Fulcrum REST API Reference

Authoritative Source: api.swagger.json

Programmatic access to Fulcrum's governance layer via HTTP/JSON.

Fulcrum provides a REST gateway (default port 8080) that maps to its core gRPC services. All requests require an X-Api-Key header or Clerk JWT.

Production Endpoint: https://api.fulcrumlayer.io

🛡️ Policy Service

List Policies

GET /v1/policies - Parameters: tenantId (string), status (enum), ruleType (enum) - Response: List of policy objects.

Create Policy

POST /v1/policies - Body: v1Policy object. - Response: Created policy with ID.

Get Policy

GET /v1/policies/{policyId} - Response: Policy details.

Evaluate Policies (Batch)

POST /v1/policies/batch-evaluate - Body: v1EvaluatePoliciesRequest - Response: Consolidated decision (ALLOW, DENY, etc.)

💰 Cost Service

List Budgets

GET /v1/budgets - Parameters: tenantId (string), status (enum) - Response: List of budgets.

Create Budget

POST /v1/budgets - Body: v1Budget object.

Get Budget Status

GET /v1/budgets/{budgetId}/status - Response: Real-time spend vs limits.

Predict Cost

POST /v1/costs/predict - Body: v1PredictCostRequest - Response: Expected cost and overrun probability.

🧠 Cognitive Layer (Brain)

Evaluate Semantic Condition

POST /v1/brain/semantic-judge/evaluate - Body: Action context + semantic intent. - Response: Whether intent is violated.

Predict Overrun

POST /v1/brain/oracle/predict-overrun - Body: Budget + workload model. - Response: Probability of exceeding budget.

📦 Envelope Service

Create Envelope

POST /v1/envelopes - Body: tenant_id, adapter_type, metadata. - Response: Authorized execution envelope.

📋 Audit & Events

Query Events

GET /v1/events - Parameters: tenantId, envelopeId, eventType - Response: List of system events.

Document	Purpose
api.swagger.json	OpenAPI specification (authoritative)
GRPC_REFERENCE.md	gRPC/Protobuf definitions
TRUTH_MAP.md	Infrastructure endpoints

Last Updated: February 2, 2026 Evidence sources: api.swagger.json, internal/ packages