Provider guide

Connect Anthropic to Stax.

Live API

Stax pulls dollar-denominated Claude costs and full token-level usage (including cache reads and cache writes) from Anthropic's Admin API. Workspace-level attribution, daily sync, read-only.

Auth

Admin API key

Starts with sk-ant-admin-

Setup time

~2 min

Console admin only

First sync

~5 min

+5 min data lag thereafter

Granularity

Workspace

No per-user attribution

Step 1

Generate the admin API key.

Click Create key, then select Admin key as the key type.
Name it Stax or similar so you can revoke it later if needed.
Copy the key. It starts with sk-ant-admin-.

Admin keys are different from regular API keys. A regular sk-ant-api- key can spend your money on Claude requests but cannot read billing. Admin keys are the opposite — read-only on billing and usage, no inference access. That's the right shape for Stax.

Step 2

Paste the key into Stax.

In Stax, go to /app → Providers → Anthropic → Connect. Paste the key into the field labeled Admin key and save.

Stax validates against /v1/organizations/cost_report before saving. The credential is then encrypted at rest with AES-256 before it touches the database.

Step 3

What you'll see after the first sync.

The initial backfill pulls cost data for the last 30 days. Anthropic's cost endpoint has a ~5 minute data lag — the dashboard will show "data through 5 minutes ago" rather than real-time. You'll see:

Daily spend in USD from /v1/organizations/cost_report.
Per-model breakdown (Claude Sonnet, Opus, Haiku) split by input tokens, output tokens, and cache.
Cache-read and cache-creation tokens broken out as separate line items so you can verify your prompt-caching strategy is actually saving money.
Per-workspace attribution if your account has multiple workspaces.

Anthropic does not expose per-user attribution at the API layer — workspace is the finest granularity available. If you need per-developer breakdowns, that's coming from Anthropic, not from Stax.

Common errors

401 invalid x-api-key

Wrong key type. A regular sk-ant-api- key won't work — you need an admin key (sk-ant-admin-). Regenerate on the keys page above and select Admin key.

missing anthropic-version

Stax sends this header automatically. If you see it during validation, something is wrong on our side — email [email protected].

Priority Tier mismatch

You're on Priority Tier (committed spend). Priority Tier usage is excluded from the cost endpoint and only shows in the message usage endpoint. Stax detects this and reconstructs dollars from tokens for those line items — they'll be labeled priority-reconstructed in the dashboard so you can verify against your invoice.

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