fix(summarizer): gracefully handle missing scikit-learn for TextRank

TextRank strategy initialization now catches ImportError when scikit-learn
is not installed, allowing the summarizer to fall back to extractive/compressive
strategies. Previously, `tenets distill` would crash with "TextRank requires
scikit-learn" even though sklearn is an optional dependency in [mcp] extras.

- Wrap TextRankStrategy() init in try/except in Summarizer.__init__
- Add test for graceful degradation when sklearn unavailable
- Bump version to v0.9.2

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: jddunn

pyproject.toml

@@ -2,7 +2,7 @@
 
 [project]
 name = "tenets"
-version = "0.9.1"
+version = "0.9.2"
 description = "MCP server for AI coding assistants — intelligent code context via Model Context Protocol"
 authors = [{name = "Tenets Team", email = "team@tenets.dev"}]
 readme = {file = "README.md", content-type = "text/markdown"}

tenets/__init__.py

@@ -23,7 +23,7 @@
 
 from __future__ import annotations
 
-__version__ = "0.9.1"
+__version__ = "0.9.2"
 __author__ = "Johnny Dunn"
 __license__ = "MIT"
 

tenets/core/summarizer/summarizer.py

@@ -162,9 +162,14 @@ def __init__(
         self.strategies: Dict[SummarizationMode, SummarizationStrategy] = {
             SummarizationMode.EXTRACTIVE: ExtractiveStrategy(),
             SummarizationMode.COMPRESSIVE: CompressiveStrategy(),
-            SummarizationMode.TEXTRANK: TextRankStrategy(),
         }
 
+        # Try to initialize TextRank (requires scikit-learn)
+        try:
+            self.strategies[SummarizationMode.TEXTRANK] = TextRankStrategy()
+        except ImportError:
+            self.logger.debug("TextRank unavailable (scikit-learn not installed)")
+
         # Try to initialize ML strategies
         self._init_ml_strategies()
 

tests/core/summarizer/test_summarizer.py

@@ -125,6 +125,20 @@ def test_initialization(self, config):
         assert SummarizationMode.EXTRACTIVE in summarizer.strategies
         assert SummarizationMode.COMPRESSIVE in summarizer.strategies
 
+    @patch("tenets.core.summarizer.summarizer.TextRankStrategy")
+    def test_initialization_without_sklearn(self, mock_textrank, config):
+        """Test summarizer gracefully handles missing sklearn for TextRank."""
+        # Simulate sklearn not installed
+        mock_textrank.side_effect = ImportError("No module named 'sklearn'")
+
+        summarizer = Summarizer(config=config)
+
+        # Core strategies should still be available
+        assert SummarizationMode.EXTRACTIVE in summarizer.strategies
+        assert SummarizationMode.COMPRESSIVE in summarizer.strategies
+        # TextRank should not be available
+        assert SummarizationMode.TEXTRANK not in summarizer.strategies
+
     def test_summarize_empty_text(self, summarizer):
         """Test summarizing empty text."""
         result = summarizer.summarize("")