diff --git a/repos/kbconfig.go b/repos/kbconfig.go
new file mode 100644
index 0000000..26c1cba
--- /dev/null
+++ b/repos/kbconfig.go
@@ -0,0 +1,116 @@
+package repos
+
+import (
+	"fmt"
+	"path/filepath"
+
+	"forge.lthn.ai/core/go-io"
+	"gopkg.in/yaml.v3"
+)
+
+// KBConfig holds knowledge base configuration for a workspace.
+// Stored at .core/kb.yaml and checked into git.
+type KBConfig struct {
+	Version int        `yaml:"version"`
+	Wiki    WikiConfig `yaml:"wiki"`
+	Search  KBSearch   `yaml:"search"`
+}
+
+// WikiConfig controls local wiki mirror behaviour.
+type WikiConfig struct {
+	// Enabled toggles wiki cloning on sync.
+	Enabled bool `yaml:"enabled"`
+	// Dir is the local directory for wiki clones, relative to .core/.
+	Dir string `yaml:"dir"`
+	// Remote is the SSH base URL for wiki repos (e.g. ssh://git@forge.lthn.ai:2223/core).
+	// Repo wikis are at {Remote}/{name}.wiki.git
+	Remote string `yaml:"remote"`
+}
+
+// KBSearch configures vector search against the OpenBrain Qdrant collection.
+type KBSearch struct {
+	// QdrantHost is the Qdrant server (gRPC).
+	QdrantHost string `yaml:"qdrant_host"`
+	// QdrantPort is the gRPC port.
+	QdrantPort int `yaml:"qdrant_port"`
+	// Collection is the Qdrant collection name.
+	Collection string `yaml:"collection"`
+	// OllamaURL is the Ollama API base URL for embedding queries.
+	OllamaURL string `yaml:"ollama_url"`
+	// EmbedModel is the Ollama model for embedding.
+	EmbedModel string `yaml:"embed_model"`
+	// TopK is the default number of results.
+	TopK int `yaml:"top_k"`
+}
+
+// DefaultKBConfig returns sensible defaults for knowledge base config.
+func DefaultKBConfig() *KBConfig {
+	return &KBConfig{
+		Version: 1,
+		Wiki: WikiConfig{
+			Enabled: true,
+			Dir:     "kb/wiki",
+			Remote:  "ssh://git@forge.lthn.ai:2223/core",
+		},
+		Search: KBSearch{
+			QdrantHost: "qdrant.lthn.sh",
+			QdrantPort: 6334,
+			Collection: "openbrain",
+			OllamaURL:  "https://ollama.lthn.sh",
+			EmbedModel: "embeddinggemma",
+			TopK:       5,
+		},
+	}
+}
+
+// LoadKBConfig reads .core/kb.yaml from the given workspace root directory.
+// Returns defaults if the file does not exist.
+func LoadKBConfig(m io.Medium, root string) (*KBConfig, error) {
+	path := filepath.Join(root, ".core", "kb.yaml")
+
+	if !m.Exists(path) {
+		return DefaultKBConfig(), nil
+	}
+
+	content, err := m.Read(path)
+	if err != nil {
+		return nil, fmt.Errorf("failed to read kb config: %w", err)
+	}
+
+	kb := DefaultKBConfig()
+	if err := yaml.Unmarshal([]byte(content), kb); err != nil {
+		return nil, fmt.Errorf("failed to parse kb config: %w", err)
+	}
+
+	return kb, nil
+}
+
+// SaveKBConfig writes .core/kb.yaml to the given workspace root directory.
+func SaveKBConfig(m io.Medium, root string, kb *KBConfig) error {
+	coreDir := filepath.Join(root, ".core")
+	if err := m.EnsureDir(coreDir); err != nil {
+		return fmt.Errorf("failed to create .core directory: %w", err)
+	}
+
+	data, err := yaml.Marshal(kb)
+	if err != nil {
+		return fmt.Errorf("failed to marshal kb config: %w", err)
+	}
+
+	path := filepath.Join(coreDir, "kb.yaml")
+	if err := m.Write(path, string(data)); err != nil {
+		return fmt.Errorf("failed to write kb config: %w", err)
+	}
+
+	return nil
+}
+
+// WikiRepoURL returns the full clone URL for a repo's wiki.
+func (kb *KBConfig) WikiRepoURL(repoName string) string {
+	return fmt.Sprintf("%s/%s.wiki.git", kb.Wiki.Remote, repoName)
+}
+
+// WikiLocalPath returns the local path for a repo's wiki clone.
