diff --git a/ingestion/internal/pipeline/pipeline.go b/ingestion/internal/pipeline/pipeline.go
new file mode 100644
index 0000000..c345dbd
--- /dev/null
+++ b/ingestion/internal/pipeline/pipeline.go
@@ -0,0 +1,120 @@
+// ingestion/internal/pipeline/pipeline.go
+package pipeline
+
+import (
+	"context"
+	"fmt"
+	"os"
+	"path/filepath"
+	"strings"
+	"time"
+
+	"github.com/mathiasbq/hyperguild/ingestion/internal/wiki"
+)
+
+// CompleteFunc is the function signature for LLM calls.
+type CompleteFunc func(ctx context.Context, system, user string) (string, error)
+
+// Config holds pipeline configuration.
+type Config struct {
+	Complete  CompleteFunc
+	ChunkSize int    // 0 = no chunking
+	Schema    string // overrides brain/CLAUDE.md when set (useful in tests)
+}
+
+// Result is the outcome of a pipeline run.
+type Result struct {
+	Pages    []string // relative paths written (or would-be written in dry-run)
+	Warnings []string
+}
+
+// Run ingests content and writes structured wiki pages to brainDir/wiki/.
+// In dry-run mode, pages are returned but not written to disk.
+func Run(ctx context.Context, cfg Config, brainDir, content, source string, dryRun bool) (Result, error) {
+	inventory, err := wiki.LoadInventory(brainDir)
+	if err != nil {
+		return Result{}, fmt.Errorf("load inventory: %w", err)
+	}
+
+	schema := cfg.Schema
+	if schema == "" {
+		schema = loadSchema(brainDir)
+	}
+
+	chunks := Chunk(content, cfg.ChunkSize)
+
+	var allPages []wiki.Page
+	var allWarnings []string
+
+	for _, chunk := range chunks {
+		userPrompt := BuildPrompt(schema, source, chunk, inventory)
+		output, err := cfg.Complete(ctx, systemPrompt, userPrompt)
+		if err != nil {
+			return Result{}, fmt.Errorf("LLM call: %w", err)
+		}
+		pages, warnings := ParsePages(output)
+		allPages = append(allPages, pages...)
+		allWarnings = append(allWarnings, warnings...)
+	}
+
+	merged := mergeAll(allPages)
+
+	date := time.Now().UTC().Format("2006-01-02")
+	var written []string
+
+	for _, page := range merged {
+		if !dryRun {
+			dest := filepath.Join(brainDir, filepath.FromSlash(page.Path))
+			if err := os.MkdirAll(filepath.Dir(dest), 0o755); err != nil {
+				return Result{}, fmt.Errorf("mkdir for %s: %w", page.Path, err)
+			}
+			if err := os.WriteFile(dest, []byte(page.Content), 0o644); err != nil {
+				return Result{}, fmt.Errorf("write %s: %w", page.Path, err)
+			}
+		}
+		written = append(written, page.Path)
+	}
+
+	if !dryRun {
+		if err := wiki.RebuildIndex(brainDir, date); err != nil {
+			allWarnings = append(allWarnings, fmt.Sprintf("rebuild index: %v", err))
+		}
+		if err := wiki.AppendLog(brainDir, source, written, allWarnings, date); err != nil {
+			allWarnings = append(allWarnings, fmt.Sprintf("append log: %v", err))
+		}
+	}
+
+	return Result{Pages: written, Warnings: allWarnings}, nil
+}
+
+// mergeAll deduplicates pages by path, merging content from later occurrences.
+func mergeAll(pages []wiki.Page) []wiki.Page {
+	order := make([]string, 0, len(pages))
+	byPath := make(map[string]wiki.Page, len(pages))
+	for _, p := range pages {
+		if _, seen := byPath[p.Path]; !seen {
+			order = append(order, p.Path)
+			byPath[p.Path] = p
+		} else {
+			byPath[p.Path] = wiki.Merge(byPath[p.Path], p)
+		}
+	}
+	result := make([]wiki.Page, 0, len(order))
+	for _, path := range order {
+		result = append(result, byPath[path])
+	}
+	return result
+}
+
+const defaultSchema = `# Brain Wiki Schema
+Three page types: wiki/sources/, wiki/concepts/, wiki/entities/.
+See brain/CLAUDE.md for the full schema.
