Security · x402 · early usage

Decide whether an agent-authored bash command complies with an execution policy, using…

by shellpermit.schemasure.com · discovered, not yet claimed by its owner · updated 2026-10-10

30d calls23

30d payers1

MethodPOST

Outputjson

Mirrored from Coinbase's public x402 Bazaar. The description is the provider's own text and has not been reviewed here; the payment requirements are copied as published.

What it does

Decide whether an agent-authored bash command complies with an execution policy, using a real shell tokenizer rather than pattern matching. Catches recursive deletes, force pushes, cluster and infrastructure teardown, raw device writes, path escapes, privilege escalation, and curl-piped-to-shell through pipelines, substitutions, quoting games and base64. Returns reason codes with spans and an optional short-lived permit bound to the exact canonical command. Never executes anything.

Tags: shell · bash · command · guard · policy · bazaar

Call contract

Method: POST
Input: json
Output: json
Last paid call: 2026-10-10

Input example from Bazaar metadata

{
  "audience": "executor:acme-prod-01",
  "command": "rm -rf ./dist && npm run build",
  "issue_permit": true,
  "policy": {
    "allow_destructive": true,
    "allow_network_egress": false,
    "allowed_roots": [
      "/srv/app"
    ],
    "cwd": "/srv/app"
  },
  "shell": "bash"
}

Output example

{
  "confidence": 1,
  "evidence": [],
  "ok": true,
  "result": {
    "canonical_command": "rm -f -r ./dist && npm run build",
    "cmd_fingerprint": "a1b2c3d4e5f60718",
    "cmd_hash": "sha256:0f4c…1c2d",
    "permit": "eyJhbGciOiJFZDI1NTE5Iiwia2lkIjoi…"
  },
  "risk_codes": [],
  "verdict": "pass",
  "warnings": [
    "cmd_fingerprint is ADVISORY and must not be used for authorization."
  ]
}

Use with an agent

Discover. Agents find this listing with GET https://bazaar.saylorinnovations.com/discovery/search?query=…, the MCP tool search_resources, or /discovery/resources.
Inspect. Fetch /resources/36454.json for the price and payment options.
Pay. Call GET https://shellpermit.schemasure.com/v1/guard/shell. The provider answers 402 with its payment requirements. An x402 client signs one of the options below and retries with PAYMENT-SIGNATURE.
Execute. The provider returns 200 with the data. Agent Bazaar is not in the request path and never sees your payment.

For humans

You don't need an account or an API key; you need a wallet holding a small amount of USDC on Base, and an x402-capable client (see the examples below). Call the endpoint unpaid first to see exactly what it asks for.

Pricing & payment

Price: $0.03 / request
Protocol: x402 v2
Auth: No account or API key. Pay per request.
Networks: Base
Demand: 23 calls · 1 unique payers in 30d (public x402 Bazaar data)

x402 payment requirements

Scheme	Network	Asset	Amount	Pay to	Timeout
exact	Base eip155:8453	USDC	$0.03	0x9876af0F6D8Ed5155Cd02d1ca56D128601612690	60s

accepts[] (raw JSON)

[
  {
    "scheme": "exact",
    "network": "eip155:8453",
    "payTo": "0x9876af0F6D8Ed5155Cd02d1ca56D128601612690",
    "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
    "amount": "30000",
    "amountUsd": 0.03,
    "maxTimeoutSeconds": 60
  }
]

Schemas

Output schema (JSON Schema)

{
  "properties": {
    "example": {
      "properties": {
        "confidence": {
          "type": "number"
        },
        "evidence": {
          "items": {
            "properties": {
              "code": {
                "description": "Stable reason code, e.g. REMOTE_CODE_EXECUTION.",
                "type": "string"
              },
              "data": {
                "type": "object"
              },
              "detail": {
                "type": "string"
              },
              "disposition": {
                "description": "What this finding does to the verdict, which is a different axis from how bad it is.",
                "enum": [
                  "block",
                  "unknown",
                  "warn",
                  "info"
                ],
                "type": "string"
              },
              "severity": {
                "enum": [
                  "info",
                  "low",
                  "medium",
                  "high",
                  "critical"
                ],
                "type": "string"
              },
              "source": {
                "type": "string"
              },
              "span": {
                "properties": {
                  "end": {
                    "type": "integer"
                  },
                  "start": {
                    "type": "integer"
                  }
                },
                "type": "object"
              }
            },
            "required": [
              "code",
              "severity",
              "detail",
              "disposition"
            ],
            "type": "object"
          },
          "type": "array"
        },
        "ok": {
          "type": "boolean"
        },
        "result": {
          "properties": {
            "canonical_command": {
              "description": "What a permit binds. Every operand preserved.",
              "type": "string"
            },
            "cmd_fingerprint": {
              "description": "ADVISORY ONLY. Operands discarded; never authorize on it.",
              "type": "string"
            },
            "cmd_hash": {
              "description": "BINDING. sha256 of canonical_command.",
              "type": "string"
            },
            "permit": {
              "description": "Compact JWS, 60s TTL, one audience.",
              "type": "string"
            }
          },
          "required": [
            "canonical_command",
            "cmd_hash",
            "cmd_fingerprint"
          ],
          "type": "object"
        },
        "risk_codes": {
          "items": {
            "type": "string"
          },
          "type": "array"
        },
        "verdict": {
          "enum": [
            "pass",
            "warn",
            "unknown",
            "block"
          ],
          "type": "string"
        },
        "warnings": {
          "items": {
            "type": "string"
          },
          "type": "array"
        }
      },
      "required": [
        "ok",
        "verdict",
        "confidence",
        "risk_codes",
        "evidence",
        "result",
        "warnings"
      ],
      "type": "object"
    },
    "type": {
      "type": "string"
    }
  },
  "required": [
    "type"
  ],
  "type": "object"
}

Example shape — generated from the schema, not a captured live response

{
  "example": {
    "confidence": 0,
    "evidence": [
      {
        "code": "string",
        "data": {},
        "detail": "string",
        "disposition": "block",
        "severity": "info",
        "source": "string",
        "span": {
          "end": 0,
          "start": 0
        }
      }
    ],
    "ok": true,
    "result": {
      "canonical_command": "string",
      "cmd_fingerprint": "string",
      "cmd_hash": "string",
      "permit": "string"
    },
    "risk_codes": [
      "string"
    ],
    "verdict": "pass",
    "warnings": [
      "string"
    ]
  },
  "type": "string"
}

Examples

curl

curl "https://shellpermit.schemasure.com/v1/guard/shell"
# -> 402 Payment Required, accepts[] lists how to pay
# retry with a PAYMENT-SIGNATURE (or PAYMENT header) once paid

JavaScript

const res = await fetch("https://shellpermit.schemasure.com/v1/guard/shell");
if (res.status === 402) {
  const { accepts } = await res.json();
  // pay one of accepts[] via an x402 client, then retry with the payment header
}

Python

import httpx
res = httpx.get("https://shellpermit.schemasure.com/v1/guard/shell")
if res.status_code == 402:
    accepts = res.json()["accepts"]
    # pay one of accepts[] via an x402 client, then retry with the payment header

Details

Provider: shellpermit.schemasure.com
Endpoint: https://shellpermit.schemasure.com/v1/guard/shell
Machine-readable: /resources/36454.json