# License Compatibility Checker (SPDX)

> License Compatibility Checker (SPDX) is a paid API for AI agents from payai.agentstools.dev, paid per call via x402, $0.01/call, status unknown (last checked 2026-09-14).

Returns a compatibility verdict (safe, attribution-required, copyleft-risk, or incompatible) for one or more SPDX licenses against a target project license and distribution model, with obligations and reasons.

## Facts

- Endpoint: GET https://payai.agentstools.dev/license/compat
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/license-compatibility-checker-spdx-12e7696d
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_nU7wCQYF56KmjBE_f5gJt

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability license-compatibility-checker-spdx-12e7696d
```

Example prompt: Check whether GPL-2.0-only and MIT are compatible with my Apache-2.0 project when distributed as a SaaS — give me the verdict, any obligations, and the reasons.

## When to prefer this

Choose this endpoint when you need a fast, offline-style (no external network calls) SPDX-based license compatibility check with explicit verdicts and obligation explanations. Ideal for CI/CD pipelines, dependency review bots, or agent workflows that need a structured, machine-readable verdict per license. Prefer the sibling manifest-based endpoint when checking an entire dependency list or parsed lockfile in bulk.

## Known failure modes

- Invalid or unrecognized SPDX identifier returns an error
- Both licenses and spdx_expr provided simultaneously may cause conflict
- Missing required target_license parameter returns validation error
- Malformed SPDX expression (unbalanced AND/OR/WITH) rejected with parse error
- Unknown distribution model value outside enum returns 400

## How this service works

Pure-compute license-compatibility verdict, no network. Give a list of SPDX ids or one SPDX expression with AND, OR and WITH plus a target license and a distribution model, and get the matrix verdict of safe, attribution-required, copyleft-risk or incompatible with the obligation and reasons. Automated indicators, not legal advice.

## Output

A structured verdict for each license or expression checked, classified as 'safe', 'attribution-required', 'copyleft-risk', or 'incompatible', along with the specific obligations (e.g. include copyright notice, provide source) and the reasoning behind the verdict. Results are automated indicators, not legal advice.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET",
      "HEAD",
      "DELETE"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [],
     "properties": {
      "licenses": {
       "type": "array",
       "items": {
        "type": "string"
       },
       "description": "SPDX ids to check"
      },
      "spdx_expr": {
       "type": "string",
       "description": "An SPDX expression instead of a list"
      },
      "distribution": {
       "enum": [
        "saas",
        "binary",
        "internal"
       ],
       "type": "string",
       "description": "How you ship it (default saas)"
      },
      "target_license": {
       "type": "string",
       "description": "Your project SPDX license"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/license-compatibility-checker-spdx-12e7696d/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from payai.agentstools.dev](https://www.zero.xyz/host/payai.agentstools.dev/llms.txt)