What a SKILL.md file is

Agent Skills are a lightweight way to extend what an AI agent knows how to do, without writing custom integration code. A SKILL.md is just a markdown file with:

• Metadata (name, description, when the agent should use it)

• Instructions written in plain language telling the agent what the resource is, how to call it, and what to do with responses

Compatible agents (Claude Code, Cursor, ChatGPT, Gemini, etc.) load this file into context and follow it like a mini playbook.

Skills Marketplace

New skills are added regularly.

Live now with BTC Echo. Access and pay for premium news articles with EURAU.

BTC-ECHO is a leading German-language media platform focused on Bitcoin, blockchain, and digital assets. It delivers in-depth coverage of cryptocurrency markets, regulation, Web3, digital financial infrastructure, and investment trends. In addition to its editorial coverage, BTC-ECHO offers market analysis, podcasts, video content, newsletters, and data-driven products.

How the skill works end to end: 

1. Discovery: the skill tells the agent BTC Echo exists, what it offers (a searchable article index, paid full-text access), and when to reach for it (e.g., "use this when the user asks about Bitcoin/crypto news").

2. Free search first: the skill documents the free /api/search endpoint, so the agent can look up relevant articles without spending anything.

3. Hit the paywall: when the agent requests a specific article, the server returns 402 Payment Required with price and accepted tokens.

4. Pay automatically: the skill instructs the agent to run the ows pay request command (or equivalent payment client), which handles the full x402 handshake: sign payment → retry request → receive article.

5. Return the result: the agent hands the article content back to the user, having paid for it autonomously, mid-conversation.

The skill file itself doesn't move money. It just teaches the agent when and how to use the paywall and payment client that AllUnity's facilitator already powers.

export BTC_ECHO_API=https://agents.btc-echo.de

# Free: search the article index
curl -sG "$BTC_ECHO_API/api/search" \
  --data-urlencode "q=bitcoin etf outflows" \
  --data-urlencode "mode=hybrid"

# Paid: one command runs the full x402 handshake,
# fetches the 402, signs the payment, retries, returns the article
ows pay request --wallet x402-demo --no-passphrase \
  "$BTC_ECHO_API/api/articles/<slug>" > article.json

export BTC_ECHO_API=https://agents.btc-echo.de

# Free: search the article index
curl -sG "$BTC_ECHO_API/api/search" \
  --data-urlencode "q=bitcoin etf outflows" \
  --data-urlencode "mode=hybrid"

# Paid: one command runs the full x402 handshake,
# fetches the 402, signs the payment, retries, returns the article
ows pay request --wallet x402-demo --no-passphrase \
  "$BTC_ECHO_API/api/articles/<slug>" > article.json

export BTC_ECHO_API=https://agents.btc-echo.de

# Free: search the article index
curl -sG "$BTC_ECHO_API/api/search" \
  --data-urlencode "q=bitcoin etf outflows" \
  --data-urlencode "mode=hybrid"

# Paid: one command runs the full x402 handshake,
# fetches the 402, signs the payment, retries, returns the article
ows pay request --wallet x402-demo --no-passphrase \
  "$BTC_ECHO_API/api/articles/<slug>" > article.json

Your endpoint already earns money. It just doesn't know it yet. The pattern is portable to any content, service, or data provider:

• One integration, many platforms. Instead of building a Claude plugin, a ChatGPT plugin, a Cursor extension, etc. separately, you ship one SKILL.md. Any agent that supports Agent Skills can use it.

• No account, no API key, no human checkout. Agents transact directly against your priced endpoints. That removes friction that normally kills agent-driven monetization (agents can't fill out signup forms or manage credentials well).

• You control what's free vs. paid. Like BTC Echo's free search / paid full-text split, a business can expose a free discovery layer (search, previews, metadata) and gate the valuable part (full documents, structured data, API calls) behind x402 pricing.

Effectively, a SKILL.md is becoming something like a machine-readable storefront: it tells agents what you sell, what it costs, and how to pay.