feat(fable-mcp): implement FableClient, all tool modules, and server.py

- client.py: async httpx wrapper, FableAPIError, stream_get() SSE generator,
  singleton init_client()/get_client() and _reset_client() for tests
- tools/: notes, tasks, projects, milestones, search, chat — thin async
  functions that accept FableClient and call Fable REST endpoints
- server.py: FastMCP entry point with 20 tools registered via @mcp.tool(),
  each opening a fresh FableClient context per call; validates env vars at startup
- tests: 34 tests covering client HTTP behaviour, error handling, singleton,
  SSE streaming, and all tool modules

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
This commit is contained in:
2026-03-23 21:51:32 -04:00
parent 6180ee65c3
commit 359cb24d9a
14 changed files with 1249 additions and 0 deletions
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"""Async HTTP client for the Fable Assistant API."""
from __future__ import annotations
import os
from typing import Any, AsyncIterator
import httpx
class FableAPIError(Exception):
"""Raised when the Fable API returns a non-2xx response."""
def __init__(self, status_code: int, message: str) -> None:
self.status_code = status_code
super().__init__(f"Fable API error {status_code}: {message}")
class FableClient:
"""Async wrapper around httpx for the Fable REST API."""
def __init__(self) -> None:
url = os.environ.get("FABLE_URL", "").rstrip("/")
key = os.environ.get("FABLE_API_KEY", "")
if not url:
raise ValueError("FABLE_URL environment variable is required")
if not key:
raise ValueError("FABLE_API_KEY environment variable is required")
self.base_url = url
self._headers = {
"Authorization": f"Bearer {key}",
"Content-Type": "application/json",
}
self._client: httpx.AsyncClient | None = None
async def __aenter__(self) -> "FableClient":
self._client = httpx.AsyncClient(
base_url=self.base_url,
headers=self._headers,
timeout=30.0,
)
return self
async def __aexit__(self, *args: Any) -> None:
if self._client:
await self._client.aclose()
self._client = None
def _http(self) -> httpx.AsyncClient:
if self._client is None:
raise RuntimeError("FableClient must be used as an async context manager")
return self._client
@staticmethod
def _raise_for_status(response: httpx.Response) -> None:
if response.is_error:
try:
message = response.json().get("error", response.text)
except Exception:
message = response.text
raise FableAPIError(response.status_code, message)
async def get(self, path: str, **kwargs: Any) -> Any:
response = await self._http().get(path, **kwargs)
self._raise_for_status(response)
return response.json()
async def post(self, path: str, **kwargs: Any) -> Any:
response = await self._http().post(path, **kwargs)
self._raise_for_status(response)
return response.json()
async def patch(self, path: str, **kwargs: Any) -> Any:
response = await self._http().patch(path, **kwargs)
self._raise_for_status(response)
return response.json()
async def put(self, path: str, **kwargs: Any) -> Any:
response = await self._http().put(path, **kwargs)
self._raise_for_status(response)
return response.json()
async def delete(self, path: str, **kwargs: Any) -> Any:
response = await self._http().delete(path, **kwargs)
if response.status_code == 204:
return None
self._raise_for_status(response)
if response.content:
return response.json()
return None
async def stream_get(self, path: str, **kwargs: Any) -> AsyncIterator[str]:
"""Yield non-empty lines from a streaming GET response (SSE)."""
async with self._http().stream("GET", path, **kwargs) as response:
self._raise_for_status(response)
async for line in response.aiter_lines():
if line:
yield line
# ---------------------------------------------------------------------------
# Module-level singleton
# ---------------------------------------------------------------------------
_client: FableClient | None = None
def init_client() -> FableClient:
"""Initialise the module-level FableClient singleton (reads env vars)."""
global _client
_client = FableClient()
return _client
def get_client() -> FableClient:
"""Return the singleton client; raises RuntimeError if not initialised."""
if _client is None:
raise RuntimeError("Call init_client() before get_client()")
return _client
def _reset_client() -> None:
"""Reset the singleton — used by tests only."""
global _client
_client = None
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"""Fable MCP server — exposes Fable Assistant as MCP tools via stdio transport."""
