zotero-library-mcp

Update Annotation

update_annotation

Update the comment or highlight color of a Zotero annotation. Specify a library or use the configured default.

Instructions

Update the comment and/or highlight color of an annotation.

Pass both library_id and library_type to target another library; omit both to use the configured default.

Input Schema

TableJSON Schema

Name	Required	Description	Default
`color`	No
`comment`	No
`library_id`	No
`library_type`	No
`annotation_key`	Yes

Output Schema

TableJSON Schema

Name	Required	Description	Default
`result`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

Changed2 schema fields changedv0.10.0Sep 14, 2026

addedInput schema / properties / library_id

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

addedInput schema / properties / library_type

Added value: +{
+  "anyOf": [
+    {
+      "enum": [
+        "user",
+        "group"
+      ],
+      "type": "string"
+    },
+    {
+      "type": "null"
+    }
+  ],
+  "default": null,
+  "title": "Library Type"
+}

First observedv0.9.0Aug 12, 2026

TDQS

A3.7/5.0

Behavior3/5

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

Annotations already convey that this is a mutating action (readOnlyHint=false). The description adds useful context: updates can affect just the comment, just the color, or both, and the library targeting defaults to a configured library. However, it does not disclose what happens with null values, invalid annotation keys, or whether changes are reversible.

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 two short sentences with no filler. The core action is front-loaded, and the library targeting rule is stated in a clear, conditional format ('Pass both... omit both...').

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?

Given the simple parameter set and the presence of an output schema, the description is mostly sufficient. The main gap is the lack of explicit null/clear semantics for optional fields, which is important for an update operation with default-null parameters.

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 0%, so the description must compensate. It clarifies that color and comment are the updatable fields and explains the relationship between library_id and library_type. But it does not explain annotation_key semantics, value formats, or how null affects each field, leaving some parameter behavior ambiguous.

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 uses a specific verb ('Update'), names the resource ('annotation'), and identifies the exact fields affected ('comment and/or highlight color'). This clearly distinguishes it from sibling tools like create_annotation, get_annotations, delete_annotation, and update_item_metadata.

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 is implied: call this when modifying an existing annotation's comment or highlight color. The description gives useful parameter guidance about targeting a library, but it does not explicitly state when to prefer this tool over alternatives or when not to use it.

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