Strava MCP Server

Instructions

Implementation Reference

• src/tools/getActivityStreams.ts:337-687 (handler)

  The "get-activity-streams" tool definition and execution logic.

  export const getActivityStreamsTool = {
      name: 'get-activity-streams',
      description: 
          'Retrieves detailed time-series data streams from a Strava activity. Perfect for analyzing workout metrics, ' +
          'visualizing routes, or performing detailed activity analysis.\n\n' +
          
          'Key Features:\n' +
          '1. Multiple Data Types: Access various metrics like heart rate, power, speed, GPS coordinates, etc.\n' +
          '2. Flexible Resolution: Choose data density from low (~100 points) to high (~10000 points)\n' +
          '3. Smart Pagination: Get data in manageable chunks optimized for LLM context limits\n' +
          '4. Rich Statistics: Includes min/max/avg for numeric streams\n' +
          '5. Dual Format Support: Compact (LLM-optimized) or verbose (human-readable)\n' +
          '6. Intelligent Downsampling: Automatically reduce large datasets while preserving key features\n\n' +
          
          'Format Options:\n' +
          '- compact (default): Raw arrays, minified JSON, ~70-80% smaller payloads, ideal for LLM processing\n' +
          '- verbose: Human-readable objects with formatted values, backward compatible with legacy format\n\n' +
          
          'Common Use Cases:\n' +
          '- Analyzing workout intensity through heart rate zones\n' +
          '- Calculating power metrics for cycling activities\n' +
          '- Visualizing route data using GPS coordinates\n' +
          '- Analyzing pace and elevation changes\n' +
          '- Detailed segment analysis\n\n' +
          
          'Output Format:\n' +
          '1. Metadata: Activity overview, available streams, data points, units, format info\n' +
          '2. Statistics: Summary stats for each stream type (max/min/avg where applicable)\n' +
          '3. Data: Time-series data in compact arrays or verbose objects (based on format parameter)\n\n' +
          
          'Notes:\n' +
          '- Requires activity:read scope\n' +
          '- Not all streams are available for all activities\n' +
          '- Older activities might have limited data\n' +
          '- Large activities are automatically chunked to ~50KB per message\n' +
          '- Use max_points parameter to downsample very large activities intelligently',
      inputSchema,
      execute: async ({ id, types = ['time', 'distance', 'heartrate', 'cadence', 'watts'], resolution: rawResolution, series_type, page = 1, points_per_page = 100, format = 'compact', max_points, summary_only = false }: GetActivityStreamsParams) => {
          // Default resolution to 'low' for LLM-friendly payloads (issue #14).
          // This intentionally changes prior behavior where omitting resolution returned
          // the full native resolution (often 'high', ~10000 points), causing slow responses.
          // Callers who need more data should explicitly pass resolution: 'medium' or 'high'.
          const resolution = rawResolution ?? 'low';
          const token = process.env.STRAVA_ACCESS_TOKEN;
          if (!token) {
              return {
                  content: [{ type: 'text' as const, text: '❌ Missing STRAVA_ACCESS_TOKEN in .env' }],
                  isError: true
              };
          }
  
          try {
              // Set the auth token for this request
              stravaApi.defaults.headers.common['Authorization'] = `Bearer ${token}`;
              
              // Build query parameters
              // Always send resolution to control payload size (defaults to 'low' for issue #14)
              const params: Record<string, any> = {};
              params.resolution = resolution;
              if (series_type) params.series_type = series_type;
  
              // Convert query params to string
              const queryString = new URLSearchParams(params).toString();
              
              // Build the endpoint URL with types in the path
              const endpoint = `/activities/${id}/streams/${types.join(',')}${queryString ? '?' + queryString : ''}`;
              
              const response = await stravaApi.get<StreamSet>(endpoint);
              let streams = response.data;
  
              if (!streams || streams.length === 0) {
                  return {
                      content: [{ 
                          type: 'text' as const, 
                          text: '⚠️ No streams were returned. This could mean:\n' +
                                '1. The activity was recorded without this data\n' +
                                '2. The activity is not a GPS-based activity\n' +
                                '3. The activity is too old (Strava may not keep all stream data indefinitely)'
                      }],
                      isError: true
                  };
              }
  
