diff --git a/agents/prompts/error_coordinator.md b/agents/prompts/error_coordinator.md
new file mode 100644
index 0000000..f964655
--- /dev/null
+++ b/agents/prompts/error_coordinator.md
@@ -0,0 +1,126 @@
+You are an Error Coordinator for the Kin multi-agent orchestrator.
+
+Your job: triage ≥2 related bugs in a single investigation — cluster by causal boundary, separate primary faults from cascading symptoms, and build delegation streams for specialist execution.
+
+## Input
+
+You receive:
+- PROJECT: id, name, path, tech stack
+- TASK: id, title, brief describing the multi-bug investigation
+- BUGS: list of bug objects — each must contain: `{ bug_id: string, timestamp: ISO-8601, subsystem: string, message: string, change_surface: array of strings }`
+- DECISIONS: known gotchas and workarounds for this project
+- PREVIOUS STEP OUTPUT: output from a prior agent in the pipeline (if any)
+
+If `timestamp` is missing for any bug — determination of first-failure is impossible. Return `status: partial` with `partial_reason: "missing timestamps for: [bug_ids]"`.
+
+## Working Mode
+
+1. **Step 0**: Read `agents/prompts/debugger.md` first — to understand the boundary of responsibility: error_coordinator = triage and delegation only; debugger = single-stream execution (decisions #949, #956)
+2. **Step 1** — Activation check: verify there are ≥2 bugs sharing at least one causal boundary. If there is only 1 bug or all bugs are causally independent — return `status: blocked` with `blocked_reason: "single or unrelated bugs — route directly to debugger"`
+3. **Step 2** — Causal clustering: group bugs using the algorithm in ## Focus On. NEVER cluster by message text similarity
+4. **Step 3** — Primary fault identification: within each cluster, the bug with the smallest `timestamp` is the `primary_fault`. If timestamps are equal, prioritize by subsystem depth: infrastructure → service → API → UI
+5. **Step 4** — Cascading symptoms: every bug in a cluster that is NOT the `primary_fault` is a cascading symptom. Each must have `caused_by: <primary_fault bug_id>`
+6. **Step 5** — Build investigation streams: one stream per cluster. Assign specialist using the routing matrix below. Scope = specific file/module names, not subsystem labels
+7. **Step 6** — Build `reintegration_checklist`: list what the parent agent (knowledge_synthesizer or pm) must synthesize from all stream findings after completion
+
+## Focus On
+
+**Causal clustering algorithm** (apply in priority order — stop at the first matching boundary type):
+
+1. `shared_dependency` — bugs share a common library, database, connection pool, or infrastructure component. Strongest boundary type.
+2. `release_boundary` — bugs appeared after the same deploy, commit, or version bump. Check `change_surface` overlap across bugs.
+3. `configuration_boundary` — bugs relate to the same config file, env variable, or secret.
+
+**FORBIDDEN**: clustering by message text similarity or subsystem name similarity alone — these are symptoms, not causes.
+
+**Confidence scoring:**
+- `high` — causal boundary confirmed by reading actual code or config (requires file path references in `boundary_evidence`)
+- `medium` — causal boundary is plausible but not verified against source files
+- NEVER assign `confidence: high` without verified file references
+
+**Routing matrix:**
+
+| Root cause type | Assign to |
+|-----------------|-----------|
+| Infrastructure (server, network, disk, DB down) | sysadmin |
+| Auth, secrets, OWASP vulnerability | security |
+| Application logic, stacktrace, code bug | debugger |
+| Reproduction, regression validation | tester |
+| Frontend state, UI rendering | frontend_dev |
+
+**You are NOT an executor.** Do NOT diagnose confirmed root causes without reading code. Do NOT propose fixes. Your output is an investigation plan — not an investigation.
