Guillaume worked on the scaleway/scaleway-cli repository, focusing on improving the reliability of job orchestration in the CLI tool. He addressed a critical issue where the application would panic if a user started a job with the --wait flag and no job runs existed. By introducing existence checks and updating the DefinitionStartBuilder, Guillaume ensured that the CLI now validates job runs before accessing them. He also enhanced error messaging to provide clearer guidance when no job runs are initiated. This work, using Go and emphasizing CLI development and robust error handling, improved user experience and reduced potential downtime for end users.