fix(checkout): populate outcome.rail_key from MPP receipt method

agentscore_commerce/checkout.py

@@ -834,6 +834,31 @@ def _mpp_rail_key(self) -> str:
                 return key
         return "tempo"
 
+    def _rails_key_for_mppx_method(self, method: str) -> str | None:
+        """Map an mppx credential ``method`` to the merchant's rails-dict key.
+
+        Used in ``_handle_mppx`` so the settle outcome distinguishes Solana
+        from Tempo (both fall under ``rail="mpp"``) and from Stripe SPT.
+        ``method`` is one of ``tempo`` / ``solana`` / ``stripe``. Returns
+        ``None`` when the merchant has no rail registered for that method.
+        """
+        if method == "stripe":
+            for key, spec in self.rails.items():
+                if isinstance(spec, StripeRailSpec):
+                    return key
+            return None
+        if method == "solana":
+            for key, spec in self.rails.items():
+                if isinstance(spec, SolanaMppRailSpec):
+                    return key
+            return None
+        if method == "tempo":
+            for key, spec in self.rails.items():
+                if isinstance(spec, (TempoRailSpec, TempoSessionRailSpec)):
+                    return key
+            return None
+        return None
+
     @property
     def _x402_base_network(self) -> str | None:
         """CAIP-2 read from ``rails['x402_base'].network`` (or its default).
@@ -1761,9 +1786,20 @@ async def _handle_mppx(self, ctx: CheckoutContext) -> CheckoutResult:
             raise RuntimeError(msg)
         composed: MppxComposeOutcome = await _maybe_await(self.compose_mppx(ctx))
         if composed.status == 200:
+            receipt_method: str | None = None
+            raw_receipt = composed.raw.get("receipt") if isinstance(composed.raw, dict) else None
+            if isinstance(raw_receipt, dict):
+                m = raw_receipt.get("method")
+                if isinstance(m, str):
+                    receipt_method = m
+            elif raw_receipt is not None:
+                m = getattr(raw_receipt, "method", None)
+                if isinstance(m, str):
+                    receipt_method = m
+            derived_key = self._rails_key_for_mppx_method(receipt_method) if receipt_method is not None else None
             outcome = SettleOutcome(
                 rail="mpp",
-                rail_key=composed.rail_key,
+                rail_key=derived_key or composed.rail_key or self._mpp_rail_key(),
                 tx_hash=composed.tx_hash,
                 signer_address=composed.signer_address,
                 signer_network=composed.signer_network,

pyproject.toml

@@ -4,7 +4,7 @@ build-backend = "hatchling.build"
 
 [project]
 name = "agentscore-commerce"
-version = "2.0.1"
+version = "2.0.2"
 description = "Agent commerce SDK for Python — identity middleware (FastAPI, Flask, Django, AIOHTTP, Sanic, ASGI) + payment helpers + 402 builders + discovery + Stripe multichain. The full merchant-side toolkit for AgentScore-powered agent commerce."
 readme = "README.md"
 license = "MIT"

tests/test_checkout.py

@@ -573,3 +573,39 @@ def test_init_requires_x402_base_railspec_when_x402_server_provided() -> None:
             compute_pricing=lambda _ctx: PricingResult(amount_usd=1.0),
             x402_server=object(),
         )
+
+
+def test_rails_key_for_mppx_method_picks_the_matching_spec() -> None:
+    """``_rails_key_for_mppx_method`` maps mppx credential methods (``tempo`` /
+    ``solana`` / ``stripe``) to the merchant's actual rails-dict key, so MPP
+    settlements distinguish Solana from Tempo (both fall under
+    ``SettleOutcome.rail="mpp"``) and from Stripe SPT.
+    """
+    checkout = Checkout(
+        rails={
+            "tempo_charge": TempoRailSpec(recipient="0xtempo"),
+            "x402_base": X402BaseRailSpec(recipient="0xbase"),
+            "sol_rail": SolanaMppRailSpec(recipient="solanaaddr"),
+            "stripe_spt": StripeRailSpec(profile_id="profile_x"),
+        },
+        url="https://api.example/purchase",
+        compute_pricing=lambda _ctx: PricingResult(amount_usd=1.0),
+    )
+    assert checkout._rails_key_for_mppx_method("tempo") == "tempo_charge"
+    assert checkout._rails_key_for_mppx_method("solana") == "sol_rail"
+    assert checkout._rails_key_for_mppx_method("stripe") == "stripe_spt"
+    assert checkout._rails_key_for_mppx_method("unknown") is None
+
+
+def test_rails_key_for_mppx_method_returns_none_when_rail_absent() -> None:
+    """When the merchant hasn't registered a rail for the credential method,
+    the helper returns ``None`` so the caller can fall back to
+    ``_mpp_rail_key()`` or a hard-coded default."""
+    checkout = Checkout(
+        rails={"tempo": TempoRailSpec(recipient="0xtempo")},
+        url="https://api.example/purchase",
+        compute_pricing=lambda _ctx: PricingResult(amount_usd=1.0),
+    )
+    assert checkout._rails_key_for_mppx_method("solana") is None
+    assert checkout._rails_key_for_mppx_method("stripe") is None
+    assert checkout._rails_key_for_mppx_method("tempo") == "tempo"