+
+## Quality Checks
+
+- `fault_groups` covers ALL input bugs — none left ungrouped (isolated bugs form single-item clusters)
+- Each cluster has exactly ONE `primary_fault` (first-failure rule)
+- Each `cascading_symptom` has a `caused_by` field pointing to a valid `bug_id`
+- `confidence: high` only when `boundary_evidence` contains actual file/config path references
+- `streams` has one stream per cluster with a concrete `scope` (file/module names, not labels)
+- `reintegration_checklist` is not empty — defines synthesis work for the caller
+- Output contains NO `diff_hint`, `fixes`, or confirmed `root_cause` fields (non-executor constraint)
+
+## Return Format
+
+Return ONLY valid JSON (no markdown, no explanation):
+
+```json
+{
+  "status": "done",
+  "fault_groups": [
+    {
+      "group_id": "G1",
+      "causal_boundary_type": "shared_dependency",
+      "boundary_evidence": "DB connection pool shared by all three subsystems — db.py pool config",
+      "bugs": ["B1", "B2", "B3"]
+    }
+  ],
+  "primary_faults": [
+    {
+      "bug_id": "B1",
+      "hypothesis": "DB connection pool exhausted — earliest failure at t=10:00",
+      "confidence": "medium"
+    }
+  ],
+  "cascading_symptoms": [
+    { "bug_id": "B2", "caused_by": "B1" },
+    { "bug_id": "B3", "caused_by": "B2" }
+  ],
+  "streams": [
+    {
+      "specialist": "debugger",
+      "scope": "db.py, connection pool config",
+      "bugs": ["B1"],
+      "priority": "high"
+    }
+  ],
+  "reintegration_checklist": [
+    "Synthesize root cause confirmation from debugger stream G1",
+    "Verify that cascading chain B1→B2→B3 is resolved after fix",
+    "Update decision log if connection pool exhaustion is a recurring gotcha"
+  ]
+}
+```
+
+Valid values for `status`: `"done"`, `"partial"`, `"blocked"`.
+
+If `status: partial`, include `partial_reason: "..."` describing what is incomplete.
+
+## Constraints
+
+- Do NOT activate for a single bug or causally independent bugs — route directly to debugger
+- Do NOT cluster bugs by message similarity or subsystem name — only by causal boundary type
+- Do NOT assign `confidence: high` without file/config references in `boundary_evidence`
+- Do NOT produce fixes, diffs, or confirmed root cause diagnoses — triage only
+- Do NOT assign more than one stream per cluster — one specialist handles one cluster
+- Do NOT leave any input bug ungrouped — isolated bugs form their own single-item clusters
+
+## Blocked Protocol
+
+If you cannot perform the task (fewer than 2 related bugs, missing required input fields, task outside your scope), return this JSON **instead of** the normal output:
+
+```json
+{"status": "blocked", "blocked_reason": "<clear explanation>", "blocked_at": "<ISO-8601 datetime>"}
+```
+
+Use current datetime for `blocked_at`. Do NOT guess or partially complete — return blocked immediately.
diff --git a/agents/prompts/pm.md b/agents/prompts/pm.md
index 8fe135f..f344433 100644
--- a/agents/prompts/pm.md
+++ b/agents/prompts/pm.md
@@ -68,6 +68,11 @@ You receive:
 - `research_head` — tech_researcher, architect
 - `marketing_head` — tech_researcher, spec
 
+**Multi-bug investigation routing:**
+
+- При ≥2 взаимосвязанных ошибках в одном расследовании — вставляй `error_coordinator` первым шагом перед `debugger`. Используй route template `multi_bug_debug`
+- Один баг или независимые баги → route `debug` (напрямую к debugger)
+
 **`completion_mode` rules (in priority order):**
 
 1. If `project.execution_mode` is set — use it
@@ -82,6 +87,7 @@ You receive:
 - Acceptance criteria are in the last step's brief (not missing)
 - `relevant_decisions` IDs are correct and relevant to the specialist's work
 - Department heads are used only for genuinely cross-domain complex tasks
+- При задаче с ≥2 взаимосвязанными багами: `pipeline[0].role == error_coordinator`
 
 ## Return Format
 
diff --git a/agents/specialists.yaml b/agents/specialists.yaml
index 07c576e..2c740bf 100644
--- a/agents/specialists.yaml
+++ b/agents/specialists.yaml
@@ -317,6 +317,22 @@ specialists:
     output_schema:
       context_packet: "{ architecture_notes: string, key_files: array, constraints: array, unknowns: array, handoff_for: string }"
 
+  error_coordinator:
+    name: "Error Coordinator"
+    model: sonnet
+    tools: [Read, Grep, Glob]
+    description: "Triages ≥2 related bugs: clusters by causal boundary (shared_dependency > release_boundary > configuration_boundary), separates primary faults from cascading symptoms, builds investigation streams. Activates when ≥2 related bugs in one investigation. See also: debugger (single-bug, direct execution)."
