3 files changed, 72 insertions, 162 deletions

diff --git a/go.mod b/go.mod
index 914896e..d641b8b 100644
--- a/go.mod
+++ b/go.mod
@@ -3,24 +3,14 @@ module code.northwest.io/codevec
 go 1.24.0
 
 require (
+        github.com/asg017/sqlite-vec-go-bindings v0.1.6
+        github.com/mattn/go-sqlite3 v1.14.33
         github.com/sabhiram/go-gitignore v0.0.0-20210923224102-525f6e181f06
         github.com/smacker/go-tree-sitter v0.0.0-20240827094217-dd81d9e9be82
         github.com/spf13/cobra v1.10.2
-        modernc.org/sqlite v1.46.1
 )
 
 require (
-        github.com/dustin/go-humanize v1.0.1 // indirect
-        github.com/google/uuid v1.6.0 // indirect
         github.com/inconshreveable/mousetrap v1.1.0 // indirect
-        github.com/mattn/go-isatty v0.0.20 // indirect
-        github.com/ncruces/go-strftime v1.0.0 // indirect
-        github.com/remyoudompheng/bigfft v0.0.0-20230129092748-24d4a6f8daec // indirect
         github.com/spf13/pflag v1.0.9 // indirect
-        golang.org/x/exp v0.0.0-20251023183803-a4bb9ffd2546 // indirect
-        golang.org/x/sync v0.19.0 // indirect
-        golang.org/x/sys v0.40.0 // indirect
-        modernc.org/libc v1.67.6 // indirect
-        modernc.org/mathutil v1.7.1 // indirect
-        modernc.org/memory v1.11.0 // indirect
 )
diff --git a/go.sum b/go.sum
index 0d5edbc..87113e7 100644
--- a/go.sum
+++ b/go.sum
@@ -1,25 +1,15 @@
+github.com/asg017/sqlite-vec-go-bindings v0.1.6 h1:Nx0jAzyS38XpkKznJ9xQjFXz2X9tI7KqjwVxV8RNoww=
+github.com/asg017/sqlite-vec-go-bindings v0.1.6/go.mod h1:A8+cTt/nKFsYCQF6OgzSNpKZrzNo5gQsXBTfsXHXY0Q=
 github.com/cpuguy83/go-md2man/v2 v2.0.6/go.mod h1:oOW0eioCTA6cOiMLiUPZOpcVxMig6NIQQ7OS05n1F4g=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
-github.com/dustin/go-humanize v1.0.1 h1:GzkhY7T5VNhEkwH0PVJgjz+fX1rhBrR7pRT3mDkpeCY=
-github.com/dustin/go-humanize v1.0.1/go.mod h1:Mu1zIs6XwVuF/gI1OepvI0qD18qycQx+mFykh5fBlto=
-github.com/google/pprof v0.0.0-20250317173921-a4b03ec1a45e h1:ijClszYn+mADRFY17kjQEVQ1XRhq2/JR1M3sGqeJoxs=
-github.com/google/pprof v0.0.0-20250317173921-a4b03ec1a45e/go.mod h1:boTsfXsheKC2y+lKOCMpSfarhxDeIzfZG1jqGcPl3cA=
-github.com/google/uuid v1.6.0 h1:NIvaJDMOsjHA8n1jAhLSgzrAzy1Hgr+hNrb57e+94F0=
-github.com/google/uuid v1.6.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
-github.com/hashicorp/golang-lru/v2 v2.0.7 h1:a+bsQ5rvGLjzHuww6tVxozPZFVghXaHOwFs4luLUK2k=
-github.com/hashicorp/golang-lru/v2 v2.0.7/go.mod h1:QeFd9opnmA6QUJc5vARoKUSoFhyfM2/ZepoAG6RGpeM=
