Worked on the juanfont/headscale repository to address a critical bug affecting the List Routes command in a Go-based command line interface. Focused on restoring expected filtering behavior, the developer ensured that node identifiers were correctly applied before generating JSON output, aligning the tool’s results with previous versions and user workflows. The technical approach involved moving JSON rendering to occur only after both identifier filtering and route existence checks, thereby preventing non-matching nodes from appearing in output. This fix, implemented in Go, improved operational reliability and reduced confusion for users relying on accurate route inventories in their automation and scripts.