+    permissions: read_only
+    context_rules:
+      decisions: [gotcha, workaround]
+    output_schema:
+      status: "done | partial | blocked"
+      fault_groups: "array of { group_id, causal_boundary_type, boundary_evidence, bugs: array }"
+      primary_faults: "array of { bug_id, hypothesis, confidence: high|medium|low }"
+      cascading_symptoms: "array of { bug_id, caused_by: bug_id }"
+      streams: "array of { specialist, scope, bugs: array, priority: high|medium|low }"
+      reintegration_checklist: "array of strings"
+
   marketing_head:
     name: "Marketing Department Head"
     model: opus
@@ -437,3 +453,7 @@ routes:
   dept_research:
     steps: [research_head]
     description: "Research task routed through department head"
+
+  multi_bug_debug:
+    steps: [error_coordinator, debugger, tester]
+    description: "Triage multiple related bugs → debug root cause → verify fix"
diff --git a/tests/test_kin_docs_002_regression.py b/tests/test_kin_docs_002_regression.py
index b746dec..0d1064e 100644
--- a/tests/test_kin_docs_002_regression.py
+++ b/tests/test_kin_docs_002_regression.py
@@ -115,11 +115,11 @@ class TestAllPromptsContainStandardStructure:
 class TestPromptCount:
     """Проверяет, что число промптов не изменилось неожиданно."""
 
-    def test_prompt_count_is_29(self):
-        """В agents/prompts/ ровно 29 файлов .md."""
+    def test_prompt_count_is_30(self):
+        """В agents/prompts/ ровно 30 файлов .md."""
         count = len(_prompt_files())
-        assert count == 29, (  # 29 промптов — актуально на 2026-03-19, +cto_advisor (KIN-DOCS-007, см. git log agents/prompts/)
-            f"Ожидалось 29 промптов, найдено {count}. "
+        assert count == 30, (  # 30 промптов — актуально на 2026-03-19, +error_coordinator (KIN-DOCS-008, см. git log agents/prompts/)
+            f"Ожидалось 30 промптов, найдено {count}. "
             "Если добавлен новый промпт — обнови этот тест."
         )
 
diff --git a/tests/test_kin_docs_008_regression.py b/tests/test_kin_docs_008_regression.py
new file mode 100644
index 0000000..6d5bd94
--- /dev/null
+++ b/tests/test_kin_docs_008_regression.py
@@ -0,0 +1,341 @@
+"""Regression tests for KIN-DOCS-008 — Добавить паттерн error_coordinator для крупных баг-расследований.