+`
+
+func loadSchema(brainDir string) string {
+	b, err := os.ReadFile(filepath.Join(brainDir, "CLAUDE.md"))
+	if err != nil {
+		return defaultSchema
+	}
+	return strings.TrimSpace(string(b))
+}
diff --git a/ingestion/internal/pipeline/pipeline_test.go b/ingestion/internal/pipeline/pipeline_test.go
new file mode 100644
index 0000000..38976b8
--- /dev/null
+++ b/ingestion/internal/pipeline/pipeline_test.go
@@ -0,0 +1,130 @@
+// ingestion/internal/pipeline/pipeline_test.go
+package pipeline
+
+import (
+	"context"
+	"encoding/json"
+	"net/http"
+	"net/http/httptest"
+	"os"
+	"path/filepath"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
+	"github.com/mathiasbq/hyperguild/ingestion/internal/llm"
+	"github.com/mathiasbq/hyperguild/ingestion/internal/wiki"
+)
+
+func TestRun_WritesPages(t *testing.T) {
+	brainDir := t.TempDir()
+	for _, sub := range []string{"wiki/concepts", "wiki/entities", "wiki/sources"} {
+		require.NoError(t, os.MkdirAll(filepath.Join(brainDir, sub), 0o755))
+	}
+
+	llmResponse := mustJSON([]wiki.Page{
+		{
+			Path:    "wiki/sources/test-article.md",
+			Content: "---\ntitle: Test Article\ntype: article\ndomain: software-engineering\ndate_ingested: 2026-04-22\nlast_updated: 2026-04-22\naliases:\n  - Test Article\n---\n\n## Summary\n\nA test article.\n\n## Key Claims\n\n- It tests things.\n\n## Concepts Introduced or Reinforced\n\n## Entities Mentioned\n\n## Open Questions Raised\n",
+		},
+		{
+			Path:    "wiki/concepts/testing.md",
+			Content: "---\ntitle: Testing\ndomain: software-engineering\nlast_updated: 2026-04-22\naliases:\n  - Testing\n---\n\n## Definition\n\nThe practice of verifying software.\n\n## Why It Matters\n\nCatches bugs.\n\n## Related Concepts\n\n## Related Entities\n\n## Sources\n\n## Evolving Notes\n",
+		},
+	})
+
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Content-Type", "application/json")
+		json.NewEncoder(w).Encode(map[string]any{
+			"choices": []map[string]any{
+				{"message": map[string]any{"role": "assistant", "content": llmResponse}},
+			},
+		})
+	}))
+	defer srv.Close()
+
+	cfg := Config{
+		Complete:  llm.New(srv.URL, "", "test-model", 30*time.Second).Complete,
+		ChunkSize: 0,
+	}
+
+	result, err := Run(context.Background(), cfg, brainDir, "An article about testing.", "test-article", false)
+	require.NoError(t, err)
+	assert.Len(t, result.Pages, 2)
+	assert.Empty(t, result.Warnings)
+
+	_, err = os.Stat(filepath.Join(brainDir, "wiki", "sources", "test-article.md"))
+	require.NoError(t, err)
+	_, err = os.Stat(filepath.Join(brainDir, "wiki", "concepts", "testing.md"))
+	require.NoError(t, err)
+	_, err = os.Stat(filepath.Join(brainDir, "wiki", "index.md"))
+	require.NoError(t, err)
+	_, err = os.Stat(filepath.Join(brainDir, "log.md"))
+	require.NoError(t, err)
+}
+
+func TestRun_DryRunDoesNotWrite(t *testing.T) {
+	brainDir := t.TempDir()
+	for _, sub := range []string{"wiki/concepts", "wiki/entities", "wiki/sources"} {
+		require.NoError(t, os.MkdirAll(filepath.Join(brainDir, sub), 0o755))
+	}
+
+	llmResponse := mustJSON([]wiki.Page{{
+		Path:    "wiki/sources/foo.md",
+		Content: "---\ntitle: Foo\n---\n\n## Summary\n\nFoo.\n",
+	}})
+
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		json.NewEncoder(w).Encode(map[string]any{
+			"choices": []map[string]any{{"message": map[string]any{"content": llmResponse}}},
+		})
+	}))
+	defer srv.Close()
+
+	cfg := Config{Complete: llm.New(srv.URL, "", "m", 30*time.Second).Complete}
+	result, err := Run(context.Background(), cfg, brainDir, "foo content", "foo", true)
+	require.NoError(t, err)
+	assert.Len(t, result.Pages, 1)
+
+	_, err = os.Stat(filepath.Join(brainDir, "wiki", "sources", "foo.md"))
+	assert.True(t, os.IsNotExist(err))
+}
+
+func TestRun_MergesDuplicatePaths(t *testing.T) {
+	brainDir := t.TempDir()
+	for _, sub := range []string{"wiki/concepts", "wiki/entities", "wiki/sources"} {
+		require.NoError(t, os.MkdirAll(filepath.Join(brainDir, sub), 0o755))
+	}
+
+	// LLM returns same path twice (simulates multi-chunk merge)
+	llmResponse := mustJSON([]wiki.Page{
+		{Path: "wiki/concepts/foo.md", Content: "---\ntitle: Foo\n---\n\n## Definition\n\nFirst.\n\n## Related Concepts\n\n- [[bar|Bar]]\n"},
+		{Path: "wiki/concepts/foo.md", Content: "---\ntitle: Foo\n---\n\n## Definition\n\nSecond.\n\n## Related Concepts\n\n- [[baz|Baz]]\n"},
+	})
+
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		json.NewEncoder(w).Encode(map[string]any{
+			"choices": []map[string]any{{"message": map[string]any{"content": llmResponse}}},
+		})
+	}))
+	defer srv.Close()
+
+	cfg := Config{Complete: llm.New(srv.URL, "", "m", 30*time.Second).Complete}
+	result, err := Run(context.Background(), cfg, brainDir, "content", "foo", false)
+	require.NoError(t, err)
+	assert.Len(t, result.Pages, 1) // deduplicated
+
+	content, err := os.ReadFile(filepath.Join(brainDir, "wiki", "concepts", "foo.md"))
+	require.NoError(t, err)
+	// keep-first for Definition, union for Related Concepts
+	assert.Contains(t, string(content), "First.")
