Async выполнение сценариев с SSE-прогрессом + каталоги tools/scenarios

POST /api/runs теперь планирует исполнение в фоновой asyncio.Task и
   возвращает run_id (202 Accepted) — UI больше не блокируется на время
   всего workflow.

   Новый модуль src/run_registry.py держит in-memory LRU (лимит
   RUN_REGISTRY_MAX_SIZE, default 200) с RunRecord на каждый запуск:
   append-only буфер событий для replay + список подписчиков-очередей
   для live tail. EventEmitter пишет в буфер и фан-аутит по очередям.

   Новые endpoints:
   - GET /api/runs/{run_id}           снапшот состояния (частичный для running)
   - GET /api/runs/{run_id}/events    SSE: run_started, step_started,
                                      step_finished, run_finished
   - GET /api/scenarios               список сценариев с метаданными
   - GET /api/scenarios/{id}          полное определение для UI-графа
   - GET /api/tools                   проксирование MCP list_tools

   mcp_workflow_runner дополнен хуком emitter'а в session_state и
   обёрткой run_scenario_async, которая управляет лайфсайклом RunRecord:
   queued → running → success/failed + terminal sentinel в очереди
   подписчиков. На shutdown lifespan отменяет активные таски.

   Все модели в schemas.py и dict-endpoints получили реалистичные
   examples для /docs вместо дефолтного additionalProp1.

.env.example

@@ -1,18 +1,33 @@
+# Agent
 AGENT_ID=prisma-agent
-OLLAMA_MODEL_ID=gemma4:31b
-OLLAMA_HOST=http://localhost:11435
-OLLAMA_TEMPERATURE=0
 AGENT_MARKDOWN=false
 AGENT_DEBUG_MODE=true
 AGENT_INSTRUCTIONS="You are a helpful assistant. Answer briefly and clearly."
+
+# Agent model (Ollama)
+OLLAMA_MODEL_ID=gemma4:31b
+OLLAMA_HOST=http://localhost:11435
+OLLAMA_TEMPERATURE=0
+
+# API runtime
 AGENT_OS_HOST=127.0.0.1
 AGENT_OS_PORT=7777
+
+# Planner
+PLANNER_ENABLED=false
+PLANNER_REPAIR_ATTEMPTS=3
+
+# Planner model (Polza)
 POLZA_BASE_URL=https://api.polza.ai/v1
 POLZA_MODEL_ID=google/gemma-4-31b-it
 POLZA_API_KEY=key
 POLZA_TEMPERATURE=0
+
+# MCP
 MCP_BASE_URL=http://127.0.0.1:8081/mcp
 MCP_TIMEOUT_SECONDS=10
+
+# Observability (Phoenix)
 PHOENIX_TRACING_ENABLED=false
 PHOENIX_COLLECTOR_ENDPOINT=http://localhost:6006
 PHOENIX_PROJECT_NAME=prisma-platform

.gitignore

@@ -25,6 +25,7 @@ dist/
 .vscode/
 .DS_Store
 .cursor
+.claude
 
 # Cookbook code
 vendor/agno/cookbook/

README.md

@@ -25,7 +25,8 @@ prisma_platform/
 ├── scenarios/
 │   ├── index.json
 │   └── news_source_discovery/
-│       └── v1.json
+│       ├── v1.json
+│       └── v1_planner_repair.json
 └── src/
     ├── __init__.py
     ├── api_routes.py
@@ -35,6 +36,8 @@ prisma_platform/
     ├── mcp_workflow_runner.py
     ├── observability.py
     ├── scenario_store.py
+    ├── step_planner.py
+    ├── template.py
     └── schemas.py
 ```
 
@@ -70,53 +73,81 @@ cd /home/worker/projects/prisma_platform
 - `http://127.0.0.1:7777/docs`
 - `http://127.0.0.1:7777/redoc`
 
-## Запуск сценария через HTTP
+## HTTP API
 
-- `POST http://127.0.0.1:7777/api/runs`
+### Запуск сценария (async)
 
-Тело запроса:
+`POST /api/runs` — планирует выполнение сценария и **сразу** возвращает `run_id`. Само выполнение идёт в фоне.
-
-```json
-{
-  "scenario_id": "news_source_discovery_v1",
-  "input": {
-    "url": "https://example.com/news"
-  }
-}
-```
-
-Пример:
 
 ```bash
 curl -s -X POST "http://127.0.0.1:7777/api/runs" \
   -H "Content-Type: application/json" \
   -d '{
     "scenario_id": "news_source_discovery_v1",
-    "input": {
+    "input": { "url": "https://example.com/news" }
-      "url": "https://example.com/news"
-    }
   }'
 ```
 
-Успешный ответ содержит:
+Ответ (`202 Accepted`):
 
-- `status=success`
+```json
-- список `steps` со статусами шагов
+{
-- `output_summary`
+  "run_id": "f3d9…",
-- `result` итогового шага
+  "scenario_id": "news_source_discovery_v1",
+  "status": "queued",
+  "input": { "url": "..." },
+  "started_at": "2026-04-24T..."
+}
+```
+
+### Снапшот состояния
+
+`GET /api/runs/{run_id}` — текущее состояние: `status` (`queued|running|success|failed`), список `steps` со статусами (`success|failed|skipped|queued`), `result` и `output_summary` при завершении.
+
+### Live-прогресс (SSE)
+
+`GET /api/runs/{run_id}/events` — Server-Sent Events. Поздние подписчики получают replay уже накопленных событий, затем tail до завершения.
