diff --git a/internal/config/config_test.go b/internal/config/config_test.go
index 047d8809..034c083f 100644
--- a/internal/config/config_test.go
+++ b/internal/config/config_test.go
@@ -1089,7 +1089,7 @@ port 3000
 	errMsg := err.Error()
 	assert.Contains(t, errMsg, "line", "Error should mention line number")
 	// Our improved format includes "column" explicitly when ParseError is detected
-	assert.True(t, strings.Contains(errMsg, "column") || strings.Contains(errMsg, "line 2"),
+	assert.Regexp(t, `\bcolumn\b|\bline\s+2\b`, errMsg,
 		"Error should mention column or line position, got: %s", errMsg)
 }
 
diff --git a/internal/config/expand_raw_json_test.go b/internal/config/expand_raw_json_test.go
index 74b08ead..eb5f3cf4 100644
--- a/internal/config/expand_raw_json_test.go
+++ b/internal/config/expand_raw_json_test.go
@@ -1,7 +1,6 @@
 package config
 
 import (
-	"strings"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
@@ -566,7 +565,7 @@ func TestValidateMounts(t *testing.T) {
 			if tt.shouldErr {
 				require.Error(t, err, "Expected an error but got none")
 				if tt.errMsg != "" {
-					assert.True(t, strings.Contains(err.Error(), tt.errMsg),
+					assert.Contains(t, err.Error(), tt.errMsg,
 						"Error message %q should contain %q", err.Error(), tt.errMsg)
 				}
 			} else {
diff --git a/internal/config/fetch_and_fix_schema_test.go b/internal/config/fetch_and_fix_schema_test.go
index 29544982..638c317a 100644
--- a/internal/config/fetch_and_fix_schema_test.go
+++ b/internal/config/fetch_and_fix_schema_test.go
@@ -245,7 +245,10 @@ func TestFixSchemaBytes_AddRegistryAndGuardPoliciesToStdioConfig(t *testing.T) {
 	require.True(t, hasGuardPolicies, "guard-policies field should be added to stdioServerConfig.properties")
 	gpMap := guardPolicies.(map[string]interface{})
 	assert.Equal(t, "object", gpMap["type"], "guard-policies.type should be 'object'")
-	assert.Equal(t, true, gpMap["additionalProperties"], "guard-policies.additionalProperties should be true")
+	additionalProperties, hasAdditionalProperties := gpMap["additionalProperties"]
+	require.True(t, hasAdditionalProperties, "guard-policies.additionalProperties should be present")
+	require.IsType(t, true, additionalProperties, "guard-policies.additionalProperties should be a bool")
+	assert.True(t, additionalProperties.(bool), "guard-policies.additionalProperties should be true")
 }
 
 // TestFixSchemaBytes_AddRegistryAndGuardPoliciesToHttpConfig covers the injection
diff --git a/internal/config/rules/rules_test.go b/internal/config/rules/rules_test.go
index 0f9cc37f..6616a3dc 100644
--- a/internal/config/rules/rules_test.go
+++ b/internal/config/rules/rules_test.go
@@ -9,6 +9,13 @@ import (
 	"github.com/stretchr/testify/require"
 )
 
+func validationErrAsError(err *ValidationError) error {
+	if err == nil {
+		return nil
+	}
+	return err
+}
+
 func TestPortRange(t *testing.T) {
 	tests := []struct {
 		name      string
@@ -74,7 +81,7 @@ func TestPortRange(t *testing.T) {
 				assert.Contains(t, err.Message, tt.errMsg, "Error message should contain expected text")
 				assert.Equal(t, tt.jsonPath, err.JSONPath, "JSONPath should match")
 			} else {
-				require.Nil(t, err, "Unexpected validation error")
+				require.NoError(t, validationErrAsError(err), "Unexpected validation error")
 			}
 		})
 	}
@@ -138,7 +145,7 @@ func TestTimeoutPositive(t *testing.T) {
 				assert.Equal(t, tt.jsonPath, err.JSONPath, "JSONPath should match")
 				assert.Equal(t, tt.fieldName, err.Field, "Field name should match")
 			} else {
-				require.Nil(t, err, "Unexpected validation error")
+				require.NoError(t, validationErrAsError(err), "Unexpected validation error")
 			}
 		})
 	}
@@ -295,7 +302,7 @@ func TestMountFormat(t *testing.T) {
 				assert.Contains(t, err.Message, tt.errMsg, "Error message should contain expected text")
 				assert.Equal(t, fmt.Sprintf("%s.mounts[%d]", tt.jsonPath, tt.index), err.JSONPath, "JSONPath should match expected pattern")
 			} else {
-				require.Nil(t, err, "Unexpected validation error")
+				require.NoError(t, validationErrAsError(err), "Unexpected validation error")
 			}
 		})
 	}
@@ -899,7 +906,7 @@ func TestNonEmptyString(t *testing.T) {
 				assert.Contains(t, err.Error(), tt.errMsg)
 				assert.Contains(t, err.Error(), tt.jsonPath)
 			} else {
-				require.Nil(t, err, "Unexpected validation error")
+				require.NoError(t, validationErrAsError(err), "Unexpected validation error")
 			}
 		})
 	}
@@ -1039,7 +1046,7 @@ func TestAbsolutePath(t *testing.T) {
 				assert.Contains(t, err.Error(), tt.errMsg)
 				assert.Contains(t, err.Error(), tt.jsonPath)
 			} else {
-				require.Nil(t, err, "Unexpected validation error")
+				require.NoError(t, validationErrAsError(err), "Unexpected validation error")
 			}
 		})
 	}
diff --git a/internal/difc/labels_test.go b/internal/difc/labels_test.go
index d3968d4b..e5ff9039 100644
--- a/internal/difc/labels_test.go
+++ b/internal/difc/labels_test.go
@@ -1,7 +1,6 @@
 package difc
 
