refactor(context): system prompt section 化重构

README.md

@@ -89,7 +89,7 @@ go run ./cmd/neocode
 核心模块职责：
 
 - **`internal/config`** — 配置管理、环境变量、YAML 加载
-- **`internal/context`** — system prompt、消息裁剪与上下文构建
+- **`internal/context`** — 多 section system prompt 组装、消息裁剪与上下文构建
 - **`internal/provider`** — LLM 提供商抽象，抹平厂商差异
 - **`internal/runtime`** — ReAct 主循环、事件流、会话管理
 - **`internal/tools`** — 工具注册表与具体工具实现
@@ -107,7 +107,7 @@ go run ./cmd/neocode
 ├── internal
 │   ├── app              # 应用装配
 │   ├── config           # 配置管理
-│   ├── context          # 上下文构建
+│   ├── context          # system prompt 组装与上下文构建
 │   ├── provider         # Provider 抽象与实现
 │   ├── runtime          # ReAct 循环与事件流
 │   ├── tools            # 工具系统

docs/runtime-provider-event-flow.md

@@ -31,7 +31,7 @@
   - 当前 `provider`
   - 当前 `model`
 - `context.Builder` 负责统一组装：
-  - 固定核心 system prompt
+  - 固定核心 system prompt sections
   - 从 `workdir` 向上发现的 `AGENTS.md`
   - 系统状态摘要（`workdir` / `shell` / `provider` / `model` / git branch / git dirty）
   - 裁剪后的历史消息
@@ -42,7 +42,7 @@
 
 当前 `system prompt` 按以下顺序拼装：
 
-1. 固定核心指令
+1. 固定核心 sections
 2. `Project Rules` section
 3. `System State` section
 
@@ -51,6 +51,7 @@
 - 规则文件只支持大写文件名 `AGENTS.md`
 - 多份命中结果按“从全局到局部”的顺序注入
 - git 只注入摘要，不注入完整 `git status`
+- 各 section 统一由 `internal/context` 内部的 `renderPromptSection` 和 `composeSystemPrompt` 渲染，`runtime` 仍只消费最终字符串
 
 ## 流式桥接
 

internal/context/builder.go

@@ -30,12 +30,12 @@ func (b *DefaultBuilder) Build(ctx context.Context, input BuildInput) (BuildResu
 		return BuildResult{}, err
 	}
 
+	sections := append([]promptSection{}, defaultSystemPromptSections()...)
+	sections = append(sections, renderProjectRulesSection(rules))
+	sections = append(sections, renderSystemStateSection(systemState))
+
 	return BuildResult{
-		SystemPrompt: composeSystemPrompt(
-			defaultSystemPrompt(),
-			renderProjectRulesSection(rules),
-			renderSystemStateSection(systemState),
-		),
-		Messages: trimMessages(input.Messages),
+		SystemPrompt: composeSystemPrompt(sections...),
+		Messages:     trimMessages(input.Messages),
 	}, nil
 }

internal/context/builder_test.go

@@ -3,6 +3,8 @@ package context
 import (
 	stdcontext "context"
 	"fmt"
+	"os"
+	"path/filepath"
 	"strings"
 	"testing"
 
@@ -27,15 +29,18 @@ func TestDefaultBuilderBuild(t *testing.T) {
 	if got.SystemPrompt == "" {
 		t.Fatalf("expected non-empty system prompt")
 	}
-	if !strings.Contains(got.SystemPrompt, defaultSystemPrompt()) {
-		t.Fatalf("expected default prompt to remain in composed prompt")
+	if !strings.Contains(got.SystemPrompt, "## Agent Identity") {
+		t.Fatalf("expected core prompt sections to be included")
 	}
 	if !strings.Contains(got.SystemPrompt, "## System State") {
 		t.Fatalf("expected system state section in composed prompt")
 	}
 	if strings.Contains(got.SystemPrompt, "## Project Rules") {
 		t.Fatalf("did not expect project rules section without AGENTS.md")
 	}
+	if strings.Contains(got.SystemPrompt, "\n\n\n") {
+		t.Fatalf("did not expect repeated blank lines in composed prompt")
+	}
 	if !strings.Contains(got.SystemPrompt, input.Metadata.Workdir) {
 		t.Fatalf("expected workdir in system state section")
 	}
@@ -60,6 +65,34 @@ func TestDefaultBuilderBuildHonorsCancellation(t *testing.T) {
 	}
 }
 