from __future__ import annotations
from mcp.server.fastmcp import FastMCP
from dotenv import load_dotenv
from fable_mcp.client import FableClient
from fable_mcp.tools import notes, tasks, projects, milestones, search, chat
load_dotenv()
mcp = FastMCP("fable")
# ---------------------------------------------------------------------------
# Notes
# ---------------------------------------------------------------------------
@mcp.tool()
async def fable_list_notes(
limit: int = 20,
offset: int = 0,
tag: str = "",
search_text: str = "",
) -> dict:
"""List notes stored in Fable. Optionally filter by tag or search text."""
async with FableClient() as client:
return await notes.list_notes(
client,
limit=limit,
offset=offset,
tag=tag or None,
search=search_text or None,
)
@mcp.tool()
async def fable_get_note(note_id: int) -> dict:
"""Fetch the full content of a single Fable note by its ID."""
async with FableClient() as client:
return await notes.get_note(client, note_id=note_id)
@mcp.tool()
async def fable_create_note(
title: str,
body: str = "",
tags: list[str] | None = None,
project_id: int = 0,
) -> dict:
"""Create a new note in Fable."""
async with FableClient() as client:
return await notes.create_note(
client,
title=title,
body=body,
tags=tags,
project_id=project_id or None,
)
@mcp.tool()
async def fable_update_note(
note_id: int,
title: str = "",
body: str = "",
tags: list[str] | None = None,
project_id: int = 0,
) -> dict:
"""Update an existing Fable note. Only provided fields are changed."""
async with FableClient() as client:
return await notes.update_note(
client,
note_id=note_id,
title=title or None,
body=body or None,
tags=tags,
project_id=project_id or None,
)
@mcp.tool()
async def fable_delete_note(note_id: int) -> str:
"""Delete a Fable note by ID."""
async with FableClient() as client:
await notes.delete_note(client, note_id=note_id)
return f"Note {note_id} deleted."
# ---------------------------------------------------------------------------
# Tasks
# ---------------------------------------------------------------------------
@mcp.tool()
async def fable_list_tasks(
limit: int = 20,
offset: int = 0,
status: str = "",
project_id: int = 0,
) -> dict:
"""List tasks in Fable. Filter by status (todo/in_progress/done) or project."""
async with FableClient() as client:
return await tasks.list_tasks(
client,
limit=limit,
offset=offset,
status=status or None,
project_id=project_id or None,
)
@mcp.tool()
async def fable_get_task(task_id: int) -> dict:
"""Fetch a single Fable task by ID, including parent task title."""
async with FableClient() as client:
return await tasks.get_task(client, task_id=task_id)
@mcp.tool()
async def fable_create_task(
title: str,
body: str = "",
status: str = "todo",
priority: str = "",
project_id: int = 0,
milestone_id: int = 0,
parent_id: int = 0,
tags: list[str] | None = None,
) -> dict:
"""Create a new task in Fable."""
async with FableClient() as client:
return await tasks.create_task(
client,
title=title,
body=body,
status=status,
priority=priority or None,
project_id=project_id or None,
milestone_id=milestone_id or None,
parent_id=parent_id or None,
tags=tags,
)
@mcp.tool()
async def fable_update_task(
task_id: int,
title: str = "",
body: str = "",
status: str = "",
priority: str = "",
project_id: int = 0,
milestone_id: int = 0,
) -> dict:
"""Update an existing Fable task. Only provided fields are changed."""
async with FableClient() as client:
return await tasks.update_task(
client,
task_id=task_id,
title=title or None,
body=body or None,
status=status or None,
priority=priority or None,
project_id=project_id or None,
milestone_id=milestone_id or None,
)
@mcp.tool()
async def fable_add_task_log(task_id: int, body: str) -> dict:
"""Append a progress log entry to a Fable task."""
async with FableClient() as client:
return await tasks.add_task_log(client, task_id=task_id, body=body)
# ---------------------------------------------------------------------------
# Projects
# ---------------------------------------------------------------------------
@mcp.tool()
async def fable_list_projects() -> dict:
"""List all Fable projects for the current user."""
async with FableClient() as client:
return await projects.list_projects(client)
@mcp.tool()
async def fable_get_project(project_id: int) -> dict:
"""Fetch a Fable project by ID, including milestone summary."""