+	assert.Contains(t, string(content), "[[bar|Bar]]")
+	assert.Contains(t, string(content), "[[baz|Baz]]")
+}
+
+func mustJSON(v any) string {
+	b, _ := json.Marshal(v)
+	return string(b)
+}
diff --git a/ingestion/internal/pipeline/prompt.go b/ingestion/internal/pipeline/prompt.go
new file mode 100644
index 0000000..4ea6c65
--- /dev/null
+++ b/ingestion/internal/pipeline/prompt.go
@@ -0,0 +1,60 @@
+// ingestion/internal/pipeline/prompt.go
+package pipeline
+
+import (
+	"fmt"
+	"strings"
+	"time"
+
+	"github.com/mathiasbq/hyperguild/ingestion/internal/wiki"
+)
+
+const systemPrompt = `You are a wiki agent. Read the source material and produce structured wiki pages following the schema provided.
+
+Output ONLY a valid JSON array — no markdown fences, no other text before or after.
+Each element must have:
+  "path"    — relative path within the wiki, e.g. "wiki/sources/foo.md"
+  "content" — full markdown content of the page including YAML frontmatter
+
+Follow the schema strictly: correct frontmatter fields, wikilinks as [[slug|Display Text]],
+dates in YYYY-MM-DD format, and paraphrase rather than quoting verbatim.`
+
+// BuildPrompt constructs the user prompt for a single chunk.
+func BuildPrompt(schema, source, content string, inventory map[wiki.PageType][]wiki.Entry) string {
+	var sb strings.Builder
+
+	fmt.Fprintf(&sb, "Today's date is %s.\n\n", time.Now().UTC().Format("2006-01-02"))
+
+	sb.WriteString("## Schema\n\n")
+	sb.WriteString(schema)
+	sb.WriteString("\n\n")
+
+	sb.WriteString("## Existing wiki pages\n\n")
+	sb.WriteString("Link ONLY to pages in this inventory or pages you are creating in this response.\n\n")
+
+	for _, pt := range []wiki.PageType{wiki.PageTypeConcept, wiki.PageTypeEntity, wiki.PageTypeSource} {
+		entries := inventory[pt]
+		label := strings.ToUpper(string(pt)[:1]) + string(pt)[1:]
+		if len(entries) == 0 {
+			fmt.Fprintf(&sb, "%s — (none yet)\n\n", label)
+			continue
+		}
+		fmt.Fprintf(&sb, "%s — link ONLY under the matching section:\n", label)
+		for _, e := range entries {
+			fmt.Fprintf(&sb, "  - [[%s|%s]]\n", e.Slug, e.Title)
+		}
+		sb.WriteString("\n")
+	}
+
+	sb.WriteString("## Non-negotiable rules\n\n")
+	sb.WriteString("1. Output ONLY a valid JSON array — no prose, no fences.\n")
+	sb.WriteString("2. Slugs are kebab-case: lowercase, spaces→hyphens, no special chars.\n")
+	sb.WriteString("3. Wikilinks: [[slug|Display Text]] — the pipe is required.\n")
+	sb.WriteString("4. Section links must match their section type.\n")
+	sb.WriteString("5. One source page per book — update it if inventory shows it exists.\n\n")
+
+	fmt.Fprintf(&sb, "## Source: %s\n\n", source)
+	sb.WriteString(content)
+
+	return sb.String()
+}