Framework-neutral shapes

Use a framework-neutral shape when a generator or adapter needs component metadata without depending on GPUI or another UI runtime. A shape can advertise value compatibility, capabilities, stable generated-name suffixes, and coarse MCP input metadata.

Declare metadata and value compatibility

#![allow(unused)]
fn main() {
extern crate component_shape;
use component_shape::{ComponentShapeFor, ComponentShapeMetadata, McpInput};

struct TextInputShape;

impl ComponentShapeMetadata for TextInputShape {
    const MCP_INPUT: McpInput = McpInput::string();
}

impl ComponentShapeFor<String> for TextInputShape {}
}

ComponentShapeFor<Value>::MCP_INPUT inherits the shape-level value. Override the associated constant on a specific shape/value pair when one shape supports values with different model-facing forms.

Choose the contract

• Put shape-owned prototyping, capabilities, and coarse MCP input in ComponentShapeMetadata.
• Use ComponentShapeFor<Value> to advertise a supported value and any value-specific MCP input.
• Require DeclaredComponentShape only when a backend accepts shapes produced by its trusted declaration surface.
• Record a selected source field and shape path with ComponentShapeUse.
• Normalize component events into ValueChange::Unchanged, ValueChange::Set, or ValueChange::Clear.

Use ComponentSuffix for generated identifier suffixes: ASCII letters, digits, and underscores, starting with a letter or underscore. Empty strings and _ are rejected. Use RustPath, RustType, and RustExpr when a generator must preserve validated Rust syntax.

Keep MCP metadata coarse

Use McpInput for common scalar, collection, object, and range shapes. The default, McpInput::unsupported(), leaves model input unadvertised. Use McpInput::any() only when arbitrary JSON is intentional. Move precise JSON Schema, typed decoding, tool registration, and transport behavior to component-shape-mcp.