feat: add 2026-01-21 weekly meeting notes (#6)

add 2026-01-21 weekly meeting notes

meetings/2026-01-21_weekly.md

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+# 2026-01-21 Transports WG (Weekly)
+
+## TL;DR
+The group reached a consensus to move forward with deprecating unsolicited
+server-to-client requests (sampling and elicitations) on the "get stream" to
+simplify protocol design and address security concerns. This decision was
+supported by data showing negligible usage in existing repositories. Mark Roth
+presented a "Multi-Roundtrip Request" proposal designed to replace the current
+SSE-based elicitation flow with a stateless, request-response model where
+clients echo back state. The group discussed the technical implications of this
+change. Finally, the group identified a need to reconcile this new proposal with
+the existing "Tasks" mechanism and will invite the Tasks author (Luca) to the
+next meeting.
+
+## Detailed Summary
+
+### Deprecation of Unsolicited Requests
+* **Proposal to Remove:** Shaun Smith proposed assuming that unsolicited
+  sampling and elicitations (server-to-client requests) are removed from the
+  session track. He argued that eliminating these unsolicited communications
+  resolves complex state transfer issues regarding cookies and session IDs.
+* **Usage Data:** Peter Alexander shared analysis results from scanning several
+  thousand MCP repositories, finding only one instance of unsolicited sampling
+  usage (which belonged to Shaun Smith).
+* **Decision:** The group agreed to draft a Specification Enhancement Proposal
+  (SEP) to formally deprecate unsolicited requests on the /GET stream.
+* **Scope:** The SEP will specifically disallow servers from sending sampling or
+  elicitation requests without an associated client request ID.
+
+### Technical Decisions: Multi-Roundtrip Requests
+* **Problem Statement:** Mark Roth outlined the inefficiency of the current
+  elicitation flow, where a server opens an SSE stream for elicitation, forcing
+  the client to make a completely independent request that must be manually
+  linked back to the original context by the server.
+* **Proposed Stateless Flow:** Mark presented a new pattern where the server
+  immediately terminates the initial request with a response indicating "more
+  information needed." The client then sends a completely new request containing
+  the original information plus the elicitation response.
+* **State Management (Hidden Fields vs. Cookies):**
+    * The group debated how to handle state persistence between the terminated
+      request and the retry.
+    * Gabriel Zimmerman and Simon Russell argued against using HTTP cookies,
+      suggesting a "hidden field" mechanism (opaque blob) is more appropriate
+      for per-tool-call state that should not persist globally.
+    * Mark Roth agreed, noting that cookies fail when multiple tool calls run in
+      parallel within the same session.
+* **SDK Impact:** Peter Alexander and Simon Russell acknowledged that while
+  switching to this model will be painful for SDK maintainers to implement
+  initially, the resulting architecture is significantly easier to maintain and
+  conceptually simpler.
+
+### Interaction with Tasks
+* **Overlap Analysis:** The group identified that the "Tasks" mechanism
+  currently duplicates some functionality discussed in the multi-roundtrip
+  proposal, specifically regarding polling and state retention.
+* **Unified Vision:** Caitie McCaffrey noted that Tasks and Tool Calls are
+  similar but necessary; she described Tasks as a "promise over a network" and
+  suggested that the handling of elicitation responses in both systems needs to
+  align.
+* **Next Steps:** The group agreed to invite Luca (author of Tasks) to the next
+  meeting to deeply dive into the relationship between the new stateless
+  proposal and the existing Tasks implementation.
+
+## Action Items
+- [ ] **Shaun Smith** to write a Specification Enhancement Proposal (SEP) to
+  deprecate unsolicited server-to-client requests (sponsored by Peter
+  Alexander).
+- [ ] **Mark Roth** to post the Multi-Roundtrip Request proposal to GitHub as a
+  Pull Request for community feedback.
+- [ ] **Caitie McCaffrey** to write a strawman proposal detailing the overlap
+  between "Tasks" and the current multi-roundtrip proposal.
+- [ ] **Kurtis Van Gent** to invite Luca to the next meeting to discuss the
+  relationship with tasks.