[media-types] [IANA #1421838] application/vnd.agent+ma rkdown registration request

Hi Darrel,

Sending a reminder for this reconsideration request/update from July 29th.

thanks,
Amanda

On Tue Jul 29 00:11:40 2025, david.dong wrote:
> Hi Darrel (filling in for Amanda),
> 
> The requester sent the follow-up statement:
> 
> --
> 
> Recent development. Anthropic adopted the standard i created. their
> new agents format is a markdown file with YAML Frontmatter and it was
> deployed globaly to all claude code users. Instead of using the .agent
> endpoint they just create the file within their own system but it is
> literally stored in the “agents” folder and uses the exact same
> system.
> 
> Does that count as in use now?
> 
> --
> 
> Best regards,
> 
> David Dong
> IANA Services Sr. Specialist
> 
> On Mon Jul 21 20:13:16 2025, amanda.baber wrote:
> > Hi Darrel,
> >
> > We received thanks and a question from the requester: "Do you or the
> > reviewer know what standards body I would need to apply with instead?
> > I’ve never tried to do anything like this before and this is who I
> > was
> > recommended to apply with. Any help on who to apply with, or how to
> > change this so that it’s the right thing would be extremely helpful."
> >
> > thanks,
> > Amanda
> >
> > On Tue Jul 15 20:19:10 2025, [email protected] wrote:
> > > 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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