Module: Btape::LLM::Prompt

Defined in:
lib/btape/llm/prompt.rb

Overview

What the model is told before it is asked for a tape.

The command list and the settings table are built from Parser and Settings rather than written out again here, so a command added to the language is a command the model is told about, and a setting cannot be described to it with a default it no longer has.

Constant Summary collapse

RULES = 
[
  'Answer with the contents of a .tape file and nothing else: no explanation, no code fences.',
  'The script must contain exactly one Output line, naming a .gif file, and it comes first.',
  'One command per line. Lines starting with # are comments.',
  'The line is split like a shell command, so any argument containing a space must be quoted ' \
  'with double quotes.',
  'Click, WaitFor and Frame take a CSS selector, or text=Some text to match on visible text.',
  'Durations are a number followed by ms or s, such as 500ms or 1.5s.',
  'Prefer WaitFor or WaitForJS over Sleep for anything the page has to finish doing; ' \
  'Sleep is for holding a finished frame on screen long enough to be seen.',
  'Use only the commands and settings listed above. Do not invent either, ' \
  'and do not use a shell, a comment or a blank line to stand in for one.'
].freeze
EXAMPLE = 
<<~TAPE
  # Signing in, recorded at half size
  Output signin.gif
  Viewport 1280x720
  Set Scale 0.5

  Goto http://localhost:3000/signin
  WaitFor "#email"
  Type "#email" "demo@example.com"
  Type "#password" "correct horse"
  Click "text=Sign in"
  WaitFor "text=Welcome back" 5s
  Sleep 2s
TAPE
VALUES =

What a setting takes, as the coercions in Settings enforce it. A default is shown as a tape would have to write it rather than as Settings holds it, since Set FrameDelay 0.1 is not something the parser would accept back.

{
  duration: 'a duration',
  url: "a #{Settings::URL_SCHEMES.join(', ')} url",
  count: 'a whole number, 0 or more',
  positive_integer: 'a whole number, 1 or more',
  positive_float: 'a number'
}.freeze

Class Method Summary collapse

Class Method Details

.commands ⇒ Object 



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# File 'lib/btape/llm/prompt.rb', line 106

def commands
  Parser::SIGNATURES.map { |name, arguments| "#{name} #{arguments}".strip }.join("\n")
end

.indent(text) ⇒ Object

Blank lines are left alone, so that indenting a block into the prompt does not leave trailing whitespace through the middle of it.



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# File 'lib/btape/llm/prompt.rb', line 128

def indent(text)
  text.strip.gsub(/^(?=.)/, '  ')
end

.literal(coercion, default) ⇒ Object

A coerced default as a tape would write it: durations are held in seconds and go back to the ms or s they were read from.



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# File 'lib/btape/llm/prompt.rb', line 119

def literal(coercion, default)
  return default.to_s unless coercion == :duration
  return "#{(default * 1000).round}ms" if default < 1

  "#{default.to_i == default ? default.to_i : default}s"
end

.repair(reason) ⇒ Object

A tape that did not parse goes back with the parser's own complaint, which names the line and what was wrong with it. Saying so beats asking again and hoping, since the model can see what it wrote.



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# File 'lib/btape/llm/prompt.rb', line 98

def repair(reason)
  <<~PROMPT
    btape rejected that tape: #{reason}

    Answer with the whole corrected tape, and nothing else.
  PROMPT
end

.settings ⇒ Object 



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# File 'lib/btape/llm/prompt.rb', line 110

def settings
  Settings::DEFINITIONS.map do |name, (_attribute, coercion, default)|
    takes = coercion.is_a?(Array) ? coercion.join('|') : VALUES.fetch(coercion)
    "Set #{name} <#{takes}>#{" — #{literal(coercion, default)} by default" unless default.nil?}"
  end.join("\n")
end

.system ⇒ Object 



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# File 'lib/btape/llm/prompt.rb', line 58

def system
  <<~PROMPT
    You write btape scripts. btape runs a .tape file against Chromium and records
    the run as an animated GIF, so a tape is a short, deliberate demonstration
    rather than a test: it moves at a pace somebody can watch.

    The commands, one per line:

    #{indent(commands)}

    A run is configured with `Set NAME VALUE`:

    #{indent(settings)}

    Rules:

    #{indent(RULES.map { |rule| "- #{rule}" }.join("\n"))}

    An example of a whole tape:

    #{indent(EXAMPLE)}
  PROMPT
end

.user(description, context: nil) ⇒ Object 



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# File 'lib/btape/llm/prompt.rb', line 82

def user(description, context: nil)
  return description if context.nil? || context.strip.empty?

  <<~PROMPT
    #{description}

    Context about the page being recorded — prefer the selectors it names over
    any you would otherwise guess at:

    #{context}
  PROMPT
end