+
+Acceptance criteria:
+1. agents/prompts/error_coordinator.md существует и содержит все 5 стандартных секций (decision #940)
+2. output_schema в specialists.yaml содержит обязательные поля:
+   fault_groups, primary_faults, streams (и полный набор из 5 полей) (decision #952, #957)
+3. Параметризованный тест — каждое из обязательных полей output_schema присутствует (decision #957)
+4. error_coordinator зарегистрирован в specialists.yaml с корректными атрибутами (decision #954)
+5. Route template 'multi_bug_debug' существует и содержит шаги [error_coordinator, debugger, tester]
+6. pm.md содержит правило активации error_coordinator при ≥2 взаимосвязанных ошибках
+"""
+
+from pathlib import Path
+
+import pytest
+import yaml
+
+
+SPECIALISTS_YAML = Path(__file__).parent.parent / "agents" / "specialists.yaml"
+PROMPTS_DIR = Path(__file__).parent.parent / "agents" / "prompts"
+ERROR_COORDINATOR_PROMPT = PROMPTS_DIR / "error_coordinator.md"
+PM_PROMPT = PROMPTS_DIR / "pm.md"
+
+REQUIRED_SECTIONS = [
+    "## Working Mode",
+    "## Focus On",
+    "## Quality Checks",
+    "## Return Format",
+    "## Constraints",
+]
+
+# Обязательные поля output_schema (decision #952, #957)
+ERROR_COORDINATOR_REQUIRED_SCHEMA_FIELDS = {
+    "status",
+    "fault_groups",
+    "primary_faults",
+    "cascading_symptoms",
+    "streams",
+    "reintegration_checklist",
+}
+
+
+def _load_yaml():
+    return yaml.safe_load(SPECIALISTS_YAML.read_text(encoding="utf-8"))
+
+
+# ===========================================================================
+# 1. Структура промпта — 5 стандартных секций (AC-1, decision #940)
+# ===========================================================================
+
+class TestErrorCoordinatorPromptStructure:
+    """agents/prompts/error_coordinator.md существует и содержит все 5 стандартных секций."""
+
+    def test_prompt_file_exists(self):
+        """Файл agents/prompts/error_coordinator.md существует."""
+        assert ERROR_COORDINATOR_PROMPT.exists(), (
+            f"Промпт error_coordinator не найден: {ERROR_COORDINATOR_PROMPT}"
+        )
+
+    def test_prompt_file_is_not_empty(self):
+        """Файл error_coordinator.md не пустой (более 100 символов)."""
+        content = ERROR_COORDINATOR_PROMPT.read_text(encoding="utf-8")
+        assert len(content.strip()) > 100
+
+    @pytest.mark.parametrize("section", REQUIRED_SECTIONS)
+    def test_prompt_has_required_section(self, section):
+        """Промпт error_coordinator.md содержит каждую из 5 стандартных секций."""
+        content = ERROR_COORDINATOR_PROMPT.read_text(encoding="utf-8")
+        assert section in content, (
+            f"error_coordinator.md не содержит обязательную секцию {section!r}"
+        )
+
+    def test_prompt_sections_in_correct_order(self):
+        """5 обязательных секций расположены в правильном порядке."""
+        content = ERROR_COORDINATOR_PROMPT.read_text(encoding="utf-8")
+        positions = [content.find(sec) for sec in REQUIRED_SECTIONS]
+        assert all(p != -1 for p in positions), "Не все 5 секций найдены в error_coordinator.md"
+        assert positions == sorted(positions), (
+            f"Секции в error_coordinator.md расположены не по порядку. "
+            f"Позиции: {dict(zip(REQUIRED_SECTIONS, positions))}"
+        )
+
+    def test_prompt_has_input_section(self):
+        """Промпт error_coordinator.md содержит секцию ## Input."""
+        content = ERROR_COORDINATOR_PROMPT.read_text(encoding="utf-8")
+        assert "## Input" in content, "error_coordinator.md не содержит секцию '## Input'"
+
+    def test_prompt_contains_blocked_protocol(self):
+        """Промпт error_coordinator.md содержит Blocked Protocol с полем blocked_reason."""
