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OneSimpleAPI for AI agents

OneSimpleAPI bundles small utility endpoints for screenshots, PDFs, QR codes, URL shortening, currency conversion, and validation. Developers use it to avoid building these one-off tools themselves. Connect it once through Arc0, and your agent, or Claude, ChatGPT and Cursor, can use it through one MCP endpoint, limited to what each user approved.

Connect OneSimpleAPISee the 15 actions ↓
Developer toolsAPI keyMCP + RESTonesimpleapi.com
AUDIT LOG · ONESIMPLEAPIPOLICY: acme-support
09:41:07 · claude · u_8f2read
onesimpleapi.list_files
List Files✓ allowed · 212ms
09:41:08 · claude · u_8f2read
onesimpleapi.validate_email
Validate Email✓ allowed · 164ms
09:41:09 · claude · u_8f2write
onesimpleapi.create_short_url
Create Short URL✓ approved · approved by user
09:41:12 · claude · u_8f2destructive
onesimpleapi.delete_file
Delete File✕ blocked · policy: deny
EVERY ONESIMPLEAPI CALL, ON THE RECORD
01 · USE CASES

What agents do in OneSimpleAPI.

01

Capture a website screenshot

Generate a screenshot of a URL for use in a report or status page.

02

Shorten a link for sharing

Create a short URL for a long tracking link before sending it in a message.

03

Delete a stored file with approval

Remove a generated file from storage only after confirming it is no longer needed.

02 · ACTIONS

15 OneSimpleAPI actions, graded by risk.

Every OneSimpleAPI action is tagged read, write or destructive, so one policy covers the whole app and new actions inherit the right default.

read

7

Look things up. Allowed by default.

  • onesimpleapi.list_files
    List Files
  • onesimpleapi.list_short_urls
    List Short URLs
  • onesimpleapi.get_image_information
    Get Image Information
  • onesimpleapi.validate_email
    Validate Email
  • onesimpleapi.convert_currency
    Convert Currency
  • onesimpleapi.analyze_readability
    Analyze Readability
  • onesimpleapi.calculate_ppp_discount
    Calculate PPP Discount

write

7

Create and change things. Allow, or ask the user first.

  • onesimpleapi.create_short_url
    Create Short URL
  • onesimpleapi.generate_pdf
    Generate PDF
  • onesimpleapi.transform_image
    Transform Image
  • onesimpleapi.expand_short_url
    Expand Short URL
  • onesimpleapi.generate_qr_code
    Generate QR Code
  • onesimpleapi.capture_screenshot
    Capture Screenshot
  • onesimpleapi.generate_or_convert_color
    Generate or Convert Color

destructive

1

Delete, cancel or archive. Ask first, or deny outright.

  • onesimpleapi.delete_file
    Delete File
03 · HOW IT WORKS

OneSimpleAPI in three steps.

  1. 01Your users connect OneSimpleAPIThey add their OneSimpleAPI api key on Arc0 Connect, under your brand. It goes straight into the vault.
  2. 02You set the rulesReads run, writes like “create Short URL” can wait for the user, and “delete File” can be denied outright.
  3. 03Any agent can actYour agent calls OneSimpleAPI through the Arc0 SDK or MCP, and so can Claude, ChatGPT and Cursor. Every call lands on the audit log.
POLICY.TS
await arc0.policies.set('onesimpleapi', {
  read: 'allow',
  write: 'ask',        // create_short_url
  destructive: 'deny',  // delete_file
})

# Claude Code: the same connection, one URL
$ claude mcp add --transport http arc0 \
    https://mcp.arc0.ai/u/u_8f2
04 · AUTH AND DATA

How OneSimpleAPI connects.

Users add their OneSimpleAPI api key on Arc0 Connect. It is encrypted in the vault, never shown to the model, and each user can rotate or revoke it at any time.

The same OneSimpleAPI connection serves your agent over MCP and your own backend over REST and the proxy, so a user connects once. How Arc0 handles credentials →

AUTH
API key
CREDENTIALS
Per-tenant encrypted vault
MODEL SEES
Results only, never credentials
AUDIT LOG
Every call, on every plan
05 · WORKS WITH

Use OneSimpleAPI from any agent.

Claude
ChatGPT
Cursor
Codex
VS Code
OpenAI Agents SDK
Claude Agent SDK
Vercel AI SDK
Mastra
LangGraph
06 · RELATED

More developer tools apps.

GitHub896 actionsSupabase129 actions0CodeKit8 actionsAbly25 actionsAbstract3 actionsAddressfinder17 actionsAddresszen2 actionsAlchemy36 actions
ALL DEVELOPER TOOLS APPS →
07 · FAQ

OneSimpleAPI and Arc0, answered.

Q01

Can I use OneSimpleAPI with Claude, ChatGPT or Cursor?

Yes. Connect OneSimpleAPI to Arc0 once, then add your Arc0 MCP URL to Claude, ChatGPT, Cursor, Claude Code or any other remote-MCP client. Each assistant only gets the OneSimpleAPI actions you allow.

Q02

How do users connect OneSimpleAPI?

Users add their OneSimpleAPI api key on Arc0 Connect. It is encrypted in the vault, never shown to the model, and each user can rotate or revoke it at any time.

Q03

Which OneSimpleAPI actions can my agent take?

15 in total: 7 read, 7 write and 1 destructive, such as “create Short URL”. Your policies decide which of them each agent may call.

Q04

Can I stop my agent from deleting things in OneSimpleAPI?

Yes. Actions like “delete File” are graded destructive. Set destructive actions to deny, or to ask so the user approves each one, and blocked calls still show up on the audit log.

Q05

Can my own backend call OneSimpleAPI too?

Yes. The same OneSimpleAPI connection is available over REST and through the Arc0 proxy, so your product and your agent share one connection per user.

Get started

Plug OneSimpleAPI into your agent.

Your users connect OneSimpleAPI once, under your brand. Your agent gets 15 actions behind your policies, with every call on the record.

Connect OneSimpleAPIBrowse all apps →

Free to build · MCP + REST · Audit log on every plan