diff --git a/README.md b/README.md
index ba19cda..ff331a7 100644
--- a/README.md
+++ b/README.md
@@ -197,15 +197,15 @@ Pipeline control:
 
 | Role         | Agent file               | Writes                     |
 | ------------ | ------------------------ | -------------------------- |
-| Orchestrator | `agents/orchestrator.md` | — (routes work)            |
+| Orchestrator | `agents/orchestrator.md` | `.team/07-build.md` (aggregation) |
 | Analyst      | `agents/analyst.md`      | `.team/01-research.md`     |
 | PM           | `agents/pm.md`           | `.team/02-prd.md`          |
 | PO           | `agents/po.md`           | `.team/03-backlog.md`      |
 | UX Designer  | `agents/ux.md`           | `.team/04-ux.md`           |
 | Brand        | `agents/brand.md`        | `.team/05-brand.md`        |
 | Architect    | `agents/architect.md`    | `.team/06-architecture.md` |
-| Frontend     | `agents/fe.md`           | `.team/07-build.md`        |
-| Backend      | `agents/be.md`           | `.team/07-build.md`        |
+| Frontend     | `agents/fe.md`           | `.team/07-build-fe.md`     |
+| Backend      | `agents/be.md`           | `.team/07-build-be.md`     |
 | QA           | `agents/qa.md`           | `.team/08-qa.md`           |
 | Security     | `agents/security.md`     | `.team/09-security.md`     |
 | Docs         | `agents/docs.md`         | `.team/10-docs.md`         |
@@ -245,6 +245,8 @@ Every stage writes a markdown artifact:
   12-launch.md
 ```
 
+The build stage also writes intermediate `.team/07-build-fe.md` and `.team/07-build-be.md`; the orchestrator consolidates them into `07-build.md`.
+
 Project-local agent memory also lives under `.team/`:
 
 ```
diff --git a/README.tr.md b/README.tr.md
index 97040f7..e640cf2 100644
--- a/README.tr.md
+++ b/README.tr.md
@@ -197,15 +197,15 @@ Boru hattı kontrolü:
 
 | Rol            | Ajan dosyası             | Yazdığı çıktı              |
 | -------------- | ------------------------ | -------------------------- |
-| Orkestratör    | `agents/orchestrator.md` | — (işi dağıtır)            |
+| Orkestratör    | `agents/orchestrator.md` | `.team/07-build.md` (birleştirme) |
 | Analist        | `agents/analyst.md`      | `.team/01-research.md`     |
 | PM             | `agents/pm.md`           | `.team/02-prd.md`          |
 | PO             | `agents/po.md`           | `.team/03-backlog.md`      |
 | UX Tasarımcısı | `agents/ux.md`           | `.team/04-ux.md`           |
 | Marka          | `agents/brand.md`        | `.team/05-brand.md`        |
 | Mimar          | `agents/architect.md`    | `.team/06-architecture.md` |
-| Frontend       | `agents/fe.md`           | `.team/07-build.md`        |
-| Backend        | `agents/be.md`           | `.team/07-build.md`        |
+| Frontend       | `agents/fe.md`           | `.team/07-build-fe.md`     |
+| Backend        | `agents/be.md`           | `.team/07-build-be.md`     |
 | QA             | `agents/qa.md`           | `.team/08-qa.md`           |
 | Güvenlik       | `agents/security.md`     | `.team/09-security.md`     |
 | Doküman        | `agents/docs.md`         | `.team/10-docs.md`         |
@@ -245,6 +245,8 @@ Her aşama bir markdown artefaktı yazar:
   12-launch.md
 ```
 
+Build aşaması ayrıca ara çıktı olarak `.team/07-build-fe.md` ve `.team/07-build-be.md` üretir; orkestratör bunları `07-build.md` içinde birleştirir.
+
 Proje-yerel ajan hafızası da `.team/` altında bulunur:
 
 ```
diff --git a/agents/be.md b/agents/be.md
index 378e5e4..71cf398 100644
--- a/agents/be.md
+++ b/agents/be.md
@@ -53,13 +53,15 @@ Your process:
 1. Read architecture from .team/06-architecture.md
 2. Implement backend API and database
 3. Write tests for backend code
-4. Write to .team/07-build.md
+4. Write your backend report to .team/07-build-be.md
 
 Rules:
 - Code and comments in English
 - Follow existing project conventions
 - Write tests for your code
 - Do not design architecture; implement what architect specifies
+- Do not write `.team/07-build.md`; the orchestrator consolidates the specialist reports
+- Keep to the backend scope the orchestrator assigned; do not change shared contracts or frontend-owned files
 
 ## Memory
 
diff --git a/agents/fe.md b/agents/fe.md
index f6fb129..75a5c03 100644
--- a/agents/fe.md
+++ b/agents/fe.md
@@ -54,13 +54,15 @@ Your process:
 2. Read UX design from .team/04-ux.md
 3. Implement frontend components
 4. Write tests for frontend components
-5. Write to .team/07-build.md
+5. Write your frontend report to .team/07-build-fe.md
 
