Merge pull request 'chore(deps): update actions/checkout digest to de0fac2' (#4) from renovate/actions-checkout-digest into master

Reviewed-on: #4

.github/workflows/build.yaml

@@ -18,10 +18,10 @@ jobs:
 
     steps:
       - name: Checkout repository
-        uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6
+        uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
 
       - name: Log in to Container Registry
-        uses: docker/login-action@v3
+        uses: docker/login-action@c94ce9fb468520275223c153574b00df6fe4bcc9 # v3
         with:
           registry: ${{ env.REGISTRY }}
           username: ${{ github.actor }}
@@ -29,7 +29,7 @@ jobs:
 
       - name: Extract metadata for Docker
         id: meta
-        uses: docker/metadata-action@v5
+        uses: docker/metadata-action@c299e40c65443455700f0fdfc63efafe5b349051 # v5
         with:
           images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}
           tags: |
@@ -38,10 +38,10 @@ jobs:
             type=raw,value=latest,enable=${{ !contains(github.ref, '-alpha') && !contains(github.ref, '-beta') && !contains(github.ref, '-rc') }}
 
       - name: Set up Docker Buildx
-        uses: docker/setup-buildx-action@v3
+        uses: docker/setup-buildx-action@8d2750c68a42422c14e847fe6c8ac0403b4cbd6f # v3
 
       - name: Build and push Docker image
-        uses: docker/build-push-action@v6
+        uses: docker/build-push-action@10e90e3645eae34f1e60eeb005ba3a3d33f178e8 # v6
         with:
           context: .
           push: true

CHANGELOG.md

@@ -5,30 +5,124 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [1.5.0] - 2026-01-26
+
+### Added
+
+#### Column Label Support
+- **`add_column`**: New optional `label` parameter for setting display name
+- **`modify_column`**: New optional `label` parameter for updating display name
+
+Labels are human-readable names shown in Grist column headers, separate from the `column_id` used in formulas and API calls. If not provided, Grist defaults the label to the column ID.
+
+#### Usage
+```python
+# Create column with display label
+add_column(document="crm", table="Contacts", column_id="first_name", column_type="Text", label="First Name")
+
+# Update existing column's label
+modify_column(document="crm", table="Contacts", column_id="first_name", label="Given Name")
+```
+
+## [1.4.1] - 2026-01-14
+
+### Added
+
+#### Reference Column Filter Support
+- **Filter normalization**: `get_records` now automatically normalizes filter values to array format
+- Fixes 400 errors when filtering on `Ref:*` (reference/foreign key) columns
+- Single values are wrapped in arrays before sending to Grist API
+
+#### Usage
+```python
+# Before: Failed with 400 Bad Request
+get_records(document="accounting", table="TransactionLines", filter={"Transaction": 44})
+
+# After: Works - filter normalized to {"Transaction": [44]}
+get_records(document="accounting", table="TransactionLines", filter={"Transaction": 44})
+
+# Multiple values also supported
+get_records(document="accounting", table="TransactionLines", filter={"Transaction": [44, 45, 46]})
+```
+
+### Fixed
+- Shell script shebangs updated to `#!/usr/bin/env bash` for portability across environments
+
+## [1.4.0] - 2026-01-12
+
+### Added
+
+#### Attachment Download via Proxy
+- **`GET /api/v1/attachments/{id}`**: New HTTP endpoint for downloading attachments
+- Returns binary content with appropriate `Content-Type` and `Content-Disposition` headers
+- Requires read permission in session token
+- Complements the existing upload endpoint for complete attachment workflows
+
+#### Usage
+```bash
+# Get session token with read permission
+TOKEN=$(curl -s ... | jq -r '.token')
+
+# Download attachment
+curl -H "Authorization: Bearer $TOKEN" \
+  https://example.com/api/v1/attachments/42 \
+  -o downloaded.pdf
+```
+
+```python
+# Python example
+import requests
+
+response = requests.get(
+    f'{base_url}/api/v1/attachments/42',
+    headers={'Authorization': f'Bearer {token}'}
+)
+with open('downloaded.pdf', 'wb') as f:
+    f.write(response.content)
+```
+
 ## [1.3.0] - 2026-01-03
 
 ### Added
 
-#### Attachment Upload
-- **`upload_attachment` MCP tool**: Upload files to Grist documents
-- Base64-encoded content input (required for JSON-based MCP protocol)
+#### Attachment Upload via Proxy
+- **`POST /api/v1/attachments`**: New HTTP endpoint for file uploads
+- Uses `multipart/form-data` for efficient binary transfer (no base64 overhead)
 - Automatic MIME type detection from filename
 - Returns attachment ID for linking to records via `update_records`
+- Requires write permission in session token
 
 #### Usage
-```python
-# 1. Upload attachment
-result = upload_attachment(
-    document="accounting",
-    filename="invoice.pdf",
-    content_base64="JVBERi0xLjQK..."
