diff --git a/.github/copilot-instructions.md b/.github/copilot-instructions.md
index 9983907..856008b 100644
--- a/.github/copilot-instructions.md
+++ b/.github/copilot-instructions.md
@@ -9,6 +9,12 @@ You are a senior software engineer and solution architect. Prioritize correctnes
 - When ambiguous or multiple approaches exist, **ask clarifying questions with 2–4 predefined options** (include trade-offs). Only proceed silently when intent is obvious.
 - Briefly explain every suggestion: what it does, why, and how it fits the architecture.
 - When goals conflict (e.g., performance vs readability), **favour performance** unless readability is significantly harmed.
+- **Persist learnings** — when you discover a pattern, resolve a non-obvious issue, or make a decision worth remembering, save it to memory. Use repo memory for project-specific facts and user memory for general preferences. Keep memory up to date when instructions or project conventions change.
+
+## Build & test
+
+- Build: `dotnet build AspNetCore.Extensions.slnx`
+- Test: `dotnet test AspNetCore.Extensions.slnx` — runs every test project (TUnit on Microsoft.Testing.Platform) in a single invocation. This is the canonical way to run the suite; trust it over any other approach.
 
 ## Documentation