Severity: Info (doc/code mismatch — silently functional but misleading to users and reviewers)

File / line: src/Servy.Core/ServiceDependencies/ServiceDependenciesValidator.cs lines 8–16, 44

Code:

// Allowed characters: letters, digits, hyphen, underscore                                       <-- comment
private static readonly Regex ValidServiceNameRegex =
    new Regex(@"^[a-zA-Z0-9_.\-]+$", RegexOptions.Compiled, AppConfig.InputRegexTimeout);        // <-- regex includes '.'

/// <summary>
/// Validates the input string containing service dependencies.
/// Service names must be separated by semicolons or new lines.
/// Each service name must contain only letters, digits, hyphens, or underscores.                 <-- doc
/// </summary>
...

if (!ValidServiceNameRegex.IsMatch(serviceName))
{
    errors.Add(
        $"Invalid service name '{serviceName}'. Only letters, digits, hyphens, and underscores are allowed."  // <-- error msg
    );
}

What's wrong: Three places (the inline comment, the <summary> XML doc, and the user-facing error message) all assert the dependency-name alphabet is [a-zA-Z0-9_-], but the actual regex character class is [a-zA-Z0-9_.\-] — it permits . (period). This is probably the correct regex (Windows SCM allows period in service names — e.g., a custom service MyApp.Updater), but the documentation everywhere insists otherwise. Net effect:

• A user who reads the docs will assume MyApp.Updater is rejected as a dependency, when in fact it's accepted.
• A user who hits the validator with MyApp@Updater and reads the error message will think they need to remove the @, then try MyApp.Updater and be (correctly) surprised that it works — but with no doc explaining why.
• A reviewer reading the regex sees . and can't tell whether it's intentional or a typo (.\ is suspicious-looking) — the code itself doesn't justify the period.

Suggested fix: Pick one of the two contracts and align all four sites.

Option A (recommended — keep period, since Windows SCM allows it):

// Allowed characters: letters, digits, hyphen, underscore, period
private static readonly Regex ValidServiceNameRegex =
    new Regex(@"^[a-zA-Z0-9_.\-]+$", RegexOptions.Compiled, AppConfig.InputRegexTimeout);

/// <summary>
/// ...
/// Each service name must contain only letters, digits, hyphens, underscores, or periods.
/// </summary>
...
errors.Add($"Invalid service name '{serviceName}'. Only letters, digits, hyphens, underscores, and periods are allowed.");

Option B (drop period — matches the doc but rejects legitimate Windows service names like MyApp.Updater):

private static readonly Regex ValidServiceNameRegex =
    new Regex(@"^[a-zA-Z0-9_\-]+$", RegexOptions.Compiled, AppConfig.InputRegexTimeout);

Option A is what the codebase appears to actually want.