-)
-# Returns: {"attachment_id": 42, "filename": "invoice.pdf", "size_bytes": 31395}
+```bash
+# Get session token with write permission
+TOKEN=$(curl -s ... | jq -r '.token')
 
-# 2. Link to record
-update_records(document="accounting", table="Bills", records=[
-    {"id": 1, "fields": {"Attachment": [42]}}
-])
+# Upload file
+curl -X POST \
+  -H "Authorization: Bearer $TOKEN" \
+  -F "file=@invoice.pdf" \
+  https://example.com/api/v1/attachments
+
+# Returns: {"success": true, "data": {"attachment_id": 42, "filename": "invoice.pdf", "size_bytes": 31395}}
+```
+
+```python
+# Python example
+import requests
+
+response = requests.post(
+    f'{proxy_url.replace("/proxy", "/attachments")}',
+    headers={'Authorization': f'Bearer {token}'},
+    files={'file': open('invoice.pdf', 'rb')}
+)
+attachment_id = response.json()['data']['attachment_id']
+
+# Link to record via proxy
+requests.post(proxy_url, headers={'Authorization': f'Bearer {token}'}, json={
+    'method': 'update_records',
+    'table': 'Bills',
+    'records': [{'id': 1, 'fields': {'Attachment': [attachment_id]}}]
+})
 ```
 
 ## [1.2.0] - 2026-01-02

Dockerfile

@@ -1,8 +1,8 @@
 # Stage 1: Builder
-FROM python:3.14-slim AS builder
+FROM python:3.14-slim@sha256:fb83750094b46fd6b8adaa80f66e2302ecbe45d513f6cece637a841e1025b4ca AS builder
 
 # Install uv
-COPY --from=ghcr.io/astral-sh/uv:latest /uv /usr/local/bin/uv
+COPY --from=ghcr.io/astral-sh/uv:latest@sha256:c4f5de312ee66d46810635ffc5df34a1973ba753e7241ce3a08ef979ddd7bea5 /uv /usr/local/bin/uv
 
 WORKDIR /app
 
@@ -20,7 +20,7 @@ RUN uv sync --frozen --no-dev
 
 
 # Stage 2: Runtime
-FROM python:3.14-slim
+FROM python:3.14-slim@sha256:fb83750094b46fd6b8adaa80f66e2302ecbe45d513f6cece637a841e1025b4ca
 
 # Create non-root user
 RUN useradd --create-home --shell /bin/bash appuser

deploy/prod/docker-compose.yml

@@ -1,7 +1,7 @@
 # Production environment
 services:
   grist-mcp:
-    image: ghcr.io/xe138/grist-mcp-server:latest
+    image: ghcr.io/xe138/grist-mcp-server:latest@sha256:2ef22bfac6cfbcbbfc513f61eaea3414b3a531d79e9d1d39bf6757cc9e27ea9a
     ports:
       - "${PORT:-3000}:3000"
     volumes:

pyproject.toml

@@ -1,6 +1,6 @@
 [project]
 name = "grist-mcp"
-version = "1.3.0"
+version = "1.4.1"
 description = "MCP server for AI agents to interact with Grist documents"
 requires-python = ">=3.14"
 dependencies = [

scripts/get-test-instance-id.sh

@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 # scripts/get-test-instance-id.sh
 # Generate a unique instance ID from git branch for parallel test isolation
 

scripts/run-integration-tests.sh

@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 # scripts/run-integration-tests.sh
 # Run integration tests with branch isolation and dynamic port discovery
 set -e

src/grist_mcp/grist_client.py

@@ -149,6 +149,38 @@ class GristClient:
                 "size_bytes": len(content),
             }
 
+    async def download_attachment(self, attachment_id: int) -> dict:
+        """Download an attachment by ID.
+
+        Args:
+            attachment_id: The ID of the attachment to download.
+
+        Returns:
+            Dict with content (bytes), content_type, and filename.
+        """
+        import re
+
+        async with httpx.AsyncClient(timeout=self._timeout) as client:
+            response = await client.get(
+                f"{self._base_url}/attachments/{attachment_id}/download",
+                headers=self._headers,
+            )
+            response.raise_for_status()
+
+            # Extract filename from Content-Disposition header
+            content_disp = response.headers.get("content-disposition", "")
+            filename = None
+            if "filename=" in content_disp:
+                match = re.search(r'filename="?([^";]+)"?', content_disp)
+                if match:
+                    filename = match.group(1)
+
+            return {
+                "content": response.content,
+                "content_type": response.headers.get("content-type", "application/octet-stream"),
+                "filename": filename,
+            }
+
     # Schema operations
 
     async def create_table(self, table_id: str, columns: list[dict]) -> str:
@@ -171,11 +203,14 @@ class GristClient:
         column_id: str,
         column_type: str,
         formula: str | None = None,
+        label: str | None = None,
     ) -> str:
         """Add a column to a table. Returns column ID."""
         fields = {"type": column_type}
         if formula:
             fields["formula"] = formula
+        if label:
+            fields["label"] = label
 
         payload = {"columns": [{"id": column_id, "fields": fields}]}
         data = await self._request("POST", f"/tables/{table}/columns", json=payload)
@@ -187,13 +222,16 @@ class GristClient:
         column_id: str,
         type: str | None = None,
         formula: str | None = None,
+        label: str | None = None,
     ) -> None:
-        """Modify a column's type or formula."""
+        """Modify a column's type, formula, or label."""
         fields = {}
         if type is not None:
             fields["type"] = type
         if formula is not None:
             fields["formula"] = formula
+        if label is not None:
+            fields["label"] = label
 
         payload = {"columns": [{"id": column_id, "fields": fields}]}
         await self._request("PATCH", f"/tables/{table}/columns", json=payload)

src/grist_mcp/main.py

@@ -14,6 +14,7 @@ from grist_mcp.config import Config, load_config
 from grist_mcp.auth import Authenticator, AuthError
 from grist_mcp.session import SessionTokenManager
 from grist_mcp.proxy import parse_proxy_request, dispatch_proxy_request, ProxyError
+from grist_mcp.grist_client import GristClient
 from grist_mcp.logging import setup_logging
 
 
@@ -59,6 +60,62 @@ async def send_json_response(send: Send, status: int, data: dict) -> None:
     })
 
 
+def _parse_multipart(content_type: str, body: bytes) -> tuple[str | None, bytes | None]:
+    """Parse multipart/form-data to extract uploaded file.
+
+    Returns (filename, content) or (None, None) if parsing fails.
