AWS MCP Proxy

Documentation

Parity with upstream

How the aws-mcp-proxy CLI maps to aws/mcp-proxy-for-aws, flag by flag.

This project targets parity+ with aws/mcp-proxy-for-aws: match the upstream CLI where practical, then add features on top. The table below maps every upstream flag to its status here.

Supported matches upstreamAdded here beyond upstreamPlanned not yet implemented

CLI flags

Upstream flagValueStatusNotes
endpointURLSupportedRequired positional SigV4 MCP endpoint URL.
--servicestringSupportedInferred from the endpoint host when omitted.
--profilestringSupportedRepeatable; first is the default. Also reads AWS_MCP_PROXY_PROFILES / AWS_PROFILE.
--regionstringSupportedInferred from the endpoint or AWS_REGION when omitted.
--metadatakey=valueSupportedRepeatable; injected into MCP requests.
--read-onlyflagSupportedDisables tools that don’t advertise readOnlyHint=true.
--retriesintSupportedDefault differs — see behavior differences.
--log-levelenumSupportedDEBUG / INFO / WARNING / ERROR / CRITICAL.
--timeoutsecondsSupportedTotal operation timeout.
--connect-timeoutsecondsSupportedConnection timeout.
--read-timeoutsecondsSupportedRead timeout.
--write-timeoutsecondsSupportedWrite timeout.
--tool-timeoutsecondsSupportedMax seconds a tool call may run before cancellation.
--skip-authflagSupportedSend unsigned requests when credentials are unavailable.
--disable-telemetryflagSupportedDisable telemetry in outbound user-agent data.
--ca-bundlepathAdded hereNot in upstream. Trust an extra PEM bundle for TLS-intercepting corporate proxies without installing roots globally. Reads AWS_CA_BUNDLE.

--help and --version are available on both.

Behavior differences

Where this proxy diverges from upstream, it leans toward resilience and convenience — the “+” in parity+:

  • Retries default to 3, not 0. Upstream disables retries by default; this proxy retries transient upstream failures out of the box (pass --retries 0 to disable).
  • Service and region are inferred from the endpoint. The host is parsed to derive the SigV4 service and region — including *.api.aws and bedrock-agentcore forms — so --service and --region are usually optional.
  • A managed CA bundle option. --ca-bundle (or AWS_CA_BUNDLE) trusts an extra PEM bundle on top of the system roots, for corporate TLS interception, without modifying the machine’s global trust store.
This table reflects the upstream CLI as documented in aws/mcp-proxy-for-aws. Upstream remains canonical for flag semantics and signing behavior — when in doubt, defer to it.