karta
// harnesses

Harnesses.

A harness is the agent runtime Karta runs your agent on. Declare one in your karta.toml; Karta resolves it to a ready runtime when you deploy.

[harness]
type = "claude-code"   # one of the ids below
version = "2"           # optional - a constraint or exact pin; omit for the default

Claude Code claude-code

default version 2.1.152 - the version an omitted constraint resolves to

Version Status Capabilities Auth
2.1.181 supported resume, approvals, file_upload, thinking api_key, oauth_subscription
2.1.152 supported resume, approvals, file_upload, thinking api_key, oauth_subscription

OpenCode opencode

default version 1.17.9 - the version an omitted constraint resolves to

Version Status Capabilities Auth
1.17.9 supported resume api_key

Machine-readable: /harnesses.json. The CLI uses it for fast pre-flight feedback; release acceptance is authoritative.