feat: add 2026-05-27 weekly meeting notes (#40)

meetings/2026-05-27_weekly.md

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+# **2026-05-27 MCP: Transport Working Group (Weekly)**
+
+# **TL;DR**
+
+The meeting achieved key technical consensus on restricting custom header
+numeric serialization and refining legacy standard IO server restart logic,
+while mapping out future specification development targets. To prevent
+serialization and comparison mismatches of floating-point numbers across
+language runtimes, the team agreed to restrict custom headers strictly to
+integer primitives. The group also resolved that clients should not proactively
+restart legacy standard IO servers to probe for protocol support, deciding
+instead to restart only if the server process crashes on the initial attempt.
+
+# **Detailed Summary**
+
+## **Custom Header Numeric Serialization**
+
+* **Floating-Point Quirks:** Mike Kistler highlighted that JSON-to-header
+  conversion of numeric values can cause mismatches due to serialization quirks
+  (e.g., 42 serializing as 42.0).  
+* **Consensus \- Integer Restrictions:** To avoid comparison errors with
+  floating-point precision, the team agreed to restrict custom header numeric
+  values strictly to primitive integers, explicitly prohibiting floating-point
+  numbers.  
+* **Validation Location:** It was established that clients must reject tool
+  inputs containing non-integer numbers in custom headers, and the server will
+  handle the verification as it unpacks the request.  
+* **Tension Point \- Integer Precision Limits:** Peter Alexander pointed out
+  that integers must be constrained to less than 2^53 (standard double-precision
+  float representation) to prevent rounding errors in JavaScript runtimes.
+
+## **Standard IO Restart Logic & Backwards Compatibility**
+
+* **Tension Point \- Proactive Server Restarts:** Under the backwards
+  compatibility flow for stateless standard IO, Kurtis Van Gent originally
+  proposed restarting the server if the initial `serverdiscover` failed. Peter
+  Alexander and Caitie McCaffrey objected to proactive restarts, noting that
+  starting heavy servers twice (e.g., Playwright taking \~1 second to spawn)
+  creates terrible performance optics for the new stateless protocol.  
+* **Consensus \- Crash-Only Restarts:** The group agreed that clients should not
+  proactively restart standard IO servers to check for compatibility. Instead,
+  clients will attempt `serverdiscover`, and if the server crashes, only then
+  will they restart and fallback to `initialize`.  
+* **Tension Point \- Ping Before Initialize:** Shaun Smith proposed using a
+  `ping` request before `initialize` to negotiate protocol versions, as the spec
+  historically allowed pings before initialization. However, Kurtis Van Gent and
+  Luca Chang verified that the spec mandates `initialize` as the first
+  interaction, meaning some servers might crash on pre-initialization pings.
+
+## **SDK Implementation Timeline & Future Roadmap**
+
+* **Timeline Sign-offs:** Kurtis Van Gent outlined the official milestones: June
+  28th for SDK and client maintainer sign-off, July 14th for the full spec
+  freeze, July 21st for Tier 1 SDK readiness, and July 28th for the official
+  spec launch.  
+* **Tension Point \- Error Message Standardization:** Kurtis Van Gent proposed
+  standardizing error messages and preferred HTTP status codes to prevent SDKs
+  from creating proprietary interpretations. Mark Roth strongly cautioned
+  against over-constraining error message text, noting that in gRPC, status
+  codes are for machines and error messages are flexible text for human
+  debugging.  
+* **Pluggable Transports:** Mark Roth emphasized that pluggable transports are a
+  high priority. Kurtis Van Gent and Mark Roth agreed to collaborate on a
+  unified proposal.
+
+# **Next Steps & Timeline**
+
+Mike Kistler will update the numeric header restriction PR and request Peter
+Alexander's review. Kurtis Van Gent will update the standard IO process
+lifecycle PR to reflect crash-only restarts and remove host process lifetime
+parity constraints. Shaun Smith will draft outcome briefs for streaming and Gzip
+transport-level compression.
+
+# **Action Items**
+
+- [ ] **Mike Kistler** Modify the pull request to mandate that numeric values in
+  custom headers must be integers less than 2^53.  
+- [ ] **Kurtis Van Gent** Update server restart guidance in the documentation to
+  specify crash-only restarts for standard IO.  
+- [ ] **Caitie McCaffrey** Review the roots PR that updates the roots example to
+  use prompts.  
+- [ ] **Peter Alexander** Investigate how the Rust SDK handles pings before
+  initialization.  
+- [ ] **Shaun Smith** Locate and present documented proof regarding whether
+  pings are allowed before initialization.  
+- [ ] **Kurtis Van Gent** Modify the standard IO process pull request to remove
+  prescriptive host application lifetime constraints.  
+- [ ] **Kurtis Van Gent** Collaborate with Mark Roth on the pluggable transports
+  proposal.  
+- [ ] **Shaun Smith** Write high-level outcome briefs for streaming and Gzip
+  compression mechanisms at the transport level.  
+- [ ] **Kurtis Van Gent** Draft a problem statement regarding standardized error
+  message formatting.  
+- [ ] **Stephen Halter** Retrieve the deferred pull request for pluggable
+  transports.
+
+Source: [Meeting Notes — May 27,
+2026](https://docs.google.com/document/d/1G5E458FlLfxzoPEWwt9xo9ELCZG4zAcwaWB5HLp1Kc8/edit?usp=drive_web&tab=t.besnu9g9mrpd)