Your training data
stays yours.
Last updated: July 22, 2026
IntervalSync connects an athlete’s Intervals.icu training account to an AI assistant chosen by the athlete through an OAuth-protected MCP server. It can work with ChatGPT, Claude, Grok, and other assistants that support a custom remote MCP connection. We use Intervals.icu access only to provide the connection and actions that the athlete authorizes.
What we store
We store account metadata, an encrypted Intervals.icu credential, public OAuth client registration metadata, hashes of short-lived OAuth authorization codes and access and refresh tokens, plan status, and a minimal interaction history containing the MCP tool name, a safe summary, outcome, and time. If your assistant sends feedback on your behalf, we store that message and our reply for one year; you can read exactly what was sent in your IntervalSync portal. Interaction records are deleted automatically 180 days after they are written, and expired sign-in sessions, OAuth authorization codes, and access and refresh token hashes are deleted once they lapse. We do not retain returned training data, raw chat content, plaintext Intervals credentials, plaintext OAuth tokens, workout instructions, wellness values, or any response data sent to a connected AI assistant. When an account is created from a link carrying campaign tags, or from another site, we record how it arrived — the campaign tags themselves, and the referring site’s host name but never the full referring address. This is written once, when the account is created, and is never updated afterwards; it tells us which channels bring athletes to IntervalSync and nothing about what you do here. It does not depend on the analytics choice below, and it is deleted with your account.
How data is used
IntervalSync uses the credential solely to request the Intervals.icu data required by MCP tools an athlete invokes. Depending on the request, those tools can return athlete profile and sport-setting data; completed-activity summaries, intervals, and selected sensor streams; planned workouts; and wellness records. This information is returned to the connected AI-assistant conversation that invoked it; IntervalSync does not retain those returned records. We do not sell training data.
Analytics
With your consent, IntervalSync uses Google Analytics 4 to understand general site use and product flow, such as page visits, prompt copies, account connection, and checkout starts. We do not send training data, account emails, Intervals.icu credentials, OAuth tokens, AI messages, connection identifiers, or support-message contents to Google. Analytics is optional and not required to use IntervalSync. You can change your choice at any time.
Calendar subscriptions
When an athlete chooses to subscribe to their training calendar, IntervalSync provides an opaque, private iCalendar feed URL for that training connection. A calendar app that has this URL can request the connection’s planned-calendar events, so athletes should treat it like a password and should not share it. We retrieve the events from Intervals.icu when the calendar app refreshes the feed and do not retain a copy. After the Free trial, a fresh calendar-feed refresh uses the calendar feed’s own one-pull-per-UTC-day allowance, separate from the allowance of each data tool. Disconnecting the associated training connection disables its calendar feed.
Read and write access policy
Every new Free account receives 30 days of full access: unlimited supported reads — including activity detail, interval execution, available power/heart-rate/cadence streams, planned workouts, wellness, and sport settings — and the currently supported, confirmation-gated write tools. After that trial, Free permits one Intervals.icu data pull per tool per UTC day and becomes read-only. An active Pro subscription retains unlimited reads and the same supported writes: create or update a planned workout on the athlete’s Intervals.icu calendar, delete one planned workout from that calendar, and update selected wellness fields. Deleting a planned workout cannot be undone; the workout is returned in the tool response as it is removed so it can be recreated. The tool request must include an explicit confirmation after the athlete has reviewed the exact change. Every attempted write is recorded in the connection’s activity history without recording the workout instructions or wellness values.
For a new account, Intervals.icu OAuth requests the supported write permissions so the athlete can use the full 30-day access period. After that trial, a Free athlete who reconnects is asked only for the read permissions needed by the read-only plan. An active Pro subscription retains full access across activities, wellness, calendar, chats, workout library, and athlete settings; each write permission also includes read access. The current MCP tool set does not yet upload completed activity files, modify chats or the workout library, delete completed Intervals.icu activities, or change account settings; it can delete a planned calendar workout, and no other calendar category; broader tools will be disclosed here before they are introduced. No write is made without a tool invocation from a connected AI assistant.
Third parties and billing
Intervals.icu processes the authenticated training requests. The AI assistant selected by the athlete processes tool requests and responses under that athlete’s relationship with its provider. Stripe processes subscription checkout and billing; IntervalSync does not receive card numbers. Google processes analytics only when an athlete or visitor consents as described above. Use of the Intervals.icu API is also subject to Intervals.icu’s API terms. If a future IntervalSync product surface displays Garmin-sourced activity data, it will provide the applicable Garmin attribution.
Security and deletion
Intervals credentials are encrypted before storage. Athletes can disconnect a training connection or delete their IntervalSync account in Settings. Account deletion removes the IntervalSync account, credentials, OAuth authorization data and token hashes, interaction history, sessions, and free-tier usage records. It does not delete, alter, or close the athlete’s Intervals.icu account or its activities. Stripe may retain payment records as required for billing and legal obligations.
Contact
For privacy questions or requests, contact the IntervalSync service operator through the support contact published with the product.