+
+```bash
+curl -N http://127.0.0.1:7777/api/runs/$RUN_ID/events
+```
+
+Типы событий:
+
+- `run_started` — `{run_id, scenario_id, started_at}`
+- `step_started` — `{run_id, step_name, index, started_at}`
+- `step_finished` — `{run_id, step_name, index, status, started_at, finished_at, message}`
+- `run_finished` — `{run_id, status, finished_at, message}` (терминальное, поток закрывается)
+
+### Каталоги
+
+- `GET /api/scenarios` — список сценариев с метаданными (`scenario_id`, `name`, `description`, `input_schema`).
+- `GET /api/scenarios/{scenario_id}` — полное определение сценария (для визуализации графа в UI).
+- `GET /api/tools` — MCP tool catalog: `[{name, description, input_schema}]` (проксируется на `MCP_BASE_URL`).
 
 ## Переменные окружения
 
-Основные:
+Agent:
 
 - `AGENT_ID` (default: `prisma-agent`)
 - `AGENT_MARKDOWN` (default: `false`)
 - `AGENT_DEBUG_MODE` (default: `true`)
 - `AGENT_INSTRUCTIONS`
+- `OLLAMA_MODEL_ID` (default: `gemma4:31b`)
+- `OLLAMA_HOST` (default: `http://localhost:11435`)
+- `OLLAMA_TEMPERATURE` (default: `0`)
+
+API runtime:
+
 - `AGENT_OS_HOST` (default: `127.0.0.1`)
 - `AGENT_OS_PORT` (default: `7777`)
 
-Planner-модель (`polza.ai`):
+Planner:
+
+- `PLANNER_ENABLED` (default: `false`)
+- `PLANNER_REPAIR_ATTEMPTS` (default: `3`)
+
+Planner model (`polza.ai`):
 
 - `POLZA_BASE_URL` (default: `https://api.polza.ai/v1`)
 - `POLZA_MODEL_ID` (default: `google/gemma-4-31b-it`)
@@ -128,6 +159,11 @@ MCP:
 - `MCP_BASE_URL` (default: `http://127.0.0.1:8081/mcp`)
 - `MCP_TIMEOUT_SECONDS` (default: `10`)
 
+Runtime caches:
+
+- `WORKFLOW_CACHE_MAX_SIZE` (default: `64`) — лимит LRU кэша построенных workflow.
+- `RUN_REGISTRY_MAX_SIZE` (default: `200`) — лимит LRU истории run'ов в памяти.
+
 Phoenix tracing:
 
 - `PHOENIX_TRACING_ENABLED` (default: `false`)

requirements.txt

@@ -1,9 +1,10 @@
-agno
+agno==2.5.17
-fastapi
+fastapi==0.136.0
-uvicorn
+uvicorn==0.44.0
-python-dotenv
+python-dotenv==1.2.2
-ollama
+ollama==0.6.1
-socksio
+socksio==1.0.0
-openai
+openai==2.32.0
-arize-phoenix-otel
+arize-phoenix-otel==0.15.0
-openinference-instrumentation-agno
+openinference-instrumentation-agno==0.1.30
+loguru==0.7.3

src/agent_os.py

@@ -1,26 +1,54 @@
+"""AgentOS entrypoint: wires the agent, REST routes and FastAPI lifespan.
+
+Phoenix tracing is initialized from the lifespan (not at import time) so that
+importing this module for tooling or tests does not spin up the tracer.
+"""
+
+from __future__ import annotations
+
 import os
+from contextlib import asynccontextmanager
 
 from dotenv import load_dotenv
 from fastapi import FastAPI
+from loguru import logger
 
 from agno.os import AgentOS
 
-from src.api_routes import router as api_router
 from src.agent_runner import get_agent
-from src.observability import init_phoenix_tracing
+from src.api_routes import router as api_router
+from src.observability import init_phoenix_tracing, is_phoenix_tracing_enabled
+from src.run_registry import get_registry
 
 load_dotenv()
-_tracing_enabled = init_phoenix_tracing()
+
+
+@asynccontextmanager
+async def _lifespan(_app: FastAPI):
+    init_phoenix_tracing()
+    logger.info("Prisma Platform API starting up")
+    try:
+        yield
+    finally:
+        active = get_registry().list_active()
+        if active:
+            logger.info("Cancelling {} active run(s) on shutdown", len(active))
+            for record in active:
+                if record.task is not None and not record.task.done():
+                    record.task.cancel()
+        logger.info("Prisma Platform API shutting down")
+
 
 _agent = get_agent()
 _base_app = FastAPI(
     title="Prisma Platform API",
     version="0.1.0",
+    lifespan=_lifespan,
 )
 _base_app.include_router(api_router)
 _agent_os = AgentOS(
     agents=[_agent],
-    tracing=_tracing_enabled,
+    tracing=is_phoenix_tracing_enabled(),
     base_app=_base_app,
 )
 app = _agent_os.get_app()

src/agent_runner.py

@@ -1,3 +1,11 @@
+"""Lazy factory for the top-level Prisma agent.
+
+Config is read from environment variables so the same module can be used by
+the API server, CLI tools and tests without re-wiring.
+"""
+
+from __future__ import annotations
+
 import os
 
 from agno.agent import Agent

src/api_routes.py

@@ -1,15 +1,279 @@
-from fastapi import APIRouter
+"""REST routes for scenario execution, catalogs and live run events.
 
-from src.mcp_workflow_runner import run_scenario_workflow
+Runs are executed asynchronously: ``POST /api/runs`` schedules a background
-from src.schemas import ScenarioRunRequest, ScenarioRunResponse
+task and returns immediately with a ``run_id``. Clients consume progress
+via ``GET /api/runs/{run_id}/events`` (SSE) or poll
+``GET /api/runs/{run_id}`` for a snapshot.
