feat(kc): commit extraction pipeline + metadata API (Phase 1)

Implements issue #141 — .kc server-side metadata integration Phase 1. When a .kc file is uploaded, the server extracts silo/manifest.json and silo/metadata.json from the ZIP archive and indexes them into the item_metadata table. Plain .fcstd files continue to work unchanged. Extraction is best-effort: failures are logged but do not block the upload. New packages: - internal/kc: ZIP extraction library (Extract, Manifest, Metadata types) - internal/db: ItemMetadataRepository (Get, Upsert, UpdateFields, UpdateLifecycle, SetTags) New API endpoints under /api/items/{partNumber}: - GET /metadata — read indexed metadata (viewer) - PUT /metadata — merge fields into JSONB (editor) - PATCH /metadata/lifecycle — transition lifecycle state (editor) - PATCH /metadata/tags — add/remove tags (editor) SSE events: metadata.updated, metadata.lifecycle, metadata.tags Lifecycle transitions (Phase 1): draft→review→released→obsolete, review→draft (reject). Closes #141
2026-02-18 16:37:39 -06:00
parent d96ba8d394
commit dd010331c0
7 changed files with 885 additions and 0 deletions
--- a/internal/api/handlers.go
+++ b/internal/api/handlers.go
@@ -53,6 +53,7 @@ type Server struct {
 	modules       *modules.Registry
 	cfg           *config.Config
 	settings      *db.SettingsRepository
+	metadata      *db.ItemMetadataRepository
 }

 // NewServer creates a new API server.
@@ -81,6 +82,7 @@ func NewServer(
 	jobs := db.NewJobRepository(database)
 	settings := db.NewSettingsRepository(database)
 	locations := db.NewLocationRepository(database)
+	metadata := db.NewItemMetadataRepository(database)
 	seqStore := &dbSequenceStore{db: database, schemas: schemas}
 	partgen := partnum.NewGenerator(schemas, seqStore)

@@ -109,6 +111,7 @@ func NewServer(
 		modules:       registry,
 		cfg:           cfg,
 		settings:      settings,
+		metadata:      metadata,
 	}
 }

@@ -1652,6 +1655,9 @@ func (s *Server) HandleUploadFile(w http.ResponseWriter, r *http.Request) {
 		Int64("size", result.Size).
 		Msg("file uploaded")

+	// .kc metadata extraction (best-effort)
+	s.extractKCMetadata(ctx, item, fileKey, rev)
+
 	writeJSON(w, http.StatusCreated, revisionToResponse(rev))
 }

--- a/internal/api/metadata_handlers.go
+++ b/internal/api/metadata_handlers.go
@@ -0,0 +1,419 @@
+package api
+
+import (
+	"context"
+	"encoding/json"
+	"io"
+	"net/http"
+
+	"github.com/go-chi/chi/v5"
+	"github.com/kindredsystems/silo/internal/auth"
+	"github.com/kindredsystems/silo/internal/db"
+	"github.com/kindredsystems/silo/internal/kc"
+)
+
+// validTransitions defines allowed lifecycle state transitions for Phase 1.
+var validTransitions = map[string][]string{
+	"draft":    {"review"},
+	"review":   {"draft", "released"},
+	"released": {"obsolete"},
+	"obsolete": {},
+}
+
+// MetadataResponse is the JSON representation returned by GET /metadata.
+type MetadataResponse struct {
+	SchemaName     *string        `json:"schema_name"`
+	LifecycleState string         `json:"lifecycle_state"`
+	Tags           []string       `json:"tags"`
+	Fields         map[string]any `json:"fields"`
+	Manifest       *ManifestInfo  `json:"manifest,omitempty"`
+	UpdatedAt      string         `json:"updated_at"`
+	UpdatedBy      *string        `json:"updated_by,omitempty"`
+}
+
+// ManifestInfo is the manifest subset included in MetadataResponse.
