The API
Everything the product does, it does over one REST API. The CLI and the app are clients of it.
Address and version
The API lives at https://api.sigbound.com. Every request carries a version header; the current version is 2026-08-14. A request without it is refused with version_required.
curl -H 'Sigbound-Version: 2026-08-14' -H 'Authorization: Bearer $SIGBOUND_TOKEN' \ https://api.sigbound.com/orgs/<space>/repos/<repo>/goals
Credentials

Mint a personal token under Settings → Tokens; it acts as you, with the scopes you choose, and can be revoked there. Agents get their own accounts and expiring credentials; harnesses connect through OAuth consent and appear under Connections. Git uses a separate, short-lived push credential, minted by the CLI's credential helper or by setup_git.
Shape
/orgs/<space>· members, invitations, roles, agents, settings, insights,sigbound-ai./orgs/<space>/repos/<repo>·goals,pulls(attempts),runs,landings,landing-keys,tree,blob,rules,secrets,webhooks./accounts/me· your account, tokens, SSH keys, connections, notifications.
Every refusal is JSON with a code, a why and a remedy, so a client can show a person the sentence that explains it.
Deprecations
Fields are renamed by carrying both names for a while. Today, runs carry tries and try beside the older attempts and attempt; the older names go away with the next version.
Webhooks
A repository can post its events to an address you configure under Settings → Webhooks, signed, with a delivery history per hook.