iOfficeAI/OfficeCLI · error · ArgumentException

unknown diagram look '{look}'. Valid: classic, handDrawn.

Error message

unknown diagram look '{look}'. Valid: classic, handDrawn.

What it means

Thrown by MermaidImageRenderer.ComposeSource (MermaidImageRenderer.cs:136) when a non-null look value is not in the accepted Looks set {classic, handDrawn} (case-insensitive). 'look' is mermaid 11's rendering style option; handDrawn produces a sketch-like appearance. The canonical camelCase spelling 'handDrawn' is normalized at injection time, but the accepted input set uses lowercase comparison.

Source

Thrown at src/officecli/Core/Diagram/MermaidImageRenderer.cs:136

    /// source unchanged when no option is set. Rejects unknown values with a
    /// message listing the valid ones. When the source already carries its own
    /// frontmatter or an <c>%%{init}%%</c> directive, the source wins and the
    /// options are ignored (caller may warn) — merging into an existing block is
    /// out of scope and would risk producing a malformed document.
    /// </summary>
    public static string ComposeSource(string mermaid, string? theme, string? layout, string? look)
    {
        theme = string.IsNullOrWhiteSpace(theme) ? null : theme.Trim();
        layout = string.IsNullOrWhiteSpace(layout) ? null : layout.Trim();
        look = string.IsNullOrWhiteSpace(look) ? null : look.Trim();
        if (theme == null && layout == null && look == null) return mermaid;

        if (theme != null && !Themes.Contains(theme))
            throw new ArgumentException($"unknown diagram theme '{theme}'. Valid: {string.Join(", ", Themes)}.");
        if (layout != null && !Layouts.Contains(layout))
            throw new ArgumentException($"unknown diagram layout '{layout}'. Valid: {string.Join(", ", Layouts)}.");
        if (look != null && !Looks.Contains(look))
            throw new ArgumentException($"unknown diagram look '{look}'. Valid: classic, handDrawn.");

        var lead = mermaid.TrimStart();
        if (lead.StartsWith("---", StringComparison.Ordinal) || lead.StartsWith("%%{", StringComparison.Ordinal))
            return mermaid; // source already declares config — do not double-inject

        var sb = new StringBuilder("---\nconfig:\n");
        if (theme != null) sb.Append("  theme: ").Append(theme.ToLowerInvariant()).Append('\n');
        if (layout != null) sb.Append("  layout: ").Append(layout.ToLowerInvariant()).Append('\n');
        // look's canonical mermaid spelling is camelCase handDrawn; normalize.
        if (look != null)
            sb.Append("  look: ")
              .Append(look.Equals("handdrawn", StringComparison.OrdinalIgnoreCase) ? "handDrawn" : "classic")
              .Append('\n');
        sb.Append("---\n").Append(mermaid);
        return sb.ToString();
    }

    /// <summary>True when the (already composed) source carries a style frontmatter,

View on GitHub (pinned to 1ced45e900)

Solutions

  1. Use one of: classic or handDrawn.
  2. Leave look unset to keep the default classic appearance.

Example fix

// before
look=sketch
// after
look=handDrawn
Defensive patterns

Strategy: validation

Validate before calling

static readonly HashSet<string> ValidLooks = new(StringComparer.OrdinalIgnoreCase) { "classic","handdrawn" };
static string ValidateLook(string look) => ValidLooks.Contains(look ?? "") ? look : throw new ArgumentException($"unknown look '{look}'");

Type guard

static bool IsValidLook(string look) => ValidLooks.Contains(look ?? "");

Try / catch

try { MermaidImageRenderer.ComposeSource(mermaid, null, null, look); }
catch (ArgumentException ex) when (ex.Message.Contains("unknown diagram look"))
{ /* default to null (classic) or pick classic/handDrawn */ }

Prevention

When it happens

Trigger: Setting a diagram look to 'sketch', 'rough', 'neon', 'hand', or any value outside {classic, handDrawn}.

Common situations: Guessing 'sketch' or 'rough' (mermaid uses 'handDrawn'); passing 'handdrawn' works (case-insensitive) but 'hand-drawn' does not; expecting a mermaid 10 theme that does not exist under the look option in v11.

Related errors

AI-assisted analysis of iOfficeAI/OfficeCLI@1ced45e900 (2026-08-13). Data as JSON: /api/errors/5f1bc22ce6480a4e. Report an issue: GitHub.