+type ManifestInfo struct {
+	UUID         *string `json:"uuid,omitempty"`
+	SiloInstance *string `json:"silo_instance,omitempty"`
+	RevisionHash *string `json:"revision_hash,omitempty"`
+	KCVersion    *string `json:"kc_version,omitempty"`
+}
+
+func metadataToResponse(m *db.ItemMetadata) MetadataResponse {
+	resp := MetadataResponse{
+		SchemaName:     m.SchemaName,
+		LifecycleState: m.LifecycleState,
+		Tags:           m.Tags,
+		Fields:         m.Fields,
+		UpdatedAt:      m.UpdatedAt.UTC().Format("2006-01-02T15:04:05Z"),
+		UpdatedBy:      m.UpdatedBy,
+	}
+	if m.ManifestUUID != nil || m.SiloInstance != nil || m.RevisionHash != nil || m.KCVersion != nil {
+		resp.Manifest = &ManifestInfo{
+			UUID:         m.ManifestUUID,
+			SiloInstance: m.SiloInstance,
+			RevisionHash: m.RevisionHash,
+			KCVersion:    m.KCVersion,
+		}
+	}
+	return resp
+}
+
+// HandleGetMetadata returns indexed metadata for an item.
+// GET /api/items/{partNumber}/metadata
+func (s *Server) HandleGetMetadata(w http.ResponseWriter, r *http.Request) {
+	ctx := r.Context()
+	partNumber := chi.URLParam(r, "partNumber")
+
+	item, err := s.items.GetByPartNumber(ctx, partNumber)
+	if err != nil {
+		s.logger.Error().Err(err).Msg("failed to get item")
+		writeError(w, http.StatusInternalServerError, "internal_error", "Failed to get item")
+		return
+	}
+	if item == nil {
+		writeError(w, http.StatusNotFound, "not_found", "Item not found")
+		return
+	}
+
+	meta, err := s.metadata.Get(ctx, item.ID)
+	if err != nil {
+		s.logger.Error().Err(err).Msg("failed to get metadata")
+		writeError(w, http.StatusInternalServerError, "internal_error", "Failed to get metadata")
+		return
+	}
+	if meta == nil {
+		writeError(w, http.StatusNotFound, "not_found", "No metadata indexed for this item")
+		return
+	}
+
+	writeJSON(w, http.StatusOK, metadataToResponse(meta))
+}
+
+// HandleUpdateMetadata merges fields into the metadata JSONB.
+// PUT /api/items/{partNumber}/metadata
+func (s *Server) HandleUpdateMetadata(w http.ResponseWriter, r *http.Request) {
+	ctx := r.Context()
+	partNumber := chi.URLParam(r, "partNumber")
+
+	item, err := s.items.GetByPartNumber(ctx, partNumber)
+	if err != nil {
+		s.logger.Error().Err(err).Msg("failed to get item")
+		writeError(w, http.StatusInternalServerError, "internal_error", "Failed to get item")
+		return
+	}
+	if item == nil {
+		writeError(w, http.StatusNotFound, "not_found", "Item not found")
+		return
+	}
+
+	var req struct {
+		Fields map[string]any `json:"fields"`
+	}
+	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
+		writeError(w, http.StatusBadRequest, "invalid_body", "Invalid JSON body")
+		return
+	}
+	if len(req.Fields) == 0 {
+		writeError(w, http.StatusBadRequest, "invalid_body", "Fields must not be empty")
+		return
+	}
+
+	username := ""
+	if user := auth.UserFromContext(ctx); user != nil {
+		username = user.Username
+	}
+
+	if err := s.metadata.UpdateFields(ctx, item.ID, req.Fields, username); err != nil {
+		s.logger.Error().Err(err).Msg("failed to update metadata fields")
+		writeError(w, http.StatusInternalServerError, "internal_error", "Failed to update metadata")
+		return
+	}
+
+	meta, err := s.metadata.Get(ctx, item.ID)
+	if err != nil {
+		s.logger.Error().Err(err).Msg("failed to read back metadata")
+		writeError(w, http.StatusInternalServerError, "internal_error", "Failed to read metadata")
+		return
+	}
+
+	s.broker.Publish("metadata.updated", mustMarshal(map[string]any{
+		"part_number":     partNumber,
+		"changed_fields":  fieldKeys(req.Fields),
+		"lifecycle_state": meta.LifecycleState,
+		"updated_by":      username,
+	}))
+
+	writeJSON(w, http.StatusOK, metadataToResponse(meta))
+}
+
+// HandleUpdateLifecycle transitions the lifecycle state.
