x402-discoverable

x402-discoverable is a skill for Cursor from Dexter-DAO/opendexter-ide. It costs 115 tokens per session (1,325 once invoked), scanned A, original, MIT.

A skill for listing an x402 API in the OpenDexter/x402gle catalogue. An x402 API is a web service that asks for payment through an HTTP 402 response, and this skill tests its paid routes before listing it.

In plain words
What is it for?
Use it after an API has an x402 payment wall to audition its paid endpoints and submit a passing service to the catalogue.
Why use it?
A paid API can work correctly yet remain undiscoverable to software agents. This process checks the live service and creates the information agents need to find and call it.

Skill for Cursor

Written for Cursor: shipped in a Cursor plugin.

Part of the opendexter plugin — 5 skills, 3 commands, 1 agent shipped together

Good fit Use it after an API has an x402 payment wall to audition its paid endpoints and submit a passing service to the catalogue.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/dexter-dao/opendexter-ide/x402-discoverable
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add Dexter-DAO/opendexter-ide --skill x402-discoverable
Clone the repo
git clone --depth 1 https://github.com/Dexter-DAO/opendexter-ide

Made for: Cursor.

Or install opendexter, the plugin that ships this one along with the rest of its 5 skills, 3 commands, 1 agent.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for x402-discoverable

README.md
[![agentmods](https://agentmods.dev/badge/skills/dexter-dao/opendexter-ide/x402-discoverable/github.svg)](https://agentmods.dev/skills/dexter-dao/opendexter-ide/x402-discoverable)
Your own site
<a href="https://agentmods.dev/skills/dexter-dao/opendexter-ide/x402-discoverable"><img src="https://agentmods.dev/badge/skills/dexter-dao/opendexter-ide/x402-discoverable/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for x402-discoverable

Your own site · 80×15
<a href="https://agentmods.dev/skills/dexter-dao/opendexter-ide/x402-discoverable"><img src="https://agentmods.dev/badge/skills/dexter-dao/opendexter-ide/x402-discoverable.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 115 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,325 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00115 $0.01325
Opus 5.5 $0.00046 $0.00530
Sonnet 5.5 $0.00023 $0.00265
Haiku 4.5 $0.00012 $0.00133

Measured 7d ago against content hash 2600c7f74ac1, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

x402-discoverable scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 7d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

packages/mcp/skills/x402-discoverable/SKILL.md · 130 lines

How it starts

The opening of the file, as written. The whole thing — 130 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Make an x402 API discoverable

Use opendexter audition to discover and register an x402 API's routes in the OpenDexter / x402gle catalog. A server origin registers routes. A specific endpoint URL requests an immediate test that can pay the endpoint, evaluate its response, and save a score. Registration and scoring are separate outcomes.

audition requests a server-side merchant test and can cause paid provider calls and catalog changes. It does not load a local signer or spend through the connected user's governed OpenDexter authority. Obtain explicit approval for the audition itself.

OpenDexter's platform verifier funds the test. Funding the seller's connected wallet does not fund this command. Check the returned result to see whether the test completed.

When this skill applies

Use it when the user's API already returns HTTP 402 with a valid payment manifest. Use the x402-server skill first if the API still needs its paywall.

The one command

npx @dexterai/[email protected] audition <server-url> --json
  • Pass a server origin to discover and register its routes without an immediate paid test.
  • To request an immediate test, pass a specific endpoint URL.
  • Use --json when an agent needs the structured result. Omit it for a human reading the summary. Add --verbose for request references and HTTP response metadata on stderr.

No global install is needed; this command requests the exact pinned package version.

Discovery requirements

The audition finds paid routes three ways, in order of preference:

  1. OpenAPI 3.1 document at /openapi.json (preferred), with info.x-guidance, a requestBody schema per paid operation, and an x-payment-info block carrying protocols (x402 and/or mpp) and a structured price.
  2. /.well-known/x402, a descriptor listing the paid routes.
  3. A bare probe of a URL that returns HTTP 402 with a valid payment manifest.

If discovery returns discovery_failed, read its message and warnings. Check that the advertised discovery document is reachable and describes the routes.

Read the full file on GitHub · 130 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 7d ago Changed 2600c7f74ac1
  2. 1mo ago Changed · +13 lines 70136959de41
  3. 1mo ago Changed 74d2378b49fc
  4. 1mo ago Changed db9a36ad3efd
  5. 2mo ago First seen · 117 lines · 115 tokens per session scan A b4377f9a9d4e

Subscribe to this mod's changes

x402-discoverable is a skill published in the GitHub repository Dexter-DAO/opendexter-ide (2 stars, last pushed 8d ago), licensed MIT. It adds 115 tokens to every session and 1,325 once invoked, about $0.0005 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

Related

x402-discoverable compared with skills from other repositories

x402-discoverable next to 6 skills from other repositories
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x402-discoverableDexter-DAO/opendexter-ideSkill28d agoMITA115Cursor
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serasera-cx/sera-agentsSkill202d agoMITA90Claude Code, Codex
x402aomi-labs/skillsSkill82d agoMITA84Claude Code
trustlayer-sybil-scannerBankrBot/skillsSkill1.2k2d agononeA43Claude Code, Codex
sera-protocolsera-cx/sera-agentsSkill202d agoMITA58Claude Code, Codex
agent-registrylxyeternal/MalSkillBenchSkill644d agononeA78Claude Code, Codex