---
mpf: '0.7'
title: MPF 0.6 Specification — ESFI Docs
url: https://docs.esfi.eu/standards/mpf/0.6/
mpf-url: https://docs.esfi.eu/standards/mpf/0.6/index.mpf
organization: European Strategy & Future Infrastructure
domain: docs.esfi.eu
lang: en
updated: '2026-11-03'
author: ESFI
provenance: human
source-hash: 266b31b04074c0e94ff3f5d5874dd695ec823d7657383fd3478716a1bee7dea9
toc:
  - level: 1
    text: Machine Page Format (MPF) 0.6
    id: machine-page-format-mpf-0-6
  - level: 2
    text: 1\. File form
    id: 1-file-form
  - level: 3
    text: 1.1 MPF identifier
    id: 1-1-mpf-identifier
  - level: 3
    text: 1.2 Source hash
    id: 1-2-source-hash
  - level: 2
    text: 2\. Page generation
    id: 2-page-generation
  - level: 2
    text: 3\. Frontmatter
    id: 3-frontmatter
  - level: 3
    text: 3.1 Fields emitted for a page
    id: 3-1-fields-emitted-for-a-page
  - level: 3
    text: 3.2 Summary
    id: 3-2-summary
  - level: 3
    text: 3.3 Content parity
    id: 3-3-content-parity
  - level: 2
    text: 4\. URLs and identity
    id: 4-urls-and-identity
  - level: 3
    text: 4.1 Canonical URL
    id: 4-1-canonical-url
  - level: 3
    text: 4.2 Content ID
    id: 4-2-content-id
  - level: 3
    text: 4.3 Language detection
    id: 4-3-language-detection
  - level: 3
    text: 4.4 Language variants
    id: 4-4-language-variants
  - level: 2
    text: 5\. Markdown body and table of contents
    id: 5-markdown-body-and-table-of-contents
  - level: 2
    text: 6\. Companion instruction
    id: 6-companion-instruction
  - level: 2
    text: 7\. Site indexes
    id: 7-site-indexes
  - level: 3
    text: 7.1 Indexed pages
    id: 7-1-indexed-pages
  - level: 3
    text: 7.2 llms.mpf
    id: 7-2-llms-mpf
  - level: 3
    text: 7.3 llms.txt
    id: 7-3-llms-txt
  - level: 3
    text: 7.4 llms-full.txt
    id: 7-4-llms-full-txt
  - level: 2
    text: 8\. Signing
    id: 8-signing
  - level: 2
    text: 9\. Command-line interface
    id: 9-command-line-interface
  - level: 2
    text: 10\. ESFI 0.6 reference configuration
    id: 10-esfi-0-6-reference-configuration
  - level: 2
    text: 11\. Non-claims
    id: 11-non-claims
  - level: 2
    text: On this page
    id: on-this-page
spec-origin: esfi.eu
content-origin: docs.esfi.eu
content-id: esfi:page:standards-mpf-0-6
content-parity:
  html: true
  human-visible-source: true
  hidden-sections: false
summary: Previous implemented specification for the Machine Page Format 0.6
index: true
confidence: confirmed
content-type: reference
companion-footer: ESFI — civilization infrastructure · https://esfi.eu
companion-contact: mailto:hermes@esfi.eu
preferred-representation: mpf
companion-scope:
  cite: true
  summarize: true
  train: true
  index: true
  relay: false
language-variants:
  en: https://docs.esfi.eu/standards/mpf/0.6/index.mpf
  fr: https://docs.esfi.eu/fr/standards/mpf/0.6/index.mpf
  nl: https://docs.esfi.eu/nl/standards/mpf/0.6/index.mpf
  de: https://docs.esfi.eu/de/standards/mpf/0.6/index.mpf
  hr: https://docs.esfi.eu/hr/standards/mpf/0.6/index.mpf
mpf-id: 1382292f7c5f8f768251b491b85eada3dc287a9167a17c8724b6d935fed4e7cc
---

Language

✕

/standards/mpf/0.6/index.mpf[open file ↗](/standards/mpf/0.6/index.mpf)[spec ↗](/standards/mpf/0.7)✕

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# Machine Page Format (MPF) 0.6 {#machine-page-format-mpf-0-6}

> **Previous version.** MPF 0.6 remains published so documents that declare it can be interpreted against their original contract. The current implemented version is [MPF 0.7](/standards/mpf/0.7).

Status: implemented specification
Version: 0.6
Reference implementation: `mpf-build`

Machine Page Format (MPF) is a generated, machine-readable companion representation of a web page. MPF 0.6 is defined here by the behavior of the current `mpf-build` implementation. This document describes what the implementation produces; it does not define unimplemented future behavior.

## 1\. File form {#1-file-form}

An MPF document is UTF-8 text with YAML frontmatter followed by a Markdown body.

```
---
mpf: '0.6'
title: Example
...
mpf-id: <sha256>
---

# Markdown body
```

The frontmatter is serialized with stable insertion order. The body is trimmed before serialization and the final document ends with a newline.

