How It Works

Pheidi Documentation

Every engine and feature behind your training plan, explained. How plans are generated, how they adapt to your life, and how to get them onto your watch and calendar.

Features

How It Works

How the Activity Log Works

How Pheidi records your training history: an append-only log of completed runs, milestones, streaks, and adaptations — the source of truth behind your feed and milestone toast.

How Age Adjustment Works

Tell Pheidi your age and it lengthens recovery between hard efforts and extends warm-ups — because recovery slows with age even when capability doesn't.

How Calendar Export Works

Sync your training plan to Google, Apple, or Outlook with a live iCal subscription — set per-day workout times, before/after buffers, and a separate work-calendar feed that blocks the time without showing your training.

How Experience Levels Work

Beginner, Intermediate, or Advanced — your experience level shapes your long-run share, base building, run-walk, and which workout types appear in your plan.

How Follow-Up Emails Work

How Pheidi's onboarding follow-up emails work — a day-3 check-in and a day-14 stalled-plan nudge, each sent at most once, straight from the founder's inbox.

How Intensity Distribution Works

How Pheidi tracks the share of your running spent in Easy, Threshold, and Hard zones over the last four weeks and nudges you out of the gray zone.

How Pheidi's Training Emails Work

Every email Pheidi can send, grouped into six categories you control independently — plus a single switch that stops all of them. Frequency caps, one-click unsubscribe, and no email you can't turn off.

How Onboarding Works

The six setup steps Pheidi uses to build your personalized training plan — race goal and units, experience, volume, pace mode, schedule, and generation.

How Pheidi Works

Every system, engine, and feature behind your Pheidi training plan, explained. Plan generation, load distribution, adaptation, exports, and pacing.

How the Pheidi Welcome Email Works

What lands in your inbox the moment you first sign up for Pheidi — a short note from the founder with a link to build your plan, when it's sent, and why there's no unsubscribe link.

How Plan Layers Work

How Pheidi modifies your training plan non-destructively through overlay layers, so every change (vacation, injury, swap) can be undone without losing the original.

How Pausing and Resuming a Plan Works

How to pause your Pheidi training plan when life gets in the way, what happens to your data, and how resuming switches the active plan.

How Plan Units Work

How Pheidi builds training plans natively in miles or kilometers, and how to regenerate your current plan in the other unit without losing your settings.

How Positive Coaching Works

Pheidi never shows you a grade, a score, or a red X. Missed runs get rescheduled, not penalized, and every log gets a positive message.

How the Readiness Check-In Works

How Pheidi's 1–5 readiness check-in lets you flag how you feel before today's workout, and the suggestion you get when you log a low score.

How Load Redistribution Works

What happens to the miles you remove from your plan, and how Pheidi safely reallocates load across future easy runs without breaching ACWR thresholds.

How Run-Walk Intervals Work

How Pheidi adds run-walk intervals to beginner Easy and Long Runs, the default ratios by phase, and how to customize them.

How Injury Management Works

How Pheidi adjusts your training plan when you report an injury: severity-based volume reductions, graduated return-to-running, and pain-based progression gates.

How Safety Guards Work

How Pheidi protects you from training load spikes and injury risk: ACWR monitoring, session spike limits, and weekly volume caps based on running research.

How Progression Works

How Pheidi increases your training volume safely: volume-aware increase rates, 3-up-1-down recovery weeks, and protection against rapid mileage spikes.

How Pacing Works

How Pheidi calculates your training paces: VDOT pace zones, Borg RPE descriptions, and heart rate alternatives for every workout type.

How Workout Logging Works

How Pheidi tracks your completed workouts: quick-complete, manual entry, post-workout feedback, and how logged data adapts future training.

How Running Workout Reminder Emails Work

How Pheidi sends a 5 AM email reminder of your scheduled run, how to opt in or out, and how the one-click unsubscribe works.

How Strava Activity Sync Works

How Pheidi imports your completed Strava runs and marks your plan's workouts done automatically — opt-in activity sync, automatic matching, and privacy.

How Taper Protection Works

Pheidi builds your taper as a progressive volume cut, and when a plan reshuffles, redistribution always skips taper weeks — so the miles you drop never get pushed back into your taper.

How Load Distribution Works

How Pheidi shapes weekly distance around your long run using a shape-based system that keeps the hierarchy of run lengths consistent across the week.

How Training Phases Work

The four training phases — Base, Build, Peak, Taper — what each one is for, how Pheidi allocates them, and the email you get when your plan crosses into a new one.

How Plan Generation Works

How Pheidi builds your personalized marathon training plan: periodization, phase splits, shape-based load distribution, taper math, and base building.

How Schedule Flexibility Works

How Pheidi adapts your training plan when life gets in the way: day blocking, workout swapping, and automatic reflow that preserves the overall training load.

How Vacation Scheduling Works

What happens to your training plan when you schedule time off: date-range blocking, load redistribution, and graduated return to normal volume.

How Volume Modes Work

Pick how many days a week you run — from three to seven, plus an Elite doubles mode. Each mode shapes how Pheidi distributes your training across the week.

How Watch Export Works <span style="font-size: 0.55em; font-weight: 700; text-transform: uppercase; letter-spacing: 0.05em; color: var(--pheidi-accent, #E37332); background: rgba(227, 115, 50, 0.1); padding: 0.15rem 0.5rem; border-radius: 50px; margin-left: 0.5rem; vertical-align: middle;">Beta</span>

Send structured workouts to your Garmin watch with pace targets and interval cues. Export FIT files from any Pheidi workout.

How Weather Pace Adjustment Works

How Pheidi slows your target paces on hot, humid days so your effort stays the same, using temperature and dew point from your local forecast.

For Developers & AI

Build on Pheidi

Agent Skills

Drop-in skill files that teach Claude and other tool-using LLMs how to fetch and interpret a Pheidi training plan correctly — every layer, no guesswork.

How the Plan API Works

A public, read-only JSON endpoint exposing the full training plan with every layer intact. Built for AI agents, integrations, and custom tooling.

Pheidi MCP Server

Connect Claude, ChatGPT, or any MCP client to your Pheidi account to read your plan and log workouts by chat. Streamable HTTP over OAuth 2.1 with PKCE.

Coming Soon

On the Roadmap

Heart Rate-Based Training

Where Pheidi is and where it is going with heart rate-based training. Polarized 3-zone model, wearable readiness, and adaptive intensity targeting.

Mobile App & Health Integration

A future native iOS and Android app that will sync your training with Apple Health and Google Fit, with offline plan access and live workout guidance.

Ready to See It on Your Own Plan?

Build a personalized training plan and watch every one of these features adapt to your life. 100% free. No paywall.