---
title: "Check whether a shell command is runnable before you (or an..."
method: POST
path: "/api/dev/preflight"
tags: ["dev"]
---

# Check whether a shell command is runnable before you (or an...

`POST /api/dev/preflight`

## Request

- Base URL: `https://2s.io`
- URL: `https://2s.io/api/dev/preflight`
- Auth: API key in header `PAYMENT-SIGNATURE`

Check whether a shell command is runnable before you (or an agent) run it — a pre-execution gate. POST { command } with a command that targets the network (curl, wget, httpie, or anything carrying a URL). Parses out the HTTP method, target URL, and headers, then returns a structured verdict: verdict ('runnable' or 'invalid'), a runnable boolean, and a checks breakdown (hasTarget, urlValid, schemeOk, hostPresent, methodValid, privateTarget). By default the check is STATIC and deterministic — no network call — answering 'is there a well-formed http(s) target and a valid method?' (a command with no URL is invalid). Pass probe=true to also run a guarded HEAD request against the target and report dnsResolves, reachable, tlsValid, and httpStatus — answering 'would this actually connect right now?'. Private/loopback/reserved targets are refused (SSRF-safe). Built for gating agent-generated commands and CI pipelines.

## Query parameters

- `trial` 1

## Request body

- object
  - `command` string, required: Command.
  - `probe` boolean: Probe.

## Other responses

- `200` (unresolved $ref)
- `400`: Invalid request — not charged. error.code: BAD_REQUEST or INVALID_PARAM (parameter validation; error.details.issues lists each problem), MALFORMED_JSON, or a request-specific code. Other client errors: 405 METHOD_NOT_ALLOWED (wrong verb; see the Allow header), 413 PAYLOAD_TOO_LARGE.
- `402`: Payment required. Body is the x402 PaymentRequirements envelope with a multi-network accepts array; the per-call price is in accepts[].amount (and on the operation as x-2s-price). Sign for whichever rail you hold USDC on (EIP-3009 for Base, partial SPL transfer for Solana) and retry with the PAYMENT-SIGNATURE header (X-PAYMENT also accepted for v1 clients). Also PAYMENT_SETTLE_FAILED (error envelope) when a verified payment failed to settle: error.details.chargeStatus is "not_charged" (retry with a fresh payment) or "unknown" (the authorization may still settle before its deadline — check it before retrying).
- `429`: Too many requests — RATE_LIMITED: our per-IP / per-payer limiter. Not charged; retry after Retry-After.
- `5XX`: Server-side failure. 500 INTERNAL: unexpected error; quote error.errorId (also the X-2s-Error-Id header). 502 UPSTREAM_UNAVAILABLE (or another UPSTREAM_* code): the data provider failed — composite endpoints refuse unbilled when every source fails. 503 SERVICE_PAUSED: endpoint paused by the operator kill switch, retry after Retry-After; 503 SPEND_CAP: daily upstream budget exhausted. 504 UPSTREAM_TIMEOUT. Not charged.

---

[API](https://skmtc.dev/2s-io/apis/2s-the-most-everything-api.md) · [All operations](https://skmtc.dev/2s-io/apis/2s-the-most-everything-api/llms.txt) · [OpenAPI document](https://skmtc.dev/2s-io/apis/2s-the-most-everything-api/revisions/da4c5caf686e?raw)