Add server-side deduplication on ingest

.env.example

@@ -26,6 +26,11 @@ OPENBRAIN__QUERY__TEXT_WEIGHT=0.4
 # VECTOR_WEIGHT=0.6
 # TEXT_WEIGHT=0.4
 
+# Ingest deduplication
+OPENBRAIN__DEDUP__THRESHOLD=0.90
+# Backward-compatible plain env alias
+# DEDUP_THRESHOLD=0.90
+
 # TTL / transient facts
 # Background cleanup interval in seconds. Set to 0 to disable automatic cleanup.
 OPENBRAIN__TTL__CLEANUP_INTERVAL_SECONDS=300

README.md

@@ -11,14 +11,15 @@ OpenBrain is a Model Context Protocol (MCP) server that provides AI agents with
 - 🐘 **PostgreSQL + pgvector**: Production-grade vector storage with HNSW indexing
 - 🔌 **MCP Protocol**: Streamable HTTP plus legacy HTTP+SSE compatibility
 - 🔐 **Multi-Agent Support**: Isolated memory namespaces per agent
+- ♻️ **Deduplicated Ingest**: Near-duplicate facts are merged instead of stored repeatedly
 - ⚡ **High Performance**: Rust implementation with async I/O
 
 ## MCP Tools
 
 | Tool | Description |
 |------|-------------|
-| `store` | Store a memory with automatic embedding generation and optional TTL for transient facts |
-| `batch_store` | Store 1-50 memories atomically in a single call |
+| `store` | Store a memory with automatic embedding generation, optional TTL, and automatic deduplication |
+| `batch_store` | Store 1-50 memories atomically in a single call with the same deduplication rules |
 | `query` | Search memories by semantic similarity |
 | `purge` | Delete memories by agent ID or time range |
 
@@ -123,6 +124,31 @@ In Gitea Actions, that means:
 
 If you want prod e2e coverage without leaving a standing CI key on the server, the workflow-generated ephemeral key handles that automatically.
 
+### Deduplication on Ingest
+
+OpenBrain checks every `store` and `batch_store` write for an existing memory in
+the same `agent_id` namespace whose vector similarity meets the configured
+dedup threshold.
+
+Default behavior:
+
+- deduplication is always on
+- only same-agent memories are considered
+- expired memories are ignored
+- if a duplicate is found, the existing memory is refreshed instead of inserting a new row
+- metadata is merged with new keys overriding old values
+- `created_at` is updated to `now()`
+- `expires_at` is preserved unless the new write supplies a fresh TTL
+
+Configure the threshold with either:
+
+- `OPENBRAIN__DEDUP__THRESHOLD=0.90`
+- `DEDUP_THRESHOLD=0.90`
+
+Tool responses expose whether a write deduplicated an existing row via the
+`deduplicated` flag. `batch_store` also returns a `status` of either
+`stored` or `deduplicated` per entry.
+
 ## Agent Zero Developer Prompt
 
 For Agent Zero / A0, add the following section to the Developer agent role

src/config.rs

@@ -12,6 +12,7 @@ pub struct Config {
     pub database: DatabaseConfig,
     pub embedding: EmbeddingConfig,
     pub query: QueryConfig,
+    pub dedup: DedupConfig,
     pub ttl: TtlConfig,
     pub auth: AuthConfig,
 }
@@ -56,6 +57,13 @@ pub struct QueryConfig {
     pub text_weight: f32,
 }
 
+/// Deduplication configuration
+#[derive(Debug, Clone, Deserialize)]
+pub struct DedupConfig {
+    #[serde(default = "default_dedup_threshold")]
+    pub threshold: f32,
+}
+
 /// TTL / expiry configuration
 #[derive(Debug, Clone, Deserialize)]
 pub struct TtlConfig {
@@ -106,6 +114,7 @@ fn default_model_path() -> String { "models/all-MiniLM-L6-v2".to_string() }
 fn default_embedding_dim() -> usize { 384 }
 fn default_vector_weight() -> f32 { 0.6 }
 fn default_text_weight() -> f32 { 0.4 }
+fn default_dedup_threshold() -> f32 { 0.90 }
 fn default_cleanup_interval_seconds() -> u64 { 300 }
 fn default_auth_enabled() -> bool { false }
 
