Tools

Tools are the primary way MCP clients interact with your data. Each tool wraps a SQL query with typed parameters, metadata, and safety annotations.

Tool Builder Layout

The tool builder uses a 3-column layout:

Column	Purpose
Left	SQL editor (Monaco) for writing the query
Center	Parameter designer for defining inputs
Right	Preview panel with execution results and code output

Writing SQL Queries

Use :param_name to define query parameters:

SELECT *
FROM users
WHERE status = :status
  AND created_at >= :start_date
LIMIT :limit

Parameters are automatically detected from the query text and appear in the center column for configuration.

Parameter Designer

Each detected parameter can be configured:

Field	Description
Name	Auto-detected from `:name` in SQL
Type	`string`, `integer`, `number`, or `boolean`
Required	Whether the client must provide this parameter
Default	Default value if not supplied
Enum Values	Restrict input to allowed values (comma-separated)
Description	Human-readable description shown to MCP clients

SQL Preview

The right column includes a Preview tab for test-executing your query:

Fill in test values for each parameter
Click Run Preview
Results display in a table format

Preview queries execute in read-only mode with an automatic LIMIT applied.

Tool Metadata

Field	Description
Name	Tool identifier (used by MCP clients to call the tool)
Description	What the tool does (shown to LLMs for tool selection)
Tags	Categorical labels for organization
Cache TTL	How long results are cached (in seconds, 0 = no cache)

Annotations

Annotations provide safety hints to MCP clients:

Annotation	Description
`read_only`	Tool only reads data
`destructive`	Tool may delete or alter data
`open_world`	Tool interacts with external systems
`idempotent`	Repeated calls produce the same result

Transform Templates (Jinja2)

Optionally add a post-processing template to transform SQL results before they reach MCP clients. The transform editor appears below the SQL editor and is collapsible.

Template Context

Variable	Type	Description
`rows`	list of dicts	Raw SQL query results
`vars`	dict	Server-level global variables (set in Settings)
`params`	dict	Tool parameter values passed by the caller

Built-in Filters

Filter	Example	Description
`tojson`	`{{ rows \| tojson }}`	Serialize to JSON
`groupby`	`rows \| groupby('category')`	Group rows by field
`sum_attr`	`rows \| sum_attr('amount')`	Sum a numeric attribute
`map_attr`	`rows \| map_attr('name')`	Extract a single field
`unique`	`rows \| unique`	Deduplicate rows

Standard Jinja2 built-ins are also available: sum, len, min, max, round, sorted, enumerate, zip, range.

Example: Sum and Count

[{"total_amount": {{ rows | sum(attribute='amount') }}, "count": {{ rows | length }}}]

Example: Filter and Restructure

[
{% for row in rows if row.status == 'active' %}
  {"name": "{{ row.name }}", "revenue": {{ row.revenue | round(2) }}}{% if not loop.last %},{% endif %}
{% endfor %}
]

Example: Use Global Variables

[
{% for row in rows %}
  {"product": "{{ row.name }}", "price": "{{ row.price }} {{ vars.currency }}"}{% if not loop.last %},{% endif %}
{% endfor %}
]

Preview with Transforms

When a transform template is set, the preview panel shows two tabs:

Raw - SQL query results as-is
Transformed - results after applying the template

Transform errors appear as warnings without blocking the raw results.

Templates run in a sandboxed environment with a 10 MB output limit. Unsafe operations (file access, imports, class introspection) are blocked.

Code Preview

The Code tab shows the generated Python code that will run inside the deployed FastMCP server. This is read-only and updates automatically.

Connection Binding

Each tool must be bound to a database connection. Select the connection from the dropdown at the top of the tool builder.

Duplicating Tools

Open a tool and click Duplicate to create a copy with the name <original>_copy.

Keyboard Shortcuts

Shortcut	Action
`Ctrl+S`	Save the current tool
`Ctrl+Enter`	Run preview execution

Connections

Create and manage the database connections that tools query against

Resources

Expose data as readable MCP resources with URI templates

Prompts

Design reusable prompt templates for LLM interactions

Flow Editor

Manage tools visually on the drag-and-drop canvas

Deployment

Deploy your tools as a running MCP server

REST API

Tool CRUD endpoints in the REST API

MCP Entities

Visual Editor

Deployment

Tool Builder Layout

Writing SQL Queries

Parameter Designer

SQL Preview

Tool Metadata

Annotations

Transform Templates (Jinja2)

Template Context

Built-in Filters

Example: Sum and Count

Example: Filter and Restructure

Example: Use Global Variables

Preview with Transforms

Code Preview

Connection Binding

Duplicating Tools

Keyboard Shortcuts

See Also

Connections

Resources

Prompts

Flow Editor

Deployment

REST API

​Tool Builder Layout

​Writing SQL Queries

​Parameter Designer

​SQL Preview

​Tool Metadata

​Annotations

​Transform Templates (Jinja2)

​Template Context

​Built-in Filters

​Example: Sum and Count

​Example: Filter and Restructure

​Example: Use Global Variables

​Preview with Transforms

​Code Preview

​Connection Binding

​Duplicating Tools

​Keyboard Shortcuts

​See Also

Connections

Resources

Prompts

Flow Editor

Deployment

REST API

Tool Builder Layout

Writing SQL Queries

Parameter Designer

SQL Preview

Tool Metadata

Annotations

Transform Templates (Jinja2)

Template Context

Built-in Filters

Example: Sum and Count

Example: Filter and Restructure

Example: Use Global Variables

Preview with Transforms

Code Preview

Connection Binding

Duplicating Tools

Keyboard Shortcuts

See Also