Fix and improve usage of launch_cmd in providers

1 files changed, 6 insertions, 2 deletions

diff --git a/README.md b/README.md
index 70fbac9..e92a677 100644
--- a/README.md
+++ b/README.md
@@ -36,7 +36,7 @@ Some of your desktop entries will probably be TUI programs that expect to be lau
 ## Extending the launcher
 
 In addition to desktop application entries and binaries, you can extend `sway-launcher-desktop` with custom item providers.
-If will read the configuration of custom item providers from `$HOME/.config/sway-launcher-desktop/providers.conf`
+If will read the configuration of custom item providers from `$HOME/.config/sway-launcher-desktop/providers.conf`.
 The structure looks like this:
 
 ```
@@ -50,4 +50,8 @@ The `list_cmd` generated the list of entries. For each entry, it has to print th
 1. The item to launch. This will get passed to `preview_cmd` and `launch_cmd` as `{1}`
 2. The name of your provider (the same as what what you put inside the brackets, so `my-provider` in this example)
 3. The text that appears in the `fzf` window. You might want to prepend it with a glyph and add some color via ANSI escape codes
-4. (optional) Metadata that you can pass to `preview_cmd` and `launch_cmd` as `{2}`. For example, this is used to specify a specific Desktop Action inside a .desktop file
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+4. (optional) Metadata that you can pass to `preview_cmd` and `launch_cmd` as `{2}`. For example, this is used to specify a specific Desktop Action inside a .desktop file
+
+The `preview_cmd` renders the contents of the `fzf` preview panel. You can use the template variable `{1}` in your command, which will be substituted with the value of the selected item.
+
+The `launch_cmd` is fired when the user has selected one of the provider's entries.
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