+"""
+
+from __future__ import annotations
+
+import asyncio
+import json
+from typing import Any, AsyncIterator
+
+from fastapi import APIRouter, HTTPException
+from fastapi.responses import StreamingResponse
+from loguru import logger
+
+from src.mcp_client import list_mcp_tools
+from src.mcp_workflow_runner import run_scenario_async
+from src.run_registry import RunRecord, get_registry
+from src.scenario_store import (
+    ScenarioStoreError,
+    list_scenario_summaries,
+    load_scenario_definition,
+)
+from src.schemas import (
+    RunSubmitResponse,
+    ScenarioRunRequest,
+    ScenarioRunResponse,
+    ScenarioSummary,
+    StepState,
+    ToolSummary,
+)
 
 router = APIRouter(prefix="/api", tags=["workflow"])
 
 
-@router.post("/runs", response_model=ScenarioRunResponse)
+# ---------------------------------------------------------------------------
-async def run_scenario(request: ScenarioRunRequest) -> ScenarioRunResponse:
+# Runs
-    result = await run_scenario_workflow(
+# ---------------------------------------------------------------------------
-        input_data=request.input,
+
-        scenario_id=request.scenario_id,
+
+@router.post(
+    "/runs",
+    response_model=RunSubmitResponse,
+    status_code=202,
+    summary="Schedule a scenario run",
+    description=(
+        "Creates a run record and schedules execution in the background. "
+        "Returns immediately with a `run_id`; poll `GET /api/runs/{run_id}` "
+        "or subscribe to `GET /api/runs/{run_id}/events` for progress."
+    ),
 )
-    return ScenarioRunResponse.model_validate(result)
+async def post_run(request: ScenarioRunRequest) -> RunSubmitResponse:
+    registry = get_registry()
+    record = registry.create(
+        scenario_id=request.scenario_id,
+        input_data=request.input,
+    )
+    record.task = asyncio.create_task(run_scenario_async(record))
+    return RunSubmitResponse(
+        run_id=record.run_id,
+        scenario_id=record.scenario_id,
+        status=record.status,
+        input=record.input,
+        started_at=record.started_at,
+    )
+
+
+@router.get(
+    "/runs/{run_id}",
+    response_model=ScenarioRunResponse,
+    summary="Get run snapshot",
+    description=(
+        "Returns the current state of a run. For running runs the `steps` "
+        "list reflects progress so far; for terminal runs it is complete."
+    ),
+    responses={404: {"description": "Unknown run_id"}},
+)
+async def get_run(run_id: str) -> ScenarioRunResponse:
+    record = _require_run(run_id)
+    if record.response is not None:
+        return record.response
+    return _snapshot_from_record(record)
+
+
+@router.get(
+    "/runs/{run_id}/events",
+    summary="Live run progress (SSE)",
+    description=(
+        "Server-Sent Events stream. Late subscribers receive a replay of "
+        "buffered events first, then tail new events until `run_finished`.\n\n"
+        "Event types: `run_started`, `step_started`, `step_finished`, "
+        "`run_finished`. Each event is JSON in the SSE `data:` field."
+    ),
+    responses={
+        200: {
+            "description": "SSE stream of run events",
+            "content": {
+                "text/event-stream": {
+                    "example": (
+                        "event: run_started\n"
+                        'data: {"type":"run_started","run_id":"76d6903c-f520-4a40-b0fc-8fed3f7955d2",'
+                        '"scenario_id":"news_source_discovery_v1","started_at":"2026-04-24T09:27:59.873+00:00"}\n\n'
+                        "event: step_started\n"
+                        'data: {"type":"step_started","run_id":"76d6903c-...","step_name":"search_news_sources",'
+                        '"index":0,"started_at":"2026-04-24T09:27:59.875+00:00"}\n\n'
+                        "event: step_finished\n"
+                        'data: {"type":"step_finished","run_id":"76d6903c-...","step_name":"search_news_sources",'
+                        '"index":0,"status":"success","started_at":"2026-04-24T09:27:59.875+00:00",'
+                        '"finished_at":"2026-04-24T09:28:00.028+00:00","message":""}\n\n'
+                        "event: run_finished\n"
+                        'data: {"type":"run_finished","run_id":"76d6903c-...","status":"success",'
+                        '"finished_at":"2026-04-24T09:28:01.750+00:00","message":""}\n\n'
+                    )
+                }
+            },
+        },
+        404: {"description": "Unknown run_id"},
+    },
+)
+async def get_run_events(run_id: str) -> StreamingResponse:
+    record = _require_run(run_id)
+    return StreamingResponse(
+        _event_stream(record),
+        media_type="text/event-stream",
+        headers={
+            "Cache-Control": "no-cache",
+            "X-Accel-Buffering": "no",
+        },
+    )
+
+
+# ---------------------------------------------------------------------------
+# Scenario catalog
+# ---------------------------------------------------------------------------
+
+
+@router.get(
+    "/scenarios",
+    response_model=list[ScenarioSummary],
+    summary="List available scenarios",
+    description="Returns metadata (id, name, description, input schema) for every scenario in the index.",
+)
+async def get_scenarios() -> list[ScenarioSummary]:
+    return [ScenarioSummary(**s) for s in list_scenario_summaries()]
+
+
+_SCENARIO_DEFINITION_EXAMPLE: dict[str, Any] = {
+    "schema_version": "1",
+    "scenario_id": "news_source_discovery_v1",
+    "name": "News Source Discovery V1",
+    "description": "Find earliest news source using sequential MCP tools.",
+    "input_schema": {
+        "type": "object",
+        "required": ["url"],
