Bug Report: An assistant using the Strava MCP connector underestimated a user's training history

Components: Strava MCP connector (list_activities), Claude (claude-sonnet-5)
Date observed: 2026-09-18
Severity: Moderate. The user got a wrong assessment of their fitness history, stated with confidence.
Status: Reported for discussion. This report doesn't claim a root cause.

User intent

The user asked for a marathon training plan based on their actual training
history. They are a former ultramarathon runner returning to training, and
wanted a plan that accounted for their long-term base rather than only their
recent weeks.

What happened

1. The assistant retrieved activities since 2026-06-01. It found a longest
   recent run of about 5 miles and advised against a 10-week marathon build.
2. The user asked: "But you see my historical base?"
3. The assistant retrieved the 100 most recent activities, back to 2023-06-16.
   The response included has_next_page: true. The assistant reported:
   "Longest run ever logged: ~9.5 miles" and "he's never built
   marathon-distance mileage."
4. The user pasted race results from UltraSignup, including a 200-mile finish
   in 2017.
5. The assistant said those races predated the Strava account.
6. A later date-filtered query (2015–2018) returned the 2017 data from the same
   account, including an activity titled "Recovery Run from Bigfoot 200."

Expected behavior

When a user asks about their training history, the assistant either retrieves
all of it or states plainly how much it retrieved.

Friction observed

In the connector

• The tool description says nothing about how much of the history one call
  returns, or how to reach the rest.
• A call with no arguments returns the 30 most recent activities.
• Responses don't include a total activity count or the date of the oldest
  activity. The only sign that more data exists is has_next_page.
• There's no single tool for retrieving the full history.
• Strava's launch announcement promises access to users' "full training
  history." The help documentation says nothing about date ranges or
  pagination.

In the conversation

• The assistant didn't tell the user which date range each query covered.
• It stated conclusions about the user's whole history ("ever," "never") after
  retrieving only part of it.
• It gave a reason for the missing data (that the account didn't exist yet)
  without checking it.
• The pasted race results ran two fields together, so division place and
  finish time appeared as one string. The assistant read them without
  separating them and reported a 200-mile time of 46:20. The actual time was
  96:20:18.

Notes

• The connector's date filters and pagination worked correctly when used.
• Searching for similar public reports found none. The connector began rolling
  out the week of June 1, 2026.