feat: add 2026-03-04 weekly meeting notes (#23)

meetings/2026-03-04_weekly.md

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+# 2026-03-04 Transports WG (Weekly)
+
+## TL;DR
+The meeting, facilitated by Kurtis Van Gent and Mark Roth, focused on finalizing
+imminent Specification Enhancement Proposals (SEPs) and discussing new protocol
+extensions. The core maintainers reviewed SEP 2322 (MRTR) positively, agreeing
+to accept SDK breaking changes in favor of the new stateless flow. SEP 2243
+(HTTP Standardization) is undergoing a final revote after consolidating header
+names and softening intermediary error handling. Significant debate occurred
+regarding the Data Layer Sessions proposal, resulting in a mandate to explicitly
+define targeted use cases before further design review. Andreas Schlapbach
+introduced a new content negotiation proposal for compact responses to support
+local LLMs with small context windows. Finally, the group reviewed remaining
+gaps for the June release.w
+
+## Detailed Summary
+
+### Process & Roadmap
+* **June Release Gaps:** Kurtis Van Gent identified two main gaps for the
+  upcoming specification release: pluggable transports and caching/optimization. 
+* **Pluggable Transports:** Mark Roth clarified that pluggable transports mostly
+  require SDK work, not SEP changes. Minor cosmetic updates to loosen the
+  JSON-RPC requirement might be needed. Stephen Halter emphasized the need to
+  ensure the transport abstraction still allows for JSON-RPC to support existing
+  proxy implementations.
+* **Caching & Standard IO:** Caching and optimization lack volunteers and will
+  likely be deferred until after the June release. Standard IO updates are also
+  firmly out of scope for the current revision.
+
+### Technical Decisions: MRTR & Tasks (SEP 2322)
+* **Core Maintainer Feedback:** Mark Roth reported that the core maintainers
+  gave positive feedback on the Ephemeral Multi-Round Trip Request (MRTR) SEP.
+  Minor schema changes were added to help SDKs discriminate between tool call
+  responses and incomplete responses. 
+* **URL-Based Elicitation:** The group agreed that the URL-based elicitation
+  workflow is incompatible with the ephemeral workflow and will be restricted to
+  the persistent (tasks) workflow.
+* **Backward Compatibility:** The consensus was to accept breaking changes in
+  the SDKs to implement the new MRTR flow, deferring backward compatibility
+  concerns unless significant user complaints arise.
+* **Task Integration:** Luca Chang confirmed that their task-related proposals
+  (including "jump scares" and "task continue") are inextricably tied to MRTR
+  and will be pursued under the Transports Working Group.
+
+### Technical Decisions: HTTP Standardization (SEP 2243)
+* **Proposal Updates:** Mike Kistler outlined recent changes to the SEP, which
+  is up for a revote. Header names (`tool name`, `resource name`, `prompt name`)
+  were consolidated into a single `MCP name` header. The payload encoding was
+  explicitly specified as the Base64 encoding of the UTF-8 value.
+* **Intermediary Handling:** The requirement for intermediaries was softened so
+  that if they reject a request based solely on header values (e.g., bad
+  encoding), they can return a standard `400` HTTP error instead of a JSON-RPC
+  error. Stephen Halter noted that a `404` should be explicitly avoided to
+  prevent ending the session.
+* **Header Limits:** Following a discussion initiated by Stephen Halter about
+  protocol limits, the group agreed to remove strict protocol-level limits on
+  header lengths. These limits will be replaced with a design note advising
+  application authors against promoting overly long parameters to headers. 
+
+### Technical Decisions: Data Layer Sessions
+* **Defining Use Cases:** Mark Roth strongly emphasized that the sessions SEP
+  cannot proceed without a concrete list of targeted use cases. Scenarios like
+  "session per tool call" are mutually exclusive with "retaining state across
+  tool calls".
+* **Scope of State:** Shaun Smith argued that sessions should manage opaque,
+  application-layer state (e.g., associating a chat thread with a sandbox)
+  rather than MCP protocol state. Peter Alexander challenged this, asking if the
+  LLM model should be in control of the session state instead of the
+  application.
+* **Concurrency:** Stephen Halter raised concerns about state synchronization
+  during parallel tool calls. Shaun Smith clarified that the proposal currently
+  uses a "last write wins" strategy to intentionally discourage high-stakes
+  strict ordering, advising it be used for low-stakes storage.
+* **Next Steps:** The group agreed to hold a special session next week to review
+  an updated document focused on use cases and design, which will inform a final
+  recommendation to the core maintainers (including the potential recommendation
+  to drop sessions entirely).
+
+### Proposals: Content Negotiation
+* **Compact Responses:** Andreas Schlapbach proposed a two-phase content
+  negotiation extension (similar to HTTP `Accept`) allowing clients with small
+  context windows (like local LLMs on mobile devices) to request "compact"
+  responses from servers. 
+* **Protocol vs. Application Layer:** Simon Russell and Kurtis Van Gent
+  questioned why this negotiation needs to live at the protocol layer instead of
+  just passing expressive parameters within individual tool calls. Andreas
+  argued that an upfront session-level negotiation reduces chattiness and
+  compute waste. Andreas will continue to refine the proposal and gather
+  feedback in the repository.
+
+## Action Items
+- [ ] **Shaun Smith** to update the Sessions document by Friday/Saturday,
+  focusing on defining use cases and the argument for keeping sessions at the
+  application layer rather than the model layer.
+- [ ] **Shaun Smith** to check availability for a special session next Tuesday
+  or Friday to discuss the updated session document.
+- [ ] **Shaun Smith & Kurtis Van Gent** to work together to ensure the Sessions
+  SEP explicitly outlines the context for application versus transport sessions.
+- [ ] **Mike Kistler** to update SEP 2243 to replace the strict limits on header
+  lengths with an implementation note/design guidance.
+- [ ] **Kurtis Van Gent** to follow up with Kryspin and Stephen Halter to
+  formulate a formal proposal/plan for pluggable transports.