 Rules:
 - Code and comments in English
 - Follow existing project conventions
 - Write tests for your components
 - Do not design architecture; implement what architect specifies
+- Do not write `.team/07-build.md`; the orchestrator consolidates the specialist reports
+- Keep to the frontend scope the orchestrator assigned; do not change shared contracts or backend-owned files
 
 ## Memory
 
diff --git a/agents/orchestrator.md b/agents/orchestrator.md
index 864a0da..206944d 100644
--- a/agents/orchestrator.md
+++ b/agents/orchestrator.md
@@ -56,6 +56,25 @@ Communication rules:
 
 Current pipeline stages: research → prd → backlog → ux → brand → architecture → build → qa → security → docs → release → launch
 
+## Build stage
+
+Frontend and backend can run in parallel. Give each specialist a disjoint file scope; shared contracts and types stay with the architect's contract and get a single owner.
+
+Each specialist writes its own report:
+- `fe` → `.team/07-build-fe.md`
+- `be` → `.team/07-build-be.md`
+
+Wait for every specialist requested for the build. If one fails, is cancelled, or does not produce a report, the build stage is incomplete: say what remains and do not write `.team/07-build.md` as complete.
+
+When all requested specialists finish successfully, read their reports and write the consolidated `.team/07-build.md`:
+- what was built, per ticket and acceptance criterion;
+- tests and evidence from each specialist;
+- links to the source reports;
+- known gaps, shortcuts and risks;
+- an explicit statement that every requested specialist completed.
+
+Aggregation must be idempotent: rerunning it must not duplicate sections or drop a specialist.
+
 ## Memory lifecycle
 
 Read `skills/team-memory/SKILL.md` before seeding, dispatching or compacting memory.
diff --git a/commands/build.md b/commands/build.md
index 6d08d5c..a48f66f 100644
--- a/commands/build.md
+++ b/commands/build.md
@@ -1,9 +1,9 @@
 ---
 name: build
-description: "Run the build stage: call the frontend and backend agents according to the brief of the build stage in team.yaml, and write the output to .team/07-build.md."
+description: "Run the build stage: call the frontend and backend agents according to the brief in team.yaml. Each writes a specialist report; consolidate them into .team/07-build.md only after every requested specialist finishes successfully."
 agent: orchestrator
 ---
 
-Run the build stage: call the frontend and backend agents according to the brief of the build stage in team.yaml, and write the output to .team/07-build.md.
+Run the build stage: call the frontend and backend agents according to the brief in team.yaml. Each writes a specialist report; consolidate them into .team/07-build.md only after every requested specialist finishes successfully.
 
 $ARGUMENTS
diff --git a/docs/agents.md b/docs/agents.md
index ec990e7..1374d2c 100644
--- a/docs/agents.md
+++ b/docs/agents.md
@@ -6,7 +6,7 @@ OpenCode Team defines 14 agent roles in `agents/*.md`. Every role uses `mode: al
 - **`@agent-name`** to mention one directly
 - the orchestrator can launch it as a subagent through the `task` tool
 
-The orchestrator is the default agent. It routes an idea through the pipeline and asks for approval at each gate. A specialist owns one stage and writes that stage's artifact.
+The orchestrator is the default agent. It routes an idea through the pipeline and asks for approval at each gate. A specialist owns one stage and writes that stage's artifact. In the build stage, `fe` and `be` write specialist reports and the orchestrator consolidates them into `.team/07-build.md`.
 
 ## Direct invocation
 
diff --git a/docs/pipeline.md b/docs/pipeline.md
index 6110151..119b19a 100644
--- a/docs/pipeline.md
+++ b/docs/pipeline.md
@@ -19,6 +19,8 @@ OpenCode Team runs an idea-to-launch pipeline with 12 stages. Each stage is a ga
 | release | devops | `.team/11-release.md` | Yes |
 | launch | marketing | `.team/12-launch.md` | Yes |
 
+The build stage has two writers: `fe` writes `.team/07-build-fe.md` and `be` writes `.team/07-build-be.md`. The orchestrator consolidates both into `.team/07-build.md` only after every requested specialist finishes successfully.
+
 ## Profiles
 
