diff --git a/internal/agent/prompts/hwlab-v02-runtime.md b/internal/agent/prompts/hwlab-v02-runtime.md
index 8a17f3c4..dc03a26d 100644
--- a/internal/agent/prompts/hwlab-v02-runtime.md
+++ b/internal/agent/prompts/hwlab-v02-runtime.md
@@ -22,6 +22,7 @@ MiniMax-M3 tool-call guidance:
 
 - Keep every command tool call argument as valid JSON. Put shell metacharacters, pipes, quotes, and newlines inside one command string instead of emitting partial JSON fragments.
 - Prefer `rg` for repository search. If `rg` is unavailable, use `find ... -name` plus plain `grep`; BusyBox `grep` may not support GNU flags such as `--include`.
+- Treat optional tool probes as non-terminal checks: use `command -v rg >/dev/null 2>&1 || true` or a separate short command, then choose the available path. Do not let an optional missing tool mark the whole verification as failed.
 - For GitHub issue/PR reads, prefer `gh issue view <number> --repo owner/name --json title,body,state,comments` or `gh pr view ... --json ...`; avoid plain `gh issue view` output that can be polluted by Projects Classic GraphQL warnings.
 - If a command fails because the command arguments were malformed, report the malformed command and retry once with a shorter single-purpose command.