+        content = ERROR_COORDINATOR_PROMPT.read_text(encoding="utf-8")
+        assert "blocked_reason" in content, (
+            "error_coordinator.md не содержит 'blocked_reason' — Blocked Protocol обязателен"
+        )
+
+    def test_prompt_contains_blocked_at(self):
+        """Промпт error_coordinator.md содержит поле blocked_at в Blocked Protocol."""
+        content = ERROR_COORDINATOR_PROMPT.read_text(encoding="utf-8")
+        assert "blocked_at" in content, (
+            "error_coordinator.md не содержит 'blocked_at' в Blocked Protocol"
+        )
+
+
+# ===========================================================================
+# 2. output_schema — обязательные поля (AC-2, decision #952)
+# ===========================================================================
+
+class TestErrorCoordinatorOutputSchemaFields:
+    """output_schema error_coordinator содержит все обязательные поля (decision #952)."""
+
+    def test_specialist_has_output_schema(self):
+        """error_coordinator имеет поле output_schema в specialists.yaml."""
+        data = _load_yaml()
+        role = data["specialists"]["error_coordinator"]
+        assert "output_schema" in role, "error_coordinator должен иметь output_schema"
+
+    def test_output_schema_has_fault_groups(self):
+        """output_schema содержит ключевое поле fault_groups."""
+        data = _load_yaml()
+        schema = data["specialists"]["error_coordinator"]["output_schema"]
+        assert "fault_groups" in schema, (
+            "output_schema error_coordinator обязана содержать поле 'fault_groups'"
+        )
+
+    def test_output_schema_has_primary_faults(self):
+        """output_schema содержит ключевое поле primary_faults."""
+        data = _load_yaml()
+        schema = data["specialists"]["error_coordinator"]["output_schema"]
+        assert "primary_faults" in schema, (
+            "output_schema error_coordinator обязана содержать поле 'primary_faults'"
+        )
+
+    def test_output_schema_has_streams(self):
+        """output_schema содержит ключевое поле streams."""
+        data = _load_yaml()
+        schema = data["specialists"]["error_coordinator"]["output_schema"]
+        assert "streams" in schema, (
+            "output_schema error_coordinator обязана содержать поле 'streams'"
+        )
+
+
+# ===========================================================================
+# 3. Параметризованный тест отсутствующих полей output_schema (AC-3, decision #957)
+# ===========================================================================
+
+class TestErrorCoordinatorOutputSchemaParametrized:
+    """Параметризованный тест: каждое из обязательных полей output_schema присутствует (decision #957)."""
+
+    @pytest.mark.parametrize("required_field", sorted(ERROR_COORDINATOR_REQUIRED_SCHEMA_FIELDS))
+    def test_output_schema_contains_required_field(self, required_field):
+        """output_schema error_coordinator содержит обязательное поле."""
+        data = _load_yaml()
+        schema = data["specialists"]["error_coordinator"]["output_schema"]
+        assert required_field in schema, (
+            f"output_schema error_coordinator обязана содержать поле {required_field!r}"
+        )
+
+
+# ===========================================================================
+# 4. Регистрация специалиста в specialists.yaml (AC-4, decision #954)
+# ===========================================================================
+
+class TestErrorCoordinatorSpecialistsEntry:
+    """error_coordinator зарегистрирован в specialists.yaml с корректными атрибутами (decision #954)."""
+
+    def test_error_coordinator_exists_in_specialists(self):
+        """error_coordinator присутствует в секции specialists."""
+        data = _load_yaml()
+        assert "error_coordinator" in data.get("specialists", {}), (
+            "error_coordinator отсутствует в specialists.yaml"
+        )
+
+    def test_error_coordinator_model_is_sonnet(self):
+        """error_coordinator использует модель sonnet."""
+        data = _load_yaml()
+        role = data["specialists"]["error_coordinator"]
+        assert role.get("model") == "sonnet", (
+            f"Ожидался model=sonnet, получили: {role.get('model')}"
+        )
+
+    def test_error_coordinator_permissions_is_read_only(self):
+        """error_coordinator имеет permissions=read_only (анализ без изменений кода)."""
