SLIM WG Call Summary - June 9th

[NickG44]

SLIM Working Group Call Summary – June 9, 2026

Participants: Nick Gill, János Sarusi-Kis, Amit Kumar, Mauro Sardara, Luca Muscariello, Mark Marton, László Puskás, Sandor Magyari, Michele Papalini, Sam Betts, Elaine Powers, Aron Kerekes.

Key Topics & Outcomes

1. Session Layer & Controller Architecture Refactoring

Peer Auto-Discovery: A new feature is being introduced to allow multiple replicas of SLIM (e.g., within a Kubernetes deployment) to organize themselves and synchronize forwarding tables without relying on a central control plane. This is configured via a new Peer session block using either static lists (full mesh) or Kubernetes label selectors.
Controller Topology Management: The control plane is being extended to connect these larger deployments/replica sets together. The controller acts as the orchestrator, creating spanning trees to distribute routes between deployments without creating network loops. Work is ongoing to resolve a few edge cases when nodes are dynamically added or removed.

2. End-to-End Header Integrity & Session Validation

Currently, published message headers are validated by default on the application side.
Work is actively underway to extend this validation functionality to cover control messages as well.
End-to-end payload integrity checks are still in progress, requiring a slight code restructure to avoid introducing unwanted locks into the MLS state.

3. Bindings Migration & "Alpha" Release Cadence

Blockers Removed: Internal dependencies on the language bindings within the main SLIM repo (specifically the channel manager and SlimCTL benchmarks) have been successfully decoupled.
Alpha Releases: To facilitate moving the bindings to their new dedicated repository, the team has cut an "Alpha 0" release (with an "Alpha 1" immediately following). This allows the new bindings repo to pull core SLIM dependencies directly from crates.io.
Moving forward, the team will adopt a frequent "dev/alpha" release cadence to ensure the external bindings repository stays perfectly synced with core SLIM updates.

4. WebAssembly (Wasm) Compilation

The PR to enable WebAssembly compilation for the data path crate is nearing completion.
The engineering team agreed to compile all core crates together into a unified Wasm target simultaneously to ensure comprehensive testing and seamless browser integration.

5. Documentation Website & CI Improvements

New Docs Site: A preview of the new SLIM documentation website (built with MkDocs) was shared. The team is proposing slim.agntcy.org as the official domain.
Versioning Strategy: A discussion was held on how to decouple the versioning of the main landing page/community blogs from the strict versioning of the technical documentation (which must remain tied to SLIM software releases).
CI Optimization: The CI pipeline was updated to ignore documentation-only changes. Modifying the docs will no longer trigger massive, time-consuming Rust rebuilds.

6. Workspace Refactoring

A PR is pending to refactor the main repository into a single Rust workspace (which will drastically improve caching and build times). This PR is intentionally paused and will be rebased and merged immediately after the language bindings are fully extracted to avoid massive merge conflicts.

Next Steps & Action Items

Bindings Extraction: Finalize the "Alpha 1" release, completely remove the bindings from the main SLIM repository, and transition CI/CD to the new dedicated bindings repo.
Workspace Refactor: Once the bindings are removed, rebase and merge the single Rust workspace refactoring PR to optimize caching.
Controller Stabilization: Resolve the remaining edge cases in the controller's spanning tree logic regarding dynamic node addition/removal.
Wasm Compilation: Finalize the Wasm data path PR and compile the remaining core crates into the unified Wasm target.
A2A Protocol Bindings: Present the WebSocket custom protocol binding proposal at the A2A TSC meeting for community review.