acp-sandbox

Is acp-sandbox MCP server safe?

• None of the hidden-instruction wordings we know were found in its tool descriptions.
• Its error messages showed no secrets or internal details.
• 3 of its 8 tools are labeled read-only; the others may change or send things.
• Overall it scored 88/100 on 2 Nov 2026.

A test can only see what the server shows from outside, not what it does with your data behind the scenes. Connect servers from makers you trust.

What it can do

8 tools, in the server's own words.

Test results

Safe mode: only tools labeled read-only were run. How the test works

• !
  Ready for the newest MCP version

  1 warning

  • !Uses an older MCP version (2025-11-25). It works today, but it isn't on the July 2026 version (2026-07-28) yet.
  note
• !
  Every tool is described

  6 warnings

  • !update_checkout: Inputs with no description: session_id, items
  • !get_checkout: Inputs with no description: session_id
  • !request_paypal_payment: Inputs with no description: session_id
  • !wait_for_payment_approval: Inputs with no description: session_id, timeout_seconds
  • !complete_checkout: Inputs with no description: session_id, payment
  • !cancel_checkout: Inputs with no description: session_id
  note
• !
  Follows MCP best practices (not scored yet)

  1 tip (not scored)

  • !1 tool answers with structured data but doesn't declare its shape (outputSchema): list_products. If those answers change shape, nothing can catch it; with a schema, every answer is checked.
  note
• ✓
  ConnectsConnected in 1.1 s
  pass
• ✓
  Lists its toolsFound 8 tools
  pass
• ✓
  Tools are labeled safe or dangerousEvery tool has a safety label
  pass
• ✓
  No known hidden instructionsNone of the hidden-instruction wordings we know were found in tool descriptions. New wordings can get past this check.
  pass
• ✓
  Tools work with good inputs

  All good

  • ✓list_products: Worked (140 ms)
  • ✓get_checkout: Answered with an error, probably because of our sample input: No sandbox key. Start with create_checkout (it returns an api_key), then pass that api_key to the other tools.
  • ✓wait_for_payment_approval: Answered with an error, probably because of our sample input: No sandbox key. Start with create_checkout (it returns an api_key), then pass that api_key to the other tools.
  • –create_checkout: Not run: labeled as changing data
  • –update_checkout: Not run: labeled dangerous
  • –request_paypal_payment: Not run: labeled as changing data
  • –complete_checkout: Not run: labeled dangerous
  • –cancel_checkout: Not run: labeled dangerous
  pass
• ✓
  Bad inputs give a clean error

  All good

  • ✓get_checkout: Refused missing required input "session_id" with a clear error
  • ✓get_checkout: Refused wrong type for "session_id" with a clear error
  • ✓wait_for_payment_approval: Refused missing required input "session_id" with a clear error
  • ✓wait_for_payment_approval: Refused wrong type for "session_id" with a clear error
  pass
• ✓
  Fast enough

  All good

  • ✓Connecting took 1.1 s
  • ✓Listing tools took 139 ms
  • ✓Average tool answer: 140 ms
  • ✓list_products: Slowest tool: list_products (140 ms)
  pass
• ✓
  No secrets leakedChecked 6 error messages: no secrets or internal details
  pass
• –
  Tools work togetherNo tool's answer could be fed into another tool, so there were no chains to test (not counted either way)
  not tested

Test it yourself

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Score over time

• 2 Nov 202688

One test so far. New tests will show here.

Reviews

Coming soon: reviews from people who use acp-sandbox, signed in with GitHub, one per person. Reviews never change the score.