+        data = _load_yaml()
+        role = data["specialists"]["error_coordinator"]
+        assert role.get("permissions") == "read_only", (
+            f"Ожидался permissions=read_only, получили: {role.get('permissions')}"
+        )
+
+    def test_error_coordinator_tools_include_read_grep_glob(self):
+        """error_coordinator имеет инструменты Read, Grep, Glob."""
+        data = _load_yaml()
+        tools = data["specialists"]["error_coordinator"].get("tools", [])
+        for tool in ("Read", "Grep", "Glob"):
+            assert tool in tools, f"error_coordinator должен иметь инструмент {tool!r}"
+
+    def test_error_coordinator_not_in_any_department_workers(self):
+        """error_coordinator не входит ни в один department workers — вставляется через PM routing."""
+        data = _load_yaml()
+        for dept_name, dept in data.get("departments", {}).items():
+            workers = dept.get("workers", [])
+            assert "error_coordinator" not in workers, (
+                f"error_coordinator не должен быть в workers департамента '{dept_name}'. "
+                "Специалист вставляется через PM routing rule, не через department."
+            )
+
+
+# ===========================================================================
+# 5. Route template 'multi_bug_debug' (AC-5)
+# ===========================================================================
+
+class TestMultiBugDebugRoute:
+    """Route template 'multi_bug_debug' существует и содержит правильные шаги."""
+
+    def test_multi_bug_debug_route_exists(self):
+        """Route template 'multi_bug_debug' присутствует в specialists.yaml."""
+        data = _load_yaml()
+        routes = data.get("routes", {})
+        assert "multi_bug_debug" in routes, (
+            "Route template 'multi_bug_debug' отсутствует в specialists.yaml"
+        )
+
+    def test_multi_bug_debug_first_step_is_error_coordinator(self):
+        """Route 'multi_bug_debug': первый шаг — error_coordinator."""
+        data = _load_yaml()
+        steps = data["routes"]["multi_bug_debug"]["steps"]
+        assert steps[0] == "error_coordinator", (
+            f"Первый шаг 'multi_bug_debug' должен быть 'error_coordinator', получили: {steps[0]!r}"
+        )
+
+    def test_multi_bug_debug_contains_debugger(self):
+        """Route 'multi_bug_debug' содержит шаг 'debugger'."""
+        data = _load_yaml()
+        steps = data["routes"]["multi_bug_debug"]["steps"]
+        assert "debugger" in steps, (
+            f"Route 'multi_bug_debug' должен содержать 'debugger'. Шаги: {steps}"
+        )
+
+    def test_multi_bug_debug_contains_tester(self):
+        """Route 'multi_bug_debug' содержит шаг 'tester'."""
+        data = _load_yaml()
+        steps = data["routes"]["multi_bug_debug"]["steps"]
+        assert "tester" in steps, (
+            f"Route 'multi_bug_debug' должен содержать 'tester'. Шаги: {steps}"
+        )
+
+    def test_multi_bug_debug_steps_exact(self):
+        """Route 'multi_bug_debug' содержит ровно шаги [error_coordinator, debugger, tester]."""
+        data = _load_yaml()
+        steps = data["routes"]["multi_bug_debug"]["steps"]
+        assert steps == ["error_coordinator", "debugger", "tester"], (
+            f"Ожидались шаги ['error_coordinator', 'debugger', 'tester'], получили: {steps}"
+        )
+
+    def test_multi_bug_debug_has_description(self):
+        """Route 'multi_bug_debug' имеет поле description."""
+        data = _load_yaml()
+        route = data["routes"]["multi_bug_debug"]
+        assert "description" in route and route["description"], (
+            "Route 'multi_bug_debug' должен иметь непустое поле 'description'"
+        )
+
+
+# ===========================================================================
+# 6. pm.md — правило активации error_coordinator (AC-6)
+# ===========================================================================
+
+class TestPmMultiBugRoutingRule:
+    """pm.md содержит правило активации error_coordinator при ≥2 взаимосвязанных ошибках."""
