Let Agents In

Agent readiness · SMS, voice and messaging

sinch.com

9 of 13 measurable points under formula 9.2, measured on 2026-08-12. 15 checks exist; each is one HTTP request with a published rule, so every sentence below can be rerun and argued with. 2 of them could not be measured from where we ask, and those are left out of the denominator rather than counted as failures.

A · Discovery

  • PASS
    Answers an agent user-agentAnswered 200 to LetAgentsIn/1.0 (+https://letagentsin.com/methodology)
  • PASS
    llms.txt publishedllms.txt present at https://docs.sinch.com/llms.txt and https://developers.sinch.com/llms.txt, and the 12 links we sampled across the file all answer
  • PASS
    Docs readable without JavaScript2,689 characters of text without JS, on https://developers.sinch.com/docs/errors/registry/invalid-credentials rather than on https://developers.sinch.com
  • PASS
    On-demand agents not blockedNo on-demand agent is blocked
  • N/A
    Paths robots.txt points at answerrobots.txt names no concrete path, only patterns or nothing, so there is no claim to check
  • PASS
    No punishing crawl delayNo Crawl-delay applies to the agents we check

B · Agent entry

  • UNMEASURED
    Agent entry pointUnmeasurable: 8 of the 9 known agent entry paths answered with a refusal rather than a file or a 404, so what you publish there is not something we measuredLet ordinary HTTP reach these paths and this becomes measurable.
  • PASS
    OAuth dynamic client registrationregistration_endpoint published, and client_credentials is among the 13 advertised grants, so an unattended agent has a documented path to a token
  • FAIL
    MCP surfaceNo MCP surface: nothing answered at mcp.sinch.com, mcp.sinch.com/mcp, mcp.sinch.com/v1/mcp, api.sinch.com/mcp, /mcp or /api/mcp, and no file mentions MCP

C · Registration

  • UNMEASURED
    No CAPTCHA in the signup HTMLUnmeasurable: the signup form at https://dashboard.sinch.com/signup is not in the server HTML, so its gates are not eitherServer-render the form, or tell us the endpoint it posts to, and the gates become visible to us and to an agent.
  • FAIL
    Signup reachable without a browserhttps://dashboard.sinch.com/signup is reachable, but its form needs JavaScript

D · Provisioning

  • PART
    Programmatic key provisioning1 of 7 provisioning phrases across the 6 documents we read: "provisioning api"
  • FAIL
    Free tier or no-card trial stated in texthttps://sinch.com/pricing/ carries a "start for free" style link and nothing else about a free tier, so what we found is a button rather than a stated price

E · Integration

  • PASS
    Typed SDK on the registry@sinch/sdk-core@1.5.0 ships types, matched from the registry by who publishes it rather than by a link on your site
  • PASS
    Machine-readable API descriptionDocs serve markdown to machines, at https://developers.sinch.com/docs/est/api-reference/est/credentials.md

Tell me when this changes

The failures here are the kind nobody notices. An edge rule that starts refusing agents changes nothing a person sees in a browser, so the first sign is usually an integration that quietly stopped working. We rescan weekly and write only when a verdict moves.

This page is the newest scan we hold for sinch.com and changes when we rescan. It is not a judgement of the product: we measure whether an unattended run can get through, not whether the thing is any good. The whole corpus is published as JSON and CSV.

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