HybridS3 MCP server

HybridS3

Lightweight object storage that speaks S3 (boto3/AWS SDK compatible), plain HTTP, and MCP. SQLite for metadata, flat files on disk.

Table of Contents

• Why
• Quick Start
• Running
• Configuration
• Keys and Access
• Key pair model
• Master key
• Bucket visibility
• HTTP API
• Authentication
• Endpoints
• Object keys

Why

Most self-hosted S3-compatible storage is designed for large-scale deployments. Distributed erasure coding, IAM policies, WORM compliance, full web consoles — useful if you're running a cloud, overkill if you just want a place to put files that various services and AI agents can read and write.

AWS Sig V4 breaks behind reverse proxy path prefixes. Most implementations verify signatures using the full original upstream path. Put them behind nginx at /storage/, nginx strips the prefix, the server sees /bucket/key instead of /storage/bucket/key, the signature check fails. HybridS3 has a path_prefix config option — set it to /storage and all routes move under that prefix. No path stripping, no special proxy headers. boto3's signed path matches what the server sees.

Three interfaces, one service. boto3 works out of the box. Plain HTTP with curl works. AI agents connect via MCP and get structured tool definitions. No separate services for different clients.

Buckets are configuration, not state. There is no API to create or delete buckets. They live in the YAML config file. You always know exactly what exists, it's version-controlled, and there are no surprise buckets accumulating garbage.

TTL expiry is built in. Set ttl: 24h on a bucket and objects expire automatically after their last write. No lifecycle policies, no cron jobs, no separate process.

Readable and modifiable. Small enough to understand in an afternoon.

Quick Start

# get the example config
wget -O config.yaml https://raw.githubusercontent.com/psyb0t/docker-hybrids3/master/config.example.yaml

# edit it — set your keys and define your buckets
vi config.yaml

# run
docker run -d --name hybrids3 \
    -p 8080:8080 \
    -v ./config.yaml:/config/config.yaml:ro \
    -v hybrids3-data:/data \
    psyb0t/hybrids3

# verify
curl http://localhost:8080/health

Running

The container expects:

• Config file at /config/config.yaml
• Data directory at /data
• Port 8080

Runs as UID 1000.

docker run:

Shortened. The full README is on GitHub.