+// PATCH /api/items/{partNumber}/metadata/lifecycle
+func (s *Server) HandleUpdateLifecycle(w http.ResponseWriter, r *http.Request) {
+	ctx := r.Context()
+	partNumber := chi.URLParam(r, "partNumber")
+
+	item, err := s.items.GetByPartNumber(ctx, partNumber)
+	if err != nil {
+		s.logger.Error().Err(err).Msg("failed to get item")
+		writeError(w, http.StatusInternalServerError, "internal_error", "Failed to get item")
+		return
+	}
+	if item == nil {
+		writeError(w, http.StatusNotFound, "not_found", "Item not found")
+		return
+	}
+
+	var req struct {
+		State string `json:"state"`
+	}
+	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
+		writeError(w, http.StatusBadRequest, "invalid_body", "Invalid JSON body")
+		return
+	}
+	if req.State == "" {
+		writeError(w, http.StatusBadRequest, "invalid_body", "State is required")
+		return
+	}
+
+	meta, err := s.metadata.Get(ctx, item.ID)
+	if err != nil {
+		s.logger.Error().Err(err).Msg("failed to get metadata")
+		writeError(w, http.StatusInternalServerError, "internal_error", "Failed to get metadata")
+		return
+	}
+	if meta == nil {
+		writeError(w, http.StatusNotFound, "not_found", "No metadata indexed for this item")
+		return
+	}
+
+	// Validate transition
+	allowed := validTransitions[meta.LifecycleState]
+	valid := false
+	for _, s := range allowed {
+		if s == req.State {
+			valid = true
+			break
+		}
+	}
+	if !valid {
+		writeError(w, http.StatusUnprocessableEntity, "invalid_transition",
+			"Cannot transition from '"+meta.LifecycleState+"' to '"+req.State+"'")
+		return
+	}
+
+	username := ""
+	if user := auth.UserFromContext(ctx); user != nil {
+		username = user.Username
+	}
+
+	fromState := meta.LifecycleState
+	if err := s.metadata.UpdateLifecycle(ctx, item.ID, req.State, username); err != nil {
+		s.logger.Error().Err(err).Msg("failed to update lifecycle")
+		writeError(w, http.StatusInternalServerError, "internal_error", "Failed to update lifecycle")
+		return
+	}
+
+	s.broker.Publish("metadata.lifecycle", mustMarshal(map[string]any{
+		"part_number": partNumber,
+		"from_state":  fromState,
+		"to_state":    req.State,
+		"updated_by":  username,
+	}))
+
+	writeJSON(w, http.StatusOK, map[string]string{"lifecycle_state": req.State})
+}
+
+// HandleUpdateTags adds/removes tags.
+// PATCH /api/items/{partNumber}/metadata/tags
+func (s *Server) HandleUpdateTags(w http.ResponseWriter, r *http.Request) {
+	ctx := r.Context()
+	partNumber := chi.URLParam(r, "partNumber")
+
+	item, err := s.items.GetByPartNumber(ctx, partNumber)
+	if err != nil {
+		s.logger.Error().Err(err).Msg("failed to get item")
+		writeError(w, http.StatusInternalServerError, "internal_error", "Failed to get item")
+		return
+	}
+	if item == nil {
+		writeError(w, http.StatusNotFound, "not_found", "Item not found")
+		return
+	}
+
+	var req struct {
+		Add    []string `json:"add"`
+		Remove []string `json:"remove"`
+	}
+	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
+		writeError(w, http.StatusBadRequest, "invalid_body", "Invalid JSON body")
+		return
+	}
+	if len(req.Add) == 0 && len(req.Remove) == 0 {
+		writeError(w, http.StatusBadRequest, "invalid_body", "Must provide 'add' or 'remove'")
+		return
+	}
+
+	meta, err := s.metadata.Get(ctx, item.ID)
+	if err != nil {
+		s.logger.Error().Err(err).Msg("failed to get metadata")
+		writeError(w, http.StatusInternalServerError, "internal_error", "Failed to get metadata")
+		return
+	}
+	if meta == nil {
+		writeError(w, http.StatusNotFound, "not_found", "No metadata indexed for this item")
+		return
+	}
+
+	// Compute new tag set: (existing + add) - remove
+	tagSet := make(map[string]struct{})
+	for _, t := range meta.Tags {
+		tagSet[t] = struct{}{}
+	}
+	for _, t := range req.Add {
+		tagSet[t] = struct{}{}
+	}
+	removeSet := make(map[string]struct{})
+	for _, t := range req.Remove {
+		removeSet[t] = struct{}{}
+	}
+	var newTags []string
+	for t := range tagSet {
+		if _, removed := removeSet[t]; !removed {
+			newTags = append(newTags, t)
+		}
+	}
+	if newTags == nil {
+		newTags = []string{}
+	}
+
+	username := ""
+	if user := auth.UserFromContext(ctx); user != nil {
+		username = user.Username
+	}
+
+	if err := s.metadata.SetTags(ctx, item.ID, newTags, username); err != nil {
+		s.logger.Error().Err(err).Msg("failed to update tags")
+		writeError(w, http.StatusInternalServerError, "internal_error", "Failed to update tags")
+		return
+	}
+
+	s.broker.Publish("metadata.tags", mustMarshal(map[string]any{
+		"part_number": partNumber,
+		"added":       req.Add,
+		"removed":     req.Remove,
+	}))
+
+	writeJSON(w, http.StatusOK, map[string]any{"tags": newTags})
+}
+
+// extractKCMetadata attempts to extract and index silo/ metadata from an
+// uploaded .kc file. Failures are logged but non-fatal for Phase 1.
