diff --git a/README.md b/README.md
index 68f829f..577f790 100644
--- a/README.md
+++ b/README.md
@@ -46,6 +46,9 @@ v0.1 ships the data layer only:
 | `tags`      | string[]     | caller (required) | Non-empty; drives routing      |
 | `text`      | string       | caller (required) | Human-readable message body    |
 | `severity`  | string       | caller / auto     | `"info"` / `"warn"` / `"error"`; defaults to `"info"` |
+| `ttl`       | number / nil | caller (optional) | Display timeout in seconds; toast mode falls back to channel/display default if unset |
+| `source`    | any / nil    | caller (optional) | Optional source reference (e.g. originating entity)  |
+| `data`      | table / nil  | caller (optional) | Structured key/value payload; detail mode renders `msg.data.*` |
 | `id`        | number       | auto              | Monotonically increasing       |
 | `timestamp` | number / nil | auto              | `engine.time.now()` if available |