The engine behind your agent.

Most fitness AIs are a model and a prompt. Fitly is a ten-layer orchestrator. Here is what happens beneath the chat bubble.

0
orchestration layers per turn
0+
structured tools
0
context queries in parallel
0
output guards on every reply

The model is the last thing we trust.

The naive AI app takes your message, glues on some profile data, sends it to a model, and renders the reply. It works for demos and collapses the moment a real person shows up with a real life, a shoulder injury, a hatred of quinoa, and a "make it harder" with no other context.

A model is a smart, expensive, occasionally-wrong text engine. Everything that makes Fitly feel like an agent instead of a chatbot is engineered around it.

Ten layers run on every message.

You type one sentence. Nine systems run before the model replies, and a tenth runs after.

1

Auth, validation & limits

Every request is verified, schema-checked, and rate-limited before a single token is spent. The layer that says no is what lets the rest feel generous.

2

Image classification

Photos are sorted into eight types (meal, label, barcode, scale, equipment, body, screenshot, other) so each one triggers the right pipeline instead of one fuzzy guess.

3

Parallel context assembly

Nine queries fan out at once: profile, macro targets, today's logs, recent workouts, active plans, history, workflow state, long-term memory, and streaks.

4

Workflow continuation

Detects whether "yes, the bigger one" is a fresh request or a reply mid-task, across nine multi-turn workflows, so the conversation just flows.

5

Dynamic prompt builder

The system prompt is assembled per turn from 20+ conditional blocks: personality, diet, targets, tools, refusal rules. Every irrelevant token is a tax on quality.

6

Dynamic tool scoping

50+ tools exist; the model only sees the few that fit this turn. Smaller tool lists mean faster, more accurate tool choices.

7

Multi-model routing

Cheap tasks run on a fast model; hard ones route to a stronger one, and a turn can escalate itself mid-flight. Thoughtful guidance at consumer prices.

8

Agentic tool loop

The model can call tools, read results, and call more, up to ten iterations, before it replies. One bubble can hide six tool calls. It checks its work.

9

Response guards

Three guards run before the reply ships: it really saved what it claimed, it can't write into future days, and it can't quietly drop a logged food.

10

Persistence & memory

After the reply, the turn is stored, memory candidates are extracted, streaks advance. The layer that makes the next conversation sharper than the last.

Want the full deep dive?

We wrote a long-form breakdown of all ten layers, what runs, why it runs, and what it costs to get right.

Read: The Orchestrator Inside Fitly →

An agent other agents can talk to.

Fitly isn't just an agent you talk to. It runs a Model Context Protocol (MCP) server, so any MCP-compatible agent can connect and use the same tools yours does, no app required. Available on Fitly AI Pro.

Your AI agents
ClaudeChatGPTGeminiCustom
→MCP
Fitly AI
your agent + 50+ tools
→
Your fitness data
read & write
Read your profile, goals, and history
Log meals, workouts, weight, and water
Check macros and today's progress
Pull up and activate your plans
Scoped, token-based access per agent
Streamable HTTP transport

And the platform around it.

Private by design

Health data is encrypted, served through pre-signed URLs, and every data change is written to an audit log. Your data is yours; we never sell it.

Built to scale

A stateless API, cursor-based pagination, Redis-cached context, and queue-backed processing on AWS, architected to serve millions from day one, not bolted on later.

Everyone has the same models.
The difference is what runs around them.

The orchestration around the model is the moat, and it is where we have spent our build cycles. That is why a sentence as ordinary as "I had a chicken bowl from Chipotle" can do as much real work as it does inside Fitly.

Download on the App Storeor open Fitly on the web →

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