diff --git a/agent-roadmap/ROADMAP.md b/agent-roadmap/ROADMAP.md
index 0d473b73..3a763618 100644
--- a/agent-roadmap/ROADMAP.md
+++ b/agent-roadmap/ROADMAP.md
@@ -19,9 +19,9 @@ nexo-owned 제품 표면은 Flutter SDK, compose, 운영 계약, 앱별 integrat
 - [검토중] 제품 기반 정리
   - 경로: `agent-roadmap/phase/product-foundation/PHASE.md`
   - 요약: nexo의 제품 경계, 모노레포 구조, upstream-followable 런타임 기준선을 고정했고 Phase 완료 확인을 기다린다.
-- [진행중] 업스트림 런타임 운영화
+- [검토중] 업스트림 런타임 운영화
   - 경로: `agent-roadmap/phase/upstream-runtime/PHASE.md`
-  - 요약: Mattermost server/webapp/push-proxy 업데이트를 계속 따라가기 위한 기준, CI/CD, 장애 대응 루프를 만든다.
+  - 요약: Mattermost server/webapp/push-proxy 업데이트를 계속 따라가기 위한 기준, CI/CD, 장애 대응 루프를 정리했고 Phase 완료 확인을 기다린다.
 - [계획] 메시징 런타임 표준화
   - 경로: `agent-roadmap/phase/messaging-runtime/PHASE.md`
   - 요약: nexo-owned Flutter SDK와 upstream runtime이 공유할 메시징/알림 계약, 테스트, 앱별 사용 채널 모델을 정리한다.
diff --git a/agent-roadmap/phase/upstream-runtime/milestones/upstream-following.md b/agent-roadmap/archive/phase/upstream-runtime/milestones/upstream-following.md
similarity index 72%
rename from agent-roadmap/phase/upstream-runtime/milestones/upstream-following.md
rename to agent-roadmap/archive/phase/upstream-runtime/milestones/upstream-following.md
index 3fb268a4..5d22d37f 100644
--- a/agent-roadmap/phase/upstream-runtime/milestones/upstream-following.md
+++ b/agent-roadmap/archive/phase/upstream-runtime/milestones/upstream-following.md
@@ -12,7 +12,7 @@ Mattermost server, webapp, push-proxy를 nexo runtime으로 계승하면서도 u
 
 ## 상태
 
-[진행중]
+[완료]
 
 ## 승격 조건
 
@@ -44,28 +44,32 @@ Mattermost server, webapp, push-proxy를 nexo runtime으로 계승하면서도 u
 
 server/webapp/push-proxy가 어떤 upstream 버전을 기준으로 움직이는지 추적 가능하게 만든다.
 
-- [ ] [source-baseline] server와 webapp의 upstream tag/commit, 적용 patch, nexo-local 변경 범위를 기록하는 기준을 정리한다.
-- [ ] [snapshot-script] 외부 `mattermost/` staging clone을 git update하고 선택한 snapshot을 `apps/mattermost`, `services/core`, `services/push-proxy`로 복사하는 workspace script 계약을 정리한다. 검증: script가 staging pull 결과를 자동 merge하지 않고, repo별 commit SHA 기록, snapshot diff 확인, smoke 검증 단계를 분리한다.
-- [ ] [push-proxy-baseline] push-proxy를 image-only로 추적할지 source mirror/fork를 둘지 판단 기준과 현재 선택을 문서화한다.
-- [ ] [release-watch] Mattermost monthly/ESR release, security patch, push-proxy update를 확인하는 주기와 담당 문서를 정리한다.
+- [x] [source-baseline] server와 webapp의 upstream tag/commit, 적용 patch, nexo-local 변경 범위를 기록하는 기준을 정리한다.
+- [x] [snapshot-script] 외부 `mattermost/` staging clone을 git update하고 선택한 snapshot을 `apps/mattermost`, `services/core`, `services/push-proxy`로 복사하는 workspace script 계약을 정리한다. 검증: script가 staging pull 결과를 자동 merge하지 않고, repo별 commit SHA 기록, snapshot diff 확인, smoke 검증 단계를 분리한다.
+- [x] [push-proxy-baseline] push-proxy를 image-only로 추적할지 source mirror/fork를 둘지 판단 기준과 현재 선택을 문서화한다.
+- [x] [release-watch] Mattermost monthly/ESR release, security patch, push-proxy update를 확인하는 주기와 담당 문서를 정리한다.
 
