feat(hexai-action): add --infile/--outfile flags; docs and tests\n\n- Add flags to read from file and write to file\n- Refactor IO open into helper for testability\n- Add CLI integration-style test for IO\n- Update README and docs/usage.md with examples\n- Update docs/testing.md with instructions

1 files changed, 22 insertions, 0 deletions

diff --git a/docs/usage.md b/docs/usage.md
index c74ee7d..a5c5dca 100644
--- a/docs/usage.md
+++ b/docs/usage.md
@@ -102,3 +102,25 @@ hexai 'install ripgrep on macOS'
 # Verbose explanation
 hexai 'install ripgrep on macOS and explain'
 ```
+
+## Hexai Action (TUI)
+
+`hexai-action` runs code actions over a selection or diagnostics+selection piped from stdin, or read from a file.
+
+- Choose an action with arrow keys, `j/k`, `g/G`, Enter, or hotkeys `[s] [r] [c] [t]`.
+- Output is written to stdout by default, or to a file via `--outfile`.
+
+Input formats are the same as described in the README (inline instruction markers for rewrite; optional `Diagnostics:` header block).
+
+Examples
+
+```sh
+# From stdin
+cat input.go | hexai-action
+
+# From file to file
+hexai-action --infile input.go --outfile output.go
+
+# Using shell redirection
+hexai-action < input.go > output.go
+```