@@ -128,6 +137,8 @@ impl Config {
             // Query settings
             .set_default("query.vector_weight", default_vector_weight() as f64)?
             .set_default("query.text_weight", default_text_weight() as f64)?
+            // Dedup settings
+            .set_default("dedup.threshold", default_dedup_threshold() as f64)?
             // TTL settings
             .set_default(
                 "ttl.cleanup_interval_seconds",
@@ -156,6 +167,11 @@ impl Config {
                 config.query.text_weight = parsed;
             }
         }
+        if let Ok(dedup_threshold) = std::env::var("DEDUP_THRESHOLD") {
+            if let Ok(parsed) = dedup_threshold.parse::<f32>() {
+                config.dedup.threshold = parsed;
+            }
+        }
 
         Ok(config)
     }
@@ -184,6 +200,9 @@ impl Default for Config {
                 vector_weight: default_vector_weight(),
                 text_weight: default_text_weight(),
             },
+            dedup: DedupConfig {
+                threshold: default_dedup_threshold(),
+            },
             ttl: TtlConfig {
                 cleanup_interval_seconds: default_cleanup_interval_seconds(),
             },

src/db.rs

@@ -5,12 +5,12 @@
 use anyhow::{Context, Result};
 use deadpool_postgres::{Config, Pool, Runtime};
 use pgvector::Vector;
-use tokio_postgres::NoTls;
+use tokio_postgres::{GenericClient, NoTls};
 use tracing::info;
 use uuid::Uuid;
 
 use serde::Serialize;
-use serde_json::Value;
+use serde_json::{Map, Value};
 use crate::config::DatabaseConfig;
 
 /// Database wrapper with connection pool
@@ -42,6 +42,69 @@ pub struct MemoryMatch {
     pub hybrid_score: f32,
 }
 
+#[derive(Debug, Clone)]
+pub struct StoreMemoryResult {
+    pub id: Uuid,
+    pub deduplicated: bool,
+    pub expires_at: Option<chrono::DateTime<chrono::Utc>>,
+}
+
+#[derive(Debug, Clone)]
+struct DedupMatch {
+    id: Uuid,
+    metadata: Value,
+    expires_at: Option<chrono::DateTime<chrono::Utc>>,
+}
+
+fn merge_metadata(existing: &Value, incoming: &Value) -> Value {
+    match (existing, incoming) {
+        (Value::Object(existing), Value::Object(incoming)) => {
+            let mut merged = Map::with_capacity(existing.len() + incoming.len());
+            for (key, value) in existing {
+                merged.insert(key.clone(), value.clone());
+            }
+            for (key, value) in incoming {
+                merged.insert(key.clone(), value.clone());
+            }
+            Value::Object(merged)
+        }
+        (_, Value::Null) => existing.clone(),
+        _ => incoming.clone(),
+    }
+}
+
+async fn find_dedup_match<C>(
+    client: &C,
+    agent_id: &str,
+    embedding: &Vector,
+    threshold: f32,
+) -> Result<Option<DedupMatch>>
+where
+    C: GenericClient + Sync,
+{
+    let row = client
+        .query_opt(
+            r#"
+            SELECT id, metadata, expires_at
+            FROM memories
+            WHERE agent_id = $1
+              AND (expires_at IS NULL OR expires_at > NOW())
+              AND (1 - (embedding <=> $2)) >= $3
+            ORDER BY (1 - (embedding <=> $2)) DESC, created_at DESC
+            LIMIT 1
+            "#,
+            &[&agent_id, embedding, &threshold],
+        )
+        .await
+        .context("Failed to check for duplicate memory")?;
+
+    Ok(row.map(|row| DedupMatch {
+        id: row.get("id"),
+        metadata: row.get("metadata"),
+        expires_at: row.get("expires_at"),
+    }))
+}
+
 impl Database {
     /// Create a new database connection pool
     pub async fn new(config: &DatabaseConfig) -> Result<Self> {
@@ -77,11 +140,38 @@ impl Database {
         keywords: &[String],
         metadata: serde_json::Value,
         expires_at: Option<chrono::DateTime<chrono::Utc>>,
-    ) -> Result<Uuid> {
+        dedup_threshold: f32,
+    ) -> Result<StoreMemoryResult> {
         let client = self.pool.get().await?;
-        let id = Uuid::new_v4();
         let vector = Vector::from(embedding.to_vec());
 