 ### Epic: [patch-policy] Patch boundary
 
 nexo 변경이 upstream merge를 어렵게 만들지 않도록 허용 경계를 만든다.
 
-- [ ] [thin-branding] webapp은 기본 메시지 앱/reference front로 유지하고, branding과 기능 숨김은 얇은 patch로 제한하는 기준을 정리한다.
-- [ ] [no-deep-rename] server/webapp/push-proxy upstream-owned 코드의 대량 rename과 deep fork를 금지하고 예외 조건을 문서화한다.
-- [ ] [feature-triage] upstream 새 기능을 keep/hide/defer/remove 후보로 분류하는 기준을 정리한다.
+- [x] [thin-branding] webapp은 기본 메시지 앱/reference front로 유지하고, branding과 기능 숨김은 얇은 patch로 제한하는 기준을 정리한다.
+- [x] [no-deep-rename] server/webapp/push-proxy upstream-owned 코드의 대량 rename과 deep fork를 금지하고 예외 조건을 문서화한다.
+- [x] [feature-triage] upstream 새 기능을 keep/hide/defer/remove 후보로 분류하는 기준을 정리한다.
 
 ## 완료 리뷰
 
-- 상태: 없음
-- 요청일: 없음
-- 완료 근거: 없음
+- 상태: 승인됨
+- 요청일: 2026-05-30
+- 완료 근거:
+  - `docs/README.md`에 baseline 기록, snapshot script 계약, push-proxy 추적 선택, release watch, patch policy를 정리했다.
+  - `services/core/UPSTREAM.md`, `services/push-proxy/UPSTREAM.md`, `apps/mattermost/UPSTREAM.md`에 모듈별 patch boundary와 update gate를 보강했다.
+  - `git diff --check`, task/status `rg`, 활성 경로 확인을 통과했고, workspace lock 관련 항목은 없었다.
+  - 현재 마일스톤 기능 Task 7개는 문서화 범위 안에서 충족되었고, 실제 snapshot 자동화 스크립트 구현은 이번 마일스톤의 계약 정리 범위를 넘는 별도 큰 작업으로 분리 가능하다.
 - 리뷰 필요:
-  - [ ] 사용자가 완료 결과를 확인했다
-  - [ ] archive 이동을 승인했다
-- 리뷰 코멘트: 없음
+  - [x] 사용자가 완료 결과를 확인했다
+  - [x] archive 이동을 승인했다
+- 리뷰 코멘트: 2026-05-30 사용자 요청에 따라 `[완료]` 전환 후 archive 이동했다.
 
 ## 범위 제외
 
@@ -81,5 +85,5 @@ nexo 변경이 upstream merge를 어렵게 만들지 않도록 허용 경계를
 - 선행 작업: 정체성 기준선
 - 후속 작업: 메시징 계약 표준화
 - 완료된 관련 작업: CI/CD와 운영 업데이트 루프는 2026-05-30 archive 완료
-- 다음 작업 지점: `[source-baseline]`에서 server/webapp upstream tag/commit, 적용 patch, nexo-local 변경 범위 기록 기준을 먼저 정리한다. 이후 `[snapshot-script]`로 staging clone update와 snapshot copy 계약을 이어간다.
+- 다음 작업 지점: `agent-roadmap/phase/messaging-runtime/milestones/messaging-contract.md`
 - 확인 필요: 없음
diff --git a/agent-roadmap/current.md b/agent-roadmap/current.md
index 92083ab3..40ba1b73 100644
--- a/agent-roadmap/current.md
+++ b/agent-roadmap/current.md
@@ -2,14 +2,14 @@
 
