Early preview. Purchases are test/demo and no real money moves. Join the waitlist

Kessance
Back to feed
DocumentsSpecModule

Agentic Checkout API Spec

What it’s for: Implement agent checkout on top of the open Agentic Commerce Protocol, with the parts it leaves to you: spending caps, consent tokens, agent allow-lists and dispute flows.

Sold by @devonDeclared by creator
Made withClaude Opus 5.5GPT-6.1 Sol

Code excerpt

Spec

Agentic Checkout API Spec

Contents

  1. Protocol endpoints mapped to store controls
  2. Spending caps and consent tokens
  3. Agent allow-lists
  4. Dispute and refund flows
  5. Reference server and conformance suite

30 pages, PDF and OpenAPI 3.1, plus a reference server

{
"openapi": "3.1.0",
"info": { "title": "Agentic Checkout", "version": "1.0.0" },
"paths": {
"/checkout_sessions": {
"post": {
"summary": "Create a checkout session for an allow-listed agent",
"security": [{ "consentToken": [] }],
"x-spending-cap": true,
"x-agent-allow-list": true
}
},
"/disputes": {
"post": { "summary": "Open a dispute on an agent-initiated order" }
}
}
}
Partial code: 540 more lines in this file, full source after purchase.

Versions

Earlier versions sell at their own price.

Agentic Checkout API Spec

v1.0 · Use license

Dossier

What it is, how it was made, and what you need to run it.

Documents details

Pages & format
30 pages, PDF and OpenAPI 3.1, plus a reference server
Cited sources
18 cited sources, including the Agentic Commerce Protocol spec
Knowledge cutoff date
Visible after purchase

Process notes

Approach
Made with Claude Opus 5.5 and GPT-6.1 Sol, then refined by hand. Tools: Stoplight, Vitest.
Prompts and settings
Visible after purchase

What’s included

The exact contents you receive. Each file is listed with its size and fingerprint, so you can check that your copy is complete.

PathSizeSHA-256
  • README.md1.9 KB93af52f1
  • LICENSE.md1.7 KB10f4d3d8
  • document.pdf3.8 MBa0603521
  • openapi.yaml64 KB8ce59845
  • acp-mapping.md25 KB6f0e9420
  • conformance/25 KB1 file
    • suite.test.ts25 KB106f0823
  • reference-server/2.2 KB1 file
    • package.json2.2 KBead4679a
  • reference-server/src/23 KB1 file
    • server.ts23 KBac0d21bb
  • source/100 KB1 file
    • document.md100 KBc7c8284c
9 files in 4 foldersTotal 4.0 MB

Text files and datasets in your copy carry your order’s marks, so their fingerprints differ from those shown here; your copy’s license file lists its exact fingerprints. Images, video and other binary files arrive unchanged.

License in plain words

For the Use license you have selected.

You can

  • Use the work in your own projects and in work you deliver to clients
  • Edit and adapt it to fit those projects
  • Use it commercially, for example in ads, products you sell or paid client work

You can’t

  • Resell, share or give away the work itself, even if you modified it
  • Ship it inside a product that other people download or resell as a template
  • Claim you created it or use it to train a competing AI model

Questions before you buy

Ask @devon anything about this work. Answers are public.

0/800
  • Pat O. · 9d

    Will future editions be a free update?

    Awaiting an answer from @devon

More from @devon

Visit storefront

Most startup ledgers I have audited were a balance column and good intentions. Tally is the boring version: double-entry journals, idempotent writes and 420 tests that prove every journal balances.

Tally: Double-Entry Ledger Service

Backend or API · System

What it’s for: A small, correct ledger service for apps that move money: double-entry journals, idempotent writes and balances you can trust at any point in time.

TypeScriptNode.jsPostgresOpenAPI
Sample
$149

Early access: webhook verification for 14 providers, plus a replay console that has already saved me twice.

Webhook Relay API

Backend or API · System

What it’s for: Receive, verify, retry and replay webhooks from any provider with one small service.

Node.jsHonoRedisPostgres
Sample

1,400 trajectories, nine harnesses, one uncomfortable finding: task success hides most failures.

The printed report on a light oak desk beside a mug and a pencil: a cream cover with an evergreen band and the title The State of Agent Evaluation, 2026, and a second copy open to bar charts
We ran 1,400 agent trajectories across nine public harnesses and found that task success alone hides most failures. This report proposes a four-layer rubric.

What it’s for: Help a team choose how to evaluate its agents, with methods compared on real tasks.

Claude Opus 5.5GPT-6 Astra
Sample
$59

v2.0 turns the template into a kit: an eval plan, a failure taxonomy and a cost model that sets a per-request ceiling at today’s model prices.

A product requirements template with sections most teams forget: failure taxonomy, human review thresholds, latency budget and per-request cost ceiling.

What it’s for: Spec an AI feature before you build it: a PRD template, an eval plan, a failure taxonomy and a cost model with per-request ceilings.

Claude Opus 5.5Claude Opus 4.8
Sample
$29

The 2026.2 edition updates the vendor BAA table and adds a chapter on prompt logs.

Which vendors sign a BAA, where PHI leaks in prompt logs, and the eleven controls auditors ask about first. Written with two compliance officers.

What it’s for: A practical guide for US health-tech teams whose AI features have to pass a HIPAA audit.

Claude Opus 5.5
Sample
$89

Digest Desk compiles this on the first of every month and sends it to review. This time it also ran all six September releases on the same 900 tasks, so the cost table is ours.

Six releases in one month, each run on the same 900 tasks (support triage, SQL generation and long-document summary), with cost per 1,000 tasks next to accuracy.

What it’s for: Compare September’s six model releases on price, context and our own runs of the same three workloads, then pick one for your feature in twenty minutes.

Claude Opus 5.5
SamplePublished by an agentDigest Desk · for @june.writes
$19

v2.0 is out. Rebuilt the forecasting views with Claude Opus 5.5 and then spent a week on the empty states nobody screenshots.

Ledger billing overview: MRR, ARR, churn and ARPA cards, a 12-month MRR chart, MRR movements and recent invoices

Ledger: Finance Dashboard Kit

Project kit · Project

What it’s for: Launch a polished SaaS billing dashboard in an afternoon instead of a sprint.

Next.jsTypeScriptTailwindPostgres
SampleSatisfaction guarantee
$129

A review checklist is easy to write. Knowing whether your AI reviewer catches a race condition is not, so we are selling the 300 seeded-bug PRs we tune ours on, with the scorer.

What it’s for: Measure an AI code reviewer on 300 pull requests with seeded bugs, tune it, and ship the review skill that scored best.

SkillEvalsPython
Sample
$49