[media-types] Re: [IANA #1421838] application/vnd.ag ent+markdown registration request

The field "Applications which use this media" is intended to describe applications that do use the media type, not ones that could use the media type.

I think that a standardization effort around a declarative agent format would be excellent.  I would encourage you to explore that possibility through a recognized standards body and then it would be appropriate to register a media type in the standards tree as "application/agent+markdown.  The vendor subtree is not intended as a way to register something as a standard in the hope that it will become a standard.

> The reason for using .agent is exactly because it is so broad. That
> way no company could lay claim to it.

But that is what you are asking to do.  You are asking to connect the format that you designed, with a broadly applicable name.
A broadly applicable standard should be designed via a collaboration with people in the space and the end result should be based on consensus.

Regards,

Darrel
________________________________
From: Amanda Baber via RT <[email protected]>
Sent: Tuesday, July 15, 2025 3:05 PM
Cc: [email protected] <[email protected]>; Darrel Miller <[email protected]>
Subject: [IANA #1421838] application/vnd.agent+markdown registration request

Hi Darrel,

Sending a reminder for this response from July 7th. (The time listed below is UTC.)

thanks,
Amanda

On Tue Jul 08 00:40:03 2025, amanda.baber wrote:
> Hi Darrel,
>
> The applicant sent the following response:
>
> =====
>
> I’m not saying it IS used by those. I’m saying it was written to be
> adopted by all of them using a format similar to what is already
> present. Every one of those platforms has “instructions” for ai but
> with no standardization.. Claude Code uses CLAUDE.md. Gemini uses
> GEMINI.md, etc.
>
> A product leader at Google tweeted about the need for standardization
> [text below]. That’s why I took it upon myself to write this. I also
> open sourced it on GitHub for that exact reason. I’m applying for this
> because people will need to be able to believe that it is a valid
> format in order for it to be adopted, but It belongs to everyone in my
> eyes. I just took what the product leader from google
> (https://www.linkedin.com/in/kathleensimpson/) asked for a delivered a
> uniform format.
>
> The reason for using .agent is exactly because it is so broad. That
> way no company could lay claim to it. If it was too specific I feared
> that one entity may try to lay claim to it. If approved, this would
> standardize something everyone using ai tools (especially software
> developers using CLI tools) use daily.
>
> Tweet from google product manager:
> Hey @_catwu @AnthropicAI @OpenAI — can we standardize around
> https://t.co/TXT5lybNcJ? There’s too much fragmentation right now. We
> need a shared spec for agent definitions before this gets messier.
> Kath Korevec (@simpsoka)
> x.com
>
> Response from me:
> @simpsoka @_catwu @AnthropicAI @OpenAI Hey @simpsoka, @_catwu,
> @AnthropicAI, & @OpenAI ... i created the ".agent" file type to
> standardize this for everyone. Me and an agent just wrote it. It's
> basically markdown with mods so that everything will support it.
> already. Hope you like it! I've already got it running. The
> Quikokas (@Quikolas17)
> x.com
>
> =====
>
> thanks,
> Amanda
>
> On Sun Jul 06 22:31:44 2025, [email protected] wrote:
> > Minor nit: The subtype name should just be vnd.agent+markdown
> >
> > The bigger concern with this registration is that the term "agent" is
> > very broadly applicable and this format is not broadly adopted from
> > what I can tell. The registration claims that this format is used by
> > Claude Code, Windsurf, VS Code, XCode, however, I can find no
> > evidence
> > of such support.  If the requester can provide such evidence, it
> > would
> > make the registration more appropriate.
> >
> > Creating a registration for something like
> > application/vnd.lancio.agent+markdown or
> > application/vnd.agentbrazley.agent+markdown would be a reasonable
> > alternative to what has been proposed.
> >
> > Regards,
> >
> > Darrel
> >
> > ________________________________
> > From: Amanda Baber via RT <[email protected]>
> > Sent: Monday, June 23, 2025 3:01 PM
> > Cc: Darrel Miller <[email protected]>; [email protected] <media-
> > [email protected]>
> > Subject: [IANA #1421838] application/vnd.agent+markdown registration
> > request
> >
> > Hi Darrel,
> >
> > New request here. Could you review this one for us by July 7th?
> >
> > thanks,
> > Amanda
> >
> > ====
> >
> > Name: Nikolas A. Brazley
> >
> > Email: [email protected]
> >
> > Media type name: application
> >
> > Media subtype name: vnd. application/vnd.agent+markdown
> >
> > Required parameters: N/A
> >
> > Optional parameters: charset (default: UTF-8)
> > version (agent schema version, e.g., "1.0")
> >
> > Encoding considerations: 8bit
> >
> > 8-bit text. Always UTF-8 encoded. Files are Markdown documents with
> > YAML frontmatter delimited by --- markers. The frontmatter section
> > must be valid YAML. The content section is standard Markdown.
> >
> > Security considerations: .agent files are Markdown documents with
> > YAML
> > frontmatter that may contain references to external resources.
> > Parsers
> > should validate the YAML frontmatter against the published schema and
> > sanitize inputs. Files may contain URLs or file paths that should be
> > validated before processing. The Markdown content follows standard
> > Markdown security considerations. No executable code is permitted in
> > the format.
> >
> > Interoperability considerations: Files must conform to YAML 1.2
> > specification with Jekyll-style frontmatter. The frontmatter section
> > must be valid YAML between --- delimiters. Parsers should gracefully
> > handle missing optional fields.
> >
> > Published specification: https://github.com/agentbrazley/dot.agent
> > Full schema documentation at:
> > https://github.com/nikbrazley/dot.agent/blob/main/docs/schema.md
> >
> > Applications which use this media: - Claude Code
> > - IDE's with agentic capabilities (Cursor, Windsurf, VS Code, XCode,
> > etc.)
> >
> > Fragment identifier considerations: Fragment identifiers follow
> > YAML/JSON Pointer syntax (RFC 6901) to reference specific fields
> > within the frontmatter section.
> > Example: #/capabilities/0 references the first capability.
> >
> > Restrictions on usage: none
> >
> > Provisional registration? (standards tree only): No
> >
> > Additional information:
> >
> > 1. Deprecated alias names for this type: N/A
> > 2. Magic number(s): ---\n (0x2D2D2D0A in hex)
> > 3. File extension(s): agent
> > 4. Macintosh file type code:
> > 5. Object Identifiers:
> >
> > General Comments: The .agent file format consists of YAML frontmatter
> > (delimited by ---) followed by optional Markdown content. The
> > frontmatter contains structured metadata about AI agents following
> > the
> > schema documented at
> > https://github.com/agentbrazley/dot.agent/blob/main/docs/schema.md
> >
> > Files always begin with "---\n" and use UTF-8 encoding. The format is
> > human-readable
> > and designed for version control systems.
> >
> > Reference implementation: https://github.com/nikbrazley/dot.agent
> > npm package: agent-frontmatter
> >
> > Person to contact for further information:
> >
> > 1. Name: Nik Brazley
> > 2. Email: [email protected]
> >
> > Intended usage: COMMON
> >
> > Author/Change controller: Nik Brazley

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