+func (s *Server) extractKCMetadata(ctx context.Context, item *db.Item, fileKey string, rev *db.Revision) {
+	if s.storage == nil {
+		return
+	}
+
+	reader, err := s.storage.Get(ctx, fileKey)
+	if err != nil {
+		s.logger.Warn().Err(err).Str("file_key", fileKey).Msg("kc: failed to read back file for extraction")
+		return
+	}
+	defer reader.Close()
+
+	data, err := io.ReadAll(reader)
+	if err != nil {
+		s.logger.Warn().Err(err).Msg("kc: failed to read file bytes")
+		return
+	}
+
+	result, err := kc.Extract(data)
+	if err != nil {
+		s.logger.Warn().Err(err).Str("part_number", item.PartNumber).Msg("kc: extraction failed")
+		return
+	}
+	if result == nil {
+		return // plain .fcstd, no silo/ directory
+	}
+
+	// Validate manifest UUID matches item
+	if result.Manifest != nil && result.Manifest.UUID != "" && result.Manifest.UUID != item.ID {
+		s.logger.Warn().
+			Str("manifest_uuid", result.Manifest.UUID).
+			Str("item_id", item.ID).
+			Msg("kc: manifest UUID does not match item, skipping indexing")
+		return
+	}
+
+	// Check for no-op (revision_hash unchanged)
+	if result.Manifest != nil && result.Manifest.RevisionHash != "" {
+		existing, _ := s.metadata.Get(ctx, item.ID)
+		if existing != nil && existing.RevisionHash != nil && *existing.RevisionHash == result.Manifest.RevisionHash {
+			s.logger.Debug().Str("part_number", item.PartNumber).Msg("kc: revision_hash unchanged, skipping")
+			return
+		}
+	}
+
+	username := ""
+	if rev.CreatedBy != nil {
+		username = *rev.CreatedBy
+	}
+
+	meta := &db.ItemMetadata{
+		ItemID:         item.ID,
+		LifecycleState: "draft",
+		Fields:         make(map[string]any),
+		Tags:           []string{},
+		UpdatedBy:      strPtr(username),
+	}
+
+	if result.Manifest != nil {
+		meta.KCVersion = strPtr(result.Manifest.KCVersion)
+		meta.ManifestUUID = strPtr(result.Manifest.UUID)
+		meta.SiloInstance = strPtr(result.Manifest.SiloInstance)
+		meta.RevisionHash = strPtr(result.Manifest.RevisionHash)
+	}
+
+	if result.Metadata != nil {
+		meta.SchemaName = strPtr(result.Metadata.SchemaName)
+		if result.Metadata.Tags != nil {
+			meta.Tags = result.Metadata.Tags
+		}
+		if result.Metadata.LifecycleState != "" {
+			meta.LifecycleState = result.Metadata.LifecycleState
+		}
+		if result.Metadata.Fields != nil {
+			meta.Fields = result.Metadata.Fields
+		}
+	}
+
+	if err := s.metadata.Upsert(ctx, meta); err != nil {
+		s.logger.Warn().Err(err).Str("part_number", item.PartNumber).Msg("kc: failed to upsert metadata")
+		return
+	}
+
+	s.broker.Publish("metadata.updated", mustMarshal(map[string]any{
+		"part_number":     item.PartNumber,
+		"lifecycle_state": meta.LifecycleState,
+		"updated_by":      username,
+	}))
+
+	s.logger.Info().Str("part_number", item.PartNumber).Msg("kc: metadata indexed successfully")
+}
+
+// strPtr returns a pointer to s, or nil if s is empty.
+func strPtr(s string) *string {
+	if s == "" {
+		return nil
+	}
+	return &s
+}
+
+// fieldKeys returns the keys from a map.
