I-D Action: draft-venkateswaran-jamwal-twophp-01.txt

Internet-Draft draft-venkateswaran-jamwal-twophp-01.txt is now available.

   Title:   2-Phase HTTP Protocol for Distributed Transaction Tracking (2PHP-DTT)
   Authors: Barathan Venkateswaran
            Aditya Jamwal
   Name:    draft-venkateswaran-jamwal-twophp-01.txt
   Pages:   27
   Dates:   2026-07-21

Abstract:

   This document specifies the 2-Phase HTTP Protocol for Distributed
   Transaction Tracking (2PHP-DTT), a backward-compatible, opt-in
   extension to HTTP mutation semantics that introduces a two-phase
   handshake at service request boundaries. 2PHP ensures that a mutation
   request is durably registered on both the client and the server
   before any processing commences, addressing a structural gap in
   existing HTTP REST semantics where no standard mechanism exists to
   confirm bilateral intent registration prior to execution.

   The acronym DTT expands to Distributed Transaction Tracking.  2PHP is
   not Two-Phase Commit (2PC).  Microservices architectures deliberately
   avoid the cross-service locking and blocking that 2PC requires. 2PHP
   standardizes the intent-tracking pattern that implementations
   currently build ad hoc, providing a common wire contract and a
   queryable ledger of registered intent without introducing a
   distributed transaction coordinator.

   A primary motivator for this work is the growing use of agent-driven
   HTTP invocations, including Model Context Protocol (MCP) tool calls
   and agent-to-agent (A2A) integrations.  When an agent does not
   receive a response, its default behavior is to retry.  Absent a
   queryable record of prior intent, retries pile onto services that may
   already be overwhelmed, causing deadlocks, resource exhaustion, and
   full outages. 2PHP's Phase 1 ledger record enables the client to
   inspect whether the prior intent was registered before issuing a
   retry, breaking the retry-storm feedback loop at the protocol layer.

   2PHP operates at the HTTP protocol layer, requires no new transport
   mechanisms, and is composable across independently operating service
   boundaries.  This document further defines a standardized Intent
   Ledger model for durable, queryable, cross-service correlation of
   request intent, distinct from execution telemetry provided by
   distributed tracing systems.

   This document does not claim novelty over existing intent-tracking,
   idempotency, or distributed-tracing patterns.  Its goal is to define
   a common HTTP-layer wire contract and a common ledger schema so that
   a single reference implementation--packaged as a library or framework
   module--can serve multiple deployments, replacing the per-team ad hoc
   implementations that currently reinvent this pattern.

   This document defines the protocol headers, phase state machine,
   idempotency and replay behavior, the three-tier Intent Ledger
   architecture, cross-service correlation model, and IANA registration
   of the associated HTTP header fields. 2PHP-DTT targets the
   synchronous request-response boundary, where no standard
   acknowledgement primitive exists to confirm bilateral intent
   registration before processing.  Asynchronous HTTP patterns -- 202
   Accepted with Location-based polling in HTTP Semantics, Prefer:
   respond-async negotiation, webhooks, and message-broker delivery --
   already provide durable acknowledgement of intent by construction,
   and are therefore out of scope for this specification.

The IETF datatracker status page for this Internet-Draft is:
https://datatracker.ietf.org/doc/draft-venkateswaran-jamwal-twophp/

There is also an HTML version available at:
https://www.ietf.org/archive/id/draft-venkateswaran-jamwal-twophp-01.html

A diff from the previous version is available at:
https://author-tools.ietf.org/iddiff?url2=draft-venkateswaran-jamwal-twophp-01

Internet-Drafts are also available by rsync at:
rsync.ietf.org::internet-drafts


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