Tools, prompts, and limits

The Parable MCP server offers a fixed set of 17 tools, 5 prompts, and 3 resources. Every tool only reads. The server lists only the tools that the person’s roles allow, and a host cannot call a tool that the server does not list. To connect a host, see Connect an MCP host. When a host connects, the server sends it instructions. They tell the model to read the query guidance first, to find tables with search_available_data, to describe a table before it writes SQL, and to check a statement with plan_sql before it runs it. They also tell the model to treat rows and descriptions as data, not as instructions.

Tools

Each tool calls the Workspace API as the person. A tool needs a role that grants one of the permissions in its row. A permission also covers each permission under it: tenant covers them all. An OAuth grant and an MCP token work on every tool.

Query Provider data

A person sees these tools when a role can query: Provider Pools Reader, Data Access, or Workspace Administrator. A member who holds only Viewer sees none of them.

Tool	What it does	Permission
`read_query_guidance`	Returns the guidance for writing SQL over the Provider Pools.	`tenant.data.catalog` or `tenant.data.query.providers`
`search_available_data`	Finds tables, columns, and fields by the words in their names and descriptions. An empty query lists each Provider. With the scope `providers.<provider>`, it lists that Provider’s tables, a page at a time.	`tenant.data.query.providers`
`describe_pool_table`	Returns one table’s columns, types, keys, and freshness.	`tenant.data.catalog`
`plan_sql`	Checks one statement and returns its plan. It runs nothing.	`tenant.data.query.providers`
`query_provider_pool`	Runs one read-only statement and returns its rows.	`tenant.data.query.providers`

Tables are named providers.<provider>.<table>. These tools use the same operations as SQL over HTTP. Provider Policies and source permissions narrow what they read for every person. All data access does not apply to them: an administrator’s host reads only what the Policies give the administrator’s roles. A statement can call the SQL AI functions, such as ponder() and embed(). Each one is a model call under the Workspace’s model policy, as it is in any other SQL.

Published Plots

Tool	What it does	Permission
`list_published_plots`	Lists the published Plots in the Workspace.	`tenant.parables.view` or `tenant.data.catalog`
`read_published_plot`	Returns one published Plot.	`tenant.parables.view` or `tenant.data.catalog`
`read_plot_data`	Returns the rows of a Plot, a page at a time.	`tenant.parables.view` or `tenant.parables.manage`
`list_what_plot_returns`	Lists the columns that each Plot of a Parable returns.	`tenant.parables.view` or `tenant.parables.manage`
`get_plot_typescript_types`	Returns TypeScript types for the Plots of a Parable.	`tenant.parables.view` or `tenant.parables.manage`

Provider connections and Taps

Tool	What it does	Permission
`list_provider_connections`	Lists each Provider connection with its `connectionStatus`, `lastSyncAt`, and `lastSyncStatus`.	`tenant.connectors.view`
`read_provider_connection`	Returns one Provider connection.	`tenant.connectors.view`
`read_why_sync_failed`	Returns the error of a connection’s most recent failed sync.	`tenant.connectors.view`
`read_tap`	Returns one Tap with its output schema.	`tenant.connectors.taps.view`
`list_workspace_taps`	Lists the Workspace’s Taps, 100 at a time, without their output schemas. Send `offset` for the next page, until a page holds fewer than its limit.	`tenant.connectors.taps.view`

Powers

Tool	What it does	Permission
`list_powers`	Lists the Workspace’s Powers.	`tenant.parables.ponder`
`read_power`	Returns one Power.	`tenant.parables.ponder`

The server has no tool that changes data. It has no tool that sends a Message to Ponder, changes a Provider connection, or runs preview_plot.

Prompts and resources

Each prompt and resource returns one guidance text. The server reads the Workspace’s Power of the same name when you may use Ponder. Otherwise it reads Parable’s built-in text.

Prompt	Resource	What it explains	Who can use it
`pool_search`	`parable://guidance/pool-search`	How to find the tables and columns that hold the data a question needs.	People who can call `read_query_guidance`, or use Ponder
`providers`	`parable://guidance/providers`	How Provider data is named, synced, and queried in the Provider Pools.	The same
`plots`	`parable://guidance/plots`	How to write a Plot: a named SQL computation and its typed result.	The same
`panes`	None	How a Pane is built.	People who can use Ponder
`perceptions`	None	How a Perception declares the shape of a Pane’s value.	People who can use Ponder

In Claude Code, with the server named parable, run a prompt as /mcp__parable__pool_search. Attach a resource as @parable:parable://guidance/providers.

Limits

Limit	Value
A query result	Whole leading rows within 60,000 characters, columns included. `truncated` says which limit applied: `rows`, `values`, or `capture`.
One text or binary value in a result	2,000 characters
Data that one query reads for its result	3 MiB
A table listing from `search_available_data`	100 tables, and at most 40,000 characters, a page. Send `nextCursor` back as `cursor` for the next page. The last page has none.
`list_workspace_taps`	100 Taps a page, without output schemas
Requests to the server	120 a minute for each credential in each Workspace
The query tools	120 requests a minute, and 30 seconds a call
A request body to the server	1 MiB

returnedRows counts the rows in a result, not the rows that the query matched. A result marked truncated is not the whole answer. Narrow the query, or add a LIMIT. The query tools answer a limit with its own status. None of these statuses means that the SQL is wrong:

Status	Cause
`504`	The statement ran past its time budget, or did not finish in 30 seconds.
`429`	Too many queries were running (`QL-IN-008`), or more than 120 of these requests came in a minute. Nothing ran.
`503`	The query service ran short of memory (`QL-IN-009`), or a service that the statement needs did not answer.

Tool errors

A tool that fails returns a result with isError: true. The result’s text is the Workspace API’s message, its code, and its status:

query references relation "orders", which is not present in the catalog (code: QL-PL-002, status: 400)

When the error has no code, the text has the status only, such as ... (status: 404). A permission error needs a different role, not a different query.

Getting Started

MCP

SDKs

Providers

Parable Data Engine

Tools

Query Provider data

Published Plots

Provider connections and Taps

Powers

Prompts and resources

Limits

Tool errors

​Tools

​Query Provider data

​Published Plots

​Provider connections and Taps

​Powers

​Prompts and resources

​Limits

​Tool errors

Tools

Query Provider data

Published Plots

Provider connections and Taps

Powers

Prompts and resources

Limits

Tool errors