Every conversation with an AI agent costs tokens. Some of those tokens do real work. A lot of them don't: the preamble that repeats your request back to you, the file that gets read a second time even though it hasn't changed, the giant output that gets pasted into context and paid for again on the next turn.
HarnessUp exists to stop that second group. It's not another model and not another harness — it's a thin layer that runs on your machine and holds the agent back at exactly the moments where the spend is predictable and avoidable.
The problem: you pay for tokens you never wanted
On a fixed plan, wasted tokens mean your 5-hour window runs out on Wednesday. On an API bill, every wasted token becomes a line on the invoice. Either way, the waste is invisible while it's happening and only shows up later, as a limit you hit or a number you can't fully explain.
HarnessUp measures that waste first. Deep Scan reads the conversations already saved on your machine and shows, conversation by conversation, where the context actually went — input, cache reads and writes, and output. That measurement is free, needs no login, and never leaves your machine.
What HarnessUp actually is
HarnessUp uses the official Anthropic and OpenAI hooks, so it fits under Claude Code and Codex without intercepting the API, without a heavy MCP server, and without asking for your token or key. Install it and it integrates in the CLI, the desktop app, and the IDE extensions.
HarnessUp runs the officialclaudeandcodexwith your account, and never reads, stores, or passes on your token or your key.
Ten fronts, one layer
The tools are organized into ten fronts, so the whole thing stays easy to navigate:
- Metering — see where every token went.
- Savings — cut re-reads, giant outputs, and pricey models on light tasks.
- Control — caps, schedules, and rules the agent follows.
- Protection — undo a turn's damage in one click.
- Productivity — four terminals, a Kanban board, and one-click deploys.
The rest — monitoring, security, builders, customization, and utilities — round out the set. You can see the full catalog, one tool per entry, in the documentation.
Measure free before you subscribe
You don't have to take the numbers on faith. Install it, run the Deep Scan on your own history, and see your own waste and your own projected savings — calculated on your machine, on your own transcripts. Only when you want the tools to start acting (not just measuring) does a plan come in, and every paid tool can be undone with a click.
Try it free. Install with one line — no login, no email, no password. Measurement runs 100% locally and stays free forever.
Why local matters
HarnessUp is designed so nothing leaves your machine. The scans, the compression, the caps — they run where your code lives. That's a privacy choice, but it's also a performance one: a layer that sits between you and the agent has to be fast, and p95 under 50 ms means it never becomes the bottleneck.
Get started
If you live on Claude Code or Codex and want the same budget to go further, the first step is measurement. Install HarnessUp, run the Deep Scan, and see the number for yourself. Then decide how far you want the plan to go.