Class: Ask::CodingHarness::SystemPrompt

Inherits:
Object
  • Object
show all
Defined in:
lib/ask/coding_harness/system_prompt.rb

Overview

Builds the agent system prompt, in the style of the pi coding agent: a composable base (custom or default), tool-aware guidelines, project context files injected as <project_context> (AGENTS.md / CLAUDE.md walked from the workspace up to the filesystem root), an append section, and the working directory as a closing footer.

SystemPrompt.build(workspace: "/path/to/project")
SystemPrompt.build(workspace: "/p", custom: "...", append: "...",
                 guidelines: ["Always run tests"])

Constant Summary collapse

CONTEXT_FILE_CANDIDATES =

Files picked up per directory when building project context.

%w[AGENTS.md AGENTS.MD CLAUDE.md CLAUDE.MD].freeze
MAX_CONTEXT_FILE_SIZE =

Context files larger than this are skipped (token hygiene).

64 * 1024
DEFAULT_GUIDELINES =

Guidelines always present, regardless of configuration.

[
  "Be concise in your responses",
  "Show file paths clearly when working with files",
  "Use absolute paths rooted at your working directory for all file and command operations",
  "Investigate before you act: read the relevant files before editing them",
  "Verify your work: run tests or checks after changing code",
  "Never claim an action you did not take"
].freeze
DEFAULT_PROMPT = 
<<~PROMPT.chomp
  You are an expert coding assistant operating inside ask-coding-harness, a coding agent
  harness for the ask-rb ecosystem. You help users by reading files, executing commands,
  editing code, and writing new files. Work autonomously: investigate the project, make
  changes, and verify your work.
PROMPT

Class Method Summary collapse

Class Method Details

.build(workspace:, custom: nil, append: nil, guidelines: [], context_files: :auto) ⇒ String

Build the full system prompt for a workspace.

Parameters:

  • workspace (String) —

    the working directory (footer + context walk)

  • custom (String, nil) (defaults to: nil) —

    custom base prompt (replaces the default; project context, append, and footer are still added)

  • append (String, nil) (defaults to: nil) —

    extra text appended after project context

  • guidelines (Array<String>) (defaults to: []) —

    extra guideline bullets

  • context_files (Array<Hash>, :auto, nil) (defaults to: :auto) —

    explicit project context files (content:), auto-discovered from the workspace walk, or none

Returns:

  • (String) 


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# File 'lib/ask/coding_harness/system_prompt.rb', line 51

def self.build(workspace:, custom: nil, append: nil, guidelines: [],
               context_files: :auto)
  files =
    case context_files
    when :auto then load_project_context(workspace)
    when nil then []
    else context_files
    end

  parts = []
  parts << (custom.nil? || custom.empty? ? DEFAULT_PROMPT : custom)
  parts << render_guidelines(guidelines)
  parts << render_project_context(files) unless files.empty?
  parts << append unless append.nil? || append.empty?
  parts << "Current working directory: #{workspace.to_s.tr("\\", "/")}"
  parts.reject { |p| p.nil? || p.empty? }.join("\n\n")
end

.context_file_in(dir) ⇒ Object

The first existing context file in a directory, or nil.



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# File 'lib/ask/coding_harness/system_prompt.rb', line 98

def self.context_file_in(dir)
  CONTEXT_FILE_CANDIDATES.each do |name|
    path = File.join(dir, name)
    next unless File.file?(path)
    size = File.size(path)
    next if size > MAX_CONTEXT_FILE_SIZE
    content = File.read(path, encoding: "UTF-8")
    return { file: { path: path, content: content }, realpath: File.realpath(path) }
  rescue SystemCallError, EncodingError
    next
  end
  nil
end

.load_project_context(workspace) ⇒ Array<Hash>

Walk from the workspace up to the filesystem root, collecting the nearest AGENTS.md / CLAUDE.md in each directory (nearest first, deduplicated by realpath). Mirrors the pi coding agent's project context discovery.

Parameters:

  • workspace (String)

Returns:

  • (Array<Hash>) —

    [content:]



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# File 'lib/ask/coding_harness/system_prompt.rb', line 76

def self.load_project_context(workspace)
  files = []
  seen = {}

  dir = File.expand_path(workspace)
  loop do
    candidate = context_file_in(dir)
    if candidate && !seen.key?(candidate[:realpath])
      seen[candidate[:realpath]] = true
      files << candidate[:file]
    end

    parent = File.dirname(dir)
    break if parent == dir
    dir = parent
  end

  # Nearest first: the walk starts at the workspace.
  files
end

.render_guidelines(extra) ⇒ Object 



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# File 'lib/ask/coding_harness/system_prompt.rb', line 112

def self.render_guidelines(extra)
  list = DEFAULT_GUIDELINES.dup
  Array(extra).each do |g|
    normalized = g.to_s.strip
    list << normalized unless normalized.empty? || list.include?(normalized)
  end
  "Guidelines:\n" + list.map { |g| "- #{g}" }.join("\n")
end

.render_project_context(files) ⇒ Object 



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# File 'lib/ask/coding_harness/system_prompt.rb', line 121

def self.render_project_context(files)
  body = files.map do |f|
    "<project_instructions path=\"#{f[:path]}\">\n#{f[:content]}\n</project_instructions>"
  end.join("\n\n")
  "<project_context>\n\nProject-specific instructions and guidelines:\n\n#{body}\n</project_context>"
end