fix: add delegation confirmation to prevent LLM confusion loops

[mikeangstadt]

Problem

When RTK runs a delegated command like ruff check, the output shows the full command in the bash tool result (e.g. $ rtk ruff check ... --fix) followed by the filtered output (Ruff: No issues found). LLMs misinterpret the $ rtk prefix as a typo for the underlying tool (ruff), causing them to re-execute the command directly in an infinite loop.

Solution

After every successful filtered command, RTK now prints a delegation confirmation line:

rtk: <tool> done

This makes it unambiguous that rtk was intentional and the command successfully completed. The LLM sees both names in the same line and understands the delegation was correct.

Example output before

$ rtk ruff check src/main.py --fix
Ruff: No issues found

Example output after

$ rtk ruff check src/main.py --fix
Ruff: No issues found
rtk: ruff done

Testing

• Unit tests on filter functions pass unchanged (the change is in the runner, not the filters)
• The rtk: <tool> done line only appears for commands that succeed (exit_code == 0)
• Commands using tee_label or no_trailing_newline paths are unaffected

Fixes #2280

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Collaborated & Orchestrated by ClosedLoop.AI | www.closedloop.ai · github.com/rtk-ai