 import (
-	"strings"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
@@ -590,11 +589,11 @@ func TestViolationError_Error(t *testing.T) {
 			msg := tt.err.Error()
 			assert.NotEmpty(t, msg)
 			for _, want := range tt.wantContains {
-				assert.True(t, strings.Contains(msg, want),
+				assert.Contains(t, msg, want,
 					"expected %q in error message %q", want, msg)
 			}
 			for _, absent := range tt.wantAbsent {
-				assert.False(t, strings.Contains(msg, absent),
+				assert.NotContains(t, msg, absent,
 					"expected %q NOT to be in error message %q", absent, msg)
 			}
 		})
@@ -616,7 +615,7 @@ func TestViolationError_Detailed(t *testing.T) {
 		base := err.Error()
 
 		// Detailed should contain the base error message
-		assert.True(t, strings.Contains(detailed, base), "detailed should include base error")
+		assert.Contains(t, detailed, base, "detailed should include base error")
 
 		// Detailed should include agent and resource tag context
 		assert.Contains(t, detailed, "Agent")
diff --git a/internal/mcp/tool_result_test.go b/internal/mcp/tool_result_test.go
index 29650ffe..f0e670f7 100644
--- a/internal/mcp/tool_result_test.go
+++ b/internal/mcp/tool_result_test.go
@@ -268,7 +268,9 @@ func TestParseToolArguments(t *testing.T) {
 		require.NotNil(t, args)
 		assert.Equal(t, "search term", args["query"])
 		assert.Equal(t, float64(10), args["limit"])
-		assert.Equal(t, true, args["active"])
+		active, ok := args["active"].(bool)
+		require.True(t, ok, "expected active to be a bool")
+		assert.True(t, active)
 	})
 
 	t.Run("nested object arguments are parsed correctly", func(t *testing.T) {
diff --git a/internal/mcp/unmarshal_params_test.go b/internal/mcp/unmarshal_params_test.go
index 0c2cb8b3..e308729d 100644
--- a/internal/mcp/unmarshal_params_test.go
+++ b/internal/mcp/unmarshal_params_test.go
@@ -153,7 +153,9 @@ func TestUnmarshalParams(t *testing.T) {
 		// JSON unmarshal converts numbers to float64 by default
 		assert.Equal(t, float64(42), target["int_val"])
 		assert.Equal(t, 3.14, target["float_val"])
-		assert.Equal(t, true, target["bool_val"])
+		boolVal, ok := target["bool_val"].(bool)
+		require.True(t, ok, "bool_val should be a bool")
+		assert.True(t, boolVal)
 		assert.Len(t, target["array_val"], 3)
 		assert.NotNil(t, target["object_val"])
 		assert.Nil(t, target["null_val"])
diff --git a/internal/middleware/jqschema_integration_test.go b/internal/middleware/jqschema_integration_test.go
index e69a24c4..f2199102 100644
--- a/internal/middleware/jqschema_integration_test.go
+++ b/internal/middleware/jqschema_integration_test.go
@@ -195,7 +195,7 @@ func TestMiddlewareWithLargePayload(t *testing.T) {
 	// Verify preview truncation in Content field (preview ends with ... when truncated)
 	previewInContent := contentMap["payloadPreview"].(string)
 	if strings.HasSuffix(previewInContent, "...") {
-		assert.True(t, len(previewInContent) <= 503, "Preview in Content should be truncated")
+		assert.LessOrEqual(t, len(previewInContent), 503, "Preview in Content should be truncated")
 	}
 
