chunkfs is object storage built for autonomous agents: an S3-compatible endpoint where every build, log, trace and report an agent produces lands in its own bucket — chunked and ready for the next agent to pick up.
aws s3 ls s3://agent-builder/ --endpoint-url https://s3.chunkfs.com
One bucket per agent. Keys are scoped to the bucket, so an agent can only touch its own artifacts — rotate or revoke one without disturbing the rest.
Point any S3 client at https://s3.chunkfs.com with path-style addressing. SigV4, multipart, presigned URLs — the API your tooling already speaks, unchanged.
What works today is path-style SigV4, multipart upload, and SigV4 presign. The free plan stores 100 MB and keeps objects for 30 days.
One agent writes, the next one reads. A presigned URL turns an output into someone else's input — no credentials change hands.
aws-cli, boto3, the JS SDK, rclone, MinIO clients. If it speaks S3, it speaks chunkfs — no wrapper library to install or maintain.
Objects are split into 8 MB parts. A dropped connection resumes from the last part, not from zero — agents on flaky VMs finish their uploads.
Every chunk is hashed before it is stored. This slice stores each object whole. Dedup is a later pass.
A key pair sees one bucket and nothing else. Read-only and write-only pairs are a flag away, so a reviewer agent cannot overwrite a builder's output.
Set a TTL per bucket or per prefix. Scratch output and screenshots expire on their own; tagged releases stay until you say otherwise.
Mint a URL that expires in minutes and pass it to another agent, a CI job or a human. The artifact moves; the credentials never do.
| No. | Property | Value | Remark |
|---|---|---|---|
| 01 | Max object size | 5 TB | Multipart above 5 GB, as in S3 |
| 02 | Part size | 8 MB | Default; 5 MB – 5 GB per part |
| 03 | Request signing | SigV4 | Path-style at https://s3.chunkfs.com |
| 04 | Default retention | 30 d | Per bucket or prefix; 1 h to forever |
| 05 | Presigned URL lifetime | 7 d | Maximum; minutes recommended for handoff |
Limits apply per bucket unless noted. Rev A.
Set the endpoint, keep everything else. The key pair is scoped to the agent's bucket; the region is us-east-1.
For aws cli v2, set path-style addressing on profile chunkfs. The endpoint stays https://s3.chunkfs.com. aws s3 presign must be SigV4 (aws cli v2). aws cli v1 query signatures are rejected with HTTP 400.
Agents that cannot run an S3 client talk to chunkfs over the Model Context Protocol instead: one HTTP endpoint at https://s3.chunkfs.com/mcp, a bearer token scoped to the bucket, eleven tools.
Claude Code writes run output through the JS or Python SDK.
Grok agents push builds between tasks with aws-cli.
opencode sessions keep traces and diffs in a scoped bucket.
Copilot hands finished work to the next step with a presigned URL.
And anything that already speaks S3 — aws-cli, boto3, rclone, MinIO clients, the autodev CLI.
Leave an email; we send a key pair and the endpoint. Paste both into your agent's environment and it has somewhere to put its work. Already have a key? Open the panel.
Paste this block. It sets endpoint https://s3.chunkfs.com, region us-east-1, and path-style addressing for the bucket just issued. Then Open the panel and sign in.