Webflow

Official

Overview Schema Source Related Servers Discussions Admin

component_builder

Insert component instances into the active page as child elements or into component slots. Supports append, prepend, before, and after positions.

Instructions

Designer Tool - Component builder to insert component instances on the current active page. Supports inserting into an element (as a child) or into a component instance's slot. Use insert_in_element to add a component inside a container/div/section. Use insert_in_slot to add a component inside a specific slot of an existing component instance.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "siteId": "<siteId>",
      "actions": "<actions>"
    },
    "name": "component_builder"
  }
}

Input Schema

Name	Required	Description	Default
`siteId`	Yes	The ID of the site. DO NOT ASSUME site id. ALWAYS ask user for site id if not already provided or known. use sites_list tool to fetch all sites and then ask user to select one of them.
`actions`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

AddedMay 5, 2026

TDQS

A4.1/5.0

Behavior4/5

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

Description adds behavioral context beyond annotations (modifies active page, supports two insertion modes). No contradiction with annotations (readOnlyHint=false, openWorldHint=true).

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?

Two concise sentences front-loading purpose and usage distinction. No unnecessary words. Highly efficient.

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?

Covers core functionality and action modes. Lacks detail on component_schema usage, error conditions, or prerequisites (e.g., active page requirement). No output schema, so return values not mentioned. Adequate for a moderately complex tool.

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 coverage is 50%, description does not add much parameter detail beyond schema. Implicitly references parent_element_id and slot_name but does not explain complex component_schema object. Adequate but could be improved.

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?

Description clearly states it inserts component instances on the current active page, with specific verbs and resource. It distinguishes two modes (insert_in_element, insert_in_slot), differentiating from sibling tools.

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?

Explicitly states when to use insert_in_element vs insert_in_slot. Provides clear context for each action type. Lacks explicit comparison with siblings or when not to use.

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