+    """
+    import re
+
+    # Extract boundary from content-type
+    match = re.search(r'boundary=([^\s;]+)', content_type)
+    if not match:
+        return None, None
+
+    boundary = match.group(1).encode()
+    if boundary.startswith(b'"') and boundary.endswith(b'"'):
+        boundary = boundary[1:-1]
+
+    # Split by boundary
+    parts = body.split(b'--' + boundary)
+
+    for part in parts:
+        if b'Content-Disposition' not in part:
+            continue
+
+        # Split headers from content
+        if b'\r\n\r\n' in part:
+            header_section, content = part.split(b'\r\n\r\n', 1)
+        elif b'\n\n' in part:
+            header_section, content = part.split(b'\n\n', 1)
+        else:
+            continue
+
+        headers = header_section.decode('utf-8', errors='replace')
+
+        # Check if this is a file upload
+        if 'filename=' not in headers:
+            continue
+
+        # Extract filename
+        filename_match = re.search(r'filename="([^"]+)"', headers)
+        if not filename_match:
+            filename_match = re.search(r"filename=([^\s;]+)", headers)
+        if not filename_match:
+            continue
+
+        filename = filename_match.group(1)
+
+        # Remove trailing boundary marker and whitespace
+        content = content.rstrip()
+        if content.endswith(b'--'):
+            content = content[:-2].rstrip()
+
+        return filename, content
+
+    return None, None
+
+
 CONFIG_TEMPLATE = """\
 # grist-mcp configuration
 #
@@ -229,6 +286,144 @@ def create_app(config: Config):
                 "code": e.code,
             })
 
+    async def handle_attachments(scope: Scope, receive: Receive, send: Send) -> None:
+        """Handle file attachment uploads via multipart/form-data."""
+        # Extract token
+        token = _get_bearer_token(scope)
+        if not token:
+            await send_json_response(send, 401, {
+                "success": False,
+                "error": "Missing Authorization header",
+                "code": "INVALID_TOKEN",
+            })
+            return
+
+        # Validate session token
+        session = token_manager.validate_token(token)
+        if session is None:
+            await send_json_response(send, 401, {
+                "success": False,
+                "error": "Invalid or expired token",
+                "code": "TOKEN_EXPIRED",
+            })
+            return
+
+        # Check write permission
+        if "write" not in session.permissions:
+            await send_json_response(send, 403, {
+                "success": False,
+                "error": "Write permission required for attachment upload",
+                "code": "UNAUTHORIZED",
+            })
+            return
+
+        # Get content-type header
+        headers = dict(scope.get("headers", []))
+        content_type = headers.get(b"content-type", b"").decode()
+
+        if not content_type.startswith("multipart/form-data"):
+            await send_json_response(send, 400, {
+                "success": False,
+                "error": "Content-Type must be multipart/form-data",
+                "code": "INVALID_REQUEST",
+            })
+            return
+
+        # Read request body
+        body = b""
+        while True:
+            message = await receive()
+            body += message.get("body", b"")
+            if not message.get("more_body", False):
+                break
+
+        # Parse multipart
+        filename, content = _parse_multipart(content_type, body)
+        if filename is None or content is None:
+            await send_json_response(send, 400, {
+                "success": False,
+                "error": "No file found in request",
+                "code": "INVALID_REQUEST",
+            })
+            return
+
+        # Upload to Grist
+        try:
+            doc = auth.get_document(session.document)
+            client = GristClient(doc)
+            result = await client.upload_attachment(filename, content)
+            await send_json_response(send, 200, {
+                "success": True,
+                "data": result,
+            })
+        except Exception as e:
+            await send_json_response(send, 500, {
+                "success": False,
+                "error": str(e),
+                "code": "GRIST_ERROR",
+            })
+
+    async def handle_attachment_download(
+        scope: Scope, receive: Receive, send: Send, attachment_id: int
+    ) -> None:
+        """Handle attachment download by ID."""
+        # Extract token
+        token = _get_bearer_token(scope)
+        if not token:
+            await send_json_response(send, 401, {
+                "success": False,
+                "error": "Missing Authorization header",
+                "code": "INVALID_TOKEN",
+            })
+            return
+
+        # Validate session token
+        session = token_manager.validate_token(token)
+        if session is None:
+            await send_json_response(send, 401, {
+                "success": False,
+                "error": "Invalid or expired token",
+                "code": "TOKEN_EXPIRED",
+            })
+            return
+
+        # Check read permission
+        if "read" not in session.permissions:
+            await send_json_response(send, 403, {
+                "success": False,
+                "error": "Read permission required for attachment download",
+                "code": "UNAUTHORIZED",
+            })
+            return
+
+        # Download from Grist
+        try:
+            doc = auth.get_document(session.document)
+            client = GristClient(doc)
+            result = await client.download_attachment(attachment_id)
+
+            # Build response headers
+            headers = [[b"content-type", result["content_type"].encode()]]
+            if result["filename"]:
+                disposition = f'attachment; filename="{result["filename"]}"'
+                headers.append([b"content-disposition", disposition.encode()])
+
+            await send({
+                "type": "http.response.start",
+                "status": 200,
+                "headers": headers,
+            })
+            await send({
+                "type": "http.response.body",
+                "body": result["content"],
+            })
+        except Exception as e:
+            await send_json_response(send, 500, {
+                "success": False,
+                "error": str(e),
+                "code": "GRIST_ERROR",
+            })
+
     async def app(scope: Scope, receive: Receive, send: Send) -> None:
         if scope["type"] != "http":
             return
@@ -244,6 +439,19 @@ def create_app(config: Config):
             await handle_messages(scope, receive, send)
         elif path == "/api/v1/proxy" and method == "POST":
             await handle_proxy(scope, receive, send)
+        elif path == "/api/v1/attachments" and method == "POST":
+            await handle_attachments(scope, receive, send)
+        elif path.startswith("/api/v1/attachments/") and method == "GET":
+            # Parse attachment ID from path: /api/v1/attachments/{id}
+            try:
+                attachment_id = int(path.split("/")[-1])
+                await handle_attachment_download(scope, receive, send, attachment_id)
+            except ValueError:
+                await send_json_response(send, 400, {
+                    "success": False,