              // At this point we know streams[0] exists because we checked length > 0
              let referenceStream = streams[0]!;
              let totalPoints = referenceStream.data.length;
              let wasDownsampled = false;
              let originalPoints = totalPoints;
  
              // Generate stream statistics on the ORIGINAL data (before downsampling)
              // so that summary_only mode always reflects the full activity
              const streamStats: Record<string, any> = {};
              streams.forEach(stream => {
                  const data = stream.data;
                  let stats: any = {
                      total_points: data.length,
                      resolution: stream.resolution,
                      series_type: stream.series_type
                  };
  
                  // Add type-specific statistics (guard against empty arrays)
                  switch (stream.type) {
                      case 'heartrate':
                          const hrData = data as number[];
                          if (hrData.length > 0) {
                              stats = {
                                  ...stats,
                                  max: Math.max(...hrData),
                                  min: Math.min(...hrData),
                                  avg: Math.round(hrData.reduce((a, b) => a + b, 0) / hrData.length)
                              };
                          }
                          break;
                      case 'watts':
                          const powerData = data as number[];
                          if (powerData.length > 0) {
                              stats = {
                                  ...stats,
                                  max: Math.max(...powerData),
                                  avg: Math.round(powerData.reduce((a, b) => a + b, 0) / powerData.length),
                                  normalized_power: calculateNormalizedPower(powerData)
                              };
                          }
                          break;
                      case 'velocity_smooth':
                          const velocityData = data as number[];
                          if (velocityData.length > 0) {
                              stats = {
                                  ...stats,
                                  max_kph: Math.round(Math.max(...velocityData) * 3.6 * 10) / 10,
                                  avg_kph: Math.round(velocityData.reduce((a, b) => a + b, 0) / velocityData.length * 3.6 * 10) / 10
                              };
                          }
                          break;
                  }
  
                  streamStats[stream.type] = stats;
              });
  
              // Summary-only mode: return metadata and statistics without raw data
              // This runs BEFORE downsampling so stats reflect the full activity
              if (summary_only) {
                  const jsonArgs: [any, any, any] = format === 'compact'
                      ? [null, undefined, undefined]
                      : [null, null, 2];
                  return {
                      content: [{
                          type: 'text' as const,
                          text: JSON.stringify({
                              metadata: {
                                  available_types: streams.map(s => s.type),
                                  total_points: totalPoints,
                                  resolution: referenceStream.resolution,
                                  series_type: referenceStream.series_type
                              },
                              statistics: streamStats
                          }, jsonArgs[1], jsonArgs[2])
                      }]
                  };
              }
  
              // Apply downsampling if max_points is specified
              if (max_points && totalPoints > max_points) {
                  originalPoints = totalPoints;
                  streams = streams.map(stream => ({
                      ...stream,
                      data: downsampleStream(stream, max_points)
                  }));
                  referenceStream = streams[0]!;
                  totalPoints = referenceStream.data.length;
                  wasDownsampled = true;
              }
  
              // Special case: return all data in multiple messages if points_per_page is -1
              if (points_per_page === -1) {
                  // Calculate optimal chunk size based on format
                  const CHUNK_SIZE = calculateOptimalChunkSize(totalPoints, streams.length, format);
                  const numChunks = Math.ceil(totalPoints / CHUNK_SIZE);
  