+func fieldKeys(m map[string]any) []string {
+	keys := make([]string, 0, len(m))
+	for k := range m {
+		keys = append(keys, k)
+	}
+	return keys
+}
--- a/internal/api/routes.go
+++ b/internal/api/routes.go
@@ -172,6 +172,7 @@ func NewRouter(server *Server, logger zerolog.Logger) http.Handler {
 				r.Get("/bom/where-used", server.HandleGetWhereUsed)
 				r.Get("/bom/export.csv", server.HandleExportBOMCSV)
 				r.Get("/bom/export.ods", server.HandleExportBOMODS)
+				r.Get("/metadata", server.HandleGetMetadata)

 				// DAG (gated by dag module)
 				r.Route("/dag", func(r chi.Router) {
@@ -209,6 +210,9 @@ func NewRouter(server *Server, logger zerolog.Logger) http.Handler {
 					r.Post("/bom/merge", server.HandleMergeBOM)
 					r.Put("/bom/{childPartNumber}", server.HandleUpdateBOMEntry)
 					r.Delete("/bom/{childPartNumber}", server.HandleDeleteBOMEntry)
+					r.Put("/metadata", server.HandleUpdateMetadata)
+					r.Patch("/metadata/lifecycle", server.HandleUpdateLifecycle)
+					r.Patch("/metadata/tags", server.HandleUpdateTags)
 				})
 			})
 		})
--- a/internal/db/item_metadata.go
+++ b/internal/db/item_metadata.go
@@ -0,0 +1,161 @@
+package db
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"time"
+
+	"github.com/jackc/pgx/v5"
+)
+
+// ItemMetadata represents a row in the item_metadata table.
+type ItemMetadata struct {
+	ItemID         string
+	SchemaName     *string
+	Tags           []string
+	LifecycleState string
+	Fields         map[string]any
+	KCVersion      *string
+	ManifestUUID   *string
+	SiloInstance   *string
+	RevisionHash   *string
+	UpdatedAt      time.Time
+	UpdatedBy      *string
+}
+
+// ItemMetadataRepository provides item_metadata database operations.
+type ItemMetadataRepository struct {
+	db *DB
+}
+
+// NewItemMetadataRepository creates a new item metadata repository.
+func NewItemMetadataRepository(db *DB) *ItemMetadataRepository {
+	return &ItemMetadataRepository{db: db}
+}
+
+// Get returns metadata for an item, or nil if none exists.
+func (r *ItemMetadataRepository) Get(ctx context.Context, itemID string) (*ItemMetadata, error) {
+	m := &ItemMetadata{}
+	var fieldsJSON []byte
+	err := r.db.pool.QueryRow(ctx, `
+		SELECT item_id, schema_name, tags, lifecycle_state, fields,
+		       kc_version, manifest_uuid, silo_instance, revision_hash,
+		       updated_at, updated_by
+		FROM item_metadata
+		WHERE item_id = $1
+	`, itemID).Scan(
+		&m.ItemID, &m.SchemaName, &m.Tags, &m.LifecycleState, &fieldsJSON,
+		&m.KCVersion, &m.ManifestUUID, &m.SiloInstance, &m.RevisionHash,
+		&m.UpdatedAt, &m.UpdatedBy,
+	)
+	if err == pgx.ErrNoRows {
+		return nil, nil
+	}
+	if err != nil {
+		return nil, fmt.Errorf("getting item metadata: %w", err)
+	}
+	if fieldsJSON != nil {
+		if err := json.Unmarshal(fieldsJSON, &m.Fields); err != nil {
+			return nil, fmt.Errorf("unmarshaling fields: %w", err)
+		}
+	}
+	if m.Fields == nil {
+		m.Fields = make(map[string]any)
+	}
+	if m.Tags == nil {
+		m.Tags = []string{}
+	}
+	return m, nil
+}
+
+// Upsert inserts or updates the metadata row for an item.
+// Used by the commit extraction pipeline.