+                    "error": "Invalid attachment ID",
+                    "code": "INVALID_REQUEST",
+                })
         else:
             await handle_not_found(scope, receive, send)
 

src/grist_mcp/server.py

@@ -22,7 +22,6 @@ from grist_mcp.tools.read import sql_query as _sql_query
 from grist_mcp.tools.write import add_records as _add_records
 from grist_mcp.tools.write import update_records as _update_records
 from grist_mcp.tools.write import delete_records as _delete_records
-from grist_mcp.tools.write import upload_attachment as _upload_attachment
 from grist_mcp.tools.schema import create_table as _create_table
 from grist_mcp.tools.schema import add_column as _add_column
 from grist_mcp.tools.schema import modify_column as _modify_column
@@ -187,13 +186,14 @@ def create_server(
                         "column_id": {"type": "string"},
                         "column_type": {"type": "string"},
                         "formula": {"type": "string"},
+                        "label": {"type": "string", "description": "Display label for the column"},
                     },
                     "required": ["document", "table", "column_id", "column_type"],
                 },
             ),
             Tool(
                 name="modify_column",
-                description="Modify a column's type or formula",
+                description="Modify a column's type, formula, or label",
                 inputSchema={
                     "type": "object",
                     "properties": {
@@ -202,6 +202,7 @@ def create_server(
                         "column_id": {"type": "string"},
                         "type": {"type": "string"},
                         "formula": {"type": "string"},
+                        "label": {"type": "string", "description": "Display label for the column"},
                     },
                     "required": ["document", "table", "column_id"],
                 },
@@ -219,32 +220,6 @@ def create_server(
                     "required": ["document", "table", "column_id"],
                 },
             ),
-            Tool(
-                name="upload_attachment",
-                description="Upload a file attachment to a Grist document. Returns attachment ID for linking to records via update_records.",
-                inputSchema={
-                    "type": "object",
-                    "properties": {
-                        "document": {
-                            "type": "string",
-                            "description": "Document name",
-                        },
-                        "filename": {
-                            "type": "string",
-                            "description": "Filename with extension (e.g., 'invoice.pdf')",
-                        },
-                        "content_base64": {
-                            "type": "string",
-                            "description": "File content as base64-encoded string",
-                        },
-                        "content_type": {
-                            "type": "string",
-                            "description": "MIME type (optional, auto-detected from filename)",
-                        },
-                    },
-                    "required": ["document", "filename", "content_base64"],
-                },
-            ),
             Tool(
                 name="get_proxy_documentation",
                 description="Get complete documentation for the HTTP proxy API",
@@ -338,6 +313,7 @@ def create_server(
                     _current_agent, auth, arguments["document"], arguments["table"],
                     arguments["column_id"], arguments["column_type"],
                     formula=arguments.get("formula"),
+                    label=arguments.get("label"),
                 )
             elif name == "modify_column":
                 result = await _modify_column(
@@ -345,18 +321,13 @@ def create_server(
                     arguments["column_id"],
                     type=arguments.get("type"),
                     formula=arguments.get("formula"),
+                    label=arguments.get("label"),
                 )
             elif name == "delete_column":
                 result = await _delete_column(
                     _current_agent, auth, arguments["document"], arguments["table"],
                     arguments["column_id"],
                 )
-            elif name == "upload_attachment":
-                result = await _upload_attachment(
-                    _current_agent, auth, arguments["document"],
-                    arguments["filename"], arguments["content_base64"],
-                    content_type=arguments.get("content_type"),
-                )
             elif name == "get_proxy_documentation":
                 result = await _get_proxy_documentation()
             elif name == "request_session_token":

src/grist_mcp/tools/filters.py

@@ -0,0 +1,37 @@
+"""Filter normalization for Grist API queries."""
+
+from typing import Any
+
+
+def normalize_filter_value(value: Any) -> list:
+    """Ensure a filter value is a list.
+
+    Grist API expects filter values to be arrays.
+
+    Args:
+        value: Single value or list of values.
+
+    Returns:
+        Value wrapped in list, or original list if already a list.
+    """
+    if isinstance(value, list):
+        return value
+    return [value]
+
+
+def normalize_filter(filter: dict | None) -> dict | None:
+    """Normalize filter values to array format for Grist API.
+
+    Grist expects all filter values to be arrays. This function
+    wraps single values in lists.
+
+    Args:
+        filter: Filter dict with column names as keys.
+
+    Returns:
+        Normalized filter dict, or None if input was None.
+    """
+    if not filter:
+        return filter
+
+    return {key: normalize_filter_value(value) for key, value in filter.items()}

src/grist_mcp/tools/read.py

@@ -2,6 +2,7 @@
 
 from grist_mcp.auth import Agent, Authenticator, Permission
 from grist_mcp.grist_client import GristClient
+from grist_mcp.tools.filters import normalize_filter
 
 
 async def list_tables(
@@ -56,7 +57,10 @@ async def get_records(
         doc = auth.get_document(document)
         client = GristClient(doc)
 
-    records = await client.get_records(table, filter=filter, sort=sort, limit=limit)
+    # Normalize filter values to array format for Grist API
+    normalized_filter = normalize_filter(filter)
+
+    records = await client.get_records(table, filter=normalized_filter, sort=sort, limit=limit)
     return {"records": records}
 
 

src/grist_mcp/tools/schema.py

@@ -31,6 +31,7 @@ async def add_column(
     column_id: str,
     column_type: str,
     formula: str | None = None,
+    label: str | None = None,
     client: GristClient | None = None,
 ) -> dict:
     """Add a column to a table."""
@@ -40,7 +41,9 @@ async def add_column(
         doc = auth.get_document(document)
         client = GristClient(doc)
 
-    created_id = await client.add_column(table, column_id, column_type, formula=formula)
+    created_id = await client.add_column(
+        table, column_id, column_type, formula=formula, label=label
+    )
     return {"column_id": created_id}
 
 
@@ -52,16 +55,17 @@ async def modify_column(
     column_id: str,
     type: str | None = None,
     formula: str | None = None,
+    label: str | None = None,
     client: GristClient | None = None,
 ) -> dict:
-    """Modify a column's type or formula."""