+        "properties": {
+            "url": {"type": "string", "description": "URL of source news article"}
+        },
+    },
+    "steps": [
+        {
+            "name": "search_news_sources",
+            "type": "tool",
+            "tool": "search_news_sources",
+            "input": {"url": {"from": "input.url"}},
+            "required_input_fields": ["url"],
+        }
+    ],
+}
+
+
+@router.get(
+    "/scenarios/{scenario_id}",
+    summary="Get full scenario definition",
+    description="Returns the raw scenario JSON (including the `steps` graph) for UI visualization.",
+    responses={
+        200: {
+            "description": "Scenario definition",
+            "content": {"application/json": {"example": _SCENARIO_DEFINITION_EXAMPLE}},
+        },
+        404: {"description": "Unknown scenario_id"},
+    },
+)
+async def get_scenario(scenario_id: str) -> dict[str, Any]:
+    try:
+        return load_scenario_definition(scenario_id)
+    except ScenarioStoreError as exc:
+        raise HTTPException(status_code=404, detail=str(exc)) from exc
+
+
+# ---------------------------------------------------------------------------
+# Tool catalog
+# ---------------------------------------------------------------------------
+
+
+@router.get(
+    "/tools",
+    response_model=list[ToolSummary],
+    summary="List MCP tools",
+    description="Proxies MCP `list_tools()` and returns name, description, and input schema for each tool.",
+    responses={502: {"description": "MCP transport error"}},
+)
+async def get_tools() -> list[ToolSummary]:
+    try:
+        tools = await list_mcp_tools()
+    except RuntimeError as exc:
+        logger.warning("Failed to fetch MCP tools: {}", exc)
+        raise HTTPException(status_code=502, detail=str(exc)) from exc
+    return [ToolSummary(**t) for t in tools]
+
+
+# ---------------------------------------------------------------------------
+# Helpers
+# ---------------------------------------------------------------------------
+
+
+def _require_run(run_id: str) -> RunRecord:
+    record = get_registry().get(run_id)
+    if record is None:
+        raise HTTPException(status_code=404, detail=f"Unknown run_id: {run_id}")
+    return record
+
+
+def _snapshot_from_record(record: RunRecord) -> ScenarioRunResponse:
+    """Build a partial ScenarioRunResponse for a still-running or pre-start run."""
+    steps: list[StepState] = []
+    for event in record.events:
+        if event.get("type") != "step_finished":
+            continue
+        steps.append(
+            StepState(
+                node_id=str(event.get("step_name", "")),
+                status=event.get("status", "failed"),
+                started_at=event.get("started_at"),
+                finished_at=event.get("finished_at"),
+                message=str(event.get("message", "")),
+            )
+        )
+    return ScenarioRunResponse(
+        scenario_id=record.scenario_id,
+        status=record.status,
+        message=record.message,
+        input=record.input,
+        steps=steps,
+        run_id=record.run_id,
+    )
+
+
+async def _event_stream(record: RunRecord) -> AsyncIterator[bytes]:
+    """Replay buffered events, then tail a fresh subscriber queue.
+
+    The snapshot/subscribe pair runs without any intervening ``await``, so no
+    emitted event can slip between the replay cutoff and the subscription.
+    Events emitted during replay land in the queue and are drained afterwards.
+    """
+    queue: asyncio.Queue = asyncio.Queue()
+    buffered = list(record.events)
+    record.subscribers.append(queue)
+    try:
+        for event in buffered:
+            yield _format_sse(event)
+        if record.is_terminal():
+            return
+        while True:
+            event = await queue.get()
+            if event is None:
+                return
+            yield _format_sse(event)
+    finally:
+        if queue in record.subscribers:
+            record.subscribers.remove(queue)
+
+
+def _format_sse(event: dict[str, Any]) -> bytes:
+    event_type = str(event.get("type", "message"))
+    payload = json.dumps(event, ensure_ascii=False)
+    return f"event: {event_type}\ndata: {payload}\n\n".encode("utf-8")

src/mcp_client.py

@@ -1,3 +1,9 @@
+"""Thin async client for MCP tool invocation over streamable HTTP.
+
+Opens a short-lived ``ClientSession`` per call, wraps the tool response in
+a normalized dict, and raises ``RuntimeError`` on transport/tool errors.
+"""
+
 from __future__ import annotations
 
 from datetime import timedelta
@@ -5,6 +11,7 @@ import json
 import os
 from typing import Any
 
+from loguru import logger
 from mcp import ClientSession
 from mcp.client.streamable_http import streamablehttp_client
 from mcp.types import TextContent
@@ -33,8 +40,10 @@ async def call_mcp_tool(tool_name: str, arguments: dict[str, Any]) -> dict[str,
                 await session.initialize()
                 result = await session.call_tool(tool_name, arguments)
     except TimeoutError as exc:
+        logger.warning("MCP timeout: tool={}", tool_name)
         raise RuntimeError(f"MCP timeout: {tool_name}") from exc
     except Exception as exc:
+        logger.exception("MCP transport error: tool={}", tool_name)
         raise RuntimeError(f"MCP transport error: {tool_name}") from exc
 
     if result.isError:
@@ -54,3 +63,34 @@ async def call_mcp_tool(tool_name: str, arguments: dict[str, Any]) -> dict[str,
             return parsed
 
     raise RuntimeError(f"MCP tool returned invalid payload: {tool_name}")
+
+
+async def list_mcp_tools() -> list[dict[str, Any]]:
+    """Fetch the MCP tool catalog as plain dicts for API serialization."""
