diff --git a/go.mod b/go.mod
index 7c79ff10e..7c253116d 100644
--- a/go.mod
+++ b/go.mod
@@ -41,7 +41,7 @@ require (
 	github.com/hashicorp/raft-wal v0.4.2
 	github.com/jackc/pglogrepl v0.0.0-20260401131349-e37c41485510
 	github.com/jackc/pgx/v5 v5.10.0
-	github.com/kaptinlin/jsonschema v0.9.3
+	github.com/kaptinlin/jsonschema v0.9.6
 	github.com/klauspost/compress v1.19.1
 	github.com/lib/pq v1.12.3
 	github.com/mattn/go-sqlite3 v1.14.49
@@ -173,7 +173,7 @@ require (
 	github.com/jackc/pgpassfile v1.0.0 // indirect
 	github.com/jackc/pgservicefile v0.0.0-20240606120523-5a60cdf6a761 // indirect
 	github.com/jsimonetti/rtnetlink v1.4.1 // indirect
-	github.com/kaptinlin/jsonpointer v0.4.27 // indirect
+	github.com/kaptinlin/jsonpointer v0.4.28 // indirect
 	github.com/lann/builder v0.0.0-20180802200727-47ae307949d0 // indirect
 	github.com/lann/ps v0.0.0-20150810152359-62de8c46ede0 // indirect
 	github.com/lucasb-eyer/go-colorful v1.4.0 // indirect
diff --git a/go.sum b/go.sum
index ad19ef58c..45ccb52b7 100644
--- a/go.sum
+++ b/go.sum
@@ -315,10 +315,10 @@ github.com/jsimonetti/rtnetlink v1.4.1/go.mod h1:xJjT7t59UIZ62GLZbv6PLLo8VFrostJ
 github.com/json-iterator/go v1.1.6/go.mod h1:+SdeFBvtyEkXs7REEP0seUULqWtbJapLOCVDaaPEHmU=
 github.com/json-iterator/go v1.1.9/go.mod h1:KdQUCv79m/52Kvf8AW2vK1V8akMuk1QjK/uOdHXbAo4=
 github.com/julienschmidt/httprouter v1.2.0/go.mod h1:SYymIcj16QtmaHHD7aYtjjsJG7VTCxuUUipMqKk8s4w=
-github.com/kaptinlin/jsonpointer v0.4.27 h1:5FOnhlkqQ4/lvHudaAWS8HJCXjN4yAHSIGl7aPKHI0Q=
-github.com/kaptinlin/jsonpointer v0.4.27/go.mod h1:dfub/n58cWS32Dyf3AZsnKblSAgrz9PyOU76GDPpx8Q=
-github.com/kaptinlin/jsonschema v0.9.3 h1:uDVd3w4aXwO0tbycblKYvFofhl3hVuE31vOl5JkDXI0=
-github.com/kaptinlin/jsonschema v0.9.3/go.mod h1:LvtQ/mO0E1e/3c3DiOWTj05LTeot8cTv7DyQq7eJMQg=
+github.com/kaptinlin/jsonpointer v0.4.28 h1:PyxOfdml9PGpxQz+JnNLGsyzQ+Rnm+OVNTGcgbVLqgg=
+github.com/kaptinlin/jsonpointer v0.4.28/go.mod h1:JzeIDw1+60bryzOFea9P3zjKg8pfJHd+UIA/zfZ70x8=
+github.com/kaptinlin/jsonschema v0.9.6 h1:RNqurZUqduQm+mINsCFbRzBQR0uKbAcRPBj3BqRA/I8=
+github.com/kaptinlin/jsonschema v0.9.6/go.mod h1:TP7RFmFBNExjBE0b3fsM6RpA/9PeOzfg2g4weXqOrDg=
 github.com/kisielk/errcheck v1.5.0/go.mod h1:pFxgyoBC7bSaBwPgfKdkLd5X25qrDl4LWUI2bnpBCr8=
 github.com/kisielk/gotool v1.0.0/go.mod h1:XhKaO+MFFWcvkIS/tQcRk01m1F5IRFswLeQ+oQHNcck=
 github.com/klauspost/compress v1.19.1 h1:VsB4HPswih7mmZ8WleSFQ75c/Ui1M4trX5oAsJnhSlk=
diff --git a/runtime/lua/modules/json/json.go b/runtime/lua/modules/json/json.go
index 1629b494c..74bf33b87 100644
--- a/runtime/lua/modules/json/json.go
+++ b/runtime/lua/modules/json/json.go
@@ -9,6 +9,7 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
+	"io"
 	"math"
 	"sort"
 	"strconv"
@@ -638,7 +639,7 @@ func compileSchema(schemaJSON []byte) (*jsonschema.Schema, error) {
 		return schema, nil
 	}
 
-	compiler := jsonschema.NewCompiler()
+	compiler := jsonschema.NewCompiler().WithDecoderJSON(decodeSchemaInstance)
 	schema, err := compiler.Compile(schemaJSON)
 	if err != nil {
 		return nil, err
@@ -648,6 +649,23 @@ func compileSchema(schemaJSON []byte) (*jsonschema.Schema, error) {
 	return schema, nil
 }
 
+func decodeSchemaInstance(data []byte, value any) error {
+	decoder := json.NewDecoder(bytes.NewReader(data))
+	decoder.UseNumber()
+	if err := decoder.Decode(value); err != nil {
+		return err
+	}
+
+	var trailing any
+	if err := decoder.Decode(&trailing); !errors.Is(err, io.EOF) {
+		if err == nil {
+			return errors.New("multiple JSON values")
+		}
+		return err
+	}
+	return nil
+}
+
 func hashSchemaJSON(data []byte) string {
 	hash := sha256.Sum256(data)
 	return hex.EncodeToString(hash[:])
diff --git a/runtime/lua/modules/json/module_test.go b/runtime/lua/modules/json/module_test.go
index d909948a8..23ae5aaeb 100644
--- a/runtime/lua/modules/json/module_test.go
+++ b/runtime/lua/modules/json/module_test.go
@@ -280,6 +280,41 @@ func TestValidateStringSuccess(t *testing.T) {
 	}
 }
 
+func TestValidateStringPreservesExactNumbers(t *testing.T) {
+	l := lua.NewState()
+	defer l.Close()
+	bindJSON(l)
+
+	err := l.DoString(`
+		local schema = '{"type":"integer","const":9007199254740993}'
+		local valid, validation_err = json.validate_string(schema, '9007199254740993')
+		if not valid then error("expected exact integer to validate: " .. tostring(validation_err)) end
+
+		valid, validation_err = json.validate_string(schema, '9007199254740992')
+		if valid then error("adjacent integer must not match exact const") end
+		if validation_err == nil then error("expected validation error") end
+	`)
+	if err != nil {
+		t.Errorf("validate_string exact number test failed: %v", err)
+	}
+}
+
+func TestValidateStringRejectsTrailingJSONValue(t *testing.T) {
+	l := lua.NewState()
+	defer l.Close()
+	bindJSON(l)
+
+	err := l.DoString(`
+		local schema = {type = "object"}
+		local valid, validation_err = json.validate_string(schema, '{} {}')
+		if valid then error("expected trailing JSON value to be rejected") end
+		if validation_err == nil then error("expected validation error") end
+	`)
+	if err != nil {
+		t.Errorf("validate_string trailing value test failed: %v", err)
+	}
+}
+
 func TestValidateMissingSchema(t *testing.T) {
 	l := lua.NewState()
 	defer l.Close()