py-ynab-mcp

by duganth

Overview Schema Source Related Servers Discussions Admin

Python

Remote

update_category

Update category details or savings target in YNAB by specifying the category ID and any fields to change.

Instructions

Update category metadata or target configuration in YNAB.

Only provide the fields you want to change.

Args: category_id: Category UUID. name: New category name. note: New category note. category_group_id: New category group UUID. target_amount: Positive target amount in dollars. target_date: Target date in YYYY-MM-DD format. target_needs_whole_amount: Whether the entire target is needed. target_frequency: Target recurrence: monthly, weekly, or yearly. Cannot be combined with target_date. budget_id: Budget ID. Defaults to last-used budget. dry_run: Validate and preview without updating.

Input Schema

TableJSON Schema

Name	Required	Description	Default
`name`	No
`note`	No
`dry_run`	No
`budget_id`	No
`category_id`	Yes
`target_date`	No
`target_amount`	No
`target_frequency`	No
`category_group_id`	No
`target_needs_whole_amount`	No

Output Schema

TableJSON Schema

Name	Required	Description	Default
`result`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

Changed6 schema fields changedv0.3.0Sep 8, 2026

addedInput schema / properties / category_group_id

Added value: +{
+  "anyOf": [
+    {
+      "type": "string"
+    },
+    {
+      "type": "null"
+    }
+  ],
+  "default": null,
+  "title": "Category Group Id"
+}

removedInput schema / properties / hidden

Removed value: -{
-  "anyOf": [
-    {
-      "type": "boolean"
-    },
-    {
-      "type": "null"
-    }
-  ],
-  "default": null,
-  "title": "Hidden"
-}

addedInput schema / properties / target_amount

Added value: +{
+  "anyOf": [
+    {
+      "type": "string"
+    },
+    {
+      "type": "null"
+    }
+  ],
+  "default": null,
+  "title": "Target Amount"
+}

addedInput schema / properties / target_date

Added value: +{
+  "anyOf": [
+    {
+      "type": "string"
+    },
+    {
+      "type": "null"
+    }
+  ],
+  "default": null,
+  "title": "Target Date"
+}

addedInput schema / properties / target_frequency

Added value: +{
+  "anyOf": [
+    {
+      "type": "string"
+    },
+    {
+      "type": "null"
+    }
+  ],
+  "default": null,
+  "title": "Target Frequency"
+}

addedInput schema / properties / target_needs_whole_amount

Added value: +{
+  "anyOf": [
+    {
+      "type": "boolean"
+    },
+    {
+      "type": "null"
+    }
+  ],
+  "default": null,
+  "title": "Target Needs Whole Amount"
+}

First observedv0.2.0Jul 12, 2026

TDQS

A4.6/5.0

Behavior4/5

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

With no annotations, the description carries full responsibility for behavioral transparency. It indicates that the operation is an update (mutation) and explains the dry_run parameter as 'Validate and preview without updating.' It also implies partial updates via 'Only provide the fields you want to change.' However, it does not mention error conditions or idempotency, which are minor gaps for a simple update tool.

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 concise and well-structured: two introductory sentences followed by a clear parameter list. It avoids unnecessary fluff and presents information in a scannable format. Each parameter has a short, focused explanation, making it easy to parse.

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?

The description covers the tool's purpose, usage guidance, and parameter semantics. Since an output schema exists, omitting return value details is acceptable per rubric. It also mentions defaults and constraints, making the description self-contained. No critical information about how to use the tool is missing.

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

Parameters5/5

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

The description explains every parameter in the schema, providing meaning beyond the raw type/title. For example, it clarifies that target_amount is in dollars, target_date uses YYYY-MM-DD format, and target_frequency offers monthly, weekly, or yearly. It also notes the default for budget_id and the constraint on target_frequency. This fully compensates for the schema's lack of parameter descriptions.

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: 'Update category metadata or target configuration in YNAB.' It specifies the action (update) and the resource (category), and distinguishes it from other category tools by mentioning both metadata and target configuration. This leaves no ambiguity about what the tool does.

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 a key usage instruction: 'Only provide the fields you want to change,' which clarifies the partial update behavior. It also lists the parameters with brief explanations, including the constraint that target_frequency cannot be combined with target_date. While it doesn't explicitly compare with sibling tools, the partial-update guidance is sufficient for most use cases.

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