📜 System Prompt Construction

buildEffectiveSystemPrompt() implementa um waterfall estrito de prioridades. Uma vez que uma fonte de maior prioridade e encontrada, camadas inferiores sao ignoradas.

export async function getSystemPrompt(tools, model, additionalDirs, mcpClients) {
  const [skillToolCommands, outputStyleConfig, envInfo] = await Promise.all([
    getSkillToolCommands(cwd),
    getOutputStyleConfig(),
    computeSimpleEnvInfo(model, additionalDirs),
  ])

  return [
    // -- Static (globally cacheable) --
    getSimpleIntroSection(outputStyleConfig),
    getSimpleSystemSection(),
    getSimpleDoingTasksSection(),
    getActionsSection(),
    getUsingYourToolsSection(enabledTools),
    getSimpleToneAndStyleSection(),
    getOutputEfficiencySection(),
    // -- Boundary marker --
    SYSTEM_PROMPT_DYNAMIC_BOUNDARY,
    // -- Dynamic (session-specific) --
    ...resolvedDynamicSections,
  ].filter(s => s !== null)
}

Referencia de Secoes Estaticas

// Memoized -- computed once per session
export function systemPromptSection(name, compute): SystemPromptSection {
  return { name, compute, cacheBreak: false }
}

// Volatile -- recomputes every turn
export function DANGEROUS_uncachedSystemPromptSection(name, compute, reason) {
  return { name, compute, cacheBreak: true }
}

A API do Claude suporta prompt caching: prefixos identicos sao cobrados a uma fracao do custo normal. Para explorar isso, o system prompt se divide em um prefixo estavel (mesmo para todos os usuarios) e um tail volatil (conteudo por sessao).

export const SYSTEM_PROMPT_DYNAMIC_BOUNDARY = '__SYSTEM_PROMPT_DYNAMIC_BOUNDARY__'

// WARNING: Do not remove or reorder this marker without updating cache logic in:
// - src/utils/api.ts (splitSysPromptPrefix)
// - src/services/api/claude.ts (buildSystemPromptBlocks)

Load Order (prioridade crescente)

A Diretiva @include

# CLAUDE.md
@shared-rules.md                    # relative path (same dir)
@./scripts/lint-conventions.md      # explicit relative
@~/company/global-standards.md      # home-relative
@/absolute/path/to/rules.md        # absolute

Arquivos incluidos sao inseridos como entradas separadas antes do arquivo que os inclui. Referencias circulares sao prevenidas via set de caminhos processados.

Frontmatter Path Filtering

---
paths:
  - src/components/**
  - "*.tsx"
---
Always use named exports in React components.

CLAUDE_CODE_SIMPLE=1

Ativa um system prompt de tres linhas -- sem instrucoes, sem CLAUDE.md, sem tool guidance. Util para benchmarking da capability raw do modelo.

if (isEnvTruthy(process.env.CLAUDE_CODE_SIMPLE)) {
  return [`You are Claude Code...\n\nCWD: ${getCwd()}\nDate: ${getSessionStartDate()}`]
}

Subagents

Subagents lancados por AgentTool nao passam por getSystemPrompt(). Eles partem de DEFAULT_AGENT_PROMPT e sao enriquecidos com enhanceSystemPromptWithEnvDetails().

export const DEFAULT_AGENT_PROMPT = `You are an agent for Claude Code,
Anthropic's official CLI for Claude. Given the user's message, you should
use the tools available to complete the task. Complete the task fully--
don't gold-plate, but don't leave it half-done.`

Proactive / KAIROS Mode

Retorna um prompt curto de identidade de agente autonomo ao inves do prompt completo de sessao interativa:

return [
  `\nYou are an autonomous agent. Use the available tools...\n\n${CYBER_RISK_INSTRUCTION}`,
  getSystemRemindersSection(),
  await loadMemoryPrompt(),
  envInfo,
  getLanguageSection(settings.language),
  getMcpInstructionsSection(mcpClients),
  getScratchpadInstructions(),
  getProactiveSection(),
].filter(s => s !== null)