Features
Resolve signing algorithm when a JWK omits alg - @DaleSeo #732
Apollo MCP Server now infers the signing algorithm from the authorization server's discovery metadata when a JWK omits the alg field, enabling support for providers like Azure AD B2C, Microsoft Entra ID, and AWS Cognito.
Capture tool call arguments and results in OpenTelemetry spans - @DaleSeo #748
Tool execution spans now include apollo.mcp.tool_arguments and apollo.mcp.tool_result attributes on the call_tool span, and apollo.mcp.graphql_query and apollo.mcp.graphql_response on the child execute span. This makes it possible to correlate traces in observability dashboards with the actual queries and data that triggered them.
Expose trace_id to the on_execute_graphql_operation Rhai hook - @DaleSeo #745
The on_execute_graphql_operation Rhai hook now exposes a read-only ctx.trace_id property, allowing scripts to access the current OpenTelemetry trace ID for custom structured logging. The value is a 32-character lowercase hex string when an OpenTelemetry trace context is active and an empty string otherwise, matching the format already used for the trace_id=<hex> prefix on server log lines. This makes it possible to emit log lines from Rhai with trace_id as a discrete field that log aggregators (Splunk, ELK, etc.) can index for correlation with distributed traces.
Fixes
Bump rmcp to 1.6 to address DNS rebinding advisory - @DaleSeo #742
Updates the rmcp Streamable HTTP server transport to 1.6.0, which patches GHSA-89vp-x53w-74fx (CVE-2026-42559). Host header validation is now performed inside rmcp itself, with a tracing::warn! event on each rejection so log-based alerting on DNS rebinding attempts continues to work; the server's existing transport.streamable_http.host_validation configuration is unchanged.
Preserve raw authorization server URLs in protected-resource metadata - @DaleSeo #749
Apollo MCP Server no longer normalizes the transport.auth.servers entries when it sets the authorization_servers field in /.well-known/oauth-protected-resource. Before, a scheme-authority-only configuration value, like https://auth.example.com, was re-parsed through url::Url, which added a trailing / to the empty path. This normalized form ended up in the metadata and caused mismatches in issuer claims for strict OAuth clients that compare authorization_servers with the auth server's discovery issuer. Now, server URLs are passed through exactly as they are, so users need to make sure each entry matches their auth server's issuer precisely.
