feat: record AI charges at gateway-settled cost under x402 upto

The claw402 gateway now settles chat routes pay-as-you-go (upto) and
reports the actual amount in the X-Claw402-Settled-Usd response header.
Capture it on all three x402 call paths (stream, simple, full), expose it
via Claw402Client.LastCallCostUSD, and prefer it over the flat catalog
estimate when recording ai_charges — cost stats now match real spend.

mcp/client.go

@@ -78,6 +78,11 @@ type Client struct {
 	Log        Logger       // Exported for sub-packages
 	Cfg        *Config      // Exported for sub-packages
 
+	// LastCallSettledUSD is the actually-settled cost (USD) of the most
+	// recent call, reported by x402 upto gateways via response header.
+	// Zero when the last call carried no settlement information.
+	LastCallSettledUSD float64
+
 	// Hooks are used to implement dynamic dispatch (polymorphism)
 	// When provider.DeepSeekClient embeds Client, Hooks point to DeepSeekClient
 	// This way methods called in Call() are automatically dispatched to the overridden version

mcp/payment/claw402.go

@@ -89,6 +89,17 @@ type Claw402Client struct {
 
 func (c *Claw402Client) BaseClient() *mcp.Client { return c.Client }
 
+// LastCallCostUSD reports the actually-settled cost of the most recent call,
+// taken from the gateway's X-Claw402-Settled-Usd header (upto scheme).
+// ok is false when the gateway did not report a settlement amount — callers
+// should then fall back to the flat catalog price.
+func (c *Claw402Client) LastCallCostUSD() (float64, bool) {
+	if c.Client.LastCallSettledUSD > 0 {
+		return c.Client.LastCallSettledUSD, true
+	}
+	return 0, false
+}
+
 // NewClaw402Client creates a claw402 client (backward compatible).
 func NewClaw402Client() mcp.AIClient {
 	return NewClaw402ClientWithOptions()

mcp/payment/x402.go

@@ -12,6 +12,7 @@ import (
 	"io"
 	"math/big"
 	"net/http"
+	"strconv"
 	"strings"
 	"time"
 
@@ -201,7 +202,35 @@ func SignBasePaymentHeader(privateKey *ecdsa.PrivateKey, paymentHeaderB64 string
 	return SignX402Payment(privateKey, senderAddr, req.Accepts[0], req.Resource)
 }
 
+// X402SettledUSDHeader carries the actually-settled cost (USD) of an upto
+// call, set by the claw402 gateway on the paid response.
+const X402SettledUSDHeader = "X-Claw402-Settled-Usd"
+
+func storeRespHeader(sink []*http.Header, h http.Header) {
+	for _, p := range sink {
+		if p != nil {
+			*p = h
+		}
+	}
+}
+
+// captureSettledUSD records the gateway-reported settled cost on the client.
+// Zero when the response carried no settlement header (e.g. exact-scheme
+// routes, where the flat catalog price applies instead).
+func captureSettledUSD(c *mcp.Client, h http.Header) {
+	c.LastCallSettledUSD = 0
+	if h == nil {
+		return
+	}
+	if v := h.Get(X402SettledUSDHeader); v != "" {
+		if f, err := strconv.ParseFloat(v, 64); err == nil && f > 0 {
+			c.LastCallSettledUSD = f
+		}
+	}
+}
+
 // DoX402Request executes an HTTP request and handles the x402 v2 payment flow.
+// An optional headerSink receives the headers of the successful response.
 func DoX402Request(
 	ctx context.Context,
 	httpClient *http.Client,
@@ -209,6 +238,7 @@ func DoX402Request(
 	signFn X402SignFunc,
 	providerTag string,
 	logger mcp.Logger,
+	headerSink ...*http.Header,
 ) ([]byte, error) {
 	if ctx == nil {
 		ctx = context.Background()
@@ -277,6 +307,7 @@ func DoX402Request(
 				if attempt > 1 {
 					logger.Infof("✅ [%s] Payment retry succeeded on attempt %d", providerTag, attempt)
 				}
+				storeRespHeader(headerSink, resp2.Header)
 				return body2, nil
 			}
 
@@ -333,6 +364,7 @@ func DoX402Request(
 	if resp.StatusCode != http.StatusOK {
 		return nil, fmt.Errorf("%s API error (status %d): %s", providerTag, resp.StatusCode, string(body))
 	}
+	storeRespHeader(headerSink, resp.Header)
 	return body, nil
 }
 
@@ -494,6 +526,7 @@ func X402CallStream(c *mcp.Client, signFn X402SignFunc, tag string, systemPrompt
 	ctx, cancel := context.WithCancel(context.Background())
 	defer cancel()
 