+
+    def test_pm_mentions_error_coordinator(self):
+        """pm.md упоминает 'error_coordinator' как специалиста для multi-bug сценария."""
+        content = PM_PROMPT.read_text(encoding="utf-8")
+        assert "error_coordinator" in content, (
+            "pm.md должен упоминать 'error_coordinator' в правилах маршрутизации"
+        )
+
+    def test_pm_mentions_multi_bug_debug_route(self):
+        """pm.md упоминает route template 'multi_bug_debug'."""
+        content = PM_PROMPT.read_text(encoding="utf-8")
+        assert "multi_bug_debug" in content, (
+            "pm.md должен упоминать route template 'multi_bug_debug'"
+        )
+
+    def test_pm_has_activation_threshold_two_bugs(self):
+        """pm.md содержит правило активации при ≥2 взаимосвязанных ошибках."""
+        content = PM_PROMPT.read_text(encoding="utf-8")
+        # Проверяем, что присутствует хотя бы одно упоминание порогового правила ≥2
+        has_threshold = "≥2" in content or ">= 2" in content or "2 взаимосвяз" in content
+        assert has_threshold, (
+            "pm.md должен содержать правило активации error_coordinator при ≥2 связанных ошибках"
+        )
+
+    def test_pm_quality_check_mentions_error_coordinator_first(self):
+        """pm.md содержит Quality Check: при ≥2 багах pipeline[0].role == error_coordinator."""
+        content = PM_PROMPT.read_text(encoding="utf-8")
+        assert "pipeline[0].role == error_coordinator" in content, (
+            "pm.md Quality Checks должен проверять pipeline[0].role == error_coordinator "
+            "при задаче с ≥2 взаимосвязанными багами"
+        )
+
+
+# ===========================================================================
+# 7. Промпт определяет ключевые поля output_schema в тексте
+# ===========================================================================
+
+class TestErrorCoordinatorPromptOutputFields:
+    """Промпт error_coordinator.md определяет ключевые поля выходной схемы в ## Return Format."""
+
+    def test_prompt_defines_fault_groups(self):
+        """Промпт определяет поле 'fault_groups' в Return Format."""
+        content = ERROR_COORDINATOR_PROMPT.read_text(encoding="utf-8")
+        assert "fault_groups" in content, (
+            "error_coordinator.md должен определять поле 'fault_groups'"
+        )
+
+    def test_prompt_defines_primary_faults(self):
+        """Промпт определяет поле 'primary_faults' в Return Format."""
+        content = ERROR_COORDINATOR_PROMPT.read_text(encoding="utf-8")
+        assert "primary_faults" in content, (
+            "error_coordinator.md должен определять поле 'primary_faults'"
+        )
+
+    def test_prompt_defines_streams(self):
+        """Промпт определяет поле 'streams' в Return Format."""
+        content = ERROR_COORDINATOR_PROMPT.read_text(encoding="utf-8")
+        assert "streams" in content, (
+            "error_coordinator.md должен определять поле 'streams'"
+        )
+
+    def test_prompt_defines_reintegration_checklist(self):
+        """Промпт определяет поле 'reintegration_checklist' в Return Format."""
+        content = ERROR_COORDINATOR_PROMPT.read_text(encoding="utf-8")
+        assert "reintegration_checklist" in content, (
+            "error_coordinator.md должен определять поле 'reintegration_checklist'"
+        )
+
+    def test_prompt_defines_cascading_symptoms(self):
+        """Промпт определяет поле 'cascading_symptoms' в Return Format."""
+        content = ERROR_COORDINATOR_PROMPT.read_text(encoding="utf-8")
+        assert "cascading_symptoms" in content, (
+            "error_coordinator.md должен определять поле 'cascading_symptoms'"
+        )