### 1.1 MPF identifier {#1-1-mpf-identifier}

`mpf-id` is a SHA-256 digest of the complete generated MPF document **before** the `mpf-id` field itself is inserted.

The digest source is exactly:

```
---
<serialized YAML without mpf-id>
---

<body>
```

This makes `mpf-id` a content identifier for the generated MPF representation, not for the source HTML.

### 1.2 Source hash {#1-2-source-hash}

`source-hash` is a SHA-256 digest of the raw source HTML read by `mpf-build`.

## 2\. Page generation {#2-page-generation}

`mpf-build` walks the source directory recursively, ignores hidden entries and `node_modules`, and processes files ending in `.html` or `.htm`.

For each page it:

1.  reads the raw HTML and file modification time;
2.  loads the site configuration and any page override;
3.  parses page metadata;
4.  extracts MPF-only material and applies the MPF HTML transformations used by the implementation;
5.  selects the configured content region;
6.  strips non-content noise;
7.  converts the selected HTML to Markdown;
8.  adds stable heading anchors and builds the table of contents;
9.  prepends MPF-only Markdown, if present;
10.  resolves canonical, MPF, identity, language and provenance metadata;
11.  prepends a companion instruction block when configured;
12.  serializes the MPF document and writes it to the output tree;
13.  writes a signature alongside the MPF document when signing is configured.

The output directory defaults to the source directory and can be overridden with `--out`.

## 3\. Frontmatter {#3-frontmatter}

### 3.1 Fields emitted for a page {#3-1-fields-emitted-for-a-page}

The current page generator emits these fields:

| Field | Behavior |
| --- | --- |
| `mpf` | MPF version from site config. |
| `title` | HTML page title. Required. |
| `url` | Canonical human-facing URL. Required. |
| `mpf-url` | Absolute URL of this MPF file. |
| `organization` | Organization from site config. |
| `domain` | Domain from site config. |
| `lang` | Page override language, otherwise inferred from path, otherwise default language. |
| `updated` | Source HTML file modification date, formatted `YYYY-MM-DD`. |
| `author` | Author from site config. |
| `provenance` | Page override or configured default. Required. |
| `source-hash` | SHA-256 of raw source HTML. |
| `toc` | Array of generated heading entries. |
| `spec-origin` | Configured spec origin, otherwise configured domain. |
| `content-origin` | Configured content origin, otherwise configured domain. |
| `content-id` | Page override or generated stable content identity. Required. |
| `content-parity` | Relationship between MPF content and human-visible HTML. |
| `mpf-id` | SHA-256 identifier of the generated MPF representation. |

The implementation can also emit the following optional fields when they resolve to a non-empty value:

-   `c2pa-manifest`
-   `section`
-   `parent`
-   `related`
-   `summary`
-   `index`
-   `confidence`
-   `valid-until`
-   `review-after`
-   `content-type`
-   `companion-instruction`
-   `companion-contact`
-   `preferred-representation`
-   `companion-scope`
-   `supersedes`
-   `superseded-by`
-   `language-variants`
-   `signature`

The builder stops with an error if the page has no title, canonical URL, provenance, or content ID.

### 3.2 Summary {#3-2-summary}

`summary` resolves in this order:

1.  page override `summary`;
2.  HTML metadata description;
3.  omitted.

### 3.3 Content parity {#3-3-content-parity}

If the HTML contains MPF-only material detected by the implementation, page frontmatter is forced to:

```
content-parity:
  html: false
  human-visible-source: false
  hidden-sections: true
```

Otherwise, `content-parity` uses the configured default. If no default is configured, the implementation uses:

```
content-parity:
  html: true
  human-visible-source: true
  hidden-sections: false
```

## 4\. URLs and identity {#4-urls-and-identity}

### 4.1 Canonical URL {#4-1-canonical-url}

If page metadata provides a canonical URL, that URL is resolved against the configured base URL and used. For an `index.html` page, the canonical pathname is normalized to end in `/`.

Without page canonical metadata:

-   root `index.html` resolves to the normalized base URL plus `/`;
-   other HTML paths resolve beneath the configured base URL after removing a terminal `index.html`.

### 4.2 Content ID {#4-2-content-id}

Generated page identity has this form:

```
<content-id-prefix>:page:<slug>
```

The configured locale prefix is removed before the slug is generated, so translations of the same route receive the same generated content ID.

The root page slug is `home`.

For non-root pages, the route is lowercased, path segments are joined with hyphens, and unsupported characters are normalized to hyphens.

Example from the ESFI implementation:

```
esfi:page:home
```

### 4.3 Language detection {#4-3-language-detection}

Configured languages come from `config.languages`. If that list is empty or absent, only the configured default language is used.

The builder checks the first path segment. If it is a configured language code, that language is assigned; otherwise the default language is assigned.

### 4.4 Language variants {#4-4-language-variants}

For every configured language, the builder generates a `language-variants` entry pointing to the expected MPF URL for the same locale-independent content path.

For the default language, no locale path prefix is inserted. Non-default variants receive `/<lang>/`.

