## What changed
- Return structured validation issues with stable codes, complete field
paths, constraints, and minimal correction examples.
- Preserve validation details through the Builder API, CLI, MCP, local
project sessions, and tRPC errors.
- Explain invalid expressions, JSX fragments, page selectors, component
inputs, asset updates, and project settings in terms an agent can act
on.
- Remove stack frames and credentials from parser details before
exposing them.
- Keep concise human-readable errors while making the complete
structured issues available to agents.
## Why
Agents previously received vague errors without enough information to
repair a request. They could repeat the same invalid call or require
manual intervention.
## User impact
CLI and MCP agents can now identify the exact invalid field, understand
the constraint, see a valid example, and retry with a corrected request.
## Validation
- Focused runtime, MCP, CLI, API, and tRPC validation tests.
- Structured error propagation tests across local and server execution.
- Typechecks and generated contract verification.
Oleg Isonen