Web view JavaScript evaluation

The webview API, JavaScript reply format, and platform implementation notes now live in day-piece-webview’s evaluation guide.

Dayscript keeps the web_eval command for existing scripts. It calls the named piece operation day.webview.eval, passing the script as text and expecting the result as JSON text. The piece registers that operation for its node kind; Day’s core registry has no browser-specific types or state. See piece operations for the shared interface.

- web_eval:
    id: reader-web
    script: "document.title"
    text: "My page"
    timeout_secs: 30

text compares the returned string or JSON representation; contains checks a substring. The runner polls pending replies and retries mismatches within the step’s wait period (five seconds by default). Set timeout_secs for cold engine startup or slow page loads; it extends both the engine’s polling budget and the runner’s reply timeout without delaying a ready page. An absent operation fails immediately. Gate the step with only_on for platforms that support evaluation.