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Provider · AI

Braintrust — Ashlr Stack Provider

Braintrust: LLM evals + observability + prompt playground. Verified against /v1/organization on paste. Wire it into your project with one command via Ashlr Stack.

AI · API key KEY-ONLY · v0.2 adds provisioning
Braintrust — LLM evals + observability + prompt playground. Verified against /v1/organization on paste.
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One command

Add Braintrust to any Ashlr Stack project with a single command. Stack runs the auth flow, verifies the credential, and writes every secret slot into Phantom. 

stack add braintrust

Or describe what you're building and let Claude pick it up via stack recommend: 

stack recommend "LLM provider for a coding assistant"

Auth flow

Paste a long-lived API key once. Stack verifies it against the provider's API before writing to Phantom.

How-to: Create a key at https://www.braintrust.dev/app/settings/api-keys.

Secret slots

stack add braintrust writes these 1 secret slot into your Phantom vault:

  • BRAINTRUST_API_KEY

The values never leave Phantom in plaintext. Your .env file references slot names, and stack exec -- <cmd> swaps them in at process-spawn time via Phantom's local proxy.

  • OpenAI — GPT, Realtime, embeddings. Key verified against /v1/models on paste.
  • Anthropic — Claude models + MCP. Key verified against the Messages API on paste.
  • xAI — Grok + tool use. Key verified on paste.
  • DeepSeek — Open-weight models. Key verified on paste.
  • Replicate — Open-source model inference with per-second billing. API token stored in Phantom.

FAQ

Do I need a Braintrust account to use it with Stack?

Yes — Stack provisions Braintrust on your behalf, but it authenticates as you. Paste a long-lived API key once. Stack verifies it against the provider's API before writing to Phantom. If you don't have a credential yet, create one at https://www.braintrust.dev/app and paste it once.

Where does Stack store my Braintrust credentials?

In Phantom Secrets, an E2E-encrypted local vault. Stack writes the secret slot names (BRAINTRUST_API_KEY) into .stack.toml — the actual values live only in Phantom and never touch disk in plaintext.

Can I rotate or revoke this integration later?

Yes. Run `stack remove braintrust` to pull the Braintrust service back out (Phantom secrets deleted, MCP entry removed, .stack.toml cleaned up). Rotate the underlying Braintrust credentials in their dashboard — https://www.braintrust.dev/app — and Stack's next `doctor --fix` will pick up the new values.

Outbound