grocy-mcp

Shopping List Update Tool

shopping_list_update_tool

Update an existing shopping list item by its ID, modifying fields like amount, note, or product_id.

Instructions

Update fields on an existing shopping list item.

Use shopping_list_view_tool first to find the item_id.

Input Schema

TableJSON Schema

Name	Required	Description	Default
`data`	Yes	JSON object with fields to update. Supported fields include "amount" (number), "note" (string), and "product_id" (integer). Example: '{"amount": 3, "note": "unsalted"}'.
`item_id`	Yes	The shopping list item ID (from shopping_list_view_tool output).

Output Schema

TableJSON Schema

Name	Required	Description	Default
`result`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.2.0Sep 15, 2026

TDQS

B3.4/5.0

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 doesn't state whether updates are partial merges or full replacements, whether the 'data' JSON replaces the entire item, or what happens to unspecified fields. For a mutation tool with zero annotation coverage, this is a significant gap.

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

Conciseness4/5

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

Two sentences with no waste. The core action is front-loaded, and the usage hint is a single follow-up sentence. It earns its place without redundancy.

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

Completeness3/5

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

The tool has an output schema and 100% schema coverage, so the description doesn't need to explain return values or parameters. However, the lack of behavioral transparency about merge semantics and the absence of annotations leave a gap for a mutation tool. It's adequate but not complete.

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 the schema already documents both parameters. The description adds the workflow hint about item_id coming from shopping_list_view_tool, which is useful, but doesn't add meaning beyond the schema for the 'data' parameter. Baseline 3 is appropriate.

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 states a specific verb ('Update') and resource ('fields on an existing shopping list item'), which clearly distinguishes it from add/remove/clear siblings. It doesn't enumerate which fields are updatable in the description itself, but the schema covers that, so the purpose is clear enough.

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 explicitly instructs to use shopping_list_view_tool first to find the item_id, which is a clear usage prerequisite. It doesn't explicitly say when not to use this tool versus shopping_list_set_amount_tool or shopping_list_set_note_tool, but the general workflow guidance is present.

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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