+func (r *ItemMetadataRepository) Upsert(ctx context.Context, m *ItemMetadata) error {
+	fieldsJSON, err := json.Marshal(m.Fields)
+	if err != nil {
+		return fmt.Errorf("marshaling fields: %w", err)
+	}
+	_, err = r.db.pool.Exec(ctx, `
+		INSERT INTO item_metadata
+			(item_id, schema_name, tags, lifecycle_state, fields,
+			 kc_version, manifest_uuid, silo_instance, revision_hash,
+			 updated_at, updated_by)
+		VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9, now(), $10)
+		ON CONFLICT (item_id) DO UPDATE SET
+			schema_name     = EXCLUDED.schema_name,
+			tags            = EXCLUDED.tags,
+			lifecycle_state = EXCLUDED.lifecycle_state,
+			fields          = EXCLUDED.fields,
+			kc_version      = EXCLUDED.kc_version,
+			manifest_uuid   = EXCLUDED.manifest_uuid,
+			silo_instance   = EXCLUDED.silo_instance,
+			revision_hash   = EXCLUDED.revision_hash,
+			updated_at      = now(),
+			updated_by      = EXCLUDED.updated_by
+	`, m.ItemID, m.SchemaName, m.Tags, m.LifecycleState, fieldsJSON,
+		m.KCVersion, m.ManifestUUID, m.SiloInstance, m.RevisionHash,
+		m.UpdatedBy)
+	if err != nil {
+		return fmt.Errorf("upserting item metadata: %w", err)
+	}
+	return nil
+}
+
+// UpdateFields merges the given fields into the existing JSONB fields column.
+func (r *ItemMetadataRepository) UpdateFields(ctx context.Context, itemID string, fields map[string]any, updatedBy string) error {
+	fieldsJSON, err := json.Marshal(fields)
+	if err != nil {
+		return fmt.Errorf("marshaling fields: %w", err)
+	}
+	tag, err := r.db.pool.Exec(ctx, `
+		UPDATE item_metadata
+		SET fields     = fields || $2::jsonb,
+		    updated_at = now(),
+		    updated_by = $3
+		WHERE item_id = $1
+	`, itemID, fieldsJSON, updatedBy)
+	if err != nil {
+		return fmt.Errorf("updating metadata fields: %w", err)
+	}
+	if tag.RowsAffected() == 0 {
+		return fmt.Errorf("item metadata not found")
+	}
+	return nil
+}
+
+// UpdateLifecycle sets the lifecycle_state column.
+func (r *ItemMetadataRepository) UpdateLifecycle(ctx context.Context, itemID, state, updatedBy string) error {
+	tag, err := r.db.pool.Exec(ctx, `
+		UPDATE item_metadata
+		SET lifecycle_state = $2,
+		    updated_at      = now(),
+		    updated_by      = $3
+		WHERE item_id = $1
+	`, itemID, state, updatedBy)
+	if err != nil {
+		return fmt.Errorf("updating lifecycle state: %w", err)
+	}
+	if tag.RowsAffected() == 0 {
+		return fmt.Errorf("item metadata not found")
+	}
+	return nil
+}
+
+// SetTags replaces the tags array.
+func (r *ItemMetadataRepository) SetTags(ctx context.Context, itemID string, tags []string, updatedBy string) error {
+	tag, err := r.db.pool.Exec(ctx, `
+		UPDATE item_metadata
+		SET tags       = $2,
+		    updated_at = now(),
+		    updated_by = $3
+		WHERE item_id = $1
+	`, itemID, tags, updatedBy)
+	if err != nil {
+		return fmt.Errorf("updating tags: %w", err)
+	}
+	if tag.RowsAffected() == 0 {
+		return fmt.Errorf("item metadata not found")
+	}
+	return nil
+}
--- a/internal/kc/kc.go
+++ b/internal/kc/kc.go
@@ -0,0 +1,106 @@
+// Package kc extracts and parses the silo/ metadata directory from .kc files.
+//
+// A .kc file is a ZIP archive (superset of .fcstd) that contains a silo/
+// directory with JSON metadata entries. This package handles extraction only —
+// no database or HTTP dependencies.
+package kc
+
+import (
+	"archive/zip"
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"io"
+	"strings"
+)
+
+// Manifest represents the contents of silo/manifest.json.
+type Manifest struct {
+	UUID         string `json:"uuid"`
+	KCVersion    string `json:"kc_version"`
+	RevisionHash string `json:"revision_hash"`
+	SiloInstance string `json:"silo_instance"`
+}
+
+// Metadata represents the contents of silo/metadata.json.
+type Metadata struct {
+	SchemaName     string         `json:"schema_name"`
+	Tags           []string       `json:"tags"`
+	LifecycleState string         `json:"lifecycle_state"`
+	Fields         map[string]any `json:"fields"`
+}
+
+// ExtractResult holds the parsed silo/ directory contents from a .kc file.
+type ExtractResult struct {
+	Manifest *Manifest
+	Metadata *Metadata
+}
+
+// Extract opens a ZIP archive from data and parses the silo/ directory.
