Claude Code
Claude Code agents as the operator backend for hillclimb model searches.
Claude Code is the default operator backend for hillclimb searches: each search operator (draft, debug, improve, ensemble) is one headless Claude Code agent call that authors or repairs a candidate model in its own sandboxed workspace. The search engine evaluates what the agent wrote; the agent never sees holdout data or credentials.
What It Provides
| Capability | Behavior |
|---|---|
| Search operators | Every candidate in a hillclimb search is authored by a headless claude agent call. |
| Subscription billing | Hosted searches authenticate with a CLAUDE_CODE_OAUTH_TOKEN (minted via claude setup-token) so agent calls bill a Claude subscription. |
| API-key billing | Alternatively, an ANTHROPIC_API_KEY bills the Anthropic API directly. |
| Rate-limit parking | When the subscription hits a usage limit, the search parks instead of failing and can be resumed later. |
| Credential hygiene | Agent-authored code runs with credentials scrubbed from its environment; only the agent process itself sees the Claude credential. |
| Model selection | --model picks the agent model per search (e.g. sonnet). |
Local Searches
rebase hillclimb start --local uses your machine's Claude Code login — no
extra configuration beyond:
claude login
rebase hillclimb start emflow://gefcom2014:solar --budget 2h --localHosted Searches
Hosted searches run in a platform-managed job image with the claude CLI
preinstalled. The workspace's Claude credential is injected from Secret
Manager at job start:
| Credential | Billing | How |
|---|---|---|
CLAUDE_CODE_OAUTH_TOKEN | Claude subscription | claude setup-token, stored as the workspace's Claude secret. |
ANTHROPIC_API_KEY | Anthropic API | Stored as the workspace's Claude secret; used when no OAuth token is present. |
Note that subscription-billed hosted searches share the subscription's rate limits with interactive use — a busy day of chatting can park a hosted search until the limit window resets.
Server-Side Requirements
Operators configure the job image and secrets once per deployment; see the
platform operations guide (toolkit/HILLCLIMB.md).