diff --git a/tests/integration_test.rs b/tests/integration_test.rs
index 0501216..9369ab2 100644
--- a/tests/integration_test.rs
+++ b/tests/integration_test.rs
@@ -3,7 +3,9 @@ use std::fs;
 use std::path::Path;
 
 use anvil::templates::{TemplateManager, TemplateContext};
-use anvil::project::config::ProjectConfig;
+use anvil::project::config::{
+    ProjectConfig, BoardProfile, CONFIG_FILENAME, set_default_in_file,
+};
 
 // ============================================================================
 // Template extraction tests
@@ -332,6 +334,467 @@ fn test_config_skips_nonexistent_include_dirs() {
     assert_eq!(flags.len(), 0, "Should skip non-existent directories");
 }
 
+// ============================================================================
+// Config: default board and [boards.X] structure
+// ============================================================================
+
+#[test]
+fn test_config_default_points_to_boards_section() {
+    let config = ProjectConfig::new("test");
+    assert_eq!(config.build.default, "uno");
+    assert!(
+        config.boards.contains_key("uno"),
+        "boards map should contain the default board"
+    );
+    assert_eq!(config.boards["uno"].fqbn, "arduino:avr:uno");
+}
+
+#[test]
+fn test_config_default_fqbn_resolves() {
+    let config = ProjectConfig::new("test");
+    let fqbn = config.default_fqbn().unwrap();
+    assert_eq!(fqbn, "arduino:avr:uno");
+}
+
+#[test]
+fn test_config_default_board_returns_fqbn_and_baud() {
+    let config = ProjectConfig::new("test");
+    let (fqbn, baud) = config.default_board().unwrap();
+    assert_eq!(fqbn, "arduino:avr:uno");
+    assert_eq!(baud, 115200);
+}
+
+#[test]
+fn test_config_resolve_board_named() {
+    let mut config = ProjectConfig::new("test");
+    config.boards.insert("mega".to_string(), BoardProfile {
+        fqbn: "arduino:avr:mega:cpu=atmega2560".to_string(),
+        baud: Some(57600),
+    });
+    let (fqbn, baud) = config.resolve_board("mega").unwrap();
+    assert_eq!(fqbn, "arduino:avr:mega:cpu=atmega2560");
+    assert_eq!(baud, 57600);
+}
+
+#[test]
+fn test_config_resolve_board_inherits_baud() {
+    let mut config = ProjectConfig::new("test");
+    config.boards.insert("nano".to_string(), BoardProfile {
+        fqbn: "arduino:avr:nano".to_string(),
+        baud: None,
+    });
+    let (_, baud) = config.resolve_board("nano").unwrap();
+    assert_eq!(
+        baud, config.monitor.baud,
+        "Should inherit monitor baud when board has no override"
+    );
+}
+
+#[test]
+fn test_config_resolve_board_unknown_fails() {
+    let config = ProjectConfig::new("test");
+    assert!(config.resolve_board("esp32").is_err());
+}
+
+#[test]
+fn test_config_new_with_board_preset() {
+    let config = ProjectConfig::new_with_board(
+        "test", "mega", "arduino:avr:mega:cpu=atmega2560", 115200,
+    );
+    assert_eq!(config.build.default, "mega");
+    assert!(config.boards.contains_key("mega"));
+    assert_eq!(
+        config.boards["mega"].fqbn,
+        "arduino:avr:mega:cpu=atmega2560"
+    );
+    assert!(
+        !config.boards.contains_key("uno"),
+        "Should only contain the specified board"
+    );
+}
+
+#[test]
+fn test_config_board_roundtrip() {
+    let tmp = TempDir::new().unwrap();
+    let mut config = ProjectConfig::new("multi");
+    config.boards.insert("mega".to_string(), BoardProfile {
+        fqbn: "arduino:avr:mega:cpu=atmega2560".to_string(),
+        baud: Some(57600),
+    });
+    config.save(tmp.path()).unwrap();
+
+    let loaded = ProjectConfig::load(tmp.path()).unwrap();
+    assert!(loaded.boards.contains_key("mega"));
+    let mega = &loaded.boards["mega"];
+    assert_eq!(mega.fqbn, "arduino:avr:mega:cpu=atmega2560");
