Compare
Carbon Forge and Anthropic's Scion
On October 13, 2026 Anthropic described Scion, the source control it built for its own agents. Scion is in-house, and Anthropic says it would be difficult to offer in a form broadly useful to others. Carbon Forge holds the same principles, and you can sign in to it today.
Carbon Forge and AEGIS, one platform, row by row. Every row cites a public page.
What Anthropic has said about Scion and its related properties
Each fact below is from Anthropic’s own article. Where the article gives no detail, neither does this page.
- Scion
- The in-house version control system; Anthropic migrated its monorepo to it in five months.
- Anthropic
- scn
- The Scion client, which asks for the trees and blobs it wants rather than negotiating what it has.
- Anthropic
- scion-daemon, scion-cache, scion-server
- The node daemon, the regional cache tier and the authoritative servers; each cache tier reports a hit rate over 99%.
- Anthropic
- Code search and source control IAM
- Named in the article as shipped in the same period; no further detail is public.
- Anthropic
Side by side
| Topic | Carbon Forge + AEGIS | Anthropic Scion |
|---|---|---|
| Availability | Carbon Forge + AEGISCarbon Forge is a hosted product; public workspaces are free and private ones are a paid plan. Carbon Forge docs | Anthropic ScionScion is in-house. Anthropic says it is "by no means a suitable replacement for git for general use" and difficult to offer in a broadly useful form. Anthropic |
| Clients are always online | Carbon Forge + AEGISEvery read and write is a call to the server; there is no clone and no local commit. Carbon Forge docs | Anthropic ScionScion's client and protocols are designed around a server that is always reachable. Anthropic |
| The unit of work | Carbon Forge + AEGISA changeset lands one or more revisions with an intent, all or nothing, sealed into a hash chain. Carbon Forge docs | Anthropic ScionA changeset is an entry in a write-ahead log, created server-side. Anthropic |
| Derived data | Carbon Forge + AEGISThe file tree, blame, the syntax index, cut notes and the git archive are derived from the record and never treated as the source. Carbon Forge docs | Anthropic ScionBlame, path history and commit-graph skip lists are derived data computed from changesets. Anthropic |
| Commits | Carbon Forge + AEGISA changeset locks the entities it writes and nothing else, with no workspace-wide lock and no merge queue. Carbon Forge docs | Anthropic ScionCommits must be cheap, incremental and lock-free; Scion accepts changesets with no locking. Anthropic |
| Merging | Carbon Forge + AEGISCarbon never merges text by itself: a patch that no longer applies is a named conflict, answered by a resolution bound to the trunk it saw. Carbon Forge docs | Anthropic ScionScion merges on the server and relies on post-merge and pre-deploy testing, so concurrent changes can conflict. Anthropic |
| Review | Carbon Forge + AEGISCarbon ships the gate and the approvals: a protected trunk, landing rules and approvals bound to a lane's exact state. Carbon Forge docs | Anthropic ScionAnthropic built its own code review surface, Antique, alongside Scion. Anthropic |
| Git | Carbon Forge + AEGISCarbon keeps git as a projection: every code tree renders to git and pushes to GitHub, always fast-forward. Carbon Forge docs | Anthropic ScionAnthropic migrated its monorepo from git to Scion. Anthropic |
| Scale | Carbon Forge + AEGISEvery workspace has its own trunk, and a changeset locks the entities it writes and nothing else, so landings in different places never wait on each other. Carbon Forge docs | Anthropic ScionMerges grew from about 2,500 a day in May 2026 to over 30,000 a day in September. Anthropic |
| Access control | Carbon Forge + AEGISRoles and token presets scope every caller; an execution token confines one agent run to one lane and one tree path, and a code tree can be private inside its workspace. Carbon SCM specificationCarbon Forge docs | Anthropic ScionScion supports access control down to individual directories. Anthropic |
Try it on your own work.
Sources, all read on 2026-10-22: Anthropic, “Redesigning source control at Anthropic” · Carbon Forge docs, “Billing and plans” · Carbon Forge docs, “Source control on the substrate” · Carbon SCM specification, “8. Identity, tokens and reach” · Carbon Forge docs, “MCP token scopes”