 github.com/inconshreveable/mousetrap v1.1.0 h1:wN+x4NVGpMsO7ErUn/mUI3vEoE6Jt13X2s0bqwp9tc8=
 github.com/inconshreveable/mousetrap v1.1.0/go.mod h1:vpF70FUmC8bwa3OWnCshd2FqLfsEA9PFc4w1p2J65bw=
-github.com/mattn/go-isatty v0.0.20 h1:xfD0iDuEKnDkl03q4limB+vH+GxLEtL/jb4xVJSWWEY=
-github.com/mattn/go-isatty v0.0.20/go.mod h1:W+V8PltTTMOvKvAeJH7IuucS94S2C6jfK/D7dTCTo3Y=
-github.com/ncruces/go-strftime v1.0.0 h1:HMFp8mLCTPp341M/ZnA4qaf7ZlsbTc+miZjCLOFAw7w=
-github.com/ncruces/go-strftime v1.0.0/go.mod h1:Fwc5htZGVVkseilnfgOVb9mKy6w1naJmn9CehxcKcls=
+github.com/mattn/go-sqlite3 v1.14.33 h1:A5blZ5ulQo2AtayQ9/limgHEkFreKj1Dv226a1K73s0=
+github.com/mattn/go-sqlite3 v1.14.33/go.mod h1:Uh1q+B4BYcTPb+yiD3kU8Ct7aC0hY9fxUwlHK0RXw+Y=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
-github.com/remyoudompheng/bigfft v0.0.0-20230129092748-24d4a6f8daec h1:W09IVJc94icq4NjY3clb7Lk8O1qJ8BdBEF8z0ibU0rE=
-github.com/remyoudompheng/bigfft v0.0.0-20230129092748-24d4a6f8daec/go.mod h1:qqbHyh8v60DhA7CoWK5oRCqLrMHRGoxYCSS9EjAz6Eo=
 github.com/russross/blackfriday/v2 v2.1.0/go.mod h1:+Rmxgy9KzJVeS9/2gXHxylqXiyQDYRxCVz55jmeOWTM=
 github.com/sabhiram/go-gitignore v0.0.0-20210923224102-525f6e181f06 h1:OkMGxebDjyw0ULyrTYWeN0UNCCkmCWfjPnIA2W6oviI=
 github.com/sabhiram/go-gitignore v0.0.0-20210923224102-525f6e181f06/go.mod h1:+ePHsJ1keEjQtpvf9HHw0f4ZeJ0TLRsxhunSI2hYJSs=
@@ -34,46 +24,7 @@ github.com/stretchr/testify v1.6.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/
 github.com/stretchr/testify v1.9.0 h1:HtqpIVDClZ4nwg75+f6Lvsy/wHu+3BoSGCbBAcpTsTg=
 github.com/stretchr/testify v1.9.0/go.mod h1:r2ic/lqez/lEtzL7wO/rwa5dbSLXVDPFyf8C91i36aY=
 go.yaml.in/yaml/v3 v3.0.4/go.mod h1:DhzuOOF2ATzADvBadXxruRBLzYTpT36CKvDb3+aBEFg=
-golang.org/x/exp v0.0.0-20251023183803-a4bb9ffd2546 h1:mgKeJMpvi0yx/sU5GsxQ7p6s2wtOnGAHZWCHUM4KGzY=
-golang.org/x/exp v0.0.0-20251023183803-a4bb9ffd2546/go.mod h1:j/pmGrbnkbPtQfxEe5D0VQhZC6qKbfKifgD0oM7sR70=
-golang.org/x/mod v0.29.0 h1:HV8lRxZC4l2cr3Zq1LvtOsi/ThTgWnUk/y64QSs8GwA=
-golang.org/x/mod v0.29.0/go.mod h1:NyhrlYXJ2H4eJiRy/WDBO6HMqZQ6q9nk4JzS3NuCK+w=
-golang.org/x/sync v0.19.0 h1:vV+1eWNmZ5geRlYjzm2adRgW2/mcpevXNg50YZtPCE4=
-golang.org/x/sync v0.19.0/go.mod h1:9KTHXmSnoGruLpwFjVSX0lNNA75CykiMECbovNTZqGI=
-golang.org/x/sys v0.6.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/sys v0.40.0 h1:DBZZqJ2Rkml6QMQsZywtnjnnGvHza6BTfYFWY9kjEWQ=
-golang.org/x/sys v0.40.0/go.mod h1:OgkHotnGiDImocRcuBABYBEXf8A9a87e/uXjp9XT3ks=
-golang.org/x/tools v0.38.0 h1:Hx2Xv8hISq8Lm16jvBZ2VQf+RLmbd7wVUsALibYI/IQ=
