- The vendor decides which tools exist and how they connect
- Every workflow bends to the product's shape
- Usage is a bill, not a record you can audit
- Switching providers means starting over
Rent the model.
Own the loop.
Most companies run AI through someone else's product: a chat window, an agent tool, a rented runtime that decides what their AI can touch. FCT builds the harness itself around your business. The loop that drives the model, the tools it reaches, the gates it stops at, and the record it leaves. You own the code.
The model is worth renting. The harness isn't.
The best models improve every few months, so renting them is the right call. The harness around the model is where your workflows, integrations, rules and records live. That layer shouldn't belong to a vendor.
- The tool layer is built around your actual systems
- Your workflows are the spec the runtime is built to
- Every run is measured: tokens, cost, actions, approvals
- Models are swappable parts: switching is a config change
Six parts, each one yours.
Every capability ships paired with its control boundary: what the agents can touch, what waits for a human, and what gets recorded.
The loop
The runtime itself: how the model is driven, how work is ordered, how a session picks up where it left off. Yours, in your repos.
The tool layer
Your CRM, databases, files, and internal APIs wired in as tools the agents can call, with explicit scopes per agent.
The approval gate
Consequential actions stop and wait for a human. Enforced in the runtime's code, where an agent can't talk its way around it.
Parallel agents
Fan work out across agents that share one cached context, so the second agent doesn't pay to re-read what the first one read.
Memory
Durable, searchable records of what was done and decided, owned as files and data you keep, not a thread in someone's cloud.
The ledger
A record of every run: tokens, cache savings, tool calls, approvals. What your AI does and costs, measured instead of guessed.
Designed around your work, so the economics follow.
An off-the-shelf harness gives every customer the same economics. An owned one is shaped to how your work actually runs. On our harness, when work fans out across parallel agents, every agent reads the same cached foundation and only its own task is new. That is a design decision in the runtime, made because we knew exactly how our work runs.
The numbers on this page aren't the product. They're what happens when the runtime is designed for your work instead of everyone's.
We run our whole company on the harness we built.
FCT's own operations, research, automations and engineering run on an AI harness FCT built for itself. Its per-run record is where these numbers come from.
Measured on FCT's harness over 67 active days, June 25 to September 2, 2026, from its own per-run record. Hit rate is cache reads over all input-side tokens. Savings price the same cache reads at each model's published fresh-input rate. Daily rates over the last ten of those days ran 99.0% to 99.4%.
Direction before spend.
Pricing is scoped at the audit, because the honest number depends on how many systems the harness touches. You hold the model-provider accounts and pay them directly.
- 01
Discovery audit
Map your current AI usage, spend, and integration points. Where an owned harness pays, and where it doesn't.
- 02
Architecture
The loop, the tool layer, the gates, and the telemetry, designed around your workflows and reviewed with your team.
- 03
First milestone
One real workflow running end to end on your own harness. Small enough to ship, real enough to judge.
- 04
Expand and hand off
More tools, more workflows, more agents, each verified against real work. The code and runbook live in your repos throughout.
Custom AI harness, answered
01 What is a custom AI harness?
A custom AI harness is your own AI runtime. It is the software loop that drives the model, the tool layer that connects it to your real systems, the approval gates that decide what waits for a person, and the record of what every run did and cost. Most companies rent this layer without noticing. It comes bundled inside a chat product or an off-the-shelf agent tool, and the vendor decides which tools exist, how data flows, and what a workflow can look like. FCT builds the harness around your business and hands you the code. The model stays rented, because the best models improve every few months and you want to swap them freely. Everything around the model becomes yours: your workflows, your integrations, your rules, and your operating record. FCT builds on the same architecture it runs its own company on, measured at a 98.9% lifetime cache hit rate across 67 active days as of September 2, 2026.
02 How is this different from the AI Integration & Automation service?
AI Integration & Automation sets up targeted automations inside the workflows you already run: a speed-to-lead desk, missed-call text-back, intake, reminders. Each one is a bounded product with guardrails, and for most businesses it is the right starting point. A custom AI harness is the layer underneath, the runtime those automations, agents and assistants all run on. It fits a company whose AI has outgrown one-off automations, where several agents touch real systems, actions need gating and auditing enforced in code, and the cost of running AI at volume starts to matter. A practical rule: if you want one leak fixed, start with AI Integration & Automation. If AI is becoming operating infrastructure for your company and you want to own that infrastructure, that is the harness. The two fit together. Automations built by FCT can run on a harness FCT built for you.
03 What does owning the harness mean concretely?
It means the agent runtime is code in your repositories, not a subscription in a vendor's cloud. You own the loop that drives the model. You own the tool definitions that connect it to your CRM, databases, files and internal APIs. You own the approval-gate rules that decide which actions wait for a person, the per-run cost record, and the documentation and runbook for operating all of it. The model providers are wired in as swappable parts. Switching or adding a provider is a configuration change, not a migration, so no vendor is load-bearing. Your data flows through paths you can read, your logs are yours, and when a better model ships, your harness picks it up without your workflows changing. FCT delivers into your repositories from the first milestone, trains the team that will run it, and can stay on retainer for new tools, new workflows and model transitions. Nothing about the system requires FCT to keep running it.
04 Can the agents act on their own, and how is that controlled?
Control is built into the code, not requested in a prompt. The harness classifies what an agent is about to do. Anything consequential, such as an action that leaves your systems, touches money or reaches a customer, stops at an approval gate and waits for a named person to approve it. That rule lives in the runtime itself, so an agent cannot talk its way around it. Below the gate, every tool call is logged with its inputs, its outcome and its cost, so you can audit what ran and why. Scopes are explicit: each agent reaches only the tools and systems it was granted, and parallel agents run in separate workspaces so they cannot overwrite each other's work. This is the same discipline FCT runs on itself: its own harness has a human-approval gate on consequential actions and a per-run record of every session. Autonomy is then a dial you turn deliberately, workflow by workflow, as trust is earned, rather than a default you inherit from a product.
05 How does an engagement start, and what does it cost?
It starts with a discovery audit. FCT maps your current AI usage, spend, integration points and the workflows that matter, and reports where an owned harness pays and where it does not. From there the build is scoped in milestones. The first milestone is deliberately small and real: one workflow running end to end on your own harness, in your repositories, with the tool layer, the approval gate and the cost record live, so you judge the architecture on working software rather than a proposal. Each later milestone adds tools, workflows or agents, and each is verified against your real work before the next is scoped. Pricing is scoped per engagement at the audit, because the honest number depends on how many systems the harness touches and how much of your work it should carry. FCT does not publish a one-size price for infrastructure. You hold the model-provider accounts and pay them directly, so FCT is never between you and your AI bill.
If AI is becoming your infrastructure, own it.
Bring how your team uses AI today. The audit maps where an owned harness pays, and the first milestone proves it on one real workflow. Want the owned brain to run on it? That's Second Brain OS.
