Create youtube_transcript.py

tools/youtube_transcript.py

@@ -0,0 +1,91 @@
+import re
+from smolagents.tools import Tool
+
+
+class YouTubeTranscriptTool(Tool):
+    name = "youtube_transcript"
+    description = (
+        "Fetches the spoken transcript of a YouTube video. "
+        "Use this for ANY question about the content of a YouTube video — "
+        "what is said, shown, demonstrated, or described in it. "
+        "Pass the full YouTube URL or just the video ID."
+    )
+    inputs = {
+        "url": {
+            "type": "string",
+            "description": (
+                "The YouTube video URL (e.g. https://www.youtube.com/watch?v=XXXXXXXXXXX) "
+                "or bare video ID (e.g. XXXXXXXXXXX)."
+            ),
+        }
+    }
+    output_type = "string"
+
+    def __init__(self, *args, **kwargs):
+        self.is_initialized = False
+
+    def forward(self, url: str) -> str:
+        try:
+            from youtube_transcript_api import YouTubeTranscriptApi
+            from youtube_transcript_api._errors import (
+                TranscriptsDisabled,
+                NoTranscriptFound,
+                VideoUnavailable,
+            )
+        except ImportError:
+            return (
+                "youtube-transcript-api is not installed. "
+                "Add 'youtube-transcript-api' to requirements.txt and rebuild."
+            )
+
+        # Extract video ID from a full URL or accept a bare ID
+        video_id = self._extract_video_id(url.strip())
+        if not video_id:
+            return f"Could not extract a YouTube video ID from: {url}"
+
+        try:
+            # Prefer English; fall back to any available language
+            transcript_list = YouTubeTranscriptApi.list_transcripts(video_id)
+
+            try:
+                transcript = transcript_list.find_transcript(["en", "en-US", "en-GB"])
+            except NoTranscriptFound:
+                # Take whatever is available
+                transcript = next(iter(transcript_list))
+
+            entries = transcript.fetch()
+            text = " ".join(entry["text"] for entry in entries)
+
+            # Truncate to a reasonable size for the agent's context window
+            if len(text) > 12000:
+                text = text[:12000] + "\n\n[Transcript truncated at 12,000 characters]"
+
+            return text
+
+        except TranscriptsDisabled:
+            return (
+                f"Transcripts are disabled for video {video_id}. "
+                "Try searching for the video title or description instead."
+            )
+        except VideoUnavailable:
+            return f"Video {video_id} is unavailable or does not exist."
+        except NoTranscriptFound:
+            return (
+                f"No transcript found for video {video_id}. "
+                "The video may not have captions."
+            )
+        except Exception as e:
+            return f"Could not retrieve transcript for {video_id}: {e}"
+
+    @staticmethod
+    def _extract_video_id(url: str) -> str:
+        """Return the 11-character YouTube video ID from a URL or bare ID."""
+        patterns = [
+            r"(?:v=|youtu\.be/|embed/|shorts/)([A-Za-z0-9_-]{11})",
+            r"^([A-Za-z0-9_-]{11})$",   # bare ID
+        ]
+        for pattern in patterns:
+            match = re.search(pattern, url)
+            if match:
+                return match.group(1)
+        return ""