-golang.org/x/tools v0.38.0/go.mod h1:yEsQ/d/YK8cjh0L6rZlY8tgtlKiBNTL14pGDJPJpYQs=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
 gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
-modernc.org/cc/v4 v4.27.1 h1:9W30zRlYrefrDV2JE2O8VDtJ1yPGownxciz5rrbQZis=
-modernc.org/cc/v4 v4.27.1/go.mod h1:uVtb5OGqUKpoLWhqwNQo/8LwvoiEBLvZXIQ/SmO6mL0=
-modernc.org/ccgo/v4 v4.30.1 h1:4r4U1J6Fhj98NKfSjnPUN7Ze2c6MnAdL0hWw6+LrJpc=
-modernc.org/ccgo/v4 v4.30.1/go.mod h1:bIOeI1JL54Utlxn+LwrFyjCx2n2RDiYEaJVSrgdrRfM=
-modernc.org/fileutil v1.3.40 h1:ZGMswMNc9JOCrcrakF1HrvmergNLAmxOPjizirpfqBA=
-modernc.org/fileutil v1.3.40/go.mod h1:HxmghZSZVAz/LXcMNwZPA/DRrQZEVP9VX0V4LQGQFOc=
-modernc.org/gc/v2 v2.6.5 h1:nyqdV8q46KvTpZlsw66kWqwXRHdjIlJOhG6kxiV/9xI=
-modernc.org/gc/v2 v2.6.5/go.mod h1:YgIahr1ypgfe7chRuJi2gD7DBQiKSLMPgBQe9oIiito=
-modernc.org/gc/v3 v3.1.1 h1:k8T3gkXWY9sEiytKhcgyiZ2L0DTyCQ/nvX+LoCljoRE=
-modernc.org/gc/v3 v3.1.1/go.mod h1:HFK/6AGESC7Ex+EZJhJ2Gni6cTaYpSMmU/cT9RmlfYY=
-modernc.org/goabi0 v0.2.0 h1:HvEowk7LxcPd0eq6mVOAEMai46V+i7Jrj13t4AzuNks=
-modernc.org/goabi0 v0.2.0/go.mod h1:CEFRnnJhKvWT1c1JTI3Avm+tgOWbkOu5oPA8eH8LnMI=
-modernc.org/libc v1.67.6 h1:eVOQvpModVLKOdT+LvBPjdQqfrZq+pC39BygcT+E7OI=
-modernc.org/libc v1.67.6/go.mod h1:JAhxUVlolfYDErnwiqaLvUqc8nfb2r6S6slAgZOnaiE=
-modernc.org/mathutil v1.7.1 h1:GCZVGXdaN8gTqB1Mf/usp1Y/hSqgI2vAGGP4jZMCxOU=
-modernc.org/mathutil v1.7.1/go.mod h1:4p5IwJITfppl0G4sUEDtCr4DthTaT47/N3aT6MhfgJg=
-modernc.org/memory v1.11.0 h1:o4QC8aMQzmcwCK3t3Ux/ZHmwFPzE6hf2Y5LbkRs+hbI=
-modernc.org/memory v1.11.0/go.mod h1:/JP4VbVC+K5sU2wZi9bHoq2MAkCnrt2r98UGeSK7Mjw=
-modernc.org/opt v0.1.4 h1:2kNGMRiUjrp4LcaPuLY2PzUfqM/w9N23quVwhKt5Qm8=
-modernc.org/opt v0.1.4/go.mod h1:03fq9lsNfvkYSfxrfUhZCWPk1lm4cq4N+Bh//bEtgns=
-modernc.org/sortutil v1.2.1 h1:+xyoGf15mM3NMlPDnFqrteY07klSFxLElE2PVuWIJ7w=
-modernc.org/sortutil v1.2.1/go.mod h1:7ZI3a3REbai7gzCLcotuw9AC4VZVpYMjDzETGsSMqJE=
-modernc.org/sqlite v1.46.1 h1:eFJ2ShBLIEnUWlLy12raN0Z1plqmFX9Qe3rjQTKt6sU=
-modernc.org/sqlite v1.46.1/go.mod h1:CzbrU2lSB1DKUusvwGz7rqEKIq+NUd8GWuBBZDs9/nA=
-modernc.org/strutil v1.2.1 h1:UneZBkQA+DX2Rp35KcM69cSsNES9ly8mQWD71HKlOA0=
-modernc.org/strutil v1.2.1/go.mod h1:EHkiggD70koQxjVdSBM3JKM7k6L0FbGE5eymy9i3B9A=
-modernc.org/token v1.1.0 h1:Xl7Ap9dKaEs5kLoOQeQmPWevfnk/DM5qcLcYlA8ys6Y=
-modernc.org/token v1.1.0/go.mod h1:UGzOrNV1mAFSEB63lOFHIpNRUVMvYTc6yu1SMY/XTDM=
diff --git a/internal/index/index.go b/internal/index/index.go
index 008e487..5ce9f4f 100644
--- a/internal/index/index.go
+++ b/internal/index/index.go
@@ -2,18 +2,16 @@ package index
 
