diff --git a/.claude/AGENTS.md b/.claude/AGENTS.md
index 6fb4ae6..1ebaa5f 100644
--- a/.claude/AGENTS.md
+++ b/.claude/AGENTS.md
@@ -125,6 +125,7 @@ Do not run full validation suites after every small edit by habit. Run the narro
   | Editing AGENTS.md, .agents/skills/, docs/ai/ | writing-docs.md |
   | Maintaining or troubleshooting ask-intern | ask-intern.md |
   | Operating or changing the learning system | learning-system.md |
+  | Running probe loops, experiment diagnostics, or tuning sessions | experiment-diagnostics.md |
 - Re-read the hard rules before implementation.
 
 ## Session Tools
diff --git a/docs/ai/experiment-diagnostics.md b/docs/ai/experiment-diagnostics.md
new file mode 100644
index 0000000..69dff99
--- /dev/null
+++ b/docs/ai/experiment-diagnostics.md
@@ -0,0 +1,14 @@
+# Experiment Diagnostics
+
+## Contract
+
+- When a probe or experiment produces implausible user-facing guidance, pause the experiment queue before logging the artifact as evidence.
+- Fix the diagnostic source first: write a behavior test capturing the bad output, fix the shared logic, and rerun the canonical probe.
+- Only promote corrected artifacts to durable evidence or curated docs. An artifact that embeds known-bad guidance becomes a misleading fixture for future agents.
+- Record both the discovered product risk and the corrected artifact path before resuming the probe queue.
+
+## Notes
+
+- Experiment artifacts are not only observations — they are validation fixtures for product guidance. When an artifact exposes bad guidance, fix the guidance and regenerate the artifact before promoting it to durable evidence.
+- What counts as implausible: a recommendation that contradicts domain constraints, a metric far outside the expected range, or guidance a product owner would immediately reject.
+- This applies to any long-running probe or tuning loop where the system being probed produces user-facing output: recommendation calibration, AI output evaluation, capacity diagnostics, or auto-populate tuning.