+func TestDefaultBuilderBuildComposesPromptSectionsInOrder(t *testing.T) {
+	t.Parallel()
+
+	root := t.TempDir()
+	if err := os.WriteFile(filepath.Join(root, ruleFileName), []byte("project-rules"), 0o644); err != nil {
+		t.Fatalf("write AGENTS.md: %v", err)
+	}
+
+	builder := NewBuilder()
+	got, err := builder.Build(stdcontext.Background(), BuildInput{
+		Messages: []provider.Message{{Role: "user", Content: "hello"}},
+		Metadata: testMetadata(root),
+	})
+	if err != nil {
+		t.Fatalf("Build() error = %v", err)
+	}
+
+	identityIndex := strings.Index(got.SystemPrompt, "## Agent Identity")
+	rulesIndex := strings.Index(got.SystemPrompt, "## Project Rules")
+	stateIndex := strings.Index(got.SystemPrompt, "## System State")
+	if identityIndex < 0 || rulesIndex < 0 || stateIndex < 0 {
+		t.Fatalf("expected all prompt sections, got %q", got.SystemPrompt)
+	}
+	if !(identityIndex < rulesIndex && rulesIndex < stateIndex) {
+		t.Fatalf("expected section order core -> project rules -> system state, got %q", got.SystemPrompt)
+	}
+}
+
 func TestTrimMessagesPreservesToolPairs(t *testing.T) {
 	t.Parallel()
 

internal/context/prompt.go

@@ -2,23 +2,83 @@ package context
 
 import "strings"
 
-func defaultSystemPrompt() string {
-	return `You are NeoCode, a local coding agent.
+type promptSection struct {
+	title   string
+	content string
+}
+
+var defaultPromptSections = []promptSection{
+	{
+		title: "Agent Identity",
+		content: "You are NeoCode, a local coding agent focused on completing the current task end-to-end.\n" +
+			"Preserve the main loop of user input, agent reasoning, tool execution, result observation, and UI feedback.",
+	},
+	{
+		title: "Tool Usage",
+		content: "- Use tools when they reduce uncertainty or are required to complete the task safely.\n" +
+			"- Inspect tool failures, explain the relevant error, and continue with the safest useful next step.\n" +
+			"- Do not claim work is done unless the needed files, commands, or verification actually succeeded.",
+	},
+	{
+		title: "Workspace Safety",
+		content: "- Stay within the current workspace unless the user clearly asks for something else.\n" +
+			"- Avoid destructive actions such as deleting files, rewriting unrelated work, or changing history unless explicitly requested.\n" +
+			"- Respect project rules and local constraints before making changes.",
+	},
+	{
+		title: "Code Changes",
+		content: "- Prefer minimal, testable changes that keep module boundaries clear.\n" +
+			"- Follow the existing architecture and keep provider, runtime, tools, config, and TUI responsibilities separated.\n" +
+			"- When behavior changes, update the relevant tests or documentation needed to keep the implementation verifiable.",
+	},
+	{
+		title: "Failure Recovery",
+		content: "- If blocked, identify the concrete blocker and try the next reasonable path before giving up.\n" +
+			"- Surface risky assumptions, partial progress, or missing verification instead of hiding them.\n" +
+			"- When constraints prevent completion, return the best safe result and explain what remains.",
+	},
+	{
+		title: "Response Style",
+		content: "- Be concise, accurate, and collaborative.\n" +
+			"- Keep updates focused on useful progress, decisions, and verification.\n" +
+			"- Base claims on the current workspace state instead of generic advice.",
+	},
+}
 