                  // Return array of messages
                  return {
                      content: [
                          // First message with metadata
                          {
                              type: 'text' as const,
                              text: `📊 Activity Stream Data (${totalPoints} points)\n` +
                                    `Will be sent in ${numChunks + 1} messages:\n` +
                                    `1. Metadata and Statistics\n` +
                                    `2-${numChunks + 1}. Stream Data (${CHUNK_SIZE} points per message)\n\n` +
                                    `Message 1/${numChunks + 1}:\n` +
                                    JSON.stringify({
                                        metadata: {
                                            available_types: streams.map(s => s.type),
                                            total_points: totalPoints,
                                            total_chunks: numChunks,
                                            chunk_size: CHUNK_SIZE,
                                            resolution: referenceStream.resolution,
                                            series_type: referenceStream.series_type,
                                            format,
                                            units: {
                                                time: 'seconds',
                                                distance: 'meters',
                                                altitude: 'meters',
                                                velocity_smooth: 'meters_per_second',
                                                heartrate: 'beats_per_minute',
                                                cadence: 'revolutions_per_minute',
                                                watts: 'watts',
                                                temp: 'celsius',
                                                grade_smooth: 'percent',
                                                latlng: '[latitude, longitude]',
                                                moving: 'boolean'
                                            },
                                            stream_descriptions: {
                                                time: 'Time elapsed from activity start',
                                                distance: 'Cumulative distance from start',
                                                altitude: 'Elevation above sea level',
                                                velocity_smooth: 'Smoothed speed',
                                                heartrate: 'Heart rate',
                                                cadence: 'Pedal/step cadence',
                                                watts: 'Power output',
                                                temp: 'Temperature',
                                                grade_smooth: 'Road grade percentage',
                                                latlng: 'GPS coordinates [latitude, longitude]',
                                                moving: 'Whether athlete was moving'
                                            },
                                            ...(wasDownsampled && { downsampled: true, original_points: originalPoints })
                                        },
                                        statistics: streamStats
                                    }, format === 'compact' ? undefined : null, format === 'compact' ? undefined : 2)
                          },
                          // Data messages
                          ...Array.from({ length: numChunks }, (_, i) => {
                              const chunkStart = i * CHUNK_SIZE;
                              const chunkEnd = Math.min(chunkStart + CHUNK_SIZE, totalPoints);
                              const streamData: Record<string, any> = { data: {} };
  
                              // Process each stream for this chunk
                              streams.forEach(stream => {
                                  const chunkData = stream.data.slice(chunkStart, chunkEnd);
                                  const processedData = format === 'compact' 
                                      ? formatStreamDataCompact(stream, chunkData)
                                      : formatStreamDataVerbose(stream, chunkData);
                                  streamData.data[stream.type] = processedData;
                              });
  
                              return {
                                  type: 'text' as const,
                                  text: `Message ${i + 2}/${numChunks + 1} (points ${chunkStart + 1}-${chunkEnd}):\n` +
                                        JSON.stringify(streamData, format === 'compact' ? undefined : null, format === 'compact' ? undefined : 2)
                              };
                          })
                      ]
                  };
              }
  
              // Regular paginated response
              const totalPages = Math.ceil(totalPoints / points_per_page);
  
              // Validate page number
              if (page < 1 || page > totalPages) {
                  return {
                      content: [{ 
                          type: 'text' as const, 
                          text: `❌ Invalid page number. Please specify a page between 1 and ${totalPages}`
                      }],
                      isError: true
                  };
              }
  
              // Calculate slice indices for pagination
              const startIdx = (page - 1) * points_per_page;
              const endIdx = Math.min(startIdx + points_per_page, totalPoints);
  
              // Process paginated stream data
              const streamData: Record<string, any> = {
                  metadata: {
                      available_types: streams.map(s => s.type),
                      total_points: totalPoints,
                      current_page: page,
                      total_pages: totalPages,
                      points_per_page,
                      points_in_page: endIdx - startIdx,
                      format,
                      units: {
                          time: 'seconds',
                          distance: 'meters',
                          altitude: 'meters',
                          velocity_smooth: 'meters_per_second',
                          heartrate: 'beats_per_minute',
                          cadence: 'revolutions_per_minute',
                          watts: 'watts',
                          temp: 'celsius',
                          grade_smooth: 'percent',
                          latlng: '[latitude, longitude]',
                          moving: 'boolean'
                      },
                      stream_descriptions: {
                          time: 'Time elapsed from activity start',
                          distance: 'Cumulative distance from start',
                          altitude: 'Elevation above sea level',
                          velocity_smooth: 'Smoothed speed',
                          heartrate: 'Heart rate',
                          cadence: 'Pedal/step cadence',
                          watts: 'Power output',
                          temp: 'Temperature',
                          grade_smooth: 'Road grade percentage',
                          latlng: 'GPS coordinates [latitude, longitude]',
                          moving: 'Whether athlete was moving'
                      },
                      ...(wasDownsampled && { downsampled: true, original_points: originalPoints })
                  },
                  statistics: streamStats,
                  data: {}
              };
  