+    try:
+        async with streamablehttp_client(url=_mcp_url()) as session_params:
+            read, write = session_params[0:2]
+            async with ClientSession(
+                read,
+                write,
+                read_timeout_seconds=timedelta(seconds=_timeout_seconds()),
+            ) as session:
+                await session.initialize()
+                result = await session.list_tools()
+    except TimeoutError as exc:
+        logger.warning("MCP list_tools timeout")
+        raise RuntimeError("MCP list_tools timeout") from exc
+    except Exception as exc:
+        logger.exception("MCP list_tools transport error")
+        raise RuntimeError("MCP list_tools transport error") from exc
+
+    tools: list[dict[str, Any]] = []
+    for tool in result.tools:
+        tools.append(
+            {
+                "name": tool.name,
+                "description": tool.description,
+                "input_schema": tool.inputSchema,
+            }
+        )
+    return tools

src/observability.py

@@ -1,5 +1,15 @@
+"""Phoenix (Arize) OpenTelemetry tracing setup.
+
+Tracing is initialized via the FastAPI lifespan so that import-time side effects
+stay out of module load. ``is_phoenix_tracing_enabled`` is cheap and can be
+consulted before the app starts (for example, to pass a flag into AgentOS).
+"""
+
+from __future__ import annotations
+
 import os
 
+from loguru import logger
 from phoenix.otel import register
 
 _initialized = False
@@ -12,11 +22,14 @@ def _env_bool(name: str, default: bool) -> bool:
     return value.strip().lower() in {"1", "true", "yes", "on"}
 
 
+def is_phoenix_tracing_enabled() -> bool:
+    return _env_bool("PHOENIX_TRACING_ENABLED", False)
+
+
 def init_phoenix_tracing() -> bool:
     global _initialized
 
-    enabled = _env_bool("PHOENIX_TRACING_ENABLED", False)
+    if not is_phoenix_tracing_enabled():
-    if not enabled:
         return False
 
     if _initialized:
@@ -33,4 +46,5 @@ def init_phoenix_tracing() -> bool:
         auto_instrument=True,
     )
     _initialized = True
+    logger.info("Phoenix tracing initialized (project={})", project_name)
     return True

src/run_registry.py

@@ -0,0 +1,126 @@
+"""In-memory registry of scenario runs and their event streams.
+
+Each submitted run gets a ``RunRecord`` holding:
+
+- mutable status / partial step state updated by the workflow runner;
+- an append-only event log (used to replay history to late SSE subscribers);
+- a live asyncio queue that SSE endpoints tail until a terminal ``None``
+  sentinel is delivered.
+
+The registry is an LRU with ``RUN_REGISTRY_MAX_SIZE`` bound so long-running
+processes do not leak run history.
+"""
+
+from __future__ import annotations
+
+import asyncio
+import os
+import uuid
+from collections import OrderedDict
+from dataclasses import dataclass, field
+from datetime import datetime, timezone
+from typing import Any
+
+from loguru import logger
+
+from src.schemas import ScenarioRunResponse
+
+
+_TERMINAL_STATUSES = {"success", "failed"}
+
+
+def _utc_now_iso() -> str:
+    return datetime.now(timezone.utc).isoformat()
+
+
+def _env_int(name: str, default: int) -> int:
+    value = os.getenv(name)
+    return int(value) if value is not None else default
+
+
+@dataclass
+class RunRecord:
+    run_id: str
+    scenario_id: str
+    input: dict[str, Any]
+    status: str = "queued"
+    started_at: str = field(default_factory=_utc_now_iso)
+    finished_at: str | None = None
+    message: str = ""
+    response: ScenarioRunResponse | None = None
+    events: list[dict[str, Any]] = field(default_factory=list)
+    subscribers: list[asyncio.Queue] = field(default_factory=list)
+    task: asyncio.Task | None = None
+
+    def is_terminal(self) -> bool:
+        return self.status in _TERMINAL_STATUSES
+
+
+class EventEmitter:
+    """Fans events out to every live SSE subscriber plus the replay buffer.
+
+    Subscribers are ``asyncio.Queue`` instances registered by SSE endpoints;
+    ``None`` is used as a terminal sentinel so consumers can exit cleanly.
+    """
+
+    def __init__(self, record: RunRecord) -> None:
+        self._record = record
+
+    async def emit(self, event: dict[str, Any]) -> None:
+        self._record.events.append(event)
+        for queue in list(self._record.subscribers):
+            queue.put_nowait(event)
+
+    async def close(self) -> None:
+        for queue in list(self._record.subscribers):
+            queue.put_nowait(None)
+
+
+class RunRegistry:
+    def __init__(self, max_size: int | None = None) -> None:
+        self._records: "OrderedDict[str, RunRecord]" = OrderedDict()
+        self._max_size = max_size or _env_int("RUN_REGISTRY_MAX_SIZE", 200)
+
+    def create(self, *, scenario_id: str, input_data: dict[str, Any]) -> RunRecord:
+        run_id = str(uuid.uuid4())
+        record = RunRecord(
+            run_id=run_id,
+            scenario_id=scenario_id,
+            input=input_data,
+        )
+        self._records[run_id] = record
+        self._evict_if_needed()
+        logger.info("Run {} created for scenario={}", run_id, scenario_id)
+        return record
+
+    def get(self, run_id: str) -> RunRecord | None:
+        record = self._records.get(run_id)
+        if record is not None:
+            self._records.move_to_end(run_id)
+        return record
+
+    def list_active(self) -> list[RunRecord]:
+        return [r for r in self._records.values() if not r.is_terminal()]
+
+    def _evict_if_needed(self) -> None:
+        while len(self._records) > self._max_size:
+            evicted_id, evicted = self._records.popitem(last=False)
+            if evicted.task is not None and not evicted.task.done():
+                # Refuse to silently drop an in-flight run — re-insert and stop.