+    assert_eq!(mega.baud, Some(57600));
+}
+
+#[test]
+fn test_toml_template_has_default_field() {
+    let tmp = TempDir::new().unwrap();
+    let ctx = TemplateContext {
+        project_name: "default_test".to_string(),
+        anvil_version: "1.0.0".to_string(),
+        board_name: "uno".to_string(),
+        fqbn: "arduino:avr:uno".to_string(),
+        baud: 115200,
+    };
+    TemplateManager::extract("basic", tmp.path(), &ctx).unwrap();
+
+    let content = fs::read_to_string(tmp.path().join(".anvil.toml")).unwrap();
+    assert!(
+        content.contains("default = \"uno\""),
+        ".anvil.toml should have default = \"uno\" in [build]"
+    );
+    assert!(
+        content.contains("[boards.uno]"),
+        ".anvil.toml should have a [boards.uno] section"
+    );
+}
+
+#[test]
+fn test_toml_template_no_fqbn_in_build_section() {
+    // New configs should NOT have fqbn directly in [build]
+    let tmp = TempDir::new().unwrap();
+    let ctx = TemplateContext {
+        project_name: "no_build_fqbn".to_string(),
+        anvil_version: "1.0.0".to_string(),
+        board_name: "uno".to_string(),
+        fqbn: "arduino:avr:uno".to_string(),
+        baud: 115200,
+    };
+    TemplateManager::extract("basic", tmp.path(), &ctx).unwrap();
+
+    let content = fs::read_to_string(tmp.path().join(".anvil.toml")).unwrap();
+
+    let mut in_build = false;
+    for line in content.lines() {
+        let trimmed = line.trim();
+        if trimmed == "[build]" {
+            in_build = true;
+            continue;
+        }
+        if trimmed.starts_with('[') {
+            in_build = false;
+        }
+        if in_build && !trimmed.starts_with('#') {
+            assert!(
+                !trimmed.starts_with("fqbn"),
+                "[build] section should not contain fqbn; it belongs in [boards.X]"
+            );
+        }
+    }
+}
+
+// ============================================================================
+// Config migration: old format -> new format
+// ============================================================================
+
+#[test]
+fn test_migrate_old_config_adds_default_and_boards() {
+    let tmp = TempDir::new().unwrap();
+    let old_config = "\
+[project]\n\
+name = \"hand\"\n\
+anvil_version = \"1.0.0\"\n\
+\n\
+[build]\n\
+fqbn = \"arduino:avr:uno\"\n\
+warnings = \"more\"\n\
+include_dirs = [\"lib/hal\", \"lib/app\"]\n\
+extra_flags = [\"-Werror\"]\n\
+\n\
+[monitor]\n\
+baud = 115200\n\
+\n\
+[boards.micro]\n\
+fqbn = \"arduino:avr:micro\"\n";
+
+    fs::write(tmp.path().join(CONFIG_FILENAME), old_config).unwrap();
+
+    let config = ProjectConfig::load(tmp.path()).unwrap();
+
+    // In-memory state
+    assert_eq!(config.build.default, "uno");
+    assert!(config.boards.contains_key("uno"));
+    assert_eq!(config.boards["uno"].fqbn, "arduino:avr:uno");
+    assert!(config.boards.contains_key("micro"));
+
+    // On-disk file rewritten
+    let content = fs::read_to_string(tmp.path().join(CONFIG_FILENAME)).unwrap();
+    assert!(
+        content.contains("default = \"uno\""),
+        "Migrated file should contain default = \"uno\""
+    );
+    assert!(
+        content.contains("[boards.uno]"),
+        "Migrated file should add [boards.uno] section"
+    );
+    // Old fqbn kept for backward compat with pre-refresh scripts
+    assert!(
+        content.contains("fqbn = \"arduino:avr:uno\""),
+        "Migration should keep old fqbn for backward compat"
+    );
+}
+
+#[test]
+fn test_migrate_preserves_comments() {
+    let tmp = TempDir::new().unwrap();
+    let old_config = "\
+[project]\n\
+name = \"test\"\n\
+anvil_version = \"1.0.0\"\n\
+\n\
+[build]\n\
+fqbn = \"arduino:avr:uno\"\n\