+        if let Some(existing) = find_dedup_match(&client, agent_id, &vector, dedup_threshold).await? {
+            let merged_metadata = merge_metadata(&existing.metadata, &metadata);
+            let refreshed_expires_at = expires_at.or(existing.expires_at);
+
+            client
+                .execute(
+                    r#"
+                    UPDATE memories
+                    SET metadata = $2,
+                        created_at = NOW(),
+                        expires_at = $3
+                    WHERE id = $1
+                    "#,
+                    &[&existing.id, &merged_metadata, &refreshed_expires_at],
+                )
+                .await
+                .context("Failed to update deduplicated memory")?;
+
+            return Ok(StoreMemoryResult {
+                id: existing.id,
+                deduplicated: true,
+                expires_at: refreshed_expires_at,
+            });
+        }
+
+        let id = Uuid::new_v4();
+
         client
             .execute(
                 r#"
@@ -93,7 +183,11 @@ impl Database {
             .await
             .context("Failed to store memory")?;
 
-        Ok(id)
+        Ok(StoreMemoryResult {
+            id,
+            deduplicated: false,
+            expires_at,
+        })
     }
 
     /// Query memories by vector similarity
@@ -257,6 +351,7 @@ impl Database {
 pub struct BatchStoreResult {
     pub id: String,
     pub status: String,
+    pub deduplicated: bool,
     pub expires_at: Option<String>,
 }
 
@@ -272,14 +367,40 @@ impl Database {
             Vec<String>,
             Option<chrono::DateTime<chrono::Utc>>,
         )>,
+        dedup_threshold: f32,
     ) -> Result<Vec<BatchStoreResult>> {
         let mut client = self.pool.get().await?;
         let transaction = client.transaction().await?;
         let mut results = Vec::with_capacity(entries.len());
 
         for (content, metadata, embedding, keywords, expires_at) in entries {
-            let id = Uuid::new_v4();
             let vector = Vector::from(embedding);
+            if let Some(existing) =
+                find_dedup_match(&transaction, agent_id, &vector, dedup_threshold).await?
+            {
+                let merged_metadata = merge_metadata(&existing.metadata, &metadata);
+                let refreshed_expires_at = expires_at.or(existing.expires_at);
+                transaction
+                    .execute(
+                        r#"
+                        UPDATE memories
+                        SET metadata = $2,
+                            created_at = NOW(),
+                            expires_at = $3
+                        WHERE id = $1
+                        "#,
+                        &[&existing.id, &merged_metadata, &refreshed_expires_at],
+                    )
+                    .await
+                    .context("Failed to update deduplicated batch memory")?;
+                results.push(BatchStoreResult {
+                    id: existing.id.to_string(),
+                    status: "deduplicated".to_string(),
+                    deduplicated: true,
+                    expires_at: refreshed_expires_at.map(|ts| ts.to_rfc3339()),
+                });
+            } else {
+                let id = Uuid::new_v4();
                 transaction.execute(
                     r#"INSERT INTO memories (id, agent_id, content, embedding, keywords, metadata, expires_at) VALUES ($1, $2, $3, $4, $5, $6, $7)"#,
                     &[&id, &agent_id, &content, &vector, &keywords, &metadata, &expires_at],
@@ -287,9 +408,11 @@ impl Database {
                 results.push(BatchStoreResult {
                     id: id.to_string(),
                     status: "stored".to_string(),
+                    deduplicated: false,
                     expires_at: expires_at.map(|ts| ts.to_rfc3339()),
                 });
             }
+        }
         transaction.commit().await?;
         Ok(results)
     }

src/tools/batch_store.rs

@@ -103,7 +103,7 @@ pub async fn execute(state: &Arc<AppState>, arguments: Value) -> Result<String>
     // 5. Batch DB insert (single transaction for atomicity)
     let results = state
         .db
-        .batch_store_memories(agent_id, processed_entries)
+        .batch_store_memories(agent_id, processed_entries, state.config.dedup.threshold)
         .await
         .context("Failed to batch store memories")?;
 

src/tools/mod.rs

@@ -15,7 +15,7 @@ pub fn get_tool_definitions() -> Vec<Value> {
     vec![
         json!({
             "name": "store",
-            "description": "Store a memory with automatic embedding