Slide contents

1. 1. Scion: Anthropic’s Git replacement for agentic development

   Anthropic's architecture, annotated commentary and integration guarantees

2. 2. Agents change infrastructure requirements

   Workload, Scion's design, evidence and transfer limits

3. 3. Change volume grew more than tenfold

   Anthropic's figures, May and September 2026

4. 4. Online clients change the autonomy tradeoff

   The server computes history; clients fetch required objects

5. 5. Many jobs need no working copy

   Diffs and history are available through APIs

6. 6. A changeset records changed files

   A change log with content-addressed storage

7. 7. Read structures evolve independently

   Blame, path history and the commit graph

8. 8. Shared pointers leave the write path

   Creating a changeset and moving a ref are separate operations

9. 9. Immutability simplifies shared caching

   Node, region and server expose matching object RPCs

10. 10. “Instantly” needs a precise contract

    Changeset acknowledgement, blob availability and index readiness

11. 11. Speedups refer to different operations

    Median Git and Scion times in the final chart

12. 12. The migration took five months

    Seven engineers, Scion, Antique and related systems

13. 13. Engineers uphold system constraints

    Change intent, architectural context and implementation checks

14. 14. Each component gains a persistent observer

    Superfans inspect telemetry and logs alongside conventional alerts

15. 15. Merge and release have separate checks

    Anthropic invests in post-merge and pre-deploy testing

16. 16. Checks apply to a specific artifact

    Main can move while the candidate stays immutable

17. 17. Stable bases allow early integration checks

    The agent's workspace and a separate integration check

18. 18. Conflicts extend beyond shared files

    Text, interfaces and behavior need different signals

19. 19. Verified versions must remain fresh

    Safe releases can still stall for a long time

20. 20. Scale and budget limit transferability

    The authors do not propose Scion as a general Git replacement

21. 21. Acceptance, checks and release need separate guarantees

    What entered history, what passed checks and what may ship