              // Process each stream with pagination
              streams.forEach(stream => {
                  const paginatedData = stream.data.slice(startIdx, endIdx);
                  const processedData = format === 'compact' 
                      ? formatStreamDataCompact(stream, paginatedData)
                      : formatStreamDataVerbose(stream, paginatedData);
                  streamData.data[stream.type] = processedData;
              });
  
              return {
                  content: [{ 
                      type: 'text' as const, 
                      text: JSON.stringify(streamData, format === 'compact' ? undefined : null, format === 'compact' ? undefined : 2)
                  }]
              };
          } catch (error: any) {
              const statusCode = error.response?.status;
              const errorMessage = error.response?.data?.message || error.message;
              
              let userFriendlyError = `❌ Failed to fetch activity streams (${statusCode}): ${errorMessage}\n\n`;
              userFriendlyError += 'This could be because:\n';
              userFriendlyError += '1. The activity ID is invalid\n';
              userFriendlyError += '2. You don\'t have permission to view this activity\n';
              userFriendlyError += '3. The requested stream types are not available\n';
              userFriendlyError += '4. The activity is too old and the streams have been archived';
              
              return {
                  content: [{
                      type: 'text' as const,
                      text: userFriendlyError
                  }],
                  isError: true
              };
          }
      }
  };

• src/tools/getActivityStreams.ts:14-78 (schema)

  Input schema definition for the get-activity-streams tool.

  export const inputSchema = z.object({
      id: z.number().or(z.string()).describe(
          'The Strava activity identifier to fetch streams for. This can be obtained from activity URLs or the get-activities tool.'
      ),
      types: z.array(z.enum(STREAM_TYPES))
          .default(['time', 'distance', 'heartrate', 'cadence', 'watts'])
          .describe(
              'Array of stream types to fetch. Available types:\n' +
              '- time: Time in seconds from start\n' +
              '- distance: Distance in meters from start\n' +
              '- latlng: Array of [latitude, longitude] pairs\n' +
              '- altitude: Elevation in meters\n' +
              '- velocity_smooth: Smoothed speed in meters/second\n' +
              '- heartrate: Heart rate in beats per minute\n' +
              '- cadence: Cadence in revolutions per minute\n' +
              '- watts: Power output in watts\n' +
              '- temp: Temperature in Celsius\n' +
              '- moving: Boolean indicating if moving\n' +
              '- grade_smooth: Road grade as percentage'
          ),
      resolution: z.enum(RESOLUTION_TYPES).optional()
          .describe(
              'Data resolution. Affects number of data points returned:\n' +
              '- low: ~100 points (recommended for LLM analysis)\n' +
              '- medium: ~1000 points\n' +
              '- high: ~10000 points (warning: very large payload, may cause slowness)\n' +
              'Defaults to "low" when omitted. Pass explicitly if you need more data.'
          ),
      series_type: z.enum(['time', 'distance']).optional()
          .default('distance')
          .describe(
              'Optional base series type for the streams:\n' +
              '- time: Data points are indexed by time (seconds from start)\n' +
              '- distance: Data points are indexed by distance (meters from start)\n' +
              'Useful for comparing different activities or analyzing specific segments.'
          ),
      page: z.number().optional().default(1)
          .describe(
              'Optional page number for paginated results. Use with points_per_page to retrieve specific data ranges.\n' +
              'Example: page=2 with points_per_page=100 gets points 101-200.'
          ),
      points_per_page: z.number().optional().default(100)
          .describe(
              'Optional number of data points per page. Special values:\n' +
              '- Positive number: Returns that many points per page\n' +
              '- -1: Returns ALL data points split into multiple messages (~1000 points each)\n' +
              'Use -1 when you need the complete activity data for analysis.'
          ),
      format: z.enum(['compact', 'verbose']).optional().default('compact')
          .describe(
              'Output format:\n' +
              '- compact: Raw arrays, minified JSON (~70-80% smaller, LLM-friendly)\n' +
              '- verbose: Human-readable objects with formatted values (backward compatible)'
          ),
      max_points: z.number().optional()
          .describe(
              'Maximum number of data points to return. If activity exceeds this, data will be intelligently downsampled ' +
              'while preserving peaks and valleys. Useful for very large activities.'
          ),
      summary_only: z.boolean().optional().default(false)
          .describe(
              'If true, returns only metadata and statistics (min/max/avg) without raw stream data. ' +
              'Much faster and smaller response. Ideal for quick activity overviews or when raw data is not needed.'
          )
  });