-	Be concise and accurate.
-	Use tools when necessary.
-	When a tool fails, inspect the error and continue safely.
-	 Stay within the workspace and avoid destructive behavior unless clearly requested.`
+func defaultSystemPromptSections() []promptSection {
+	return defaultPromptSections
 }
 
-func composeSystemPrompt(parts ...string) string {
-	sections := make([]string, 0, len(parts))
-	for _, part := range parts {
-		part = strings.TrimSpace(part)
+func composeSystemPrompt(sections ...promptSection) string {
+	rendered := make([]string, 0, len(sections))
+	for _, section := range sections {
+		part := renderPromptSection(section)
 		if part == "" {
 			continue
 		}
-		sections = append(sections, part)
+		rendered = append(rendered, part)
+	}
+	return strings.Join(rendered, "\n\n")
+}
+
+func renderPromptSection(section promptSection) string {
+	title := strings.TrimSpace(section.title)
+	content := strings.TrimSpace(section.content)
+
+	switch {
+	case title == "" && content == "":
+		return ""
+	case title == "":
+		return content
+	case content == "":
+		return ""
+	default:
+		var builder strings.Builder
+		builder.Grow(len(title) + len(content) + len("## \n\n"))
+		builder.WriteString("## ")
+		builder.WriteString(title)
+		builder.WriteString("\n\n")
+		builder.WriteString(content)
+		return builder.String()
 	}
-	return strings.Join(sections, "\n\n")
 }

internal/context/prompt_test.go

@@ -0,0 +1,76 @@
+package context
+
+import "testing"
+
+func TestDefaultSystemPromptSectionsReturnsCachedSections(t *testing.T) {
+	t.Parallel()
+
+	sections := defaultSystemPromptSections()
+	if len(sections) != len(defaultPromptSections) {
+		t.Fatalf("expected %d default sections, got %d", len(defaultPromptSections), len(sections))
+	}
+	if len(sections) == 0 {
+		t.Fatalf("expected non-empty default sections")
+	}
+	if sections[0].title != "Agent Identity" {
+		t.Fatalf("expected first default section title, got %q", sections[0].title)
+	}
+}
+
+func TestRenderPromptSectionBranches(t *testing.T) {
+	t.Parallel()
+
+	tests := []struct {
+		name    string
+		section promptSection
+		want    string
+	}{
+		{
+			name:    "empty title and content renders empty",
+			section: promptSection{},
+			want:    "",
+		},
+		{
+			name: "content only renders content",
+			section: promptSection{
+				content: "content only",
+			},
+			want: "content only",
+		},
+		{
+			name: "title only renders empty",
+			section: promptSection{
+				title: "Title Only",
+			},
+			want: "",
+		},
+		{
+			name: "title and content render heading",
+			section: promptSection{
+				title:   "Section",
+				content: "body",
+			},
+			want: "## Section\n\nbody",
+		},
+		{
+			name: "title and content are trimmed before rendering",
+			section: promptSection{
+				title:   " Section ",
+				content: "\nbody\n",
+			},
+			want: "## Section\n\nbody",
+		},
+	}
+
+	for _, tt := range tests {
+		tt := tt
+		t.Run(tt.name, func(t *testing.T) {
+			t.Parallel()
+
+			got := renderPromptSection(tt.section)
+			if got != tt.want {
+				t.Fatalf("renderPromptSection() = %q, want %q", got, tt.want)
+			}
+		})
+	}
+}

internal/context/source_rules.go

@@ -119,15 +119,14 @@ func findExactRuleFile(dir string) (string, error) {
 	return "", nil
 }
 
-func renderProjectRulesSection(documents []ruleDocument) string {
+func renderProjectRulesSection(documents []ruleDocument) promptSection {
 	if len(documents) == 0 {
-		return ""
+		return promptSection{}
 	}
 
 	const totalTruncationNotice = "\n[additional project rules truncated to fit total limit]\n"
 
 	var builder strings.Builder
-	builder.WriteString("## Project Rules\n")
 
 	remaining := maxTotalRuleRunes
 	totalBudgetTruncated := false
@@ -162,7 +161,10 @@ func renderProjectRulesSection(documents []ruleDocument) string {
 		}
 	}
 