+// Returns nil, nil if no silo/ directory is found (plain .fcstd file).
+// Returns nil, error if silo/ entries exist but fail to parse.
+func Extract(data []byte) (*ExtractResult, error) {
+	r, err := zip.NewReader(bytes.NewReader(data), int64(len(data)))
+	if err != nil {
+		return nil, fmt.Errorf("kc: open zip: %w", err)
+	}
+
+	var manifestFile, metadataFile *zip.File
+	hasSiloDir := false
+
+	for _, f := range r.File {
+		if f.Name == "silo/" || strings.HasPrefix(f.Name, "silo/") {
+			hasSiloDir = true
+		}
+		switch f.Name {
+		case "silo/manifest.json":
+			manifestFile = f
+		case "silo/metadata.json":
+			metadataFile = f
+		}
+	}
+
+	if !hasSiloDir {
+		return nil, nil // plain .fcstd, no extraction
+	}
+
+	result := &ExtractResult{}
+
+	if manifestFile != nil {
+		m, err := readJSON[Manifest](manifestFile)
+		if err != nil {
+			return nil, fmt.Errorf("kc: parse manifest.json: %w", err)
+		}
+		result.Manifest = m
+	}
+
+	if metadataFile != nil {
+		m, err := readJSON[Metadata](metadataFile)
+		if err != nil {
+			return nil, fmt.Errorf("kc: parse metadata.json: %w", err)
+		}
+		result.Metadata = m
+	}
+
+	return result, nil
+}
+
+// readJSON opens a zip.File and decodes its contents as JSON into T.
+func readJSON[T any](f *zip.File) (*T, error) {
+	rc, err := f.Open()
+	if err != nil {
+		return nil, err
+	}
+	defer rc.Close()
+
+	data, err := io.ReadAll(rc)
+	if err != nil {
+		return nil, err
+	}
+
+	var v T
+	if err := json.Unmarshal(data, &v); err != nil {
+		return nil, err
+	}
+	return &v, nil
+}
--- a/internal/kc/kc_test.go
+++ b/internal/kc/kc_test.go
@@ -0,0 +1,188 @@
+package kc
+
+import (
+	"archive/zip"
+	"bytes"
+	"encoding/json"
+	"testing"
+)
+
+// buildZip creates a ZIP archive in memory from a map of filename → content.
+func buildZip(t *testing.T, files map[string][]byte) []byte {
+	t.Helper()
+	var buf bytes.Buffer
+	w := zip.NewWriter(&buf)
+	for name, content := range files {
+		f, err := w.Create(name)
+		if err != nil {
+			t.Fatalf("creating zip entry %s: %v", name, err)
+		}
+		if _, err := f.Write(content); err != nil {
+			t.Fatalf("writing zip entry %s: %v", name, err)
+		}
+	}
+	if err := w.Close(); err != nil {
+		t.Fatalf("closing zip: %v", err)
+	}
+	return buf.Bytes()
+}
+
+func mustJSON(t *testing.T, v any) []byte {
+	t.Helper()
+	data, err := json.Marshal(v)
+	if err != nil {
+		t.Fatalf("marshaling JSON: %v", err)
+	}
+	return data
+}
+
+func TestExtract_PlainFCStd(t *testing.T) {
+	data := buildZip(t, map[string][]byte{
+		"Document.xml":     []byte("<xml/>"),
+		"thumbnails/a.png": []byte("png"),
+	})
+
+	result, err := Extract(data)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if result != nil {
+		t.Fatalf("expected nil result for plain .fcstd, got %+v", result)
+	}
+}
+
+func TestExtract_ValidKC(t *testing.T) {
+	manifest := Manifest{
+		UUID:         "550e8400-e29b-41d4-a716-446655440000",
+		KCVersion:    "1.0",
+		RevisionHash: "abc123",
+		SiloInstance: "https://silo.example.com",
+	}
+	metadata := Metadata{
+		SchemaName:     "mechanical-part-v2",
+		Tags:           []string{"structural", "aluminum"},
+		LifecycleState: "draft",
+		Fields: map[string]any{
+			"material":  "6061-T6",
+			"weight_kg": 0.34,
+		},
+	}
+
+	data := buildZip(t, map[string][]byte{
+		"Document.xml":       []byte("<xml/>"),
+		"silo/manifest.json": mustJSON(t, manifest),
+		"silo/metadata.json": mustJSON(t, metadata),
+	})
+
+	result, err := Extract(data)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if result == nil {
+		t.Fatal("expected non-nil result")