The implementation generates these URLs from configuration and path identity; it does not check in this step whether every translated file exists.

Example:

```
language-variants:
  en: https://esfi.eu/index.mpf
  fr: https://esfi.eu/fr/index.mpf
  nl: https://esfi.eu/nl/index.mpf
  de: https://esfi.eu/de/index.mpf
```

## 5\. Markdown body and table of contents {#5-markdown-body-and-table-of-contents}

The selected HTML content is converted to Markdown before MPF serialization.

Headings at levels H1 through H4 are included in `toc` and receive explicit Markdown anchors:

```
## Example heading {#example-heading}
```

Each TOC entry has:

```
- level: 2
  text: Example heading
  id: example-heading
```

Anchor generation:

-   lowercases the heading;
-   keeps Unicode letters and numbers;
-   replaces other runs with `-`;
-   collapses repeated hyphens;
-   trims leading and trailing hyphens;
-   falls back to `section` if no slug remains;
-   resolves duplicates by appending `-2`, `-3`, and so on.

Headings inside fenced code blocks are ignored.

Existing inline Markdown formatting and links are removed from the heading text used for TOC identity.

## 6\. Companion instruction {#6-companion-instruction}

If `companion-instruction` is present, the builder prepends it to the Markdown body as a blockquote.

Single-line form:

```
> Companion instruction: <instruction>
```

Multiline form:

```
> Companion instruction:
> <line 1>
> <line 2>
```

## 7\. Site indexes {#7-site-indexes}

A build also produces three site-level discovery outputs:

-   `llms.mpf`
-   `llms.txt`
-   `llms-full.txt`

### 7.1 Indexed pages {#7-1-indexed-pages}

A page is included in generated indexes only when its resolved frontmatter has:

```
index: true
```

Indexed entries are sorted lexicographically by MPF URL.

### 7.2 llms.mpf {#7-2-llms-mpf}

`llms.mpf` is itself an MPF 0.6 document. Its generated frontmatter uses:

-   title `Site Index — <organization>`;
-   language = configured default language;
-   provenance = `human`;
-   content type = `reference`;
-   `index: true`;
-   `content-id: <content-id-prefix>:page:llms`;
-   hidden/non-HTML content parity.

Its body contains the organization heading, optional configured description, and a Markdown list of all indexed MPF pages. Each item includes the page summary when available.

The current implementation includes indexed pages from all configured languages in `llms.mpf`.

### 7.3 llms.txt {#7-3-llms-txt}

The builder maintains an MPF discovery section in `llms.txt`:

```
MPF: <version>
MPF-index: /llms.mpf

## Pages
...
```

If no `llms.txt` exists, it creates one with an organization heading. If a previous MPF section exists, it replaces that section while preserving content before and after it.

### 7.4 llms-full.txt {#7-4-llms-full-txt}

`llms-full.txt` concatenates the bodies of indexed pages in the configured default language only.

For each page it writes the title, canonical URL, and generated MPF body.

## 8\. Signing {#8-signing}

The builder loads a signing key from the configured signing-key setting.

When a signing key is available:

-   page frontmatter receives a `signature` URL;
-   `llms.mpf` also receives a `signature` URL;
-   the implementation writes a signature artifact alongside generated MPF content.

When no signing key is configured, the `signature` field is omitted.

## 9\. Command-line interface {#9-command-line-interface}

The implemented CLI is:

```
mpf-build <source-dir> [options]
```

Options:

| Option | Effect |
| --- | --- |
| `--config <path>` | Use a specific `mpf.config.json`. |
| `--out <path>` | Write generated files to another output directory. |
| `--dry-run` | Report generated paths without writing files. |
| `--verbose` | Log each processed file with title, URL and TOC count. |
| `--watch` | Rebuild on HTML, page-override or config changes. |

In watch mode, rebuild requests are serialized: if a change occurs during a running build, one queued rebuild runs afterward.

## 10\. ESFI 0.6 reference configuration {#10-esfi-0-6-reference-configuration}

The ESFI 0.6 deployment used:

```
{
  "mpf": "0.6",
  "organization": "European Strategy & Future Infrastructure",
  "domain": "esfi.eu",
  "base-url": "https://esfi.eu/",
  "author": "ESFI",
  "default-lang": "en",
  "languages": ["en", "fr", "nl", "de"],
  "content-id-prefix": "esfi"
}
```

That deployment additionally defined provenance, confidence, content type, indexing, companion scope, companion contact, preferred representation and content parity defaults.

## 11\. Non-claims {#11-non-claims}

MPF 0.6 does **not** gain a capability merely because a field name could describe it. This specification only claims behavior present in the reference implementation.

In particular, generated metadata such as `language-variants`, `confidence`, `companion-scope`, `valid-until`, or `review-after` is descriptive metadata. The builder emits or derives it as described above; no additional policy engine, network validation, translation verification, expiry enforcement, or confidence calculation is implied by the 0.6 implementation.

## On this page {#on-this-page}

ESFI — civilization infrastructure · https://esfi.eu