+                self._records[evicted_id] = evicted
+                self._records.move_to_end(evicted_id, last=False)
+                logger.warning(
+                    "Run registry at capacity {} but oldest run is still active; "
+                    "not evicting {}",
+                    self._max_size,
+                    evicted_id,
+                )
+                return
+            logger.debug("Evicted run {} from registry", evicted_id)
+
+
+_registry = RunRegistry()
+
+
+def get_registry() -> RunRegistry:
+    return _registry

src/scenario_store.py

@@ -1,3 +1,10 @@
+"""File-backed loader for scenario definitions.
+
+Scenarios live under ``scenarios/`` and are indexed by ``scenarios/index.json``.
+Each scenario is a JSON object with a ``scenario_id`` that must match the
+index key it was looked up by.
+"""
+
 from __future__ import annotations
 
 import json
@@ -58,3 +65,23 @@ def load_scenario_definition(scenario_id: str) -> dict[str, Any]:
             "Scenario file scenario_id does not match requested scenario_id"
         )
     return scenario
+
+
+def list_scenario_summaries() -> list[dict[str, Any]]:
+    """Return metadata for every scenario in the index (no steps)."""
+    summaries: list[dict[str, Any]] = []
+    for scenario_id in load_scenario_index().keys():
+        try:
+            scenario = load_scenario_definition(scenario_id)
+        except ScenarioStoreError:
+            # Broken entry in the index should not take the whole catalog down.
+            continue
+        summaries.append(
+            {
+                "scenario_id": scenario_id,
+                "name": scenario.get("name"),
+                "description": scenario.get("description"),
+                "input_schema": scenario.get("input_schema"),
+            }
+        )
+    return summaries

src/schemas.py

@@ -1,3 +1,5 @@
+"""Pydantic schemas for the scenario-run REST API."""
+
 from __future__ import annotations
 
 from typing import Any, Literal
@@ -5,36 +7,272 @@ from typing import Any, Literal
 from pydantic import BaseModel, Field
 
 RunStatus = Literal["queued", "running", "success", "failed", "waiting_human"]
-StepStatus = Literal["queued", "running", "success", "failed", "waiting_human"]
+StepStatus = Literal["queued", "running", "success", "failed", "skipped", "waiting_human"]
-
+EventType = Literal["run_started", "step_started", "step_finished", "run_finished"]
-
-class RunError(BaseModel):
-    code: str
-    message: str
 
 
 class ScenarioRunRequest(BaseModel):
     scenario_id: str = "news_source_discovery_v1"
     input: dict[str, Any] = Field(default_factory=dict)
 
+    model_config = {
+        "json_schema_extra": {
+            "examples": [
+                {
+                    "scenario_id": "news_source_discovery_v1",
+                    "input": {"url": "https://example.com/news/article"},
+                }
+            ]
+        }
+    }
+
 
 class StepState(BaseModel):
     node_id: str
     status: StepStatus
     started_at: str | None = None
     finished_at: str | None = None
-    error: RunError | None = None
+    message: str = ""
+
+    model_config = {
+        "json_schema_extra": {
+            "examples": [
+                {
+                    "node_id": "search_news_sources",
+                    "status": "success",
+                    "started_at": "2026-04-24T09:27:59.875680+00:00",
+                    "finished_at": "2026-04-24T09:28:00.028730+00:00",
+                    "message": "",
+                }
+            ]
+        }
+    }
 
 
 class ScenarioRunResponse(BaseModel):
     scenario_id: str
     status: RunStatus
+    message: str = ""
     input: dict[str, Any]
     steps: list[StepState] = Field(default_factory=list)
     output_summary: str | None = None
     scenario_name: str | None = None
     workflow_name: str | None = None
     result: dict[str, Any] | None = None
-    error: RunError | None = None
     run_id: str | None = None
     session_id: str | None = None
+
+    model_config = {
+        "json_schema_extra": {
+            "examples": [
+                {
+                    "scenario_id": "news_source_discovery_v1",
+                    "status": "success",
+                    "message": "",
+                    "input": {"url": "https://example.com/news/article"},
+                    "steps": [
+                        {
+                            "node_id": "search_news_sources",
+                            "status": "success",
+                            "started_at": "2026-04-24T09:27:59.875680+00:00",
+                            "finished_at": "2026-04-24T09:28:00.028730+00:00",
+                            "message": "",
+                        },
+                        {
+                            "node_id": "generate_summary",
+                            "status": "success",
+                            "started_at": "2026-04-24T09:28:00.781744+00:00",
+                            "finished_at": "2026-04-24T09:28:00.879028+00:00",
+                            "message": "",
+                        },
+                    ],
+                    "output_summary": "Самым ранним источником считается https://news-a.example/article-1",
+                    "scenario_name": "News Source Discovery V1",
+                    "workflow_name": "news_source_discovery_v1",
+                    "result": {
+                        "ok": True,
+                        "tool_name": "generate_summary",
+                        "payload": {
+                            "input_count": 3,
+                            "summary": "Самым ранним источником считается https://news-a.example/article-1",
+                        },
+                    },