+	}
+
+	if result.Manifest == nil {
+		t.Fatal("expected manifest")
+	}
+	if result.Manifest.UUID != manifest.UUID {
+		t.Errorf("manifest UUID = %q, want %q", result.Manifest.UUID, manifest.UUID)
+	}
+	if result.Manifest.KCVersion != manifest.KCVersion {
+		t.Errorf("manifest KCVersion = %q, want %q", result.Manifest.KCVersion, manifest.KCVersion)
+	}
+	if result.Manifest.RevisionHash != manifest.RevisionHash {
+		t.Errorf("manifest RevisionHash = %q, want %q", result.Manifest.RevisionHash, manifest.RevisionHash)
+	}
+	if result.Manifest.SiloInstance != manifest.SiloInstance {
+		t.Errorf("manifest SiloInstance = %q, want %q", result.Manifest.SiloInstance, manifest.SiloInstance)
+	}
+
+	if result.Metadata == nil {
+		t.Fatal("expected metadata")
+	}
+	if result.Metadata.SchemaName != metadata.SchemaName {
+		t.Errorf("metadata SchemaName = %q, want %q", result.Metadata.SchemaName, metadata.SchemaName)
+	}
+	if result.Metadata.LifecycleState != metadata.LifecycleState {
+		t.Errorf("metadata LifecycleState = %q, want %q", result.Metadata.LifecycleState, metadata.LifecycleState)
+	}
+	if len(result.Metadata.Tags) != 2 {
+		t.Errorf("metadata Tags len = %d, want 2", len(result.Metadata.Tags))
+	}
+	if result.Metadata.Fields["material"] != "6061-T6" {
+		t.Errorf("metadata Fields[material] = %v, want 6061-T6", result.Metadata.Fields["material"])
+	}
+}
+
+func TestExtract_ManifestOnly(t *testing.T) {
+	manifest := Manifest{
+		UUID:      "550e8400-e29b-41d4-a716-446655440000",
+		KCVersion: "1.0",
+	}
+
+	data := buildZip(t, map[string][]byte{
+		"Document.xml":       []byte("<xml/>"),
+		"silo/manifest.json": mustJSON(t, manifest),
+	})
+
+	result, err := Extract(data)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if result == nil {
+		t.Fatal("expected non-nil result")
+	}
+	if result.Manifest == nil {
+		t.Fatal("expected manifest")
+	}
+	if result.Metadata != nil {
+		t.Errorf("expected nil metadata, got %+v", result.Metadata)
+	}
+}
+
+func TestExtract_InvalidJSON(t *testing.T) {
+	data := buildZip(t, map[string][]byte{
+		"silo/manifest.json": []byte("{not valid json"),
+	})
+
+	result, err := Extract(data)
+	if err == nil {
+		t.Fatal("expected error for invalid JSON")
+	}
+	if result != nil {
+		t.Errorf("expected nil result on error, got %+v", result)
+	}
+}
+
+func TestExtract_NotAZip(t *testing.T) {
+	result, err := Extract([]byte("this is not a zip file"))
+	if err == nil {
+		t.Fatal("expected error for non-ZIP data")
+	}
+	if result != nil {
+		t.Errorf("expected nil result on error, got %+v", result)
+	}
+}
+
+func TestExtract_EmptySiloDir(t *testing.T) {
+	// silo/ directory entry exists but no manifest or metadata files
+	data := buildZip(t, map[string][]byte{
+		"Document.xml": []byte("<xml/>"),
+		"silo/":        {},
+	})
+
+	result, err := Extract(data)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if result == nil {
+		t.Fatal("expected non-nil result for silo/ dir")
+	}
+	if result.Manifest != nil {
+		t.Errorf("expected nil manifest, got %+v", result.Manifest)
+	}
+	if result.Metadata != nil {
+		t.Errorf("expected nil metadata, got %+v", result.Metadata)
+	}
+}
--- a/internal/testutil/testutil.go
+++ b/internal/testutil/testutil.go
@@ -79,6 +79,7 @@ func TruncateAll(t *testing.T, pool *pgxpool.Pool) {

 	_, err := pool.Exec(context.Background(), `
 		TRUNCATE
+			item_metadata, item_dependencies, approval_signatures, item_approvals, item_macros,
 			settings_overrides, module_state,
 			job_log, jobs, job_definitions, runners,
 			dag_cross_edges, dag_edges, dag_nodes,