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rreusser

Observable Notebook Kit Debug MCP Server

by rreusser

ListValues

Inspect all named values in an Observable notebook's reactive graph to debug state and data flow across cells.

Instructions

List all named values in the Observable runtime's reactive graph.

Input Schema

TableJSON Schema
NameRequiredDescriptionDefault
notebookNoTarget notebook (URL, path like "index" or "voronoi", or index like "0"). Optional if you've used FocusNotebook or only one notebook is connected.
timeout_msNoMaximum time to wait in milliseconds

Schema Changelog

Changes observed during successful MCP inspections. Dates show when Glama detected each change.

  1. First observedv1.0.2

TDQS

B3.2/5.0
Behavior2/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

No annotations are provided, so the description carries the full burden of behavioral disclosure. It only states the action 'List,' which implies read-only enumeration, but it does not describe what happens when multiple notebooks are connected, whether the call can block, or what the returned list actually contains. This is sparse for a tool with no annotation safety net.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single, efficient sentence with no filler or repetition. The core action and object are front-loaded, making it easy for an agent to parse quickly.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness2/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Despite having only two optional parameters and full schema coverage, the tool has no annotations and no output schema. The description does not explain the response shape, how notebook disambiguation works, or how this relates to sibling tools, leaving meaningful gaps for an agent deciding whether and how to call it.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so both notebook and timeout_ms are already documented in the input schema. The tool description adds no additional parameter-level meaning, which puts it at the baseline of 3.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description uses a specific verb ('List') and a clear target resource ('all named values in the Observable runtime's reactive graph'), so an agent understands the core operation. However, it does not explicitly distinguish this from sibling tools like GetValues or GetValue, which could appear to overlap in function.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines3/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The intended use case is implied: use this tool to enumerate all named values in the runtime. But there is no explicit guidance about when to choose ListValues over GetValues, GetValue, or GetValueMetadata, and no mention of exclusions, prerequisites, or fallback behavior.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

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