Update an existing character style in Adobe InDesign by changing its font family, style, size, tracking, or text color.
Modify properties of an existing character style
| Name | Required | Description | Default |
|---|---|---|---|
| fontSize | No | Font size in points | |
| tracking | No | Character tracking | |
| fontStyle | No | Font style (Regular, Bold, Italic) | |
| styleName | Yes | Character style name to modify | |
| textColor | No | Text color (swatch name) | |
| fontFamily | No | Font family |
Changes observed during successful MCP inspections.
v1.0.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden of behavioral disclosure, but it only states the action and object. It does not mention that changes overwrite the style definition, how existing text using the style is affected, whether missing style names cause errors, or any permission requirements. This is a significant gap for a mutation tool.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is a single, direct sentence with no filler or repetition. It front-loads the action and target resource, making it instantly scannable.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Although the schema documents parameter names and types, the description provides no context about side effects, return values, error conditions, or the relationship between modifying a character style and text that already uses it. For a tool with no annotations and no output schema, this is too thin for an agent to understand the full implications of calling it.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema description coverage is 100%, so all six parameters already have meaningful descriptions in the schema. The tool description adds no parameter-level detail beyond the generic phrase 'properties', but because the schema does the heavy lifting, the baseline score of 3 is appropriate.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description uses a specific verb ('Modify') with a specific resource ('existing character style'), which clearly distinguishes it from sibling tools like create_character_style and modify_paragraph_style. The word 'existing' also signals that this is not a creation tool.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The phrase 'existing character style' implies this tool is for modifying already-created styles rather than creating new ones, but it never explicitly states when to choose this tool over create_character_style, modify_paragraph_style, or modify_object_style. The guidance is present only by implication from the name and the word 'existing'.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.