Get an Anthropic API key — Documentation

ShellYard’s Magellan AI requires your own API key when you select the Anthropic provider. Keys are minted in the Anthropic Console — separate from the consumer Claude.ai login, even if you already use Claude.ai for chat.

Steps

Create an Anthropic Console account. Go to console.anthropic.com and sign up with email or Google. If you already use Claude.ai, the Console is a separate sign-up — API access lives there, not in the chat app.
Add a payment method. API usage is pay-as-you-go. Navigate to Settings → Billing → Payment methods, add a card, and either purchase credits or enable auto-recharge. Keys won’t successfully call the API until billing is set up.
Mint an API key. Open Settings → API Keys → Create Key. Name it something you’ll recognize later — e.g. shellyard-laptop or shellyard-work-mac. The key is shown once; copy it immediately. Anthropic does not let you view it again afterward.
Paste it into ShellYard. Open Settings → Magellan → Provider: Anthropic → API key and paste. ShellYard fires a small test request to confirm the key works, then stores it (see BYO key for storage details by tier).

Key format

Anthropic keys start with sk-ant-api03- followed by ~95 characters. If yours doesn’t start with that prefix, you’ve probably copied the wrong value from the dashboard.

Picking a model

ShellYard exposes a smart model + fast model pair under the provider settings — Magellan routes per stage (e.g. the Explain stage uses the fast model, the Draft stage uses the smart model). Typical pairings:

Tier	Smart model	Fast model
Best quality	Claude Opus	Claude Sonnet
Balanced (default)	Claude Sonnet	Claude Haiku
Lowest cost	Claude Haiku	Claude Haiku

The exact model identifiers update over time. See docs.anthropic.com/en/docs/about-claude/models for the current list.

Pricing

Anthropic prices per-token, separating input and output rates. The current rate card is at anthropic.com/pricing. Magellan’s five-stage flow attaches scoped context per turn rather than full transcripts, which keeps spend modest — most infrastructure-engineering workflows land under $10/month on typical use.

You can set a monthly hard cap in Settings → Billing → Limits to avoid surprises.

Rotating

If a key leaks, return to Settings → API Keys, revoke the compromised key, mint a new one, and overwrite the value in ShellYard. The revoked key stops working within seconds — no need to coordinate.

Troubleshooting

“401 Unauthorized” on first use — usually means the key was copied with a trailing space or the billing setup hasn’t propagated yet. Try minting a fresh key after confirming credits are loaded.
“529 Overloaded” — Anthropic’s API is rate-limited globally during peak hours. Retry in a few seconds; Magellan retries automatically with backoff.
Key works in curl but not in ShellYard — check Settings → Magellan → Provider is set to Anthropic, not OpenAI-compatible (which expects a different base URL).