WorkoutContext.fit - Free & open-source hosted Intervals MCP server

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1

Hi all — sharing a project I’ve been building on top of the Intervals.icu API, in case it’s useful to others here.

What it is: WorkoutContext is an MCP server — nothing more. It doesn’t have its own app, UI, or opinions about how you should train. It simply gives an MCP-capable AI assistant (Claude, today) authenticated access to your Intervals.icu account: reading your activities, wellness, sport settings, fitness numbers, and writing structured workouts, events, and NOTEs back to your calendar.

Why MCP-only matters: because there’s no coaching engine baked in, you drive the plan entirely through conversation. There’s no fixed methodology, no “our system says do 80/20,” no preset templates you have to bend to. You describe how you actually train — your periodization, your zones, your constraints, your Tuesday club run — and the assistant works within Intervals.icu to build and maintain exactly that. It adapts to you instead of the other way around:

  • Any discipline or mix — run, bike, swim, strength, triathlon, whatever.
  • Your own progression rules, recovery logic, and naming conventions.
  • Workouts written as Intervals’ DSL so they render on the chart and push to Garmin/Coros like any structured workout.
  • Plans stored as dated NOTEs on your calendar, so context carries between conversations rather than living in a separate app.

Because it’s a thin, faithful bridge to the API, it’s only as good as the API — which is why I’ve genuinely appreciated how capable and well-documented it is. (Optional extras: it can also pull in Hevy, Oura, and Withings if you connect them, but Intervals.icu is the spine.)

It’s free and open-source (github.com/agiantwhale/workoutcontext); you connect it with your Intervals.icu login at workoutcontext.fit. Auth is standard OAuth — you grant access, and can revoke it anytime.

Would love feedback from this community in particular, since you all push the API harder than most. Happy to answer questions about how it works under the hood.

2 Likes
2

Very interesting!
Finally, a way to connect strength training sessions recorded with Hevy to Intervals.icu.
I need to understand better. It only works with Claude at the moment, right?

3

Been dabbling with this, it’s very good. Appreciate that it’s a thin layer over the intervals.icu API

Would it be possible to add a few extra fields to the EventInputShape to allow (in my case) the color and not_on_fitness_chart to be set for events? I’ve been using an llm to pull data from various sources and insert them into my intervals calendar that might affect my ability to schedule training one way or another, and I color code them depending on a few things.

Edit: end_date_local would be handy too

4

Thanks for doing this!

I have connected Hevy and Intervals.icu and enabled the built-in Hevy → Intervals strength sync. Future workouts are covered, but is there a way to backfill existing Hevy workout history using the same WorkoutContext mapping, including kg_lifted, icu_rpe and icu_training_load? I already have matching Strava activities in Intervals, so ideally the backfill would update/merge rather than create duplicates.

5

Works so far with Perplexity Pro it seems! Amazing!