How should transport choice change deployment, security, and recovery?

2026-07-28 core · deterministic JSON-RPC fixtures

Atlas Release Evidence Server. Read-only evidence, deterministic scoring, and an explicit evaluation Task across replicas and protocol eras.

01 · Smallest useful mechanism

Keep protocol semantics stable while treating transport failures honestly.

stdio uses a locally managed process and newline-delimited messages. Streamable HTTP posts each message to one endpoint and returns JSON or request-scoped SSE, with standard HTTP security obligations.

Transport success is not method success, and a closed stream is not proof that no work occurred.

02 · Experiment

Test the prediction

Deterministic protocol fixture

This workbench uses inspectable JSON-RPC fixtures and injected failures. It does not make live calls or execute external effects.

Protocol workbench · atlas-transport-v2

Question to consider

Which deployment remains correct behind a load balancer?

Complication

The response connection closes after dispatch and the retry reaches another replica.

What would you do?

Choose the approach you would be prepared to defend in a design review.

Depend on sticky sessionsKeep implicit state in replica memory and retry anywhere.Bind state to the SSE connectionAssume the stream can always resume.Use self-contained requestsCarry metadata and explicit handles; reconcile operations by ID.

Consider the trade-offs first.

Choose an answer, then run the scenario. You’ll see what the system checks, what happens under the complication, and where the control boundary holds or breaks.

03 · Implementation brief

Build it, break it, prove the outcome.

Implement: Run the same semantic fixture over stdio and HTTP with explicit timeouts and error categories.
Break it on purpose: Corrupt stdout, buffer SSE, reject an origin, expire auth, and disconnect after dispatch.
Completion evidence: Framing remains valid, remote policy rejects unsafe traffic, and unknown outcomes reconcile without blind retry.

Your learning artifact

Write the argument you would defend

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Your response

04 · Check your understanding

What may a modern Streamable HTTP response use?

Primary sources · verified 2026-08-02

What the fixture does not prove

Remote deployment adds DNS, TLS, proxies, origins, authorization, load balancing, timeouts, and ambiguous network failures that local examples do not exercise.

Common mistake: SSE means the modern protocol maintains a resumable session. Modern Streamable HTTP may stream a response, but the core is stateless and the 2026-07-28 revision removes legacy SSE resumability.

Transfer exercise: Route consecutive requests to different replicas, terminate one response stream, and identify what evidence is required before retry.

MCP — TransportsNormative stdio and Streamable HTTP framing, request-scoped streaming, metadata, security, and compatibility behavior.MCP — 2026-07-28 key changesOfficial migration summary covering session removal, discovery, MRTR, extensions, Tasks, caching, and deprecations.Model Context Protocol — 2026-07-28 specificationThe authoritative modern MCP protocol: stateless requests, per-request metadata, capabilities, and server features.

Optional referenceDeep dive / reference chapterOpen the complete essay, diagrams, mathematics, exercises, glossary, and sources when you want more depth.on demand

Next: Transport independence becomes much easier once the core request is stateless—the central change in MCP 2026-07-28.