+warnings = \"more\"\n\
+include_dirs = [\"lib/hal\", \"lib/app\"]\n\
+extra_flags = [\"-Werror\"]\n\
+\n\
+[monitor]\n\
+baud = 115200\n\
+# port = \"/dev/ttyUSB0\"  # Uncomment to skip auto-detect\n";
+
+    fs::write(tmp.path().join(CONFIG_FILENAME), old_config).unwrap();
+    ProjectConfig::load(tmp.path()).unwrap();
+
+    let content = fs::read_to_string(tmp.path().join(CONFIG_FILENAME)).unwrap();
+    assert!(
+        content.contains("# port = \"/dev/ttyUSB0\""),
+        "Migration should preserve comments"
+    );
+}
+
+#[test]
+fn test_migrate_matches_preset_name() {
+    // A mega FQBN should get board name "mega", not "default"
+    let tmp = TempDir::new().unwrap();
+    let old_config = "\
+[project]\n\
+name = \"test\"\n\
+anvil_version = \"1.0.0\"\n\
+\n\
+[build]\n\
+fqbn = \"arduino:avr:mega:cpu=atmega2560\"\n\
+warnings = \"more\"\n\
+include_dirs = [\"lib/hal\", \"lib/app\"]\n\
+extra_flags = [\"-Werror\"]\n\
+\n\
+[monitor]\n\
+baud = 115200\n";
+
+    fs::write(tmp.path().join(CONFIG_FILENAME), old_config).unwrap();
+
+    let config = ProjectConfig::load(tmp.path()).unwrap();
+    assert_eq!(config.build.default, "mega");
+    assert!(config.boards.contains_key("mega"));
+}
+
+#[test]
+fn test_migrate_unknown_fqbn_uses_default_name() {
+    let tmp = TempDir::new().unwrap();
+    let old_config = "\
+[project]\n\
+name = \"test\"\n\
+anvil_version = \"1.0.0\"\n\
+\n\
+[build]\n\
+fqbn = \"some:custom:board\"\n\
+warnings = \"more\"\n\
+include_dirs = [\"lib/hal\", \"lib/app\"]\n\
+extra_flags = [\"-Werror\"]\n\
+\n\
+[monitor]\n\
+baud = 115200\n";
+
+    fs::write(tmp.path().join(CONFIG_FILENAME), old_config).unwrap();
+
+    let config = ProjectConfig::load(tmp.path()).unwrap();
+    assert_eq!(config.build.default, "default");
+    assert!(config.boards.contains_key("default"));
+    assert_eq!(config.boards["default"].fqbn, "some:custom:board");
+}
+
+#[test]
+fn test_migrate_skips_if_already_has_default() {
+    let tmp = TempDir::new().unwrap();
+    let new_config = "\
+[project]\n\
+name = \"test\"\n\
+anvil_version = \"1.0.0\"\n\
+\n\
+[build]\n\
+default = \"uno\"\n\
+warnings = \"more\"\n\
+include_dirs = [\"lib/hal\", \"lib/app\"]\n\
+extra_flags = [\"-Werror\"]\n\
+\n\
+[monitor]\n\
+baud = 115200\n\
+\n\
+[boards.uno]\n\
+fqbn = \"arduino:avr:uno\"\n";
+
+    fs::write(tmp.path().join(CONFIG_FILENAME), new_config).unwrap();
+
+    let config = ProjectConfig::load(tmp.path()).unwrap();
+    assert_eq!(config.build.default, "uno");
+
+    // File should be unchanged
+    let content = fs::read_to_string(tmp.path().join(CONFIG_FILENAME)).unwrap();
+    assert_eq!(
+        content, new_config,
+        "New-format config should not be modified"
+    );
+}
+
+#[test]
+fn test_migrate_does_not_duplicate_board_section() {
+    // If [boards.uno] already exists, migration should not add a second one
+    let tmp = TempDir::new().unwrap();
+    let old_config = "\
+[project]\n\
+name = \"test\"\n\
+anvil_version = \"1.0.0\"\n\
+\n\
+[build]\n\
+fqbn = \"arduino:avr:uno\"\n\
+warnings = \"more\"\n\
+include_dirs = [\"lib/hal\", \"lib/app\"]\n\
+extra_flags = [\"-Werror\"]\n\
+\n\
+[monitor]\n\
+baud = 115200\n\
+\n\
+[boards.uno]\n\
+fqbn = \"arduino:avr:uno\"\n";
+
+    fs::write(tmp.path().join(CONFIG_FILENAME), old_config).unwrap();
+    ProjectConfig::load(tmp.path()).unwrap();
+
+    let content = fs::read_to_string(tmp.path().join(CONFIG_FILENAME)).unwrap();
+    let count = content.matches("[boards.uno]").count();
+    assert_eq!(count, 1, "Should not duplicate [boards.uno] section");
+}
+
+#[test]
+fn test_migrate_default_appears_before_fqbn() {
+    // After migration, default = "..." should come before fqbn = "..."
