Class: Rubino::Tools::ReadTool

Inherits:
Base
  • Object
show all
Defined in:
lib/rubino/tools/read_tool.rb

Overview

Reads a file with ‘cat -n` style line numbers, offset/limit windowing, and a hard cap on per-line length. Line numbers let the LLM cite or edit exact lines instead of “the second occurrence of X”; offset/limit let it page through files that would otherwise blow the context.

Constant Summary collapse

DEFAULT_LIMIT = 
2000
MAX_LINE_WIDTH = 
2000
MAX_OUTPUT_BYTES =

Hard cap on the bytes a single read returns (~25k tokens at 4 bytes/tok, matching Claude Code’s read gate). A window of 2000 lines × 2000 chars could otherwise build multiple MB in memory and blow up prefill/TTFT; past this we stop and tell the model to narrow the range or grep.

100_000

Instance Attribute Summary

Attributes inherited from Base

#cancel_token, #read_tracker, #stream_chunk

Instance Method Summary collapse

Methods inherited from Base

#cancellation_requested?, #config_key, #emit_chunk, #risky?, #to_tool_definition, workspace_root, workspace_roots

Instance Method Details

#call(arguments) ⇒ Object 



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# File 'lib/rubino/tools/read_tool.rb', line 45

def call(arguments)
  file_path = arguments["file_path"] || arguments[:file_path]
  offset    = (arguments["offset"]   || arguments[:offset]   || 1).to_i
  limit     = (arguments["limit"]    || arguments[:limit]    || DEFAULT_LIMIT).to_i

  return "Error: file_path is required" if file_path.nil? || file_path.to_s.empty?

  expanded = File.expand_path(file_path)
  return "Error: File not found: #{file_path}" unless File.exist?(expanded)
  return "Error: Not a regular file: #{file_path}" unless File.file?(expanded)

  if binary?(expanded)
    size = File.size(expanded)
    return { output: "Error: #{file_path} appears to be a binary file (#{size} bytes). " \
                     "Reading it as text would corrupt the buffer. " \
                     "Use the shell tool with xxd/file/strings for inspection.",
             error_code: :binary_file }
  end

  offset = 1 if offset < 1
  limit  = DEFAULT_LIMIT if limit <= 0

  # Stash mtime BEFORE rendering so a slow render on a huge file doesn't
  # race with a concurrent writer — we want the mtime the model "saw",
  # not the one at end-of-render.
  mtime = File.mtime(expanded)
  @read_tracker&.register(expanded, mtime)

  # Re-reading the exact same window (same file, offset, limit, unchanged
  # mtime) within a turn just re-injects bytes already in context. Return
  # a short nudge instead so the conversation doesn't carry the same
  # content twice. A real edit bumps mtime, so legitimate re-reads pass.
  dup = @read_tracker&.register_window(expanded, offset, limit, mtime)
  if dup && dup > 1
    return { output: "[DUPLICATE READ] Exact repeat of an earlier read of #{file_path} " \
                     "(lines #{offset}-#{offset + limit - 1}) this turn — reuse that result " \
                     "instead of re-reading.",
             metrics: "duplicate" }
  end

  render(expanded, file_path, offset, limit)
rescue StandardError => e
  "Error reading #{file_path}: #{e.message}"
end

#description ⇒ Object 



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# File 'lib/rubino/tools/read_tool.rb', line 22

def description
  "Read a text file from the filesystem with line numbers (cat -n style). " \
    "Supports offset (1-based start line) and limit (max lines returned). " \
    "Long lines are truncated at #{MAX_LINE_WIDTH} chars. " \
    "Default window: first #{DEFAULT_LIMIT} lines."
end

#input_schema ⇒ Object 



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# File 'lib/rubino/tools/read_tool.rb', line 29

def input_schema
  {
    type: "object",
    properties: {
      file_path: { type: "string", description: "Absolute or relative file path" },
      offset: { type: "integer", description: "1-based line to start at (default 1)" },
      limit: { type: "integer", description: "Max lines to return (default #{DEFAULT_LIMIT})" }
    },
    required: %w[file_path]
  }
end

#name ⇒ Object 



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# File 'lib/rubino/tools/read_tool.rb', line 18

def name
  "read"
end

#risk_level ⇒ Object 



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# File 'lib/rubino/tools/read_tool.rb', line 41

def risk_level
  :low
end