diff --git a/CHANGELOG.md b/CHANGELOG.md
index 74a0f9f..1561500 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,7 @@ First formal multi-tool release for this repository.
 ### Included tools
 
 - `errnfo` - HRESULT/NTSTATUS/Win32 decode + message-table scan/dump
+- `hdrinfo` - display HDR/output metadata and Windows HDR troubleshooting context
 - `modsnap` - process module snapshot (table/path/csv/count)
 - `quuid` - GUID/COM parse + registry/scan/type-lib tooling
 - `rawwhp` - WHP sparse area mapping, execution, dumps, reports
diff --git a/README.md b/README.md
index 640c7b7..8c704ba 100644
--- a/README.md
+++ b/README.md
@@ -10,6 +10,7 @@ A small collection of **single-file C CLI tools** for Windows. Each tool is desi
 ## Tools
 
 - `errnfo` — decode HRESULT/NTSTATUS/Win32 error codes; scan and dump message tables.
+- `hdrinfo` — report Windows display HDR/output metadata, color encoding, and troubleshooting hints.
 - `modsnap` — snapshot a process module list (base, size, name, path) with table/CSV/path/count output.
 - `quuid` — GUID/COM discovery: parse, registry lookup, scan binaries, inspect type libraries.
 - `rawwhp` — define multiple WHP guest memory areas, run code, and dump selected GPA ranges.