browser_console(expression="document.body") returned the cryptic CDP error
"Object reference chain is too long" instead of a usable result.
With returnByValue=true, Chrome deep-serializes the eval result; for a live
DOM Node/NodeList/Window that serialization overruns CDP's recursion guard
and fails the whole call with a protocol-level error (not a JS exception),
which _browser_eval surfaced raw.
- browser_supervisor.evaluate_runtime: on that specific error, retry once
with returnByValue=false so Chrome returns the node's description string —
the same graceful path already used for document.querySelector() results.
- browser_tool._browser_eval (CLI subprocess fallback): the subprocess can't
retry, so convert the reference-chain error into actionable guidance
(extract a primitive / use JSON.stringify) instead of leaking it raw.
No expression rewriting — normal evals (1+41 -> 42) are untouched.
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