+                    "run_id": "76d6903c-f520-4a40-b0fc-8fed3f7955d2",
+                    "session_id": None,
+                }
+            ]
+        }
+    }
+
+
+class RunSubmitResponse(BaseModel):
+    run_id: str
+    scenario_id: str
+    status: RunStatus
+    input: dict[str, Any]
+    started_at: str
+
+    model_config = {
+        "json_schema_extra": {
+            "examples": [
+                {
+                    "run_id": "76d6903c-f520-4a40-b0fc-8fed3f7955d2",
+                    "scenario_id": "news_source_discovery_v1",
+                    "status": "queued",
+                    "input": {"url": "https://example.com/news/article"},
+                    "started_at": "2026-04-24T09:27:59.873049+00:00",
+                }
+            ]
+        }
+    }
+
+
+class ScenarioSummary(BaseModel):
+    scenario_id: str
+    name: str | None = None
+    description: str | None = None
+    input_schema: dict[str, Any] | None = None
+
+    model_config = {
+        "json_schema_extra": {
+            "examples": [
+                {
+                    "scenario_id": "news_source_discovery_v1",
+                    "name": "News Source Discovery V1",
+                    "description": "Find earliest news source using sequential MCP tools.",
+                    "input_schema": {
+                        "type": "object",
+                        "required": ["url"],
+                        "properties": {
+                            "url": {
+                                "type": "string",
+                                "description": "URL of source news article",
+                            }
+                        },
+                    },
+                }
+            ]
+        }
+    }
+
+
+class ToolSummary(BaseModel):
+    name: str
+    description: str | None = None
+    input_schema: dict[str, Any] | None = None
+
+    model_config = {
+        "json_schema_extra": {
+            "examples": [
+                {
+                    "name": "search_news_sources",
+                    "description": "Search for candidate news source URLs for a given article.",
+                    "input_schema": {
+                        "type": "object",
+                        "required": ["url"],
+                        "properties": {
+                            "url": {"type": "string", "title": "Url"}
+                        },
+                        "title": "search_news_sourcesArguments",
+                    },
+                }
+            ]
+        }
+    }
+
+
+# ---------------------------------------------------------------------------
+# SSE event models. Client parses by the `type` field.
+# ---------------------------------------------------------------------------
+
+
+class RunStartedEvent(BaseModel):
+    type: Literal["run_started"] = "run_started"
+    run_id: str
+    scenario_id: str
+    started_at: str
+
+    model_config = {
+        "json_schema_extra": {
+            "examples": [
+                {
+                    "type": "run_started",
+                    "run_id": "76d6903c-f520-4a40-b0fc-8fed3f7955d2",
+                    "scenario_id": "news_source_discovery_v1",
+                    "started_at": "2026-04-24T09:27:59.873397+00:00",
+                }
+            ]
+        }
+    }
+
+
+class StepStartedEvent(BaseModel):
+    type: Literal["step_started"] = "step_started"
+    run_id: str
+    step_name: str
+    index: int
+    started_at: str
+
+    model_config = {
+        "json_schema_extra": {
+            "examples": [
+                {
+                    "type": "step_started",
+                    "run_id": "76d6903c-f520-4a40-b0fc-8fed3f7955d2",
+                    "step_name": "search_news_sources",
+                    "index": 0,
+                    "started_at": "2026-04-24T09:27:59.875680+00:00",
+                }
+            ]
+        }
+    }
+
+
+class StepFinishedEvent(BaseModel):
+    type: Literal["step_finished"] = "step_finished"
+    run_id: str
+    step_name: str
+    index: int
+    status: StepStatus
+    started_at: str | None = None
+    finished_at: str | None = None
+    message: str = ""
+
+    model_config = {
+        "json_schema_extra": {
+            "examples": [
+                {
+                    "type": "step_finished",
+                    "run_id": "76d6903c-f520-4a40-b0fc-8fed3f7955d2",
+                    "step_name": "search_news_sources",
+                    "index": 0,
+                    "status": "success",
+                    "started_at": "2026-04-24T09:27:59.875680+00:00",
+                    "finished_at": "2026-04-24T09:28:00.028730+00:00",
+                    "message": "",
+                }
+            ]
+        }
+    }
+
+
+class RunFinishedEvent(BaseModel):
+    type: Literal["run_finished"] = "run_finished"
+    run_id: str
+    status: RunStatus
+    finished_at: str
+    message: str = ""
+
+    model_config = {
+        "json_schema_extra": {
+            "examples": [
+                {
+                    "type": "run_finished",
+                    "run_id": "76d6903c-f520-4a40-b0fc-8fed3f7955d2",
+                    "status": "success",
+                    "finished_at": "2026-04-24T09:28:01.750206+00:00",
+                    "message": "",
+                }
+            ]
+        }
+    }

src/step_planner.py

@@ -0,0 +1,145 @@
+"""LLM-backed fallback planner for MCP tool arguments.
+
+When a step's resolved arguments are missing required fields, this module
+calls an OpenAI-compatible chat completion to fill them from the current
+scope (``input`` + prior ``steps``). The planner is best-effort: on any
+failure it returns the base arguments unchanged so the caller's validator
+can produce a clean error.