+func (kb *KBConfig) WikiLocalPath(root, repoName string) string {
+	return filepath.Join(root, ".core", kb.Wiki.Dir, repoName)
+}
diff --git a/repos/kbconfig_test.go b/repos/kbconfig_test.go
new file mode 100644
index 0000000..db72a5d
--- /dev/null
+++ b/repos/kbconfig_test.go
@@ -0,0 +1,107 @@
+package repos
+
+import (
+	"testing"
+
+	"forge.lthn.ai/core/go-io"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+// ── DefaultKBConfig ────────────────────────────────────────────────
+
+func TestDefaultKBConfig_Good(t *testing.T) {
+	kb := DefaultKBConfig()
+	assert.Equal(t, 1, kb.Version)
+	assert.True(t, kb.Wiki.Enabled)
+	assert.Equal(t, "kb/wiki", kb.Wiki.Dir)
+	assert.Contains(t, kb.Wiki.Remote, "forge.lthn.ai")
+	assert.Equal(t, "qdrant.lthn.sh", kb.Search.QdrantHost)
+	assert.Equal(t, 6334, kb.Search.QdrantPort)
+	assert.Equal(t, "openbrain", kb.Search.Collection)
+	assert.Equal(t, "embeddinggemma", kb.Search.EmbedModel)
+	assert.Equal(t, 5, kb.Search.TopK)
+}
+
+// ── Load / Save round-trip ─────────────────────────────────────────
+
+func TestKBConfig_LoadSave_Good(t *testing.T) {
+	m := io.NewMockMedium()
+	_ = m.EnsureDir("/workspace/.core")
+
+	kb := DefaultKBConfig()
+	kb.Search.TopK = 10
+	kb.Search.Collection = "custom_brain"
+
+	err := SaveKBConfig(m, "/workspace", kb)
+	require.NoError(t, err)
+
+	loaded, err := LoadKBConfig(m, "/workspace")
+	require.NoError(t, err)
+
+	assert.Equal(t, 1, loaded.Version)
+	assert.Equal(t, 10, loaded.Search.TopK)
+	assert.Equal(t, "custom_brain", loaded.Search.Collection)
+	assert.True(t, loaded.Wiki.Enabled)
+}
+
+func TestKBConfig_Load_Good_NoFile(t *testing.T) {
+	m := io.NewMockMedium()
+	_ = m.EnsureDir("/workspace/.core")
+
+	kb, err := LoadKBConfig(m, "/workspace")
+	require.NoError(t, err)
+	assert.Equal(t, DefaultKBConfig().Search.Collection, kb.Search.Collection)
+}
+
+func TestKBConfig_Load_Good_PartialOverride(t *testing.T) {
+	m := io.NewMockMedium()
+	_ = m.Write("/workspace/.core/kb.yaml", `
+version: 1
+search:
+  top_k: 20
+  collection: my_brain
+`)
+
+	kb, err := LoadKBConfig(m, "/workspace")
+	require.NoError(t, err)
+
+	assert.Equal(t, 20, kb.Search.TopK)
+	assert.Equal(t, "my_brain", kb.Search.Collection)
+	// Defaults preserved
+	assert.True(t, kb.Wiki.Enabled)
+	assert.Equal(t, "embeddinggemma", kb.Search.EmbedModel)
+}
+
+func TestKBConfig_Load_Bad_InvalidYAML(t *testing.T) {
+	m := io.NewMockMedium()
+	_ = m.Write("/workspace/.core/kb.yaml", "{{{{broken")
+
+	_, err := LoadKBConfig(m, "/workspace")
+	assert.Error(t, err)
+	assert.Contains(t, err.Error(), "failed to parse")
+}
+
+// ── WikiRepoURL ────────────────────────────────────────────────────
+
+func TestKBConfig_WikiRepoURL_Good(t *testing.T) {
+	kb := DefaultKBConfig()
+	url := kb.WikiRepoURL("go-scm")
+	assert.Equal(t, "ssh://git@forge.lthn.ai:2223/core/go-scm.wiki.git", url)
+}
+
+func TestKBConfig_WikiRepoURL_Good_CustomRemote(t *testing.T) {
+	kb := &KBConfig{
+		Wiki: WikiConfig{Remote: "ssh://git@git.example.com/org"},
+	}
+	url := kb.WikiRepoURL("my-repo")
+	assert.Equal(t, "ssh://git@git.example.com/org/my-repo.wiki.git", url)
+}
+
+// ── WikiLocalPath ──────────────────────────────────────────────────
+
+func TestKBConfig_WikiLocalPath_Good(t *testing.T) {
+	kb := DefaultKBConfig()
+	path := kb.WikiLocalPath("/workspace", "go-scm")
+	assert.Equal(t, "/workspace/.core/kb/wiki/go-scm", path)
+}