Evaluate Core IR JSON Policy

Evaluate a policy expressed as a Core IR JSON object directly, without CNL parsing or compilation. Use this endpoint when your application manages its own compilation pipeline and sends pre-compiled policy representations to the engine.

Endpoint

POST /api/v1/policies/evaluate-json

Required Role

MEMBER

Headers

Header	Value	Required
Authorization	Bearer <token>	Yes
Content-Type	application/json	Yes
X-Tenant-ID	Tenant identifier string	Yes

Request Body

{
  "policy": "string (Core IR JSON)",
  "context": {}
}

Field	Type	Required	Description
policy	string	Yes	A JSON-encoded string containing the Core IR representation of the policy. This is the serialized form produced by the Aster compiler's IR emission stage. The engine deserializes and executes this IR directly, bypassing all CNL parsing steps.
context	object	Yes	A single object whose keys map to the declared parameter names of the entry-point function in the Core IR.

Core IR JSON Format

The policy field must be a string-serialized JSON object conforming to the Core IR schema. A minimal example with a single function:

{
  "moduleName": "Discount",
  "functions": [
    {
      "name": "calculate",
      "params": [{ "name": "order", "type": "Order" }],
      "rules": [
        {
          "condition": { "op": "gt", "left": { "ref": "order.total" }, "right": { "lit": 100 } },
          "result": { "lit": 10 }
        },
        {
          "condition": null,
          "result": { "lit": 0 }
        }
      ]
    }
  ]
}

When embedding this as the policy field in the request, the object must be JSON-stringified (i.e. the entire object becomes a string value).

Response Body

{
  "result": "<any>",
  "executionTimeMs": 0,
  "error": null,
  "decisionTrace": null
}

Field	Type	Description
result	any	The value returned by the entry-point function in the Core IR.
executionTimeMs	number	Wall-clock time in milliseconds from IR deserialization to response dispatch.
error	string | null	IR deserialization or runtime error message; null on success.
decisionTrace	object | null	Always null for this endpoint. Tracing is not supported for Core IR evaluation.

HTTP Status Codes

Status	Meaning
200 OK	Evaluation attempted. Check error for IR parsing or runtime failures.
400 Bad Request	Malformed request body, invalid Core IR JSON, or missing required fields.
401 Unauthorized	Missing or invalid bearer token.
403 Forbidden	Token is valid but the caller lacks the MEMBER role.
500 Internal Server Error	Unexpected engine failure.

Examples

curl

curl -X POST https://policy.aster-lang.dev/api/v1/policies/evaluate-json \
  -H "Authorization: Bearer <token>" \
  -H "Content-Type: application/json" \
  -H "X-Tenant-ID: acme-corp" \
  -d '{
    "policy": "{\"moduleName\":\"Discount\",\"functions\":[{\"name\":\"calculate\",\"params\":[{\"name\":\"order\",\"type\":\"Order\"}],\"rules\":[{\"condition\":{\"op\":\"gt\",\"left\":{\"ref\":\"order.total\"},\"right\":{\"lit\":100}},\"result\":{\"lit\":10}},{\"condition\":null,\"result\":{\"lit\":0}}]}]}",
    "context": {
      "order": { "total": 150 }
    }
  }'

JavaScript

// Build the Core IR object
const coreIR = {
  moduleName: 'Discount',
  functions: [
    {
      name: 'calculate',
      params: [{ name: 'order', type: 'Order' }],
      rules: [
        {
          condition: { op: 'gt', left: { ref: 'order.total' }, right: { lit: 100 } },
          result: { lit: 10 },
        },
        {
          condition: null,
          result: { lit: 0 },
        },
      ],
    },
  ],
};

const response = await fetch(
  'https://policy.aster-lang.dev/api/v1/policies/evaluate-json',
  {
    method: 'POST',
    headers: {
      Authorization: 'Bearer <token>',
      'Content-Type': 'application/json',
      'X-Tenant-ID': 'acme-corp',
    },
    body: JSON.stringify({
      // Core IR must be serialized as a string
      policy: JSON.stringify(coreIR),
      context: {
        order: { total: 150 },
      },
    }),
  }
);

const data = await response.json();
// data.result → 10

Example Response

{
  "result": 10,
  "executionTimeMs": 3,
  "error": null,
  "decisionTrace": null
}