{"id":"alexwangda-s3-mcp-server-java","name":"s3-mcp-server-java","homepage":null,"repo_url":"https://github.com/AlexWangDa/s3-mcp-server-java","category":"infrastructure","subcategories":[],"tags":["mcp","s3","object-storage","spring-ai","java","stdio","presigned-url","automation"],"what_it_does":"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.","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)"],"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.","alternatives":["AWS SDKs directly (Java) for S3 operations","MinIO client SDKs (for MinIO environments)","Community MCP servers for specific storage providers","Custom MCP tooling that wraps AWS SDK with your own hardened policies and observability"],"af_score":35.8,"security_score":41.0,"reliability_score":17.5,"package_type":"mcp_server","discovery_source":["github"],"priority":"low","status":"evaluated","version_evaluated":null,"last_evaluated":"2026-04-04T20:00:00.344526+00:00","interface":{"has_rest_api":false,"has_graphql":false,"has_grpc":false,"has_mcp_server":true,"mcp_server_url":null,"has_sdk":false,"sdk_languages":["Java"],"openapi_spec_url":null,"webhooks":false},"auth":{"methods":["AWS-style access key/secret key for S3 API authentication"],"oauth":false,"scopes":false,"notes":"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":{"model":null,"free_tier_exists":false,"free_tier_limits":null,"paid_tiers":[],"requires_credit_card":false,"estimated_workload_costs":null,"notes":"Open-source (Apache-2.0) per metadata; pricing would be your S3 provider costs plus hosting for the MCP server."},"requirements":{"requires_signup":false,"requires_credit_card":false,"domain_verification":false,"data_residency":[],"compliance":[],"min_contract":null},"agent_readiness":{"af_score":35.8,"security_score":41.0,"reliability_score":17.5,"mcp_server_quality":70.0,"documentation_accuracy":55.0,"error_message_quality":0.0,"error_message_notes":null,"auth_complexity":45.0,"rate_limit_clarity":0.0,"tls_enforcement":60.0,"auth_strength":60.0,"scope_granularity":20.0,"dependency_hygiene":40.0,"secret_handling":20.0,"security_notes":"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.","uptime_documented":0.0,"version_stability":30.0,"breaking_changes_history":20.0,"error_recovery":20.0,"idempotency_support":"false","idempotency_notes":null,"pagination_style":"next-marker style (NextMarker support mentioned for listObjects)","retry_guidance_documented":false,"known_agent_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."]}}