(registered 2025-10-30, last updated 2025-10-30)

Media type name: application

Media subtype name: vnd.faf+yaml

Required parameters: N/A

Optional parameters: Format version (e.g., version=1.0)

Encoding considerations: binary

UTF-8 encoding required. Binary content may be base64-encoded within YAML structure. Lines may exceed 1000 octets due to embedded project metadata.

Security considerations: 

.faf files contain project metadata and configuration information. Implementations should:

- Validate YAML structure before parsing
- Sanitize file paths to prevent directory traversal
- Verify score and confidence values are within valid ranges (0-100, 0-1.0)
- Not execute code contained in .faf files
- Treat content as untrusted user input

Privacy: .faf files may contain project-specific information including dependencies, architecture details, and development workflows. Sensitive information should not be included in publicly shared .faf files.

Interoperability considerations: .faf extends YAML with specific structure for AI context representation. All .faf files are valid YAML documents. Standard YAML parsers can read .faf files, though specialized parsers are recommended for validation and scoring features.

Cross-platform compatibility achieved through:

- Platform-agnostic YAML format
- UTF-8 encoding
- No platform-specific path conventions in core specification

Published specification: 

https://github.com/Wolfe-Jam/faf (primary specification)
https://faf.one (documentation and reference implementation)

Applications which use this media: 

This media type is used by:

- AI development tools and coding assistants for project context
understanding
- Command-line interface tools for generating and validating project
metadata
- IDE extensions and editor integrations for AI-assisted development
- Browser extensions for extracting project information from repositories
- Model Context Protocol servers for persistent AI context management
- CI/CD pipelines for tracking project evolution
- Development workflow automation tools requiring structured project
metadata

Fragment identifier considerations: N/A

Restrictions on usage: None (MIT License, open source)

Additional information:

1. Deprecated alias names for this type: N/A
2. Magic number(s): Files typically begin with YAML structure starting with "version:" key or YAML document marker "---"
3. File extension(s): .faf
4. Macintosh file type code: N/A
5. Object Identifiers: N/A

General Comments: .faf is designed as a universal format for AI project context representation across all development environments and AI platforms. Current adoption includes official integration with Anthropic's Model Context Protocol ecosystem, 10,000+ npm package downloads, and validation across major AI platforms (Claude, OpenAI Codex, Google Gemini). The format addresses fundamental AI context incompleteness in software development workflows.

Person to contact for further information:

1. Name: Wolfe James
2. Email: James&wolfejames.com

Intended usage: COMMON

Author/Change controller: Wolfe James
Creator and Maintainer, .faf Format Specification
Email: james&wolfejames.com
ORCID: 0009-0007-0801-3841
GitHub: https://github.com/Wolfe-Jam/faf