test(tools): add unit tests for error handling functions

* Implement tests for error functions like errRequiredField, errInvalidField, and errEntityNotFound.
* Ensure proper metadata is returned for various error scenarios.
* Validate error handling in CRM, Files, and other tools.
* Introduce tests for parsing stored file IDs and UUIDs.
* Enhance coverage for helper functions related to project resolution and session management.

internal/tools/version_test.go

@@ -0,0 +1,38 @@
+package tools
+
+import (
+	"context"
+	"testing"
+
+	"git.warky.dev/wdevs/amcs/internal/buildinfo"
+)
+
+func TestVersionToolReturnsBuildInformation(t *testing.T) {
+	tool := NewVersionTool("amcs", buildinfo.Info{
+		Version:   "v1.2.3",
+		TagName:   "v1.2.3",
+		Commit:    "abc1234",
+		BuildDate: "2026-03-31T12:34:56Z",
+	})
+
+	_, out, err := tool.GetInfo(context.Background(), nil, GetVersionInfoInput{})
+	if err != nil {
+		t.Fatalf("GetInfo() error = %v", err)
+	}
+
+	if out.ServerName != "amcs" {
+		t.Fatalf("server_name = %q, want %q", out.ServerName, "amcs")
+	}
+	if out.Version != "v1.2.3" {
+		t.Fatalf("version = %q, want %q", out.Version, "v1.2.3")
+	}
+	if out.TagName != "v1.2.3" {
+		t.Fatalf("tag_name = %q, want %q", out.TagName, "v1.2.3")
+	}
+	if out.Commit != "abc1234" {
+		t.Fatalf("commit = %q, want %q", out.Commit, "abc1234")
+	}
+	if out.BuildDate != "2026-03-31T12:34:56Z" {
+		t.Fatalf("build_date = %q, want %q", out.BuildDate, "2026-03-31T12:34:56Z")
+	}
+}