+	c.LastCallSettledUSD = 0
 	resp, err := DoX402RequestStream(ctx, c.HTTPClient, func() (*http.Request, error) {
 		return c.Hooks.BuildRequest(c.Hooks.BuildUrl(), jsonData)
 	}, signFn, tag, c.Log)
@@ -501,6 +534,7 @@ func X402CallStream(c *mcp.Client, signFn X402SignFunc, tag string, systemPrompt
 		return "", err
 	}
 	defer resp.Body.Close()
+	captureSettledUSD(c, resp.Header)
 
 	ct := resp.Header.Get("Content-Type")
 	c.Log.Infof("📡 [%s] Response Content-Type: %s", tag, ct)
@@ -590,12 +624,15 @@ func X402Call(c *mcp.Client, signFn X402SignFunc, tag string, systemPrompt, user
 		return "", err
 	}
 
+	c.LastCallSettledUSD = 0
+	var respHeader http.Header
 	body, err := DoX402Request(context.Background(), c.HTTPClient, func() (*http.Request, error) {
 		return c.Hooks.BuildRequest(c.Hooks.BuildUrl(), jsonData)
-	}, signFn, tag, c.Log)
+	}, signFn, tag, c.Log, &respHeader)
 	if err != nil {
 		return "", err
 	}
+	captureSettledUSD(c, respHeader)
 	return c.Hooks.ParseMCPResponse(body)
 }
 
@@ -616,12 +653,15 @@ func X402CallFull(c *mcp.Client, signFn X402SignFunc, tag string, req *mcp.Reque
 		return nil, err
 	}
 
+	c.LastCallSettledUSD = 0
+	var respHeader http.Header
 	body, err := DoX402Request(x402ContextFromRequest(req), c.HTTPClient, func() (*http.Request, error) {
 		return c.Hooks.BuildRequest(c.Hooks.BuildUrl(), jsonData)
-	}, signFn, tag, c.Log)
+	}, signFn, tag, c.Log, &respHeader)
 	if err != nil {
 		return nil, err
 	}
+	captureSettledUSD(c, respHeader)
 	return c.Hooks.ParseMCPResponseFull(body)
 }
 

store/ai_charge.go

@@ -56,12 +56,18 @@ func (s *AIChargeStore) initTables() error {
 
 // Record records a new AI charge
 func (s *AIChargeStore) Record(traderID, model, provider string) error {
-	cost := GetModelPrice(model)
+	return s.RecordWithCost(traderID, model, provider, GetModelPrice(model))
+}
+
+// RecordWithCost records a charge with an explicit cost — e.g. the actual
+// settled amount reported by the payment gateway (upto scheme) — instead of
+// the flat per-call estimate from modelPrices.
+func (s *AIChargeStore) RecordWithCost(traderID, model, provider string, costUSD float64) error {
 	charge := &AICharge{
 		TraderID: traderID,
 		Model:    model,
 		Provider: provider,
-		CostUSD:  cost,
+		CostUSD:  costUSD,
 	}
 	return s.db.Create(charge).Error
 }

trader/auto_trader_loop.go

@@ -135,12 +135,24 @@ func (at *AutoTrader) runCycle() error {
 	// Use the effective model name (custom model, e.g. "gpt-5.6") so the
 	// per-call price lookup matches what was actually invoked — at.aiModel is
 	// the provider id (e.g. "claw402") and would fall back to the default price.
+	// Prefer the gateway-reported settled amount (upto scheme) over the flat
+	// catalog estimate when the client exposes it.
 	if aiDecision != nil && at.store != nil {
 		chargeModel := at.config.CustomModelName
 		if chargeModel == "" {
 			chargeModel = at.aiModel
 		}
-		if chargeErr := at.store.AICharge().Record(at.id, chargeModel, at.config.AIModel); chargeErr != nil {
+		var chargeErr error
+		if r, ok := at.mcpClient.(interface{ LastCallCostUSD() (float64, bool) }); ok {
+			if actual, has := r.LastCallCostUSD(); has {
+				chargeErr = at.store.AICharge().RecordWithCost(at.id, chargeModel, at.config.AIModel, actual)
+			} else {
+				chargeErr = at.store.AICharge().Record(at.id, chargeModel, at.config.AIModel)
+			}
+		} else {
+			chargeErr = at.store.AICharge().Record(at.id, chargeModel, at.config.AIModel)
+		}
+		if chargeErr != nil {
 			at.logWarnf("⚠️ Failed to record AI charge: %v", chargeErr)
 		}
 	}