Bring your own Anthropic API key
Route agent LLM traffic through your own Anthropic account so token spend lands on your key, with your rate limits and commitments.
By default, agents call Claude through Ellipsis-managed keys and token spend appears on your Ellipsis bill. With your own Anthropic API key connected, every agent model call bills your Anthropic account instead: your usage tier, your rate limits, and any credits or commitments you have with Anthropic. This is an account-level setting; it applies to all agents and requires no YAML changes.
Add and verify your key
- Open Models in the dashboard and find Bring your own Anthropic API key.
- Click Add key, paste a key from the Anthropic Console, and click Save & verify.
- Verification makes one minimal Messages call on your key against
claude-opus-4-8. Agents run on Claude models, so the key's organization needs access to them. On success the card shows Enabled and routing is live for new sessions.
A saved key never routes until it verifies. Verify re-runs the check at any time; if Anthropic rejects the key (revoked, out of quota, missing model access), routing is disabled rather than left to fail mid-session.
How routing works
Your key is stored write-only: no API response or dashboard surface ever returns it (the card shows the last 4 characters), and it never enters a sandbox. Sandboxes keep the same scoped, revocable proxy credential they always have; a real Anthropic key never enters the sandbox. On each model call, the Ellipsis proxy forwards the request to the Anthropic API with your key, server-side.
Two behaviors follow from that design:
- No silent fallback. If your key is removed or disabled while a session is running, its model calls fail with an error naming the cause. Traffic never quietly moves back to an Ellipsis key.
- Your limits apply. Requests count against your Anthropic organization's rate limits. The proxy retries throttled calls with backoff, but a sustained limit stalls your agents; size your tier to your agent traffic.
Ellipsis caches model responses per account. A cache hit is served without calling Anthropic, so repeated identical calls (replays, retries) cost nothing on your key.
What changes on your bill
The token line of your Ellipsis bill drops to zero; Anthropic bills you for tokens directly. Sandbox compute and the platform fee are unchanged, and the fee is computed on actual usage (tokens plus compute) whether or not the tokens run on your key. Session cost breakdowns in the dashboard still show real token spend, so budgets and spend limits keep working: a session that reaches its budget stops, even though the tokens are billed to your Anthropic account.
Rotate or remove the key
To rotate, click Replace key, paste the new key, and Save & verify. New sessions use the new key immediately; a session already running may complete its current work on the previous key.
To disconnect, click Remove. New sessions return to Ellipsis-managed keys and token spend returns to your Ellipsis bill. Sessions started before the removal fail on their next model call rather than silently switching keys; start them again after removing.