 	// Also check data return value
@@ -204,7 +204,7 @@ func TestMiddlewareWithLargePayload(t *testing.T) {
 	// Verify preview truncation (check if it ends with ...)
 	preview := dataMap["payloadPreview"].(string)
 	if strings.HasSuffix(preview, "...") {
-		assert.True(t, len(preview) <= 503, "Preview should be truncated")
+		assert.LessOrEqual(t, len(preview), 503, "Preview should be truncated")
 	}
 
 	// Verify payload file has complete data
diff --git a/internal/proxy/proxy_test.go b/internal/proxy/proxy_test.go
index 2861020c..70a46d8c 100644
--- a/internal/proxy/proxy_test.go
+++ b/internal/proxy/proxy_test.go
@@ -682,7 +682,11 @@ func TestRewrapSearchResponse(t *testing.T) {
 		result := rewrapSearchResponse(original, filtered)
 		m := result.(map[string]interface{})
 		assert.Equal(t, float64(2), m["total_count"])
-		assert.Equal(t, false, m["incomplete_results"])
+		incompleteResults, ok := m["incomplete_results"]
+		require.True(t, ok)
+		incompleteResultsBool, ok := incompleteResults.(bool)
+		require.True(t, ok)
+		assert.False(t, incompleteResultsBool)
 		assert.Len(t, m["items"].([]interface{}), 2)
 	})
 
diff --git a/internal/proxy/rest_backend_caller_tool_test.go b/internal/proxy/rest_backend_caller_tool_test.go
index 48c9da8e..8c498783 100644
--- a/internal/proxy/rest_backend_caller_tool_test.go
+++ b/internal/proxy/rest_backend_caller_tool_test.go
@@ -6,7 +6,6 @@ import (
 	"fmt"
 	"net/http"
 	"net/http/httptest"
-	"strings"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
@@ -574,5 +573,5 @@ func TestRestBackendCaller_IssueRead_ResponseFormat(t *testing.T) {
 
 	text, ok := content[0]["text"].(string)
 	require.True(t, ok)
-	assert.True(t, strings.Contains(text, "Bug report"), "response text should contain the issue title")
+	assert.Contains(t, text, "Bug report", "response text should contain the issue title")
 }
diff --git a/internal/server/call_backend_tool_test.go b/internal/server/call_backend_tool_test.go
index 268a7a3f..7a60b585 100644
--- a/internal/server/call_backend_tool_test.go
+++ b/internal/server/call_backend_tool_test.go
@@ -5,7 +5,6 @@ import (
 	"encoding/json"
 	"net/http"
 	"net/http/httptest"
-	"strings"
 	"testing"
 	"time"
 
@@ -482,8 +481,8 @@ func TestCallBackendTool_AllowedToolsError_MessageFormat(t *testing.T) {
 	require.True(result.IsError)
 	require.Len(result.Content, 1)
 	text := result.Content[0].(*sdk.TextContent).Text
-	assert.True(t, strings.Contains(text, `"blocked"`), "error message should include tool name: %s", text)
-	assert.True(t, strings.Contains(text, "allowed-tools"), "error message should mention allowed-tools: %s", text)
+	assert.Contains(t, text, `"blocked"`, "error message should include tool name: %s", text)
+	assert.Contains(t, text, "allowed-tools", "error message should mention allowed-tools: %s", text)
 }
 
 // TestCallBackendTool_ToolTimeoutEnforcedViaContext verifies that the configured
diff --git a/test/integration/large_payload_test.go b/test/integration/large_payload_test.go
index 19ad1b1c..77067084 100644
--- a/test/integration/large_payload_test.go
+++ b/test/integration/large_payload_test.go
@@ -10,7 +10,6 @@ import (
 	"os"
 	"os/exec"
 	"path/filepath"
-	"strings"
 	"testing"
 	"time"
 
@@ -698,5 +697,5 @@ func TestLargePayload_PayloadPathStructure(t *testing.T) {
 
 	// This test documents the expected behavior
 	assert.Equal(t, "{payloadDir}/{sessionID}/{queryID}/payload.json", expectedStructure)
-	assert.True(t, strings.Contains(expectedStructure, "sessionID"), "Structure should include sessionID for isolation")
+	assert.Contains(t, expectedStructure, "sessionID", "Structure should include sessionID for isolation")
 }