 import (
         "database/sql"
-        "encoding/binary"
-        "math"
         "os"
         "path/filepath"
-        "sort"
 
-        _ "modernc.org/sqlite"
+        sqlite_vec "github.com/asg017/sqlite-vec-go-bindings/cgo"
+        _ "github.com/mattn/go-sqlite3"
 
         "code.northwest.io/codevec/internal/chunker"
 )
 
-// Index stores chunks and embeddings in SQLite
+// Index stores chunks and embeddings in SQLite with sqlite-vec
 type Index struct {
         db   *sql.DB
         dims int
@@ -21,13 +19,16 @@ type Index struct {
 
 // Open opens or creates an index at the given path
 func Open(path string, dims int) (*Index, error) {
+        // Register sqlite-vec extension
+        sqlite_vec.Auto()
+
         // Ensure directory exists
         dir := filepath.Dir(path)
         if err := os.MkdirAll(dir, 0755); err != nil {
                 return nil, err
         }
 
-        db, err := sql.Open("sqlite", path)
+        db, err := sql.Open("sqlite3", path)
         if err != nil {
                 return nil, err
         }
@@ -42,7 +43,7 @@ func Open(path string, dims int) (*Index, error) {
 }
 
 func (idx *Index) init() error {
-        // Create chunks table with embedding column
+        // Create chunks table
         _, err := idx.db.Exec(`
                 CREATE TABLE IF NOT EXISTS chunks (
                         id INTEGER PRIMARY KEY,
@@ -53,7 +54,6 @@ func (idx *Index) init() error {
                         name TEXT,
                         content TEXT NOT NULL,
                         hash TEXT NOT NULL,
-                        embedding BLOB,
                         created_at INTEGER DEFAULT (unixepoch())
                 )
         `)
@@ -84,6 +84,17 @@ func (idx *Index) init() error {
                 return err
         }
 
+        // Create vec0 virtual table for vectors
+        _, err = idx.db.Exec(`
+                CREATE VIRTUAL TABLE IF NOT EXISTS vectors USING vec0(
+                        chunk_id INTEGER PRIMARY KEY,
+                        embedding FLOAT[768] distance_metric=cosine
+                )
+        `)
+        if err != nil {
+                return err
+        }
+
         // Index on file for faster deletion
         _, err = idx.db.Exec(`CREATE INDEX IF NOT EXISTS idx_chunks_file ON chunks(file)`)
         return err
@@ -96,11 +107,27 @@ func (idx *Index) Close() error {
 
 // InsertChunk inserts a chunk with its embedding
 func (idx *Index) InsertChunk(chunk chunker.Chunk, embedding []float32) error {
-        embeddingBlob := serializeEmbedding(embedding)
-        _, err := idx.db.Exec(`
-                INSERT INTO chunks (file, start_line, end_line, chunk_type, name, content, hash, embedding)
-                VALUES (?, ?, ?, ?, ?, ?, ?, ?)
-        `, chunk.File, chunk.StartLine, chunk.EndLine, chunk.Type, chunk.Name, chunk.Content, chunk.Hash, embeddingBlob)
+        // Insert chunk
+        result, err := idx.db.Exec(`
+                INSERT INTO chunks (file, start_line, end_line, chunk_type, name, content, hash)
+                VALUES (?, ?, ?, ?, ?, ?, ?)
+        `, chunk.File, chunk.StartLine, chunk.EndLine, chunk.Type, chunk.Name, chunk.Content, chunk.Hash)
+        if err != nil {
+                return err
+        }
+
+        chunkID, err := result.LastInsertId()
+        if err != nil {
+                return err
+        }
+
+        // Insert vector
+        vecBlob, err := sqlite_vec.SerializeFloat32(embedding)
+        if err != nil {
+                return err
+        }
+
+        _, err = idx.db.Exec(`INSERT INTO vectors (chunk_id, embedding) VALUES (?, ?)`, chunkID, vecBlob)
         return err
 }
 
@@ -110,62 +137,39 @@ type SearchResult struct {
         Distance float64
 }
 
-// Search finds chunks similar to the query embedding using cosine similarity
+// Search finds chunks similar to the query embedding using sqlite-vec
 func (idx *Index) Search(queryEmb []float32, limit int) ([]SearchResult, error) {
-        // Load all embeddings
-        rows, err := idx.db.Query(`
-                SELECT id, file, start_line, end_line, chunk_type, name, content, hash, embedding
-                FROM chunks
-                WHERE embedding IS NOT NULL
-        `)
+        vecBlob, err := sqlite_vec.SerializeFloat32(queryEmb)
         if err != nil {
                 return nil, err
         }
-        defer rows.Close()
 