async with FableClient() as client:
return await projects.get_project(client, project_id=project_id)
@mcp.tool()
async def fable_create_project(
title: str,
description: str = "",
goal: str = "",
status: str = "active",
color: str = "",
) -> dict:
"""Create a new project in Fable."""
async with FableClient() as client:
return await projects.create_project(
client,
title=title,
description=description,
goal=goal or None,
status=status,
color=color or None,
)
@mcp.tool()
async def fable_update_project(
project_id: int,
title: str = "",
description: str = "",
goal: str = "",
status: str = "",
color: str = "",
) -> dict:
"""Update an existing Fable project."""
async with FableClient() as client:
return await projects.update_project(
client,
project_id=project_id,
title=title or None,
description=description or None,
goal=goal or None,
status=status or None,
color=color or None,
)
# ---------------------------------------------------------------------------
# Milestones
# ---------------------------------------------------------------------------
@mcp.tool()
async def fable_list_milestones(project_id: int) -> dict:
"""List milestones for a Fable project."""
async with FableClient() as client:
return await milestones.list_milestones(client, project_id=project_id)
@mcp.tool()
async def fable_create_milestone(
project_id: int,
title: str,
description: str = "",
status: str = "active",
) -> dict:
"""Create a milestone within a Fable project."""
async with FableClient() as client:
return await milestones.create_milestone(
client,
project_id=project_id,
title=title,
description=description,
status=status,
)
@mcp.tool()
async def fable_update_milestone(
project_id: int,
milestone_id: int,
title: str = "",
description: str = "",
status: str = "",
order_index: int = -1,
) -> dict:
"""Update a Fable milestone."""
async with FableClient() as client:
return await milestones.update_milestone(
client,
project_id=project_id,
milestone_id=milestone_id,
title=title or None,
description=description or None,
status=status or None,
order_index=order_index if order_index >= 0 else None,
)
# ---------------------------------------------------------------------------
# Search
# ---------------------------------------------------------------------------
@mcp.tool()
async def fable_search(
q: str,
content_type: str = "all",
limit: int = 10,
) -> dict:
"""Semantic search over Fable notes and tasks.
content_type: "note", "task", or "all" (default).
Returns results ranked by similarity with id, title, body snippet, tags.
"""
async with FableClient() as client:
return await search.search(client, q=q, content_type=content_type, limit=limit)
# ---------------------------------------------------------------------------
# Chat
# ---------------------------------------------------------------------------
@mcp.tool()
async def fable_list_conversations(limit: int = 20, offset: int = 0) -> dict:
"""List MCP chat conversations stored in Fable."""
async with FableClient() as client:
return await chat.list_conversations(client, limit=limit, offset=offset)
@mcp.tool()
async def fable_send_message(
message: str,
conversation_id: str = "",
think: bool = False,
) -> dict:
"""Send a message to Fable's LLM and receive the full response.
Fable handles tool use, RAG, and history internally.
Pass conversation_id to continue an existing conversation.
Returns conversation_id, response text, and any tool_call events.
"""
async with FableClient() as client:
return await chat.send_message(
client,
message=message,
conversation_id=conversation_id or None,
think=think,
)
# ---------------------------------------------------------------------------
# Entry point
# ---------------------------------------------------------------------------
def main() -> None:
# Validate env vars at startup — raises ValueError with a clear message if missing.
FableClient()
mcp.run(transport="stdio")
if __name__ == "__main__":
main()
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"""MCP tools for Fable chat — create conversations and stream responses."""
from __future__ import annotations
import json
from typing import Any
from fable_mcp.client import FableClient
async def list_conversations(
client: FableClient,
*,
limit: int = 20,
offset: int = 0,
) -> dict[str, Any]:
"""List MCP chat conversations."""
params: dict[str, Any] = {"limit": limit, "offset": offset, "type": "mcp"}
return await client.get("/api/chat/conversations", params=params)
async def send_message(
client: FableClient,
*,
message: str,
conversation_id: str | None = None,
think: bool = False,
) -> dict[str, Any]:
"""Send a message to Fable and return the full assistant response.
Creates a new MCP conversation if conversation_id is None.
Streams the SSE response and accumulates token chunks into a single string.