+    // in [build] for natural reading order.
+    let tmp = TempDir::new().unwrap();
+    let old_config = "\
+[project]\n\
+name = \"test\"\n\
+anvil_version = \"1.0.0\"\n\
+\n\
+[build]\n\
+fqbn = \"arduino:avr:uno\"\n\
+warnings = \"more\"\n\
+include_dirs = [\"lib/hal\", \"lib/app\"]\n\
+extra_flags = [\"-Werror\"]\n\
+\n\
+[monitor]\n\
+baud = 115200\n";
+
+    fs::write(tmp.path().join(CONFIG_FILENAME), old_config).unwrap();
+    ProjectConfig::load(tmp.path()).unwrap();
+
+    let content = fs::read_to_string(tmp.path().join(CONFIG_FILENAME)).unwrap();
+    let default_pos = content.find("default = ").expect("should have default");
+    let fqbn_pos = content.find("fqbn = ").expect("should have fqbn");
+    assert!(
+        default_pos < fqbn_pos,
+        "default should appear before fqbn in [build] section"
+    );
+}
+
+// ============================================================================
+// set_default_in_file: text-based config editing
+// ============================================================================
+
+#[test]
+fn test_set_default_replaces_existing() {
+    let tmp = TempDir::new().unwrap();
+    let config = ProjectConfig::new("test");
+    config.save(tmp.path()).unwrap();
+
+    let config_path = tmp.path().join(CONFIG_FILENAME);
+    let old = set_default_in_file(&config_path, "mega").unwrap();
+    assert_eq!(old, "uno");
+
+    let content = fs::read_to_string(&config_path).unwrap();
+    assert!(content.contains("default = \"mega\""));
+    assert!(!content.contains("default = \"uno\""));
+}
+
+#[test]
+fn test_set_default_adds_when_missing() {
+    let tmp = TempDir::new().unwrap();
+    let content = "\
+[project]\n\
+name = \"test\"\n\
+anvil_version = \"1.0.0\"\n\
+\n\
+[build]\n\
+warnings = \"more\"\n\
+include_dirs = [\"lib/hal\", \"lib/app\"]\n\
+extra_flags = [\"-Werror\"]\n\
+\n\
+[monitor]\n\
+baud = 115200\n\
+\n\
+[boards.uno]\n\
+fqbn = \"arduino:avr:uno\"\n";
+
+    let config_path = tmp.path().join(CONFIG_FILENAME);
+    fs::write(&config_path, content).unwrap();
+
+    let old = set_default_in_file(&config_path, "uno").unwrap();
+    assert_eq!(old, "", "Should return empty string when no previous default");
+
+    let result = fs::read_to_string(&config_path).unwrap();
+    assert!(result.contains("default = \"uno\""));
+}
+
+#[test]
+fn test_set_default_is_idempotent() {
+    let tmp = TempDir::new().unwrap();
+    let config = ProjectConfig::new("test");
+    config.save(tmp.path()).unwrap();
+
+    let config_path = tmp.path().join(CONFIG_FILENAME);
+
+    set_default_in_file(&config_path, "mega").unwrap();
+    let content_after_first = fs::read_to_string(&config_path).unwrap();
+
+    set_default_in_file(&config_path, "mega").unwrap();
+    let content_after_second = fs::read_to_string(&config_path).unwrap();
+
+    assert_eq!(
+        content_after_first, content_after_second,
+        "Second set should not change file"
+    );
+}
+
+#[test]
+fn test_set_default_preserves_other_fields() {
+    let tmp = TempDir::new().unwrap();
+    let config = ProjectConfig::new("test");
+    config.save(tmp.path()).unwrap();
+
+    let config_path = tmp.path().join(CONFIG_FILENAME);
+    set_default_in_file(&config_path, "mega").unwrap();
+
+    // Reload and check nothing else broke
+    let loaded = ProjectConfig::load(tmp.path()).unwrap();
+    assert_eq!(loaded.build.default, "mega");
+    assert_eq!(loaded.build.warnings, "more");
+    assert_eq!(loaded.project.name, "test");
+    assert_eq!(loaded.monitor.baud, 115200);
+    assert!(loaded.build.include_dirs.contains(&"lib/hal".to_string()));
+}
+
 // ============================================================================
 // Full project creation test (end-to-end in temp dir)
 // ============================================================================
@@ -1074,7 +1537,15 @@ fn test_board_preset_fqbn_in_config() {
     let config = ProjectConfig::load(tmp.path()).unwrap();
     assert_eq!(
