Werkzeugkasten: PDF-Text aus Anhaengen und Dateien (#692)

- DocumentText reads PDF with PdfPig 0.1.16 (managed, Apache-2.0): page by
  page in reading order, at most 300 pages; a PDF without a text layer is
  named as probably scanned; broken and protected files are named.
- Mail read_attachment and FileRW read/read_many take PDF like Word/Excel.
- nuget.config maps exactly "PdfPig" - "UglyToad.PdfPig" is a package of a
  different account and stays out.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

NuGet.Config

@@ -28,6 +28,9 @@
       <package pattern="WTelegramClient" />
       <!-- WebFetch Stufe 1: HTML5-Parser mit CSS-Selektoren (#602) -->
       <package pattern="AngleSharp" />
+      <!-- PDF-Text aus Anhaengen (#692). Genau dieser Name, ohne Platzhalter: unter
+           "UglyToad.PdfPig" liegt ein Paket eines fremden Kontos. -->
+      <package pattern="PdfPig" />
       <!-- Oberflaeche (Avalonia-Portierung) -->
       <package pattern="Avalonia" />
       <package pattern="Avalonia.*" />

docs/Organisation-Konzept.md

@@ -806,7 +806,12 @@ beidem.
    > legt die Datei im eigenen Arbeitsbereich ab (nie über eine vorhandene, nie außerhalb).
    > FileRW `read`/`read_many` gibt Word- und Excel-Dateien als Text zurück; schreiben kann
    > es sie weiterhin nicht. Der Text ist Fremdinhalt und wird von der Engine gerahmt.
-   > **Offen: PDF** — ein verlässlicher PDF-Textauszug ist eine Bibliotheksentscheidung.
+   > **PDF** liest PdfPig (Paket `PdfPig`, Apache-2.0, nur verwalteter Code; Entscheidung des
+   > Nutzers vom 2026-10-01 für eine lokale Bibliothek statt der Auslese über OpenRouter):
+   > Seite für Seite in Leserichtung, höchstens 300 Seiten. Ein gescanntes PDF ohne Textebene
+   > wird als solches benannt — OCR gibt es nicht. Achtung beim Paketnamen: unter
+   > `UglyToad.PdfPig` liegt eine Vorabversion eines fremden Kontos; `nuget.config` lässt nur
+   > genau `PdfPig` zu.
 3. **Der MCP-Client (#197) bleibt nützlich** — aber als *eine* Fähigkeit unter anderen,
    für Dienste, die ohnehin als Server bereitstehen. Nicht als Anbindungsstrategie.
 

src/ClawdDotNet.Core/ClawdDotNet.Core.csproj

@@ -23,6 +23,11 @@
     <PackageReference Include="System.Security.Cryptography.ProtectedData" Version="10.0.0" />
     <PackageReference Include="Microsoft.Extensions.Logging" Version="10.0.8" />
     <PackageReference Include="Microsoft.Extensions.Logging.Abstractions" Version="10.0.8" />
+
+    <!-- #692: PDF text, managed code only, Apache-2.0. Das Paket heisst "PdfPig" (Eigentuemer
+         EliotJones/BobLd, github.com/UglyToad/PdfPig) - NICHT "UglyToad.PdfPig": unter diesem
+         Namen liegt eine fremde Vorabversion eines anderen Kontos. -->
+    <PackageReference Include="PdfPig" Version="0.1.16" />
   </ItemGroup>
 
 </Project>

src/ClawdDotNet.Core/Documents/DocumentText.cs

@@ -22,8 +22,8 @@ public sealed record DocumentExtraction(bool Ok, string Text, string Kind, bool
 /// <para><b>Bounded.</b> Office files are zip archives, and a zip can unpack to anything. Every
 /// part is read up to <see cref="MaxPartBytes"/>, the whole up to the caller's character limit.</para>
 ///
-/// <para>PDF is not read here yet: a reliable PDF text extractor is a library decision, not a
-/// hundred lines of code — fonts with their own encodings come out as garbage otherwise.</para>
+/// <para><b>PDF</b> is read with PdfPig (managed code only): the text of each page in reading
+/// order. A scanned PDF has no text layer and is named as such — reading it would need OCR.</para>
 /// </summary>
 public static class DocumentText
 {
@@ -40,7 +40,10 @@ public static class DocumentText
 
     /// <summary>Whether the file is a document whose text needs extracting (not plain text).</summary>
     public static bool IsOfficeDocument(string fileName)
-        => Path.GetExtension(fileName).ToLowerInvariant() is ".docx" or ".xlsx";
+        => Path.GetExtension(fileName).ToLowerInvariant() is ".docx" or ".xlsx" or ".pdf";
+
+    /// <summary>Pages read from one PDF — an invoice has a few, a catalogue is not read whole.</summary>
+    public const int MaxPdfPages = 300;
 
     public static DocumentExtraction Extract(byte[] content, string fileName, int maxChars)
     {
@@ -51,7 +54,7 @@ public static class DocumentText
             {
                 ".docx" => Bounded(Docx(content), "Word document", maxChars),
                 ".xlsx" => Bounded(Xlsx(content), "spreadsheet", maxChars),
-                ".pdf" => DocumentExtraction.Fail("PDF", "PDF text cannot be read in this version yet."),
+                ".pdf" => Pdf(content, maxChars),
                 _ when PlainText.Contains(ext) => Bounded(Decode(content), "text", maxChars),
                 _ => DocumentExtraction.Fail(ext.TrimStart('.'), $"'{ext}' files cannot be read as text.")
             };
@@ -62,6 +65,44 @@ public static class DocumentText
         }
     }
 
