Module validate 

Semantic validation of a component tree.

JSON Schema can say that children is an array of strings. It cannot say that every one of those strings names a component that exists, that the tree has a root, or that a → b → a is a loop the renderer will never finish drawing. That is what this module checks.

Every failure is a ValidationError carrying a machine-readable ErrorCode, a path locator into the components list, and a sentence written to be fed straight back to a model on retry. The validator collects all errors rather than stopping at the first, so one retry can fix everything at once.

Depth

The component graph is walked iteratively, with an explicit worklist, in every case — cycle detection, reachability, and scope assignment. That is not a style preference: the graph is model-generated and its depth is bounded by nothing, so a recursive walk would abort the process rather than fail a request. MAX_DEPTH is therefore a policy about what a renderer will draw, not what keeps this crate standing, and it can be raised safely.

Full surfaces and incremental updates

A payload that creates a surface is held to the full contract: a root must exist and every child reference must resolve within the payload. An incremental updateComponents is not — its components may legitimately reference ids the renderer already holds, and it need not include the root. ValidateOptions::incremental_update relaxes exactly those two rules; duplicate ids and cycles still fail, because those are broken either way.

use ag_ui_a2ui::{catalog::Catalog, message::Component, validate::{ErrorCode, Validator}};
use serde_json::json;

let catalog = Catalog::basic();
let report = Validator::new(&catalog).validate(&[
    Component::new("root", "Card").with("child", json!("nope")),
]);
assert_eq!(report.errors[0].code, ErrorCode::UnresolvedChild);
assert_eq!(report.errors[0].path, "components[0].child");

Structs

ValidateOptions

What the validator should demand of a payload.

ValidationError

One semantic failure, located and explained.

ValidationReport

What a validation run found.

Validator

Validates component trees against a catalog.

Enums

ErrorCode

The complete set of semantic failures this validator reports.

Constants

MAX_DEPTH

Deepest nesting accepted by default, for both the component graph and the raw JSON of a message.

MAX_FUNCTION_CALL_DEPTH

Deepest chain of nested function calls accepted by default.