M0 e M1 revisados e fixes implementados

RI/services/example_mcp_servers/finance_domain/server.py

@@ -0,0 +1,111 @@
+"""Example Finance-domain MCP server (EP-06-T03).
+
+invoice.get (R1, read-only), payment.create (R2, side-effecting, not yet
+executed), payment.execute (R3, high-impact -- REQUIRE_APPROVAL above
+Finance.Payments' `restrictions.approval_threshold`, enforced entirely by
+config/policies/transaction.rego before the call ever reaches here). Backed
+by static mock data -- this server is deliberately "dumb" (ADR-023): it never
+authorizes anything, only the Gateway/PDP does that, upstream of this process.
+
+Run directly for local development:
+
+    python -m example_mcp_servers.finance_domain.server
+"""
+
+from __future__ import annotations
+
+import itertools
+import os
+
+from mcp.server.mcpserver import MCPServer
+from starlette.types import ASGIApp
+
+from emcp_bus.audit.bypass_detection import BackendCredentialGate
+from emcp_bus.audit.sink import JSONLFileAuditSink
+from emcp_bus.common.otel import setup_tracing
+
+setup_tracing("finance-domain-mcp-server")
+
+server = MCPServer(name="finance-domain", version="0.1.0")
+
+_INVOICES: dict[str, dict[str, object]] = {
+    "inv-001": {
+        "invoice_id": "inv-001",
+        "customer_id": "cust-001",
+        "amount": 5000,
+        "status": "open",
+    },
+    "inv-002": {
+        "invoice_id": "inv-002",
+        "customer_id": "cust-002",
+        "amount": 25000,
+        "status": "overdue",
+    },
+}
+
+_PAYMENTS: dict[str, dict[str, object]] = {}
+_payment_ids = itertools.count(1)
+
+
+@server.tool(name="finance.invoice.get", description="Get a single finance invoice by id.")
+def invoice_get(invoice_id: str) -> dict[str, object]:
+    invoice = _INVOICES.get(invoice_id)
+    if invoice is None:
+        return {"error": "not_found", "invoice_id": invoice_id}
+    return invoice
+
+
+@server.tool(
+    name="finance.payment.create", description="Create a draft payment against an invoice."
+)
+def payment_create(invoice_id: str, amount: float) -> dict[str, object]:
+    payment_id = f"pay-{next(_payment_ids):03d}"
+    payment = {
+        "payment_id": payment_id,
+        "invoice_id": invoice_id,
+        "amount": amount,
+        "status": "draft",
+    }
+    _PAYMENTS[payment_id] = payment
+    return payment
+
+
+@server.tool(name="finance.payment.execute", description="Execute a previously created payment.")
+def payment_execute(payment_id: str, amount: float) -> dict[str, object]:
+    """`amount` is declared by the caller (not re-derived from the stored
+    payment) so it is visible to `config/policies/transaction.rego`'s
+    `approval_threshold` check (README.md §26) -- the transaction policy
+    inspects call arguments, never backend state, matching `sales.quote.create`'s
+    same pattern (EP-06-T02)."""
+    payment = _PAYMENTS.get(payment_id)
+    if payment is None:
+        return {"error": "not_found", "payment_id": payment_id}
+    payment["status"] = "executed"
+    payment["executed_amount"] = amount
+    return payment
+
+
+def main() -> None:
+    host = os.environ.get("FINANCE_DOMAIN_HOST", "127.0.0.1")
+    port = int(os.environ.get("FINANCE_DOMAIN_PORT", "8101"))
+    expected_token = os.environ.get("FINANCE_DOMAIN_SERVICE_TOKEN")
+    audit_log_path = os.environ.get("EMCP_AUDIT_LOG_PATH", "/tmp/emcp-audit.jsonl")
+
+    app: ASGIApp = server.streamable_http_app(host=host)
+    if expected_token:
+        # EP-05-T07: reject anything that didn't come through the Gateway's
+        # outbound identity (EP-07-T01) with the matching service credential.
+        app = BackendCredentialGate(
+            app,
+            expected_token=expected_token,
+            backend="finance-domain",
+            audit_sink=JSONLFileAuditSink(audit_log_path),
+        )
+
+    import uvicorn
+
+    uvicorn.run(app, host=host, port=port, log_level="info")
+
+
+if __name__ == "__main__":
+    main()