+    // ─── PDF ───
+
+    private static DocumentExtraction Pdf(byte[] content, int maxChars)
+    {
+        try
+        {
+            using var document = UglyToad.PdfPig.PdfDocument.Open(content, new UglyToad.PdfPig.ParsingOptions { UseLenientParsing = true });
+            var sb = new StringBuilder();
+            var pages = document.NumberOfPages;
+            var read = 0;
+            foreach (var page in document.GetPages())
+            {
+                if (read >= MaxPdfPages || sb.Length > maxChars)
+                    break;
+                read++;
+                var text = UglyToad.PdfPig.DocumentLayoutAnalysis.TextExtractor.ContentOrderTextExtractor.GetText(page).Trim();
+                if (pages > 1)
+                    sb.AppendLine($"## Page {page.Number}");
+                sb.AppendLine(text).AppendLine();
+            }
+
+            var all = sb.ToString().Trim();
+            if (all.Replace("## Page", "").All(c => char.IsWhiteSpace(c) || char.IsDigit(c)))
+                return DocumentExtraction.Fail("PDF", "The PDF has no text layer — it is probably scanned, and reading it would need OCR.");
+            if (read < pages)
+                all += $"\n\n(Read {read} of {pages} pages.)";
+            var bounded = Bounded(all, "PDF", maxChars);
+            return bounded with { Truncated = bounded.Truncated || read < pages };
+        }
+        catch (Exception ex) when (ex is not OutOfMemoryException)
+        {
+            // PdfPig throws its own exceptions for broken and encrypted files.
+            return DocumentExtraction.Fail("PDF", ex.Message.Contains("password", StringComparison.OrdinalIgnoreCase) || ex.Message.Contains("encrypt", StringComparison.OrdinalIgnoreCase)
+                ? "The PDF is protected by a password."
+                : $"The PDF could not be read: {ex.Message}");
+        }
+    }
+
     private static DocumentExtraction Bounded(string text, string kind, int maxChars)
     {
         var limit = Math.Max(1, maxChars);

src/ClawdDotNet.Tools.Mail/MailTool.cs

@@ -18,7 +18,7 @@ public sealed class MailTool : IAgentTool, IToolJobProvider
     /// <summary>#715: Brings text from outside into the context — mails from anyone.</summary>
     public bool ReadsForeignContent => true;
 
-    public string Description => "Allows sending and receiving emails via SMTP and IMAP. read_message lists a message's attachments; read_attachment returns an attachment's text (Word, Excel, text and CSV files); save_attachment stores it in your workspace.";
+    public string Description => "Allows sending and receiving emails via SMTP and IMAP. read_message lists a message's attachments; read_attachment returns an attachment's text (PDF, Word, Excel, text and CSV files); save_attachment stores it in your workspace.";
 
     public JsonElement InputSchema { get; } = JsonDocument.Parse("""
         {

tests/ClawdDotNet.Core.Tests/Documents/DocumentTextTests.cs

@@ -109,10 +109,40 @@ public sealed class DocumentTextTests
     }
 
     [Fact]
-    public void Pdf_and_unknown_files_are_named_not_guessed()
+    public void Broken_and_unknown_files_are_named_not_guessed()
     {
         DocumentText.Extract([1, 2, 3], "invoice.pdf", 100).Problem!.ShouldContain("PDF");
         DocumentText.Extract([1, 2, 3], "image.png", 100).Ok.ShouldBeFalse();
         DocumentText.Extract([1, 2, 3], "broken.docx", 100).Ok.ShouldBeFalse();
     }
+
+    private static byte[] Pdf(params string?[] pages)
+    {
+        var builder = new UglyToad.PdfPig.Writer.PdfDocumentBuilder();
+        var font = builder.AddStandard14Font(UglyToad.PdfPig.Fonts.Standard14Fonts.Standard14Font.Helvetica);
+        foreach (var text in pages)
+        {
+            var page = builder.AddPage(UglyToad.PdfPig.Content.PageSize.A4);
+            if (text is not null)
+                page.AddText(text, 12, new UglyToad.PdfPig.Core.PdfPoint(40, 700), font);
+        }
+        return builder.Build();
+    }
+
+    [Fact]
+    public void A_pdf_comes_out_page_by_page()
+    {
+        var text = DocumentText.Extract(Pdf("Invoice 4711", "Total 150.00 EUR"), "invoice.pdf", 10_000);
+
+        text.Ok.ShouldBeTrue(text.Problem);
+        text.Kind.ShouldBe("PDF");
+        text.Text.ShouldContain("## Page 1");
+        text.Text.ShouldContain("Invoice 4711");
+        text.Text.ShouldContain("## Page 2");
+        text.Text.ShouldContain("Total 150.00 EUR");
+    }
+
+    [Fact]
+    public void A_pdf_without_text_is_named_as_probably_scanned()
+        => DocumentText.Extract(Pdf((string?)null), "scan.pdf", 10_000).Problem!.ShouldContain("no text layer");
 }