 ## 활성 Phase
 
-- [진행중] 업스트림 런타임 운영화
-  - 경로: `agent-roadmap/phase/upstream-runtime/PHASE.md`
+- [계획] 메시징 런타임 표준화
+  - 경로: `agent-roadmap/phase/messaging-runtime/PHASE.md`
 
 ## 활성 Milestone
 
-- [진행중] 업스트림 팔로잉 기준선
-  - Phase: `agent-roadmap/phase/upstream-runtime/PHASE.md`
-  - 경로: `agent-roadmap/phase/upstream-runtime/milestones/upstream-following.md`
+- [계획] 메시징 계약 표준화
+  - Phase: `agent-roadmap/phase/messaging-runtime/PHASE.md`
+  - 경로: `agent-roadmap/phase/messaging-runtime/milestones/messaging-contract.md`
 
 ## 선택 규칙
 
diff --git a/agent-roadmap/phase/upstream-runtime/PHASE.md b/agent-roadmap/phase/upstream-runtime/PHASE.md
index 6dee62f7..c7230c30 100644
--- a/agent-roadmap/phase/upstream-runtime/PHASE.md
+++ b/agent-roadmap/phase/upstream-runtime/PHASE.md
@@ -2,7 +2,7 @@
 
 ## 상태
 
-[진행중]
+[검토중]
 
 ## 목표
 
@@ -18,9 +18,9 @@ Mattermost server, webapp, push-proxy를 nexo의 upstream-followable 메시징 
 - [완료] CI/CD와 운영 업데이트 루프
   - 경로: `agent-roadmap/archive/phase/upstream-runtime/milestones/cicd-operations.md`
   - 요약: upstream update, compose 배포, 검증 실패 이슈화를 반복 가능한 파이프라인으로 만든다.
-- [진행중] 업스트림 팔로잉 기준선
-  - 경로: `agent-roadmap/phase/upstream-runtime/milestones/upstream-following.md`
-  - 요약: server/webapp/push-proxy의 upstream baseline, patch 경계, update 판단 기준을 정한다.
+- [완료] 업스트림 팔로잉 기준선
+  - 경로: `agent-roadmap/archive/phase/upstream-runtime/milestones/upstream-following.md`
+  - 요약: server/webapp/push-proxy의 upstream baseline, snapshot script 계약, patch 경계, update 판단 기준을 정리하고 사용자 승인에 따라 archive했다.
 
 ## Phase 경계
 
diff --git a/apps/mattermost/UPSTREAM.md b/apps/mattermost/UPSTREAM.md
index bb05a034..8ac19e86 100644
--- a/apps/mattermost/UPSTREAM.md
+++ b/apps/mattermost/UPSTREAM.md
@@ -9,4 +9,22 @@
 - Snapshot source: `/config/workspace/mattermost/mattermost-mobile/`
 - Snapshot target: `/config/workspace/nexo/apps/mattermost/`
 
