each other because they are the same artifact.

Preview before writing

Before committing the file, use --dry-run --verbose to see the rendered output without writing anything:

diecut new ./templates/event --defaults \
  -d name="Grok Conf" \
  -d free=false \
  -d ticket_price=279 \
  --dry-run --verbose \
  -o content/events/grok-2026.md

[dry-run] would write: content/events/grok-2026.md

The rendered content is printed to the terminal. Useful for inspecting the output before it lands in your content directory.

The difference

The PyData example at the start of this article — wrong field names, invented timezone strings, mismatched date formats — came from a contributor who didn’t know the schema. A style guide in a README can go stale; diecut.toml is the schema, so it can’t drift from itself.

For LLM workflows this matters directly: the LLM reads diecut.toml to understand what fields exist and what values are valid. That is the same file diecut uses to validate at generation time. There is no separate source of truth — no README, no wiki page — that can fall out of sync with what the tool accepts.

Validation happens at generation time, before anything lands in the content directory. US/Eastern for the timezone field is rejected at the prompt, not discovered later when the date library fails at render time.

To learn more about variable types and conditional fields, see Creating Templates. For all CLI flags, see the Commands reference.