diff --git a/README.md b/README.md
index 49d9706..db6f7f4 100644
--- a/README.md
+++ b/README.md
@@ -5,6 +5,23 @@
 
   The tool was implemented using Python 3.9.
 
+# Sarif format information
+
+  The tool operates on sarif generated by LGTM 1.27.0 (by default) or by the CodeQL CLI (enabled with the -f flag given a value of `CLI`).
+
+  The values that the -f flag accepts are: `LGTM` and `CLI`.
+
+  The CLI versions used against development of the CLI support were: 2.6.3, 2.9.4, and 2.11.4.
+
+  The CLI sarif **MUST** contain one additional property `versionControlProvenance` - which needs to look like:
+  ```
+  "versionControlProvenance": [
+        {
+          "repositoryUri": "https://github.com/testorg/testrepo.git",
+          "revisionId": "testsha"
+        }
+  ```
+
 # Test Setup
   This repository includes some test data (in `data`) and uses =git lfs= for storing those test files; installation steps are at
   [[https://git-lfs.github.com][git-lfs]]; on a mac with homebrew, install it via