Apply a named object style to selected InDesign objects on a specified page, using object index when no objects are selected.
Apply an object style to selected objects
| Name | Required | Description | Default |
|---|---|---|---|
| pageIndex | No | Page index | |
| styleName | Yes | Object style name | |
| objectIndex | No | Object index on page (optional if objects selected) |
Changes observed during successful MCP inspections.
v1.0.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations provided, the description carries the full burden. It does not disclose whether the operation is destructive/reversible, what happens when objectIndex is missing and no selection exists, or whether existing styles are overridden. The minimal text provides no behavioral detail beyond the action itself.
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, tightly worded sentence with no redundancy. It front-loads the action and target. However, it is arguably under-specified, though that's not a conciseness issue.
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?
The tool has no annotations or output schema, and the description offers only the core action. It fails to explain selection vs. objectIndex behavior, error conditions, or document prerequisites, leaving significant gaps for an agent to invoke it correctly.
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 coverage is 100% with descriptions for all three parameters, so the baseline is 3. The description's mention of 'selected objects' adds slight context for objectIndex's optionality, but it doesn't add substantive meaning beyond the schema.
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 states a specific verb ('apply') and resource ('object style') targeting 'selected objects', clearly distinguishing it from siblings like apply_paragraph_style (different style type) and create/modify_object_style (different action). A single sentence communicates exactly 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.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The phrase 'to selected objects' implies the use case requiring a selection, but no explicit guidance is given on when to prefer this over create_object_style or modify_object_style, nor any exclusion conditions. It's implied usage at best, with no alternatives mentioned.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.