Merge pull request #11 from wenwu35/add-multi-db-schemas-support

Add Multi-Database-Schema Support and Improved Configuration

Author: isaacwasserman

README.md

@@ -36,10 +36,23 @@ The server offers six core tools:
    - Returns: Confirmation of table creation
 
 #### Schema Tools
+- `list_databases`
+  - Get a list of all databases in the Snowflake instance.
+  - No input required
+  - Returns: Array of database names.
+
+- `list_schemas`
+  - Get a list of all schemas in a specific database.
+  - Input:
+    - `database` (string): Name of the database.
+  - Returns: Array of schema names.
+
 - `list_tables`
-   - Get a list of all tables in the database
-   - No input required
-   - Returns: Array of table names
+  - Get a list of all tables in a specific database and schema.
+  - Input:
+    - `database` (string): Name of the database.
+    - `schema` (string): Name of the schema.
+  - Returns: Array of table metadata.
 
 - `describe-table`
    - View column information for a specific table
@@ -66,10 +79,10 @@ To install Snowflake Server for Claude Desktop automatically via [Smithery](http
 npx -y @smithery/cli install mcp_snowflake_server --client claude
 ```
 
-### Installing via UVX
+### Installing via UVX 
 
 ```python
-# Add the server to your claude_desktop_config.json
+# Add the server to your claude_desktop_config.json (Claude -> Settings -> Developer -> Edit Config)
 "mcpServers": {
   "snowflake_pip": {
       "command": "uvx",
@@ -99,35 +112,49 @@ npx -y @smithery/cli install mcp_snowflake_server --client claude
 ```
 
 ### Installing locally
+
+1. Install [Claude AI Desktop App](https://claude.ai/download)
+
+2. Install `uv` by:
+```
+curl -LsSf https://astral.sh/uv/install.sh | sh
+```
+
+3. Create a `.env` file using the following template under this dir
+```
+SNOWFLAKE_USER="[email protected]"
+SNOWFLAKE_ACCOUNT="XXX"
+SNOWFLAKE_ROLE="XXX"     # This determines the access scope of the MCP
+SNOWFLAKE_DATABASE="XXX" # This doesn't affect the MCP's access scope
+SNOWFLAKE_SCHEMA="XXX"   # This doesn't affect the MCP's access scope
+SNOWFLAKE_WAREHOUSE="XXX"
+SNOWFLAKE_PASSWORD="XXX"
+# Alternatively, you can use external browser for authentication without specifying the password
+# SNOWFLAKE_AUTHENTICATOR="externalbrowser" 
+```
+
+4. [Optional] Modify the `exclude_patterns` in `runtime_config.json` to filter out the resources you want to exclude.
+   
+5. Test locally using 
+```
+uv --directory /absolute/path/to/mcp_snowflake_server run mcp_snowflake_server
+```
+
+6. Add the server to your `claude_desktop_config.json` (Claude -> Settings -> Developer -> Edit Config)
 ```python
-# Add the server to your claude_desktop_config.json
 "mcpServers": {
   "snowflake_local": {
-      "command": "uv",
+      "command": "/absolute/path/to/uv", # obtained by using `which uv`
       "args": [
           "--directory",
           "/absolute/path/to/mcp_snowflake_server",
           "run",
           "mcp_snowflake_server",
-          "--account",
-          "the_account",
-          "--warehouse",
-          "the_warehouse",
-          "--user",
-          "the_user",
-          "--password",
-          "their_password",
-          "--role",
-          "the_role"
-          "--database",
-          "the_database",
-          "--schema",
-          "the_schema",
           # Optionally: "--allow_write" (but not recommended)
           # Optionally: "--log_dir", "/absolute/path/to/logs"
           # Optionally: "--log_level", "DEBUG"/"INFO"/"WARNING"/"ERROR"/"CRITICAL"
           # Optionally: "--exclude_tools", "{tool name}", ["{other tool name}"]
       ]
   }
 }
-```
+```

runtime_config.json

@@ -0,0 +1,14 @@
+{
+  "exclude_patterns": {
+    "databases": [
+      "temp"
+    ],
+    "schemas": [
+      "temp",
+      "information_schema"
+    ],
+    "tables": [
+      "temp"
+    ]
+  }
+}

src/mcp_snowflake_server/__init__.py

@@ -21,7 +21,7 @@ def parse_args():
         "--prefetch",
         action="store_true",
         dest="prefetch",
-        default=True,
+        default=False,
         help="Prefetch table descriptions (when enabled, list_tables and describe_table are disabled)",
     )
     parser.add_argument(
@@ -88,10 +88,10 @@ def main():
 
     assert (
         "database" in connection_args
-    ), 'You must provide the account identifier as "--database" argument or "SNOWFLAKE_DATABASE" environment variable. This MCP server can only operate on a single database.'
+    ), 'You must provide the account identifier as "--database" argument or "SNOWFLAKE_DATABASE" environment variable.'
     assert (
         "schema" in connection_args
-    ), 'You must provide the username as "--schema" argument or "SNOWFLAKE_SCHEMA" environment variable. This MCP server can only operate on a single schema.'
+    ), 'You must provide the username as "--schema" argument or "SNOWFLAKE_SCHEMA" environment variable.'
 
     asyncio.run(
         server.main(