diff --git a/AGENTS.md b/AGENTS.md
index 186a592..9cd2f40 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -40,6 +40,7 @@ This architecture provides compile-time correctness, observability through event
 - Compile time correctness is a super-power, and investment in it speeds up flywheel for development and user value.
 - **CLI/Service Interchangeability**: Both the CLI and service must produce identical artifacts (BEL events, logs, metrics, outputs) in the same locations. Users should be able to build with one interface and query/inspect results from the other seamlessly. This principle applies to all DataBuild operations, not just builds.
 - The BEL represents real things that happen: job run processes that are started or fail, requests from the user, dep misses, etc.
+- We focus on highly impactful tests anchored to stable interfaces. For instance, using BEL events to create valid application states to test orchestration logic via shared scenarios. This helps us keep a high ratio from "well tested functionality" to "test brittleness".
 
 ## Build & Test
 ```bash
diff --git a/DESIGN.md b/DESIGN.md
index 0862dfb..92bc49b 100644
--- a/DESIGN.md
+++ b/DESIGN.md
@@ -68,5 +68,4 @@ What about situations where data is configured by a web app, etc? Taints are a g
 ## Assumptions
 
 - Job -> partition relationships are canonical, job runs are idempotent
-- The data deps / partitions read by a fully parameterized job run is consistent over time: same parameters = same read partitions