What external agents cost
What a coding agent costs depends on where it runs and which credential it uses. Harmony only charges for work it carries, and every charge shows in your Usage tab.
Who pays
| How the agent runs | Who bills you | Harmony fee | Counts against your usage limit |
|---|---|---|---|
| On your own computer, with its own login or key | The agent's provider, on your plan | No | No |
| On a Harmony computer, with your provider key | That provider | 10% of what the provider bills | No |
| On a Harmony computer, with your organization's key | That provider, on your organization's account | 10% of what the provider bills | No |
| On a Harmony computer, on Harmony's models (Uses Harmony credits) | Harmony | Included | Yes |
| A local model on your own computer | Nobody | No | No |
The fee is charged only on work that finished, never on work that failed or was cancelled. See Model provider keys and local models for which credential an agent uses.
Limits that can stop a turn
- Usage limits. On Harmony's models, a coding agent's turn counts against your five-hour and weekly limits like any other Harmony Agent work. When you reach one, the turn stops with a message, and extra usage applies if it's on. See Usage limits.
- A ceiling per turn. One turn on Harmony's models can only spend so much. When it reaches that, the agent stops with This turn reached the most one coding agent turn may spend on Harmony. Start a new turn, or switch to your own key.
- Budgets. Work on provider keys doesn't touch usage limits, but an admin's money budget for you or your team holds it. When a turn would go past it, the agent stops with This would take you past your … AI budget. Ask an admin to raise it. See Budgets and spend.
- A rate limit per computer. A computer that makes too many model calls in a minute is slowed, so one runaway agent can't starve the rest.
Where it shows up
- Profile → Usage: Harmony Agent usage shows your limit shares, including coding agent work on Harmony's models. Your AI spend lists money spent outside your plan this month, by key, for example Your Anthropic key, alongside AI subscriptions, Other AI tools and Extra usage.
- Spend: admins see coding agent spend by team and person. See Spend and models.
FAQs
Does Harmony see what my agent does on my own computer? It sees the steps and answer the agent reports in chat, not its model calls. Those go straight from your computer to the provider, so Harmony neither records nor charges them.
Why is there a fee on my own key? Calls from Harmony computers go through Harmony to reach the provider. The 10% covers carrying them; the provider bills you for the calls themselves.
Do local models cost anything? No. They run on your hardware and never count against limits.