         config.build.default, "mega",
-        ".anvil.toml should contain mega FQBN"
+        ".anvil.toml should have default = mega"
+    );
+    assert!(
+        config.boards.contains_key("mega"),
+        ".anvil.toml should have [boards.mega]"
+    );
+    assert_eq!(
+        config.boards["mega"].fqbn, "arduino:avr:mega:cpu=atmega2560",
+        "[boards.mega] should have the correct FQBN"
     );
 }
 
@@ -1194,4 +1665,204 @@ fn test_toml_template_has_board_profile_comments() {
         content.contains("[boards.mega]") || content.contains("boards.mega"),
         ".anvil.toml should show board profile examples in comments"
     );
+}
+
+// ==========================================================================
+// Scripts read default board from [build] section
+// ==========================================================================
+
+#[test]
+fn test_scripts_read_default_board() {
+    let tmp = TempDir::new().unwrap();
+    let ctx = TemplateContext {
+        project_name: "default_read".to_string(),
+        anvil_version: "1.0.0".to_string(),
+        board_name: "uno".to_string(),
+        fqbn: "arduino:avr:uno".to_string(),
+        baud: 115200,
+    };
+    TemplateManager::extract("basic", tmp.path(), &ctx).unwrap();
+
+    for script in &["build.sh", "upload.sh", "monitor.sh"] {
+        let content = fs::read_to_string(tmp.path().join(script)).unwrap();
+        assert!(
+            content.contains("DEFAULT_BOARD") && content.contains("'default'"),
+            "{} should read 'default' field from .anvil.toml into DEFAULT_BOARD",
+            script
+        );
+        assert!(
+            content.contains("ACTIVE_BOARD"),
+            "{} should resolve ACTIVE_BOARD from DEFAULT_BOARD or --board flag",
+            script
+        );
+    }
+
+    for bat in &["build.bat", "upload.bat", "monitor.bat"] {
+        let content = fs::read_to_string(tmp.path().join(bat)).unwrap();
+        assert!(
+            content.contains("DEFAULT_BOARD"),
+            "{} should read default field into DEFAULT_BOARD",
+            bat
+        );
+    }
+}
+
+// ==========================================================================
+// USB_VID/USB_PID fix: compiler.cpp.extra_flags (not build.extra_flags)
+// ==========================================================================
+
+#[test]
+fn test_scripts_use_compiler_extra_flags_not_build() {
+    // Regression: build.extra_flags clobbers board defaults (USB_VID, USB_PID)
+    // on ATmega32U4 boards (Micro, Leonardo). Scripts must use
+    // compiler.cpp.extra_flags and compiler.c.extra_flags instead,
+    // which are additive.
+    let tmp = TempDir::new().unwrap();
+    let ctx = TemplateContext {
+        project_name: "usb_fix".to_string(),
+        anvil_version: "1.0.0".to_string(),
+        board_name: "uno".to_string(),
+        fqbn: "arduino:avr:uno".to_string(),
+        baud: 115200,
+    };
+    TemplateManager::extract("basic", tmp.path(), &ctx).unwrap();
+
+    let compile_scripts = vec![
+        "build.sh", "build.bat",
+        "upload.sh", "upload.bat",
+    ];
+
+    for script in &compile_scripts {
+        let content = fs::read_to_string(tmp.path().join(script)).unwrap();
+        assert!(
+            !content.contains("build.extra_flags"),
+            "{} must NOT use build.extra_flags (clobbers USB_VID/USB_PID on ATmega32U4)",
+            script
+        );
+        assert!(
+            content.contains("compiler.cpp.extra_flags"),
+            "{} should use compiler.cpp.extra_flags (additive, USB-safe)",
+            script
+        );
+        assert!(
+            content.contains("compiler.c.extra_flags"),
+            "{} should use compiler.c.extra_flags (additive, USB-safe)",
+            script
+        );
+    }
+}
+
+#[test]
+fn test_monitor_scripts_have_no_compile_flags() {
+    // monitor.sh and monitor.bat should NOT contain any compile flags
+    // since they don't compile anything.
