s3-mcp-server-java
Provides an MCP (Model Context Protocol) STDIO server (Spring AI based) that exposes S3-style operations (bucket and object management plus presigned URL generation) against Amazon S3 and S3-compatible object storage systems.
Score Breakdown
⚙ Agent Friendliness
🔒 Security
Uses accessKey/secretKey (IAM-backed) and can generate 15-minute presigned URLs. However, provided docs include an example that places secrets in command-line arguments, which can leak via process listings/logs. Scope granularity is not described (likely all-or-nothing based on IAM permissions). No rate limit or security error-handling details were provided in the README.
⚡ Reliability
Best When
You want an agent-friendly way to bridge MCP tools to S3-compatible storage using a local STDIO MCP server process.
Avoid When
You cannot control/limit the IAM permissions of the access keys used by the MCP server, or you need publicly auditable API contracts and operational guarantees beyond basic README-level documentation.
Use Cases
- • AI agents that need to list buckets/objects and fetch or upload files to S3-compatible storage
- • Generating short-lived share/download links for private S3 objects
- • Automating object discovery with prefix filtering and pagination for downstream processing
- • Creating virtual “directories” in object storage via zero-length object markers
Not For
- • Running with highly privileged credentials without tight IAM controls (because it can upload/download/list and generate access URLs)
- • Use cases requiring a fully managed/hosted service with enterprise support and explicit SLAs
- • Workloads needing strong, documented enterprise security guarantees (the repo data provided does not show detailed security posture or threat modeling)
Interface
Authentication
Auth appears to be done via configured S3 endpoint/accessKey/secretKey. The interface for scoping is not described (likely relies on IAM policy rather than application-layer OAuth scopes).
Pricing
Open-source (Apache-2.0) per metadata; pricing would be your S3 provider costs plus hosting for the MCP server.
Agent Metadata
Known Gotchas
- ⚠ Credentials are passed as command-line args in the example; agents should avoid logging process arguments and prefer safer secret injection methods (env vars/secret files) when running the server.
- ⚠ Object listing/pagination semantics depend on S3-compatible provider behavior; the README mentions NextMarker but does not describe edge-case handling (e.g., marker correctness across providers/versions).
- ⚠ Download/upload paths are specified in tool calls; agents must ensure correct local filesystem permissions and avoid path traversal/unsafe filenames.
Alternatives
Full Evaluation Report
Comprehensive deep-dive: security analysis, reliability audit, agent experience review, cost modeling, competitive positioning, and improvement roadmap for s3-mcp-server-java.
AI-powered analysis · PDF + markdown · Delivered within 30 minutes
Package Brief
Quick verdict, integration guide, cost projections, gotchas with workarounds, and alternatives comparison.
Delivered within 10 minutes
Score Monitoring
Get alerted when this package's AF, security, or reliability scores change significantly. Stay ahead of regressions.
Continuous monitoring
Scores are editorial opinions as of 2026-04-04.