-Keep nexo-specific changes outside this snapshot where possible.
+## Patch Boundary
+
+Keep nexo-specific changes outside this snapshot where possible. This app is a
+Mattermost mobile reference clone for runtime verification, not the nexo
+product app surface.
+
+Do not add app-specific nexo product UI or business logic here. Prefer docs,
+test evidence, wrapper scripts, or small compatibility patches when the clone
+is needed for runtime validation.
+
+## Update Gate
+
+A Mattermost mobile snapshot update must stay separate from core and
+push-proxy updates. Before a merge request, record the selected upstream
+commit, review the snapshot diff, and run the relevant app smoke or test lane.
+
+When app verification depends on local-only credentials or endpoints, record
+only sanitized evidence in tracked docs and keep raw environment values outside
+git.
diff --git a/docs/README.md b/docs/README.md
index aa44a082..f9378ee7 100644
--- a/docs/README.md
+++ b/docs/README.md
@@ -14,3 +14,91 @@ Module-specific instructions stay with the module that owns them.
 - Mattermost mobile app upstream snapshot baseline: `../apps/mattermost/UPSTREAM.md`
 - Mattermost push-proxy upstream snapshot baseline: `../services/push-proxy/UPSTREAM.md`
 - Runtime Image Validation details: `runtime-image-validation.md`
+
+## Upstream Following Policy
+
+Mattermost upstream repositories are runtime baselines, not the main nexo
+product surface. Keep `apps/mattermost`, `services/core`, and
+`services/push-proxy` close to their recorded upstream snapshots, and put
+nexo-owned behavior in the Flutter SDK, compose/runtime wrappers, docs, or
+small explicit compatibility patches.
+
+### Baseline Records
+
+Each upstream snapshot owner keeps an `UPSTREAM.md` file with:
+
+- source repository URL;
+- tracked branch and release tag when applicable;
+- exact upstream commit SHA;
+- snapshot date;
+- snapshot source and target path;
+- accepted nexo-local patch boundary;
+- update gate and smoke evidence expected before a merge request.
+
+When a baseline changes, update the matching `UPSTREAM.md` in the same change
+as the snapshot. Do not mix app, core, and push-proxy snapshot updates in one
+merge request.
+
+### Snapshot Script Contract
+
+A workspace snapshot helper may automate only the mechanical staging and copy
+steps. Its contract is:
+
+- update the external `mattermost/` staging clone for one selected upstream
+  repository at a time;
+- read the tracked branch from the module's `UPSTREAM.md` or project rules;
+- copy the chosen snapshot only to the matching target directory;
+- exclude `.git`, dependency caches, build outputs, runtime data, logs, and
+  ignored secret-bearing files;
+- record the selected upstream commit SHA for the operator to apply to the
+  matching `UPSTREAM.md`;
+- print the follow-up diff review and smoke checklist.
+
+The helper must not commit, push, update multiple upstream repositories in one
+run, promote runtime images, or auto-merge staging pull results into this
+workspace. Snapshot diff review and smoke verification remain separate gates.
+
+### Push-Proxy Baseline
+
+Current choice: keep `services/push-proxy` as a source snapshot mirror of
+`mattermost-push-proxy`, and build nexo-owned runtime images from that source
+when needed. Runtime image tags and digests are deployment evidence, not the
+source baseline.
+
+Image-only tracking is allowed only after a separate roadmap decision when no
+local source build, patch, config packaging, or smoke diagnosis needs the
+source snapshot. If that decision changes, update `services/push-proxy/UPSTREAM.md`
+and this section together.
+
+### Release Watch
+
+Check Mattermost server/webapp monthly releases, active ESR updates, security
+notices, Mattermost mobile updates used for verification, and push-proxy
+releases before opening a baseline update. Security patches are triaged as soon
+as they are noticed; normal monthly or ESR refreshes can wait for an explicit
+snapshot lane.
+
+The public record for a release watch is the relevant `UPSTREAM.md` plus
+sanitized runtime evidence in `runtime-image-validation.md` when images or
+compose inputs change. Raw credentials, private endpoints, and environment
+values stay out of tracked docs.
+
+### Patch Policy
+
+Webapp branding and feature visibility changes must stay thin: prefer upstream
+configuration, feature flags, small compatibility wrappers, or isolated style
+patches. Do not rewrite the webapp into a nexo-owned product surface in this
+runtime baseline.
+
+Do not apply bulk renames, package-wide reformatting, repository reshaping, or
+deep fork changes to upstream-owned server, webapp, app, or push-proxy code
+without a separate roadmap decision. Exceptions require an explicit rollback
+path and a note explaining why an upstream-compatible wrapper is insufficient.
+
+Classify upstream features during refresh as:
+
+- `keep`: compatible with nexo runtime and low maintenance cost;
+- `hide`: available upstream but disabled or hidden by configuration or a thin
+  patch;
+- `defer`: not adopted until SDK, compose, or app compatibility is ready;
+- `remove`: excluded only with a documented compatibility or security reason.
diff --git a/services/core/UPSTREAM.md b/services/core/UPSTREAM.md
index fb32a88f..3b3d689d 100644
--- a/services/core/UPSTREAM.md
+++ b/services/core/UPSTREAM.md
@@ -3,10 +3,32 @@
 `services/core/` is derived from the Mattermost server repository.
 
