diff --git a/apps/edge/internal/openai/request_coordinator.go b/apps/edge/internal/openai/request_coordinator.go
index 7a0d1a27..67047b71 100644
--- a/apps/edge/internal/openai/request_coordinator.go
+++ b/apps/edge/internal/openai/request_coordinator.go
@@ -15,6 +15,7 @@ const (
 	defaultLogicalRequestTTL              = 30 * time.Minute
 	defaultLogicalRequestFrontierCapacity = 64
 	defaultLogicalRequestMappingCapacity  = 512
+	maxOpaqueProviderToolIDLength         = 16 * 1024
 )
 
 var (
@@ -585,6 +586,17 @@ func validateLogicalRequestContinuationLineage(prefix logicalRequestLineage, exp
 }
 
 func validLogicalRequestID(value string) bool {
+	if strings.HasPrefix(value, geminiThoughtSignatureToolIDPrefix) {
+		if len(value) > maxOpaqueProviderToolIDLength {
+			return false
+		}
+		decodedID, _, encoded, err := decodeGeminiThoughtSignatureToolID(value)
+		return err == nil && encoded && validPlainLogicalRequestID(decodedID)
+	}
+	return validPlainLogicalRequestID(value)
+}
+
+func validPlainLogicalRequestID(value string) bool {
 	if value == "" || len(value) > 256 {
 		return false
 	}
diff --git a/apps/edge/internal/openai/request_coordinator_test.go b/apps/edge/internal/openai/request_coordinator_test.go
index 51cd93e4..df28ca13 100644
--- a/apps/edge/internal/openai/request_coordinator_test.go
+++ b/apps/edge/internal/openai/request_coordinator_test.go
@@ -4,6 +4,7 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
+	"strings"
 	"sync"
 	"testing"
 	"time"
@@ -1120,6 +1121,22 @@ func TestLogicalRequestExpiredStateIsRejected(t *testing.T) {
 	}
 }
 
+func TestValidLogicalRequestIDAcceptsBoundedGeminiSignatureEnvelope(t *testing.T) {
+	encoded := encodeGeminiThoughtSignatureToolID("provider_call", strings.Repeat("signature", 128))
+	if len(encoded) <= 256 {
+		t.Fatalf("fixture is not larger than the plain id limit: %d", len(encoded))
+	}
+	if !validLogicalRequestID(encoded) {
+		t.Fatal("bounded Gemini signature envelope was rejected")
+	}
+	if validLogicalRequestID(geminiThoughtSignatureToolIDPrefix + "not-base64!") {
+		t.Fatal("malformed Gemini signature envelope was accepted")
+	}
+	if validLogicalRequestID(encodeGeminiThoughtSignatureToolID("provider_call", strings.Repeat("x", maxOpaqueProviderToolIDLength))) {
+		t.Fatal("oversized Gemini signature envelope was accepted")
+	}
+}
+
 func mustChatLogicalRequestLineage(t *testing.T, content string, tools ...any) logicalRequestLineage {
 	t.Helper()
 	raw, err := json.Marshal(chatCompletionRequest{