OpenAI's coding agent

Use TextKit with Codex.SMS, phone verification, and real numbers, as capabilities.

Codex reads SKILL.md files; give it TextKit's and it stops hand-rolling OTP over raw SMS and uses the verify primitive instead.

1. Install the skills

Three SKILL.md files teach Codex the API, the verification rules, and SMS compliance, so it writes correct integration code the first time:

curl -sSL https://jointextkit.com/skills/install.sh | sh

textkit · textkit-verify · sms-best-practices

2. Connect the MCP server

Texts, numbers, verification, contacts, broadcasts and automations become tool calls. Add this to its MCP configuration. A client that supports sign-in needs only the URL; otherwise pass a test key:

{
  "mcpServers": {
    "textkit": {
      "url": "https://mcp.jointextkit.com",
      "headers": { "Authorization": "Bearer ssms_sk_test_YOUR_KEY" }
    }
  }
}

Every tool and how sign-in works: MCP server docs

3. Ask for the feature

A prompt like this now resolves against the real API, with a sandbox key that simulates everything and costs nothing:

Add phone verification to signup using TextKit Verify
(POST /v1/verify, then /v1/verify/check). Docs:
https://jointextkit.com/docs/verify.md

Everything Codex needs is machine-readable: an OpenAPI spec, markdown twins of every docs page, and a single-file llms.txt of the whole documentation set.

/llms.txt
/api/v1/openapi.yaml
/docs/llms-full.txt

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