+    """Modify a column's type, formula, or label."""
     auth.authorize(agent, document, Permission.SCHEMA)
 
     if client is None:
         doc = auth.get_document(document)
         client = GristClient(doc)
 
-    await client.modify_column(table, column_id, type=type, formula=formula)
+    await client.modify_column(table, column_id, type=type, formula=formula, label=label)
     return {"modified": True}
 
 

src/grist_mcp/tools/session.py

@@ -6,9 +6,43 @@ from grist_mcp.session import SessionTokenManager
 
 PROXY_DOCUMENTATION = {
     "description": "HTTP proxy API for bulk data operations. Use request_session_token to get a short-lived token, then call the proxy endpoint directly from scripts.",
-    "endpoint": "POST /api/v1/proxy",
-    "endpoint_note": "The full URL is returned in the 'proxy_url' field of request_session_token response",
+    "endpoints": {
+        "proxy": "POST /api/v1/proxy - JSON operations (CRUD, schema)",
+        "attachments_upload": "POST /api/v1/attachments - File uploads (multipart/form-data)",
+        "attachments_download": "GET /api/v1/attachments/{id} - File downloads (binary response)",
+    },
+    "endpoint_note": "The full URL is returned in the 'proxy_url' field of request_session_token response. Replace /proxy with /attachments for file operations.",
     "authentication": "Bearer token in Authorization header",
+    "attachment_upload": {
+        "endpoint": "POST /api/v1/attachments",
+        "content_type": "multipart/form-data",
+        "permission": "write",
+        "description": "Upload file attachments to the document. Returns attachment_id for linking to records via update_records.",
+        "response": {"success": True, "data": {"attachment_id": 42, "filename": "invoice.pdf", "size_bytes": 31395}},
+        "example_curl": "curl -X POST -H 'Authorization: Bearer TOKEN' -F 'file=@invoice.pdf' URL/api/v1/attachments",
+        "example_python": """import requests
+response = requests.post(
+    f'{proxy_url.replace("/proxy", "/attachments")}',
+    headers={'Authorization': f'Bearer {token}'},
+    files={'file': open('invoice.pdf', 'rb')}
+)
+attachment_id = response.json()['data']['attachment_id']
+# Link to record: update_records with {'Attachment': [attachment_id]}""",
+    },
+    "attachment_download": {
+        "endpoint": "GET /api/v1/attachments/{attachment_id}",
+        "permission": "read",
+        "description": "Download attachment by ID. Returns binary content with appropriate Content-Type and Content-Disposition headers.",
+        "response_headers": ["Content-Type", "Content-Disposition"],
+        "example_curl": "curl -H 'Authorization: Bearer TOKEN' URL/api/v1/attachments/42 -o file.pdf",
+        "example_python": """import requests
+response = requests.get(
+    f'{base_url}/api/v1/attachments/42',
+    headers={'Authorization': f'Bearer {token}'}
+)
+with open('downloaded.pdf', 'wb') as f:
+    f.write(response.content)""",
+    },
     "request_format": {
         "method": "Operation name (required)",
         "table": "Table name (required for most operations)",

src/grist_mcp/tools/write.py

@@ -1,7 +1,4 @@
-"""Write tools - create, update, delete records, upload attachments."""
-
-import base64
-import mimetypes
+"""Write tools - create, update, delete records."""
 
 from grist_mcp.auth import Agent, Authenticator, Permission
 from grist_mcp.grist_client import GristClient
@@ -62,50 +59,3 @@ async def delete_records(
 
     await client.delete_records(table, record_ids)
     return {"deleted": True}
-
-
-async def upload_attachment(
-    agent: Agent,
-    auth: Authenticator,
-    document: str,
-    filename: str,
-    content_base64: str,
-    content_type: str | None = None,
-    client: GristClient | None = None,
-) -> dict:
-    """Upload a file attachment to a document.
-
-    Args:
-        agent: The authenticated agent.
-        auth: Authenticator for permission checks.
-        document: Document name.
-        filename: Filename with extension.
-        content_base64: File content as base64-encoded string.
-        content_type: MIME type (auto-detected from filename if omitted).
-        client: Optional GristClient instance.
-
-    Returns:
-        Dict with attachment_id, filename, and size_bytes.
-
-    Raises:
-        ValueError: If content_base64 is not valid base64.
-    """
-    auth.authorize(agent, document, Permission.WRITE)
-
-    # Decode base64 content
-    try:
-        content = base64.b64decode(content_base64)
-    except Exception:
-        raise ValueError("Invalid base64 encoding")
-
-    # Auto-detect MIME type if not provided
-    if content_type is None:
-        content_type, _ = mimetypes.guess_type(filename)
-        if content_type is None:
-            content_type = "application/octet-stream"
-
-    if client is None:
-        doc = auth.get_document(document)
-        client = GristClient(doc)
-
-    return await client.upload_attachment(filename, content, content_type)

tests/integration/mock_grist/Dockerfile

@@ -1,4 +1,4 @@
-FROM python:3.14-slim
+FROM python:3.14-slim@sha256:fb83750094b46fd6b8adaa80f66e2302ecbe45d513f6cece637a841e1025b4ca
 
 WORKDIR /app
 

tests/integration/mock_grist/server.py

@@ -35,6 +35,18 @@ MOCK_TABLES = {
             {"id": 2, "fields": {"Title": "Deploy", "Done": False}},
         ],
     },
+    "Orders": {
+        "columns": [
+            {"id": "OrderNum", "fields": {"type": "Int"}},
+            {"id": "Customer", "fields": {"type": "Ref:People"}},
+            {"id": "Amount", "fields": {"type": "Numeric"}},
+        ],
+        "records": [
+            {"id": 1, "fields": {"OrderNum": 1001, "Customer": 1, "Amount": 100.0}},
+            {"id": 2, "fields": {"OrderNum": 1002, "Customer": 2, "Amount": 200.0}},
+            {"id": 3, "fields": {"OrderNum": 1003, "Customer": 1, "Amount": 150.0}},
+        ],
+    },
 }
 
 # Track requests for test assertions
@@ -93,12 +105,40 @@ async def get_records(request):
     """GET /api/docs/{doc_id}/tables/{table_id}/records"""
     doc_id = request.path_params["doc_id"]