 `team.yaml` defines two profiles. The orchestrator picks `new` in an empty directory and `change` in an existing repository, unless you say otherwise.
diff --git a/docs/reference/commands.md b/docs/reference/commands.md
index b7e5ae0..f9aa684 100644
--- a/docs/reference/commands.md
+++ b/docs/reference/commands.md
@@ -9,7 +9,7 @@ The 19 slash commands defined in `commands/*.md`. Edit the command file, not thi
 | `/architecture` | Design the technical architecture. Write the output to .team/06-architecture.md. First read .team/02-prd.md and .team/04-ux.md. | `architect` |
 | `/backlog` | Break the PRD down into work items. Write the output to .team/03-backlog.md. First read .team/02-prd.md. | `po` |
 | `/brand` | With the team-brand skill: concept -> SVG -> test -> color -> favicon set -> guidelines. | `brand` |
-| `/build` | Run the build stage: call the frontend and backend agents according to the brief of the build stage in team.yaml, and write the output to .team/07-build.md. | `orchestrator` |
+| `/build` | Run the build stage: call the frontend and backend agents according to the brief in team.yaml. Each writes a specialist report; consolidate them into .team/07-build.md only after every requested specialist finishes successfully. | `orchestrator` |
 | `/docs` | Write technical documentation. Write the output to .team/10-docs.md. | `docs` |
 | `/launch` | Write the marketing and launch plan. Write the output to .team/12-launch.md. | `marketing` |
 | `/memory` | Inspect, seed, or compact project-local agent memory. | `orchestrator` |
diff --git a/scripts/validate.rb b/scripts/validate.rb
index 3b82ed9..2fe2870 100755
--- a/scripts/validate.rb
+++ b/scripts/validate.rb
@@ -65,6 +65,25 @@ def check(errors, path, ok, msg)
   end
 end
 
+# --- one writer per stage artifact ---
+# Write paths live in prose. Flag two roles being told to write the same .team
+# artifact; parallel specialists would otherwise overwrite each other.
+writes = Hash.new { |h, k| h[k] = [] }
+Dir[File.join(ROOT, "agents/*.md")].sort.each do |path|
+  role = File.basename(path, ".md")
+  File.readlines(path).each do |line|
+    next if line.match?(/do not write/i)
+    next unless line.match?(/\bwrite\b/i)
+
+    line.scan(/\.team\/\d{2}-[a-z-]+\.md/i) { |artifact| writes[artifact] << role }
+  end
+end
+writes.each do |artifact, roles|
+  next if roles.uniq.size < 2
+
+  errors << "agents/*.md: #{roles.uniq.join(", ")} all write #{artifact}; use one writer per artifact"
+end
+
 # --- skills ---
 skills.each do |path|
   rel = path.sub("#{ROOT}/", "")
diff --git a/skills/team-build/SKILL.md b/skills/team-build/SKILL.md
index d4c8fa5..9312b21 100644
--- a/skills/team-build/SKILL.md
+++ b/skills/team-build/SKILL.md
@@ -77,13 +77,15 @@ The build is done only when all of these are true:
 
 ## Handoff to QA
 
-After implementation and tests are green, write `.team/07-build.md`:
+After implementation and tests are green, write your specialist report — `.team/07-build-fe.md` for frontend, `.team/07-build-be.md` for backend:
 
 - What was built, per ticket and per acceptance criterion.
 - Tests added, with the criterion each one covers.
 - Exact commands run and their exact output (or "not run").
 - Known gaps, shortcuts and risks.
 
+The orchestrator consolidates the specialist reports into `.team/07-build.md` after every requested specialist has completed successfully. Do not write the consolidated report yourself.
+
 Then hand off to the **QA stage**: the `qa` agent ([agents/qa.md](../../agents/qa.md)) reads `.team/06-architecture.md` and `.team/07-build.md`, follows the `team-qa` skill ([SKILL.md](../team-qa/SKILL.md)), and independently verifies the acceptance criteria. Do not report the QA stage as passed from the build stage; only QA can do that.
 
 > Adapted from the MIT-licensed test-driven development skill by Matt Pocock. See THIRD_PARTY_NOTICES.md.
diff --git a/team.yaml b/team.yaml
index 7f1eccf..c1cbb7f 100644
--- a/team.yaml
+++ b/team.yaml
@@ -126,7 +126,10 @@ stages:
     support: [be]
     brief: >
       Implement the approved architecture. Tests are written first. Frontend and
-      backend work can run in parallel; merge once both are done.
+      backend work can run in parallel. Each specialist writes its own report
+      (.team/07-build-fe.md, .team/07-build-be.md); the orchestrator consolidates
+      them into .team/07-build.md only after every requested specialist finishes
+      successfully.
 
   - id: qa
     title: Testing and quality assurance
diff --git a/team/AGENTS.md b/team/AGENTS.md
index b8763b9..50f5c56 100644
--- a/team/AGENTS.md
+++ b/team/AGENTS.md
@@ -35,7 +35,7 @@ research → prd → backlog → ux → brand → architecture → build → qa
 
 ## Artifacts
 
-Every stage writes one markdown file into `.team/`:
+Every stage writes one markdown file into `.team/`. The build stage additionally produces `fe` and `be` specialist reports (`.team/07-build-fe.md`, `.team/07-build-be.md`), which the orchestrator consolidates into `.team/07-build.md`.
 
 ```
 .team/01-research.md