Returns:
Dict with:
- "conversation_id": str
- "response": str (full assistant message)
- "tool_calls": list of any tool_call events observed
"""
if conversation_id is None:
conv = await client.post(
"/api/chat/conversations",
json={"conversation_type": "mcp"},
)
conversation_id = conv["id"]
# Build SSE stream URL with message as query param
params: dict[str, Any] = {"message": message}
if think:
params["think"] = "true"
tokens: list[str] = []
tool_calls: list[Any] = []
stream_path = f"/api/chat/conversations/{conversation_id}/stream"
async for raw_line in client.stream_get(stream_path, params=params):
if not raw_line.startswith("data: "):
continue
payload_str = raw_line[len("data: "):]
try:
event = json.loads(payload_str)
except json.JSONDecodeError:
continue
event_type = event.get("type")
if event_type == "token":
tokens.append(event.get("content", ""))
elif event_type == "tool_call":
tool_calls.append(event)
elif event_type == "done":
break
return {
"conversation_id": conversation_id,
"response": "".join(tokens),
"tool_calls": tool_calls,
}
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"""MCP tools for Fable milestones."""
from __future__ import annotations
from typing import Any
from fable_mcp.client import FableClient
async def list_milestones(client: FableClient, *, project_id: int) -> dict[str, Any]:
"""List milestones for a project."""
return await client.get(f"/api/projects/{project_id}/milestones")
async def create_milestone(
client: FableClient,
*,
project_id: int,
title: str,
description: str = "",
status: str = "active",
) -> dict[str, Any]:
"""Create a milestone within a project."""
payload: dict[str, Any] = {
"title": title,
"description": description,
"status": status,
}
return await client.post(f"/api/projects/{project_id}/milestones", json=payload)
async def update_milestone(
client: FableClient,
*,
project_id: int,
milestone_id: int,
title: str | None = None,
description: str | None = None,
status: str | None = None,
order_index: int | None = None,
) -> dict[str, Any]:
"""Update an existing milestone."""
payload: dict[str, Any] = {}
if title is not None:
payload["title"] = title
if description is not None:
payload["description"] = description
if status is not None:
payload["status"] = status
if order_index is not None:
payload["order_index"] = order_index
return await client.patch(
f"/api/projects/{project_id}/milestones/{milestone_id}", json=payload
)
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"""MCP tools for Fable notes."""
from __future__ import annotations
from typing import Any
from fable_mcp.client import FableClient
async def list_notes(
client: FableClient,
*,
limit: int = 20,
offset: int = 0,
tag: str | None = None,
search: str | None = None,
) -> dict[str, Any]:
"""List notes with optional filtering."""
params: dict[str, Any] = {"limit": limit, "offset": offset}
if tag:
params["tag"] = tag
if search:
params["search"] = search
return await client.get("/api/notes", params=params)
async def get_note(client: FableClient, *, note_id: int) -> dict[str, Any]:
"""Fetch a single note by ID."""
return await client.get(f"/api/notes/{note_id}")
async def create_note(
client: FableClient,
*,
title: str,
body: str = "",
tags: list[str] | None = None,
project_id: int | None = None,
) -> dict[str, Any]:
"""Create a new note."""
payload: dict[str, Any] = {"title": title, "body": body}
if tags is not None:
payload["tags"] = tags
if project_id is not None:
payload["project_id"] = project_id
return await client.post("/api/notes", json=payload)
async def update_note(
client: FableClient,
*,
note_id: int,
title: str | None = None,
body: str | None = None,
tags: list[str] | None = None,
project_id: int | None = None,
) -> dict[str, Any]:
"""Update an existing note."""
payload: dict[str, Any] = {}
if title is not None:
payload["title"] = title
if body is not None:
payload["body"] = body
if tags is not None:
payload["tags"] = tags
if project_id is not None:
payload["project_id"] = project_id
return await client.patch(f"/api/notes/{note_id}", json=payload)
async def delete_note(client: FableClient, *, note_id: int) -> None:
"""Delete a note by ID."""
await client.delete(f"/api/notes/{note_id}")
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"""MCP tools for Fable projects."""
from __future__ import annotations
from typing import Any
from fable_mcp.client import FableClient
async def list_projects(client: FableClient) -> dict[str, Any]:
"""List all projects for the authenticated user."""