-        type candidate struct {
-                chunk    chunker.Chunk
-                distance float64
+        // Query similar vectors
+        rows, err := idx.db.Query(`
+                SELECT v.chunk_id, v.distance, c.file, c.start_line, c.end_line, c.chunk_type, c.name, c.content, c.hash
+                FROM vectors v
+                JOIN chunks c ON c.id = v.chunk_id
+                WHERE v.embedding MATCH ? AND k = ?
+                ORDER BY v.distance
+        `, vecBlob, limit)
+        if err != nil {
+                return nil, err
         }
-        var candidates []candidate
+        defer rows.Close()
 
+        var results []SearchResult
         for rows.Next() {
-                var id int64
+                var chunkID int64
+                var distance float64
                 var c chunker.Chunk
-                var embBlob []byte
-                err := rows.Scan(&id, &c.File, &c.StartLine, &c.EndLine, &c.Type, &c.Name, &c.Content, &c.Hash, &embBlob)
+                err := rows.Scan(&chunkID, &distance, &c.File, &c.StartLine, &c.EndLine, &c.Type, &c.Name, &c.Content, &c.Hash)
                 if err != nil {
                         return nil, err
                 }
-
-                emb := deserializeEmbedding(embBlob)
-                dist := cosineDistance(queryEmb, emb)
-                candidates = append(candidates, candidate{chunk: c, distance: dist})
-        }
-
-        if err := rows.Err(); err != nil {
-                return nil, err
-        }
-
-        // Sort by distance (lower is better)
-        sort.Slice(candidates, func(i, j int) bool {
-                return candidates[i].distance < candidates[j].distance
-        })
-
-        // Return top-k
-        if limit > len(candidates) {
-                limit = len(candidates)
+                results = append(results, SearchResult{Chunk: c, Distance: distance})
         }
 
-        results := make([]SearchResult, limit)
-        for i := 0; i < limit; i++ {
-                results[i] = SearchResult{
-                        Chunk:    candidates[i].chunk,
-                        Distance: candidates[i].distance,
-                }
-        }
-
-        return results, nil
+        return results, rows.Err()
 }
 
 // GetFileHash returns the stored hash for a file, or empty string if not indexed
@@ -189,7 +193,13 @@ func (idx *Index) SetFileHash(path, hash string) error {
 
 // DeleteChunksForFile removes all chunks for a file
 func (idx *Index) DeleteChunksForFile(path string) error {
-        _, err := idx.db.Exec(`DELETE FROM chunks WHERE file = ?`, path)
+        // Delete vectors for chunks in this file
+        _, err := idx.db.Exec(`DELETE FROM vectors WHERE chunk_id IN (SELECT id FROM chunks WHERE file = ?)`, path)
+        if err != nil {
+                return err
+        }
+
+        _, err = idx.db.Exec(`DELETE FROM chunks WHERE file = ?`, path)
         if err != nil {
                 return err
         }
@@ -228,44 +238,3 @@ func (idx *Index) GetMetadata(key string) (string, error) {
         }
         return value, err
 }
-
-// serializeEmbedding converts float32 slice to bytes
-func serializeEmbedding(embedding []float32) []byte {
-        buf := make([]byte, len(embedding)*4)
-        for i, v := range embedding {
-                binary.LittleEndian.PutUint32(buf[i*4:], math.Float32bits(v))
-        }
-        return buf
-}
-
-// deserializeEmbedding converts bytes back to float32 slice
-func deserializeEmbedding(data []byte) []float32 {
-        n := len(data) / 4
-        result := make([]float32, n)
-        for i := 0; i < n; i++ {
-                bits := binary.LittleEndian.Uint32(data[i*4:])
-                result[i] = math.Float32frombits(bits)
-        }
-        return result
-}
-
-// cosineDistance computes 1 - cosine_similarity (so lower is more similar)
-func cosineDistance(a, b []float32) float64 {
-        if len(a) != len(b) {
-                return 1.0
-        }
-
-        var dotProduct, normA, normB float64
-        for i := range a {
-                dotProduct += float64(a[i]) * float64(b[i])
-                normA += float64(a[i]) * float64(a[i])
-                normB += float64(b[i]) * float64(b[i])
-        }
-
-        if normA == 0 || normB == 0 {
-                return 1.0
-        }
-
-        similarity := dotProduct / (math.Sqrt(normA) * math.Sqrt(normB))
-        return 1.0 - similarity
-}