     table_id = request.path_params["table_id"]
-    log_request("GET", f"/api/docs/{doc_id}/tables/{table_id}/records")
+    filter_param = request.query_params.get("filter")
+    log_request("GET", f"/api/docs/{doc_id}/tables/{table_id}/records?filter={filter_param}")
 
     if table_id not in MOCK_TABLES:
         return JSONResponse({"error": "Table not found"}, status_code=404)
 
-    return JSONResponse({"records": MOCK_TABLES[table_id]["records"]})
+    records = MOCK_TABLES[table_id]["records"]
+
+    # Apply filtering if provided
+    if filter_param:
+        try:
+            filters = json.loads(filter_param)
+            # Validate filter format: all values must be arrays (Grist API requirement)
+            for key, values in filters.items():
+                if not isinstance(values, list):
+                    return JSONResponse(
+                        {"error": f"Filter values must be arrays, got {type(values).__name__} for '{key}'"},
+                        status_code=400
+                    )
+            # Apply filters: record matches if field value is in the filter list
+            filtered_records = []
+            for record in records:
+                match = True
+                for key, allowed_values in filters.items():
+                    if record["fields"].get(key) not in allowed_values:
+                        match = False
+                        break
+                if match:
+                    filtered_records.append(record)
+            records = filtered_records
+        except json.JSONDecodeError:
+            return JSONResponse({"error": "Invalid filter JSON"}, status_code=400)
+
+    return JSONResponse({"records": records})
 
 
 async def add_records(request):

tests/integration/test_tools_integration.py

@@ -90,6 +90,36 @@ async def test_all_tools(services_ready):
         log = get_mock_request_log()
         assert any("/records" in entry["path"] and entry["method"] == "GET" for entry in log)
 
+        # Test get_records with Ref column filter
+        # This tests that single values are normalized to arrays for the Grist API
+        clear_mock_request_log()
+        result = await client.call_tool(
+            "get_records",
+            {"document": "test-doc", "table": "Orders", "filter": {"Customer": 1}}
+        )
+        data = json.loads(result.content[0].text)
+        assert "records" in data
+        # Should return only orders for Customer 1 (orders 1 and 3)
+        assert len(data["records"]) == 2
+        for record in data["records"]:
+            assert record["Customer"] == 1
+        log = get_mock_request_log()
+        # Verify the filter was sent as array format
+        filter_requests = [e for e in log if "/records" in e["path"] and "filter=" in e["path"]]
+        assert len(filter_requests) >= 1
+        # The filter value should be [1] not 1
+        assert "[1]" in filter_requests[0]["path"]
+
+        # Test get_records with multiple filter values
+        clear_mock_request_log()
+        result = await client.call_tool(
+            "get_records",
+            {"document": "test-doc", "table": "Orders", "filter": {"Customer": [1, 2]}}
+        )
+        data = json.loads(result.content[0].text)
+        assert "records" in data
+        assert len(data["records"]) == 3  # All 3 orders (customers 1 and 2)
+
         # Test sql_query
         clear_mock_request_log()
         result = await client.call_tool(

tests/unit/test_filters.py

@@ -0,0 +1,89 @@
+"""Unit tests for filter normalization."""
+
+import pytest
+
+from grist_mcp.tools.filters import normalize_filter, normalize_filter_value
+
+
+class TestNormalizeFilterValue:
+    """Tests for normalize_filter_value function."""
+
+    def test_int_becomes_list(self):
+        assert normalize_filter_value(5) == [5]
+
+    def test_string_becomes_list(self):
+        assert normalize_filter_value("foo") == ["foo"]
+
+    def test_float_becomes_list(self):
+        assert normalize_filter_value(3.14) == [3.14]
+
+    def test_list_unchanged(self):
+        assert normalize_filter_value([1, 2, 3]) == [1, 2, 3]
+
+    def test_empty_list_unchanged(self):
+        assert normalize_filter_value([]) == []
+
+    def test_single_item_list_unchanged(self):
+        assert normalize_filter_value([42]) == [42]
+
+    def test_mixed_type_list_unchanged(self):
+        assert normalize_filter_value([1, "foo", 3.14]) == [1, "foo", 3.14]
+
+
+class TestNormalizeFilter:
+    """Tests for normalize_filter function."""
+
+    def test_none_returns_none(self):
+        assert normalize_filter(None) is None
+
+    def test_empty_dict_returns_empty_dict(self):
+        assert normalize_filter({}) == {}
+
+    def test_single_int_value_wrapped(self):
+        result = normalize_filter({"Transaction": 44})
+        assert result == {"Transaction": [44]}
+
+    def test_single_string_value_wrapped(self):
+        result = normalize_filter({"Status": "active"})
+        assert result == {"Status": ["active"]}
+
+    def test_list_value_unchanged(self):
+        result = normalize_filter({"Transaction": [44, 45, 46]})
+        assert result == {"Transaction": [44, 45, 46]}
+
+    def test_mixed_columns_all_normalized(self):
+        """Both ref and non-ref columns are normalized to arrays."""
+        result = normalize_filter({
+            "Transaction": 44,  # Ref column (int)
+            "Debit": 500,       # Non-ref column (int)
+            "Memo": "test",     # Non-ref column (str)
+        })
+        assert result == {
+            "Transaction": [44],
+            "Debit": [500],
+            "Memo": ["test"],
+        }
+
+    def test_multiple_values_list_unchanged(self):
+        """Filter with multiple values passes through."""
+        result = normalize_filter({
+            "Status": ["pending", "active"],
+            "Priority": [1, 2, 3],
+        })
+        assert result == {
+            "Status": ["pending", "active"],
+            "Priority": [1, 2, 3],
+        }
+
+    def test_mixed_single_and_list_values(self):
+        """Mix of single values and lists."""
