YNAB MCP Server

YNAB Tool Index

ynab_tool_index

Read-onlyIdempotent

Discover available YNAB MCP tools for managing budgets, accounts, categories, transactions, and more.

Instructions

Discover the YNAB MCP server tools. Use this when you need YNAB budgets, accounts, categories, payees, transactions, scheduled transactions, unapproved transaction review, approval, or budget cleanup tools.

Input Schema

TableJSON Schema

Name	Required	Description	Default
No arguments

Output Schema

TableJSON Schema

Name	Required	Description	Default
`result`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

Changed1 schema field changedv5.4.0Sep 15, 2026
- removedOutput schema / properties / result / description
```
Removed value: -"Structured result returned by YNAB Tool Index."
```

Changed1 schema field changedv5.1.1Jul 21, 2026

changedOutput schema / (root)

Previous value: -nullNew value: +{
+  "$schema": "http://json-schema.org/draft-07/schema#",
+  "additionalProperties": false,
+  "properties": {
+    "result": {
+      "description": "Structured result returned by YNAB Tool Index."
+    }
+  },
+  "required": [
+    "result"
+  ],
+  "type": "object"
+}

Addedv3.1.0Jul 5, 2026

TDQS

A4.3/5.0

Behavior3/5

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

Annotations already declare readOnlyHint=true and idempotentHint=true, so the agent knows this is a safe, non-destructive operation. The description adds that the tool discovers available server tools, which is consistent with the annotations but does not add much beyond the title and the obvious meta-tool behavior. There is no contradiction.

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, front-loaded sentence with no filler. It opens with the action and object, then lists the relevant domains. Every word contributes to helping an agent decide whether to call this tool.

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

Completeness5/5

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

For a zero-parameter discovery tool with rich annotations and an output schema, the description is complete. It tells the agent exactly when to use the tool, what domains are covered, and the tool's safe read-only nature is already captured by annotations. No return-value explanation is necessary because an output schema exists.

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

Parameters4/5

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

The tool has zero parameters, and schema description coverage is 100%, so there are no parameter details that need compensation. The baseline of 4 applies because there is nothing to document; the description does not need to add parameter meaning.

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

Purpose5/5

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

The description clearly states the tool's purpose: 'Discover the YNAB MCP server tools.' It enumerates specific domain areas such as budgets, accounts, categories, payees, transactions, and cleanup tools, distinguishing it from the sibling tools that perform those operations directly. The verb 'Discover' plus the resource makes the meta-tool nature obvious.

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

Usage Guidelines4/5

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

The description provides explicit usage context: 'Use this when you need YNAB budgets, accounts, categories, payees, transactions, scheduled transactions, unapproved transaction review, approval, or budget cleanup tools.' This tells an agent when to invoke the tool, though it does not explicitly name alternatives or state when not to use it. For an index/discovery tool, this is clear and sufficient.

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