April 21st - SLIM Working Group Meeting Notes

[NickG44]

SLIM Working Group Summary - April 21st, 2026

Attendees: (14)

Nick Gill
Marton Mark
Sandor Magyari
Cody Hartsook
Dominik Kolonits
Janos Sarusi
Elaine Powers
Laszlo Gecse
Laszlo Puskas
Michele Papalini
Amit Kumar
Aron Kerekes
Bendeguz Csirmaz
Benjamin Torres

1. SLIM v1.4 Release & Performance Optimizations

Release Candidate: A release candidate for SLIM v1.4 was pushed today, incorporating all controller and data plane improvements developed for the multi-cluster demo.

Performance Benchmarks: Recent benchmarking identified computational bottlenecks in OpenTelemetry (OTel) instrumentation and the forwarding table's matching algorithm (specifically, random generation of output interfaces).

Resolution: Two pull requests have been created to address these bottlenecks, showing significant performance improvements. They will be rebased and merged this week.

2. SLIM Multi-Cluster Demo (Kubernetes Remediation)

A comprehensive demo was presented showcasing SLIM used for a Kubernetes remediation use case (the Splunk scenario).

Architecture: A cloud cluster runs a single public-facing SLIM node. A customer cluster (behind firewalls/proxies) runs a local SLIM node that makes a single outbound, bidirectional gRPC streaming connection to the cloud. This eliminates the need for complex reverse proxies or multiple public ingresses.

Execution: The demo utilized Spire for token distribution and an MCP proxy to route requests to unmodified, standard MCP servers (Kubernetes and Atlassian/Jira). An automated background job detected a failing pod and created a Jira ticket, while a Copilot CLI (using an A2A skill over SLIM) was used to query the cluster status and root cause.

Availability: A blog post detailing this scenario was published today, and the code is available on the multi-cluster-demo branch.

3. Language Support Updates (Kotlin, Java, TypeScript)

Kotlin & Java: A PR is currently up for Kotlin SlimRPC support, and work is actively progressing on A2A Java support for SLIM. This will complete A2A integration across all languages that currently have SLIM bindings.

TypeScript/JavaScript: The TS/JS SDK is fully prepared. The team is currently waiting on a pending PR to update UniFFI tooling; once merged, the TS SDK will be rebased and merged.

4. MLS Cipher Negotiation & A2A Transports

Cipher Negotiation: A successful Proof of Concept (POC) for MLS cipher suite negotiation was completed. A formal proposal has been submitted to GitHub discussions for review before full implementation begins.

New Transports: Proposals and specifications for adding WebSocket and Standard IO (STDIO) transports to A2A have been drafted and are undergoing internal review.

5. GitHub Project Restructuring

Due to reaching the repository limit on the existing GitHub project board, the workspace has been split into three distinct projects: Core (docs, blogs, identity, CI/CD), Messaging (tracking for this SLIM working group), and Discovery.
The migration is complete, and automation remains intact. Links have been shared in Slack.