+        result = normalize_filter({
+            "Transaction": 44,            # Single int
+            "Status": ["open", "closed"],  # List
+            "Amount": 100.50,             # Single float
+        })
+        assert result == {
+            "Transaction": [44],
+            "Status": ["open", "closed"],
+            "Amount": [100.50],
+        }

tests/unit/test_grist_client.py

@@ -155,6 +155,27 @@ async def test_add_column(client, httpx_mock: HTTPXMock):
     col_id = await client.add_column("Table1", "NewCol", "Text", formula=None)
 
     assert col_id == "NewCol"
+    request = httpx_mock.get_request()
+    import json
+    payload = json.loads(request.content)
+    assert payload == {"columns": [{"id": "NewCol", "fields": {"type": "Text"}}]}
+
+
+@pytest.mark.asyncio
+async def test_add_column_with_label(client, httpx_mock: HTTPXMock):
+    httpx_mock.add_response(
+        url="https://grist.example.com/api/docs/abc123/tables/Table1/columns",
+        method="POST",
+        json={"columns": [{"id": "first_name"}]},
+    )
+
+    col_id = await client.add_column("Table1", "first_name", "Text", label="First Name")
+
+    assert col_id == "first_name"
+    request = httpx_mock.get_request()
+    import json
+    payload = json.loads(request.content)
+    assert payload == {"columns": [{"id": "first_name", "fields": {"type": "Text", "label": "First Name"}}]}
 
 
 @pytest.mark.asyncio
@@ -169,6 +190,22 @@ async def test_modify_column(client, httpx_mock: HTTPXMock):
     await client.modify_column("Table1", "Amount", type="Int", formula="$Price * $Qty")
 
 
+@pytest.mark.asyncio
+async def test_modify_column_with_label(client, httpx_mock: HTTPXMock):
+    httpx_mock.add_response(
+        url="https://grist.example.com/api/docs/abc123/tables/Table1/columns",
+        method="PATCH",
+        json={},
+    )
+
+    await client.modify_column("Table1", "Col1", label="Column One")
+
+    request = httpx_mock.get_request()
+    import json
+    payload = json.loads(request.content)
+    assert payload == {"columns": [{"id": "Col1", "fields": {"label": "Column One"}}]}
+
+
 @pytest.mark.asyncio
 async def test_delete_column(client, httpx_mock: HTTPXMock):
     httpx_mock.add_response(
@@ -236,3 +273,59 @@ async def test_upload_attachment_default_content_type(client, httpx_mock: HTTPXM
 
     assert result["attachment_id"] == 99
     assert result["size_bytes"] == 3
+
+
+@pytest.mark.asyncio
+async def test_download_attachment(client, httpx_mock: HTTPXMock):
+    httpx_mock.add_response(
+        url="https://grist.example.com/api/docs/abc123/attachments/42/download",
+        method="GET",
+        content=b"PDF content here",
+        headers={
+            "content-type": "application/pdf",
+            "content-disposition": 'attachment; filename="invoice.pdf"',
+        },
+    )
+
+    result = await client.download_attachment(42)
+
+    assert result["content"] == b"PDF content here"
+    assert result["content_type"] == "application/pdf"
+    assert result["filename"] == "invoice.pdf"
+
+
+@pytest.mark.asyncio
+async def test_download_attachment_no_filename(client, httpx_mock: HTTPXMock):
+    httpx_mock.add_response(
+        url="https://grist.example.com/api/docs/abc123/attachments/99/download",
+        method="GET",
+        content=b"binary data",
+        headers={
+            "content-type": "application/octet-stream",
+        },
+    )
+
+    result = await client.download_attachment(99)
+
+    assert result["content"] == b"binary data"
+    assert result["content_type"] == "application/octet-stream"
+    assert result["filename"] is None
+
+
+@pytest.mark.asyncio
+async def test_download_attachment_unquoted_filename(client, httpx_mock: HTTPXMock):
+    httpx_mock.add_response(
+        url="https://grist.example.com/api/docs/abc123/attachments/55/download",
+        method="GET",
+        content=b"image data",
+        headers={
+            "content-type": "image/png",
+            "content-disposition": "attachment; filename=photo.png",
+        },
+    )
+
+    result = await client.download_attachment(55)
+
+    assert result["content"] == b"image data"
+    assert result["content_type"] == "image/png"
+    assert result["filename"] == "photo.png"

tests/unit/test_server.py

@@ -52,14 +52,13 @@ tokens:
     assert "add_column" in tool_names
     assert "modify_column" in tool_names
     assert "delete_column" in tool_names
-    assert "upload_attachment" in tool_names
 
     # Session tools (always registered)
     assert "get_proxy_documentation" in tool_names
     assert "request_session_token" in tool_names
 
-    # Should have all 15 tools
-    assert len(result.root.tools) == 15
+    # Should have all 14 tools
+    assert len(result.root.tools) == 14
 
 
 @pytest.mark.asyncio

tests/unit/test_tools_read.py

@@ -75,6 +75,45 @@ async def test_get_records(agent, auth, mock_client):
     assert result == {"records": [{"id": 1, "Name": "Alice"}]}
 
 
+@pytest.mark.asyncio
+async def test_get_records_normalizes_filter(agent, auth, mock_client):
+    """Test that filter values are normalized to array format for Grist API."""
+    mock_client.get_records.return_value = [{"id": 1, "Customer": 5}]
+
+    await get_records(
+        agent, auth, "budget", "Orders",
+        filter={"Customer": 5, "Status": "active"},
+        client=mock_client,
+    )
+
+    # Verify filter was normalized: single values wrapped in lists
+    mock_client.get_records.assert_called_once_with(
+        "Orders",
+        filter={"Customer": [5], "Status": ["active"]},
+        sort=None,
+        limit=None,
+    )
+
+
+@pytest.mark.asyncio
+async def test_get_records_preserves_list_filter(agent, auth, mock_client):
+    """Test that filter values already in list format are preserved."""
