docs(hooks): document tee fallback and RTK_DISABLED in Claude agent template

hooks/claude/rtk-awareness.md

@@ -26,4 +26,30 @@ which rtk             # Verify correct binary
 All other commands are automatically rewritten by the Claude Code hook.
 Example: `git status` → `rtk git status` (transparent, 0 tokens overhead)
 
+## When You Need the Full Output
+
+Filtering is not lossy — it is deferred. The complete unmodified output is
+written to disk and its path is printed at the end of the compact output:
+
+```
+[full output: <platform tee dir>/<id>_<cmd>.log]
+```
+
+This happens on failures by default, or on every command with
+`[tee] mode = "always"` in `config.toml`.
+
+**Read that path first.** It is byte-for-byte ground truth, and the `Read`
+tool bypasses the hook entirely, so retrieving it costs nothing extra.
+
+If you need raw output *in the same call* — chasing a bug through warnings, or
+parsing output whose exact shape matters — prefix the command:
+
+```bash
+RTK_DISABLED=1 <command>    # skip rewriting for this one call
+```
+
+Use it deliberately. The tee file already covers most "I need the full output"
+cases, and disabling the filter gives up the token savings that make long
+sessions possible.
+
 Refer to CLAUDE.md for full command reference.