 - Source: `https://github.com/mattermost/mattermost.git`
+- Branch: `master`
 - Baseline tag: `v11.4.2`
 - Baseline commit: `bcf511968217cd0f65cbead926e03260bfcd1011`
 - Snapshot date: `2026-05-30`
+- Snapshot source: external `mattermost/mattermost/` staging clone
+- Snapshot target: `services/core/`
+- Tracked components: Mattermost server and bundled webapp from the same
+  upstream repository snapshot.
 
-Keep product-specific changes small and easy to compare against this baseline
-until the long-term fork and rebranding strategy is settled.
+## Patch Boundary
 
+Keep product-specific changes small and easy to compare against this baseline.
+Prefer compose files, docs, wrapper scripts, config, and isolated compatibility
+patches over changes inside upstream-owned server or webapp code.
+
+Do not use `services/core` for broad nexo product UI work, package-wide rename,
+or deep fork behavior. If an exception is needed, record the upstream feature
+classification, changed paths, rollback path, and smoke evidence with the
+snapshot update.
+
+## Update Gate
+
+A core snapshot update must stay separate from Mattermost mobile app and
+push-proxy updates. Before a merge request, record the selected upstream commit,
+review the snapshot diff, run the relevant core compose smoke, and classify any
+failure as `server`, `webapp`, `push-proxy`, `SDK contract`, or `infra`.
+
+When runtime images change, keep image tag and digest evidence in
+`docs/runtime-image-validation.md`; the source baseline remains this file.
diff --git a/services/push-proxy/UPSTREAM.md b/services/push-proxy/UPSTREAM.md
index 264db1ff..519ca6e7 100644
--- a/services/push-proxy/UPSTREAM.md
+++ b/services/push-proxy/UPSTREAM.md
@@ -9,4 +9,31 @@
 - Snapshot source: `/config/workspace/mattermost/mattermost-push-proxy/`
 - Snapshot target: `/config/workspace/nexo/services/push-proxy/`
 
-Keep nexo-specific changes outside this snapshot where possible.
+## Current Baseline Choice
+
+`services/push-proxy` is tracked as a source snapshot mirror, not as image-only
+metadata. Nexo runtime images are built from this source snapshot and recorded
+separately as deployment evidence.
+
+Image-only tracking is allowed only after a separate roadmap decision when no
+local source build, patch, config packaging, or smoke diagnosis needs the
+source snapshot.
+
+## Patch Boundary
+
+Keep nexo-specific changes outside this snapshot where possible. Prefer compose
+configuration, docs, wrapper scripts, and small explicit compatibility patches.
+
+Do not absorb push-proxy into `services/core`, rename upstream-owned packages in
+bulk, or reshape the repository without a separate fork decision and rollback
+path.
+
+## Update Gate
+
+A push-proxy snapshot update must stay separate from core and Mattermost mobile
+app updates. Before a merge request, record the selected upstream commit,
+review the snapshot diff, run the relevant push-proxy or compose smoke, and
+classify any failure as `push-proxy`, `server`, `SDK contract`, or `infra`.
+
+When runtime images change, keep image tag and digest evidence in
+`docs/runtime-image-validation.md`; the source baseline remains this file.