-	return strings.TrimSpace(builder.String())
+	return promptSection{
+		title:   "Project Rules",
+		content: strings.TrimSpace(builder.String()),
+	}
 }
 
 func renderRuleDocumentChunk(document ruleDocument) string {

internal/context/source_rules_test.go

@@ -38,7 +38,7 @@ func TestLoadProjectRulesOrdersGlobalToLocal(t *testing.T) {
 		t.Fatalf("expected global-to-local order, got %+v", documents)
 	}
 
-	section := renderProjectRulesSection(documents)
+	section := renderPromptSection(renderProjectRulesSection(documents))
 	rootIndex := strings.Index(section, rootRules)
 	localIndex := strings.Index(section, localRules)
 	if rootIndex < 0 || localIndex < 0 || rootIndex >= localIndex {
@@ -140,25 +140,29 @@ func TestRenderProjectRulesSectionTruncatesSingleFileAndTotalBudget(t *testing.T
 	largeTotalA := strings.Repeat("b", 7000)
 	largeTotalB := strings.Repeat("c", 7000)
 
-	section := renderProjectRulesSection([]ruleDocument{
+	section := renderPromptSection(renderProjectRulesSection([]ruleDocument{
 		{Path: "/repo/AGENTS.md", Content: largeSingle[:maxRuleFileRunes], Truncated: true},
-	})
+	}))
 	if !strings.Contains(section, "[truncated to fit per-file limit]") {
 		t.Fatalf("expected per-file truncation marker, got %q", section)
 	}
 
-	totalSection := renderProjectRulesSection([]ruleDocument{
+	totalPromptSection := renderProjectRulesSection([]ruleDocument{
 		{Path: "/repo/root/AGENTS.md", Content: largeTotalA},
 		{Path: "/repo/root/app/AGENTS.md", Content: largeTotalB},
 	})
+	totalSection := renderPromptSection(totalPromptSection)
 	if !strings.Contains(totalSection, "[additional project rules truncated to fit total limit]") {
 		t.Fatalf("expected total truncation marker, got %q", totalSection)
 	}
 	if strings.Contains(totalSection, strings.Repeat("c", 6500)) {
 		t.Fatalf("expected total rules section to be truncated")
 	}
-	body := strings.TrimPrefix(totalSection, "## Project Rules\n")
-	if runeCount(body) > maxTotalRuleRunes {
-		t.Fatalf("expected rendered rules body to respect total rune budget, got %d > %d", runeCount(body), maxTotalRuleRunes)
+	if runeCount(totalPromptSection.content) > maxTotalRuleRunes {
+		t.Fatalf(
+			"expected rendered rules body to respect total rune budget, got %d > %d",
+			runeCount(totalPromptSection.content),
+			maxTotalRuleRunes,
+		)
 	}
 }

internal/context/source_system.go

@@ -48,10 +48,8 @@ func collectSystemState(ctx context.Context, metadata Metadata, runner gitComman
 	return state, nil
 }
 
-func renderSystemStateSection(state SystemState) string {
+func renderSystemStateSection(state SystemState) promptSection {
 	lines := []string{
-		"## System State",
-		"",
 		fmt.Sprintf("- workdir: `%s`", promptValue(state.Workdir)),
 		fmt.Sprintf("- shell: `%s`", promptValue(state.Shell)),
 		fmt.Sprintf("- provider: `%s`", promptValue(state.Provider)),
@@ -68,7 +66,10 @@ func renderSystemStateSection(state SystemState) string {
 		lines = append(lines, "- git: unavailable")
 	}
 
-	return strings.Join(lines, "\n")
+	return promptSection{
+		title:   "System State",
+		content: strings.Join(lines, "\n"),
+	}
 }
 
 func runGitCommand(ctx context.Context, workdir string, args ...string) (string, error) {