HeyRocky

Bound Hermes File Reads and Tool Output Safely

A single minified bundle, generated JSON file, or noisy build can consume a large share of the model context. Hermes places separate limits on a file read, terminal output, requested line count, and individual line length.

file_read_max_chars: 100000

tool_output:
  max_bytes: 50000
  max_lines: 2000
  max_line_length: 2000

A read above file_read_max_chars is rejected with guidance to use offset and limit. This is safer than silently injecting a huge file. Terminal output above max_bytes keeps the beginning and end with a truncation marker between them. max_lines clamps a read_file request, while max_line_length shortens pathological individual lines in the numbered view.

Size limits to the model and task

Large-context models can afford more raw evidence, but larger limits are not automatically better. Focused retrieval usually produces better reasoning than flooding the prompt.

  • Lower limits for small local models.
  • Keep enough terminal head and tail to preserve the initiating error and final stack trace.
  • Search for matching files or lines before reading a giant artifact.
  • Page through a file with offsets when the middle matters.
  • Redirect extremely noisy build logs to a file, then inspect targeted sections.

Safe inspection pattern

  1. Check file size and type without reading the body.
  2. Search for the relevant symbol, error, or heading.
  3. Read a bounded window with context lines.
  4. Continue with the returned offset only if needed.
  5. Preserve the exact truncation notice in diagnostic reports.

Checklist

  • Limits match the active model context size.
  • Large files are searched before they are read wholesale.
  • Minified or binary-like files are not injected as prose.
  • Truncated output is not described as complete.
  • The first and last retained terminal sections contain enough diagnostic context.
  • Any raised limit is temporary and justified.

Common pitfalls

  • Treating truncation as success. The omitted middle may contain the root cause.
  • Raising all caps permanently. One exceptional file should not reshape every session.
  • Using terminal output as a file reader. Purpose-built paginated reads are safer and clearer.
  • Ignoring huge single lines. A file may have few lines and still be enormous.

Verification

Create a disposable text file just over the configured character limit and confirm an oversized read is rejected or paginated as expected. Produce harmless terminal output above max_bytes and verify the truncation marker plus retained head and tail. Confirm a normal source file remains fully readable.

Official reference: Hermes configuration.

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