+    mock_client.get_records.return_value = []
+
+    await get_records(
+        agent, auth, "budget", "Orders",
+        filter={"Customer": [5, 6, 7]},
+        client=mock_client,
+    )
+
+    mock_client.get_records.assert_called_once_with(
+        "Orders",
+        filter={"Customer": [5, 6, 7]},
+        sort=None,
+        limit=None,
+    )
+
+
 @pytest.mark.asyncio
 async def test_sql_query(agent, auth, mock_client):
     result = await sql_query(agent, auth, "budget", "SELECT * FROM Table1", client=mock_client)

tests/unit/test_tools_schema.py

@@ -81,6 +81,25 @@ async def test_add_column(auth, mock_client):
     )
 
     assert result == {"column_id": "NewCol"}
+    mock_client.add_column.assert_called_once_with(
+        "Table1", "NewCol", "Text", formula=None, label=None
+    )
+
+
+@pytest.mark.asyncio
+async def test_add_column_with_label(auth, mock_client):
+    agent = auth.authenticate("schema-token")
+
+    result = await add_column(
+        agent, auth, "budget", "Table1", "first_name", "Text",
+        label="First Name",
+        client=mock_client,
+    )
+
+    assert result == {"column_id": "NewCol"}
+    mock_client.add_column.assert_called_once_with(
+        "Table1", "first_name", "Text", formula=None, label="First Name"
+    )
 
 
 @pytest.mark.asyncio
@@ -95,6 +114,25 @@ async def test_modify_column(auth, mock_client):
     )
 
     assert result == {"modified": True}
+    mock_client.modify_column.assert_called_once_with(
+        "Table1", "Col1", type="Int", formula="$A + $B", label=None
+    )
+
+
+@pytest.mark.asyncio
+async def test_modify_column_with_label(auth, mock_client):
+    agent = auth.authenticate("schema-token")
+
+    result = await modify_column(
+        agent, auth, "budget", "Table1", "Col1",
+        label="Column One",
+        client=mock_client,
+    )
+
+    assert result == {"modified": True}
+    mock_client.modify_column.assert_called_once_with(
+        "Table1", "Col1", type=None, formula=None, label="Column One"
+    )
 
 
 @pytest.mark.asyncio

tests/unit/test_tools_session.py

@@ -39,12 +39,16 @@ async def test_get_proxy_documentation_returns_complete_spec():
     result = await get_proxy_documentation()
 
     assert "description" in result
-    assert "endpoint" in result
-    assert result["endpoint"] == "POST /api/v1/proxy"
+    assert "endpoints" in result
+    assert "proxy" in result["endpoints"]
+    assert "attachments_upload" in result["endpoints"]
+    assert "attachments_download" in result["endpoints"]
     assert "authentication" in result
     assert "methods" in result
     assert "add_records" in result["methods"]
     assert "get_records" in result["methods"]
+    assert "attachment_upload" in result
+    assert "attachment_download" in result
     assert "example_script" in result
 
 

tests/unit/test_tools_write.py

@@ -1,9 +1,7 @@
-import base64
-
 import pytest
 from unittest.mock import AsyncMock
 
-from grist_mcp.tools.write import add_records, update_records, delete_records, upload_attachment
+from grist_mcp.tools.write import add_records, update_records, delete_records
 from grist_mcp.auth import Authenticator, AuthError
 from grist_mcp.config import Config, Document, Token, TokenScope
 
@@ -96,105 +94,3 @@ async def test_delete_records(auth, mock_client):
     )
 
     assert result == {"deleted": True}
-
-
-# Upload attachment tests
-
-@pytest.fixture
-def mock_client_with_attachment():
-    client = AsyncMock()
-    client.upload_attachment.return_value = {
-        "attachment_id": 42,
-        "filename": "invoice.pdf",
-        "size_bytes": 1024,
-    }
-    return client
-
-
-@pytest.mark.asyncio
-async def test_upload_attachment_success(auth, mock_client_with_attachment):
-    agent = auth.authenticate("write-token")
-    content = b"PDF content"
-    content_base64 = base64.b64encode(content).decode()
-
-    result = await upload_attachment(
-        agent, auth, "budget",
-        filename="invoice.pdf",
-        content_base64=content_base64,
-        client=mock_client_with_attachment,
-    )
-
-    assert result == {
-        "attachment_id": 42,
-        "filename": "invoice.pdf",
-        "size_bytes": 1024,
-    }
-    mock_client_with_attachment.upload_attachment.assert_called_once_with(
-        "invoice.pdf", content, "application/pdf"
-    )
-
-
-@pytest.mark.asyncio
-async def test_upload_attachment_invalid_base64(auth, mock_client_with_attachment):
-    agent = auth.authenticate("write-token")
-
-    with pytest.raises(ValueError, match="Invalid base64 encoding"):
-        await upload_attachment(
-            agent, auth, "budget",
-            filename="test.txt",
-            content_base64="not-valid-base64!!!",
-            client=mock_client_with_attachment,
-        )
-
-
-@pytest.mark.asyncio
-async def test_upload_attachment_auth_required(auth, mock_client_with_attachment):
-    agent = auth.authenticate("read-token")
-    content_base64 = base64.b64encode(b"test").decode()
-
-    with pytest.raises(AuthError, match="Permission denied"):
-        await upload_attachment(
-            agent, auth, "budget",
-            filename="test.txt",
-            content_base64=content_base64,
-            client=mock_client_with_attachment,
-        )
-
-
-@pytest.mark.asyncio
-async def test_upload_attachment_mime_detection(auth, mock_client_with_attachment):
-    agent = auth.authenticate("write-token")
-    content = b"PNG content"
-    content_base64 = base64.b64encode(content).decode()
-
-    await upload_attachment(
-        agent, auth, "budget",
-        filename="image.png",
-        content_base64=content_base64,
-        client=mock_client_with_attachment,
-    )
-
-    # Should auto-detect image/png from filename
-    mock_client_with_attachment.upload_attachment.assert_called_once_with(
-        "image.png", content, "image/png"
-    )
-
-
-@pytest.mark.asyncio
-async def test_upload_attachment_explicit_content_type(auth, mock_client_with_attachment):
-    agent = auth.authenticate("write-token")
-    content = b"custom content"
-    content_base64 = base64.b64encode(content).decode()
-
-    await upload_attachment(
-        agent, auth, "budget",
-        filename="file.dat",
-        content_base64=content_base64,
-        content_type="application/custom",
-        client=mock_client_with_attachment,
-    )
-
-    # Should use explicit content type
-    mock_client_with_attachment.upload_attachment.assert_called_once_with(
-        "file.dat", content, "application/custom"
-    )

uv.lock

@@ -153,7 +153,7 @@ wheels = [
 
 [[package]]
 name = "grist-mcp"
-version = "1.2.0"
+version = "1.4.1"
 source = { editable = "." }
 dependencies = [
     { name = "httpx" },