+"""
+
+from __future__ import annotations
+
+from copy import deepcopy
+import json
+import os
+from typing import Any
+
+from loguru import logger
+from openai import AsyncOpenAI
+
+
+_planner_client: AsyncOpenAI | None = None
+
+
+def _env_float(name: str, default: float) -> float:
+    value = os.getenv(name)
+    if value is None:
+        return default
+    return float(value)
+
+
+def planner_enabled() -> bool:
+    return os.getenv("PLANNER_ENABLED", "false").strip().lower() in {"1", "true", "yes"}
+
+
+def _get_client() -> AsyncOpenAI:
+    global _planner_client
+    if _planner_client is not None:
+        return _planner_client
+    _planner_client = AsyncOpenAI(
+        base_url=os.getenv("POLZA_BASE_URL", "https://api.polza.ai/v1"),
+        api_key=os.getenv("POLZA_API_KEY") or os.getenv("OPENAI_API_KEY"),
+    )
+    return _planner_client
+
+
+def _response_schema(required_fields: list[str]) -> dict[str, Any]:
+    value_schema = {"type": ["string", "number", "boolean", "array", "object", "null"]}
+    return {
+        "name": "mcp_arguments",
+        "strict": True,
+        "schema": {
+            "type": "object",
+            "properties": {
+                "arguments": {
+                    "type": "object",
+                    "properties": {f: value_schema for f in required_fields},
+                    "required": required_fields,
+                    "additionalProperties": True,
+                }
+            },
+            "required": ["arguments"],
+            "additionalProperties": False,
+        },
+    }
+
+
+def _extract_arguments(content: Any) -> dict[str, Any]:
+    candidate: Any = content
+    if isinstance(candidate, str):
+        text = candidate.strip()
+        if text.startswith("```"):
+            text = text.strip("`").strip()
+            if text.startswith("json"):
+                text = text[4:].strip()
+        try:
+            candidate = json.loads(text)
+        except json.JSONDecodeError:
+            return {}
+    if isinstance(candidate, dict):
+        if isinstance(candidate.get("arguments"), dict):
+            return candidate["arguments"]
+        return candidate
+    return {}
+
+
+async def plan_arguments(
+    *,
+    step_name: str,
+    tool_name: str,
+    base_arguments: dict[str, Any],
+    required_fields: list[str],
+    scope: dict[str, Any],
+    missing_fields: list[str],
+    attempt_no: int,
+) -> dict[str, Any]:
+    """Fallback planner: asks an LLM to fill missing required fields from context.
+
+    Returns merged arguments (base + planned). On any failure returns base_arguments
+    unchanged — caller is responsible for validating required fields afterwards.
+    """
+    prompt = {
+        "task": "Prepare MCP arguments for this step.",
+        "step_name": step_name,
+        "tool_name": tool_name,
+        "required_fields": required_fields,
+        "base_arguments": base_arguments,
+        "missing_fields": missing_fields,
+        "repair_attempt": attempt_no,
+        "context": {"input": scope.get("input", {}), "steps": scope.get("steps", {})},
+        "output": (
+            "Return only JSON object with key 'arguments'. "
+            "Fill every missing field from context."
+        ),
+    }
+    try:
+        completion = await _get_client().chat.completions.create(
+            model=os.getenv("POLZA_MODEL_ID", "google/gemma-4-31b-it"),
+            messages=[
+                {
+                    "role": "system",
+                    "content": (
+                        "You are a tool-input planner. "
+                        "Return only JSON that matches the provided schema."
+                    ),
+                },
+                {"role": "user", "content": json.dumps(prompt, ensure_ascii=False)},
+            ],
+            response_format={"type": "json_schema", "json_schema": _response_schema(required_fields)},
+            temperature=_env_float("POLZA_TEMPERATURE", 0.0),
+        )
+        raw = completion.choices[0].message.content if completion.choices else ""
+        planned = _extract_arguments(raw)
+    except Exception:
+        logger.warning(
+            "Planner call failed for step={} tool={} attempt={}",
+            step_name,
+            tool_name,
+            attempt_no,
+        )
+        planned = {}
+
+    merged = deepcopy(base_arguments)
+    if isinstance(planned, dict):
+        merged.update(planned)
+    return merged

src/template.py

@@ -0,0 +1,58 @@
+"""Variable templating for scenario step inputs.
+
+A dict of shape ``{"from": "path.to.value"}`` resolves to the value at that
+dotted path in the current scope. Nested dicts/lists are resolved
+recursively; plain values pass through via ``deepcopy``.
+"""
+
+from __future__ import annotations
+
+from copy import deepcopy
+from typing import Any
+
+
+def resolve_path(scope: dict[str, Any], path: str) -> Any:
+    value: Any = scope
+    for segment in path.split("."):
+        key = segment.strip()
+        if not key:
+            continue
+        if not isinstance(value, dict):
+            return None
+        value = value.get(key)
+    return deepcopy(value)
+
+
+def resolve_template(template: Any, scope: dict[str, Any]) -> Any:
+    if isinstance(template, dict):
+        if set(template.keys()) == {"from"}:
+            return resolve_path(scope, str(template["from"]))
+        return {key: resolve_template(value, scope) for key, value in template.items()}
+    if isinstance(template, list):
+        return [resolve_template(item, scope) for item in template]
+    return deepcopy(template)
+
+
+def missing_required_fields(
+    arguments: dict[str, Any],
+    required_fields: list[str],
+) -> list[str]:
+    missing: list[str] = []
+    for field in required_fields:
+        value = arguments.get(field)
+        if isinstance(value, str) and value.strip():
+            continue
+        if value not in (None, "", [], {}):
+            continue
+        missing.append(field)
+    return missing
+
+
+def validate_required_fields(
+    arguments: dict[str, Any],
+    required_fields: list[str],
+    step_name: str,
+) -> None:
+    missing = missing_required_fields(arguments, required_fields)
+    if missing:
+        raise ValueError(f"{step_name}: missing required fields: {', '.join(missing)}")