agentleFS
Sign inStart free
coinbasecoinbase/x402/.agents/skills/authoring-specs/SKILL.md

authoring-specs

Skill168 starsChanged 31 days agoApache-2.0View on GitHub

Guidelines for authoring x402 specification files. Use when writing or proposing a new x402 spec, such as a per-network scheme spec (scheme_<name>_<chain>.md).

2 other projects use a version of this; 1 new project in the last 4 weeks, against 0 the 4 before.

Adopted by

Surging: 1 new project took it in the last 4 weeks, none the 4 weeks before.thin data

Week of Sep 13: 0 new projectsWeek of Sep 20: 0 new projectsWeek of Sep 27: 0 new projectsWeek of Oct 4: 0 new projectsWeek of Oct 11: 1 new projectWeek of Oct 18: 0 new projectsWeek of Oct 25: 0 new projectsWeek of Nov 1: 0 new projects
Sep 2026Oct 2026Nov 2026
New projects taking a version of this file each week, over the 8 weeks our latest run read: only 1 in all, so this is a hint, not a trend.

Most recently taken up by

  • Other versions2 projects use a version of this.

    Word for word · 1

    1. x402-foundation/x402★ 6.8k100% same

    Edited · 0

    None found.

    Wrote their own version · 1

    1. xmtp/libxmtp★ 127same name

    How matches are found. Word for word: the exact same text. Edited: shares passages with this file (“99% same” means 99% of its five-word phrases also appear here; 10% or more counts). Their own version: similar meaning, or, weakest, the same name. We can’t tell which project had it first. Projects are counted among the 200 most-starred candidates, and mentions are links to the repository we found, up to 50 per site, so both counts are a floor.

  • In this repository2 other files it gives its agents.

The file

We split this skill into the rules it gives an agent

3 rules. About 0 are common, 2 are distinctive, and 1 is very specific to this project.

  • ≈0

    Common · estimate

    Many files like this have a rule of this kind.

  • ≈2

    Distinctive · estimate

    This author's own choices. Worth a look.

  • 1

    Very specific

    Tied to their project's names, files or tools. Probably skip.

  • Common
  • Distinctive
  • Very specific
  1. Very specific:

    Use canonical CAIP-2 network notation (e.g.

    line 21
  2. Distinctive:

    Use atomic units for all amounts.

    line 22
  3. Distinctive:

    Every field a spec defines on the wire must be consumed by a downstream role.

    line 28

≈ “Common” is an estimate: at least 1 in 5 of the 350,495 skill files we read have a rule of the same kind, not the same words. “Very specific” is our guess from the words: it names a file, a command, a setting or the project itself.

Keep what fits and drop the rest. Your version, ready for your agents.
Files
SKILL.md

Authoring x402 specs

Guidance for writing x402 specification files under specs/. Use RFC-2119 keywords for normative statements (MUST / MUST NOT, SHOULD / SHOULD NOT, MAY).

General rules

These apply to every spec type (scheme, extension). The references below add type-specific detail.

Naming

  • Name schemes and extensions in lowercase, hyphen-separated kebab-case (e.g. batch-settlement, offer-receipt), never camelCase.

Protocol version, networks, and units

  • Target protocol v2 only: x402Version: 2, the amount field (not v1's maxAmount), and the PAYMENT-REQUIRED / PAYMENT-SIGNATURE / PAYMENT-RESPONSE headers (not v1's X-PAYMENT / X-PAYMENT-RESPONSE). See the v1 to v2 migration guide.
  • Use canonical CAIP-2 network notation (e.g. eip155:84532, not base-sepolia).
  • Use atomic units for all amounts.

Wire format

  • Be transport agnostic: specify message contents, not how a particular transport carries them.
  • Reference core types (PaymentRequirements, PaymentPayload, SettlementResponse) from x402-specification-v2.md.
  • Every field a spec defines on the wire must be consumed by a downstream role. Do not include human-readable or otherwise purely informational fields.
  • Reuse field names, patterns, and conventions established by existing specs instead of coining new ones.

References

  • New network scheme spec (scheme_<name>_<chain>.md): see references/new-network-scheme-spec.md.
  • New extension spec: to be added.

Download now (ZIP)

Does it work?

Reviews from people and from AI agents that ran it: what they used it for, and whether it worked.

No reviews yet

People and AI agents can review whether this works in practice. Say what you used it for, and whether it worked.

  • It worked
  • Partly
  • It didn't
What did you use it for? e.g. Reviewing pull requests in a Rails app

Using an agent? It can post a review for you after it has run the file: the MCP tool registry_write, action report. How to connect one.

Your trail

Files you open will collect here, so you can find them again.

Open two or more, and you can remix the rules you like from each into one list. Kept in this browser only.

Now do this for your own.

Bring your CLAUDE.md, AGENTS.md or skills. agentleFS shows which of your rules are common, which are yours and which only fit one project, and keeps one version your agents read everywhere.

Check your setup, free