+    let tmp = TempDir::new().unwrap();
+    let ctx = TemplateContext {
+        project_name: "mon_flags".to_string(),
+        anvil_version: "1.0.0".to_string(),
+        board_name: "uno".to_string(),
+        fqbn: "arduino:avr:uno".to_string(),
+        baud: 115200,
+    };
+    TemplateManager::extract("basic", tmp.path(), &ctx).unwrap();
+
+    for script in &["monitor.sh", "monitor.bat"] {
+        let content = fs::read_to_string(tmp.path().join(script)).unwrap();
+        assert!(
+            !content.contains("compiler.cpp.extra_flags")
+                && !content.contains("compiler.c.extra_flags")
+                && !content.contains("build.extra_flags"),
+            "{} should not contain any compile flags",
+            script
+        );
+    }
+}
+
+// ==========================================================================
+// Script error messages: helpful guidance without requiring anvil
+// ==========================================================================
+
+#[test]
+fn test_script_errors_show_manual_fix() {
+    // Error messages should explain how to fix .anvil.toml by hand,
+    // since the project is self-contained and anvil may not be installed.
+    let tmp = TempDir::new().unwrap();
+    let ctx = TemplateContext {
+        project_name: "err_msg".to_string(),
+        anvil_version: "1.0.0".to_string(),
+        board_name: "uno".to_string(),
+        fqbn: "arduino:avr:uno".to_string(),
+        baud: 115200,
+    };
+    TemplateManager::extract("basic", tmp.path(), &ctx).unwrap();
+
+    let all_scripts = vec![
+        "build.sh", "build.bat",
+        "upload.sh", "upload.bat",
+        "monitor.sh", "monitor.bat",
+    ];
+
+    for script in &all_scripts {
+        let content = fs::read_to_string(tmp.path().join(script)).unwrap();
+        assert!(
+            content.contains("default = "),
+            "{} error messages should show the manual fix (default = \"...\")",
+            script
+        );
+    }
+}
+
+#[test]
+fn test_script_errors_mention_arduino_cli() {
+    // Error messages should mention arduino-cli board listall as a
+    // discovery option, since the project doesn't require anvil.
+    let tmp = TempDir::new().unwrap();
+    let ctx = TemplateContext {
+        project_name: "cli_err".to_string(),
+        anvil_version: "1.0.0".to_string(),
+        board_name: "uno".to_string(),
+        fqbn: "arduino:avr:uno".to_string(),
+        baud: 115200,
+    };
+    TemplateManager::extract("basic", tmp.path(), &ctx).unwrap();
+
+    let all_scripts = vec![
+        "build.sh", "build.bat",
+        "upload.sh", "upload.bat",
+        "monitor.sh", "monitor.bat",
+    ];
+
+    for script in &all_scripts {
+        let content = fs::read_to_string(tmp.path().join(script)).unwrap();
+        assert!(
+            content.contains("arduino-cli board listall"),
+            "{} error messages should mention 'arduino-cli board listall' for board discovery",
+            script
+        );
+    }
+}
+
+#[test]
+fn test_script_errors_mention_toml_section_syntax() {
+    // The "board not found" error in build/upload scripts should show
+    // the [boards.X] section syntax so users know exactly what to add.
+    let tmp = TempDir::new().unwrap();
+    let ctx = TemplateContext {
+        project_name: "section_err".to_string(),
+        anvil_version: "1.0.0".to_string(),
+        board_name: "uno".to_string(),
+        fqbn: "arduino:avr:uno".to_string(),
+        baud: 115200,
+    };
+    TemplateManager::extract("basic", tmp.path(), &ctx).unwrap();
+
+    // build and upload scripts have both no-default and board-not-found errors
+    for script in &["build.sh", "build.bat", "upload.sh", "upload.bat"] {
+        let content = fs::read_to_string(tmp.path().join(script)).unwrap();
+        assert!(
+            content.contains("[boards."),
+            "{} board-not-found error should show [boards.X] section syntax",
+            script
+        );
+    }
 }
\ No newline at end of file