Module trace 

One-line structured trace per CLI dispatch.

Every CLI command builds a CommandTrace at entry and finishes it at exit. The trace is emitted at tracing::Level::INFO so it lands by default (BROWSER_CONTROL_LOG=info), with a fixed field schema:

command   – static command name (eval / fetch / tab-open / ...)
browser   – resolved registered name, or empty for external URLs
engine    – "cdp" | "bidi" | ""
route     – which code path the command took (scratch / named-tab / ...)
tab_name  – name of the named tab if any
target_id – engine-specific id touched, if known
elapsed_ms – wall-clock duration from CommandTrace::new to .finish*
outcome   – "ok" | "err"

Agents and operators consume these by tailing stderr and grepping target=browser_control::cli.

Structs

CommandTrace

Mutable trace builder for a single CLI command invocation.