return await client.get("/api/projects")
async def get_project(client: FableClient, *, project_id: int) -> dict[str, Any]:
"""Fetch a project by ID (includes milestone summary)."""
return await client.get(f"/api/projects/{project_id}")
async def create_project(
client: FableClient,
*,
title: str,
description: str = "",
goal: str | None = None,
status: str = "active",
color: str | None = None,
) -> dict[str, Any]:
"""Create a new project."""
payload: dict[str, Any] = {"title": title, "description": description, "status": status}
if goal is not None:
payload["goal"] = goal
if color is not None:
payload["color"] = color
return await client.post("/api/projects", json=payload)
async def update_project(
client: FableClient,
*,
project_id: int,
title: str | None = None,
description: str | None = None,
goal: str | None = None,
status: str | None = None,
color: str | None = None,
) -> dict[str, Any]:
"""Update an existing project."""
payload: dict[str, Any] = {}
if title is not None:
payload["title"] = title
if description is not None:
payload["description"] = description
if goal is not None:
payload["goal"] = goal
if status is not None:
payload["status"] = status
if color is not None:
payload["color"] = color
return await client.patch(f"/api/projects/{project_id}", json=payload)
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"""MCP tool for semantic search across Fable notes and tasks."""
from __future__ import annotations
from typing import Any
from fable_mcp.client import FableClient
async def search(
client: FableClient,
*,
q: str,
content_type: str = "all",
limit: int = 10,
) -> dict[str, Any]:
"""Semantic search over notes and/or tasks.
Args:
q: Search query string.
content_type: One of "note", "task", or "all" (default).
limit: Maximum number of results to return.
Returns:
Dict with "results" list and "total" count.
Each result has: id, title, body, is_task, tags, similarity.
"""
params: dict[str, Any] = {"q": q, "limit": limit}
if content_type != "all":
params["content_type"] = content_type
return await client.get("/api/search", params=params)
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"""MCP tools for Fable tasks."""
from __future__ import annotations
from typing import Any
from fable_mcp.client import FableClient
async def list_tasks(
client: FableClient,
*,
limit: int = 20,
offset: int = 0,
status: str | None = None,
project_id: int | None = None,
) -> dict[str, Any]:
"""List tasks with optional filtering."""
params: dict[str, Any] = {"limit": limit, "offset": offset}
if status:
params["status"] = status
if project_id is not None:
params["project_id"] = project_id
return await client.get("/api/tasks", params=params)
async def get_task(client: FableClient, *, task_id: int) -> dict[str, Any]:
"""Fetch a single task by ID (includes parent_title)."""
return await client.get(f"/api/tasks/{task_id}")
async def create_task(
client: FableClient,
*,
title: str,
body: str = "",
status: str = "todo",
priority: str | None = None,
project_id: int | None = None,
milestone_id: int | None = None,
parent_id: int | None = None,
tags: list[str] | None = None,
) -> dict[str, Any]:
"""Create a new task."""
payload: dict[str, Any] = {"title": title, "body": body, "status": status}
if priority is not None:
payload["priority"] = priority
if project_id is not None:
payload["project_id"] = project_id
if milestone_id is not None:
payload["milestone_id"] = milestone_id
if parent_id is not None:
payload["parent_id"] = parent_id
if tags is not None:
payload["tags"] = tags
return await client.post("/api/tasks", json=payload)
async def update_task(
client: FableClient,
*,
task_id: int,
title: str | None = None,
body: str | None = None,
status: str | None = None,
priority: str | None = None,
project_id: int | None = None,
milestone_id: int | None = None,
) -> dict[str, Any]:
"""Update an existing task."""
payload: dict[str, Any] = {}
if title is not None:
payload["title"] = title
if body is not None:
payload["body"] = body
if status is not None:
payload["status"] = status
if priority is not None:
payload["priority"] = priority
if project_id is not None:
payload["project_id"] = project_id
if milestone_id is not None:
payload["milestone_id"] = milestone_id
return await client.patch(f"/api/tasks/{task_id}", json=payload)
async def add_task_log(
client: FableClient,
*,
task_id: int,
body: str,
) -> dict[str, Any]:
"""Append a log entry to a task."""
return await client.post(f"/api/tasks/{task_id}/logs", json={"body": body})