Keep the message proportionate
Use the shortest explanation that still tells the truth about the event, impact, and current position. For a message about how to address a coworker taking credit for your work, use this factual base: use recent examples, observable impact, and the work requirement rather than labels about personality.
Give timing that can be trusted
Give a realistic date, a simple option, or a direct yes-or-no question and avoid vague promises such as soon. Ask for a specific change, decision, or working agreement and choose a time to review it. Make the immediate next step clear enough that the recipient can answer without reconstructing the entire history.
Close the loop without drama
Do not diagnose, gossip, embarrass a colleague, or turn one incident into a judgment about their character. Move harassment, discrimination, threats, health risk, and retaliation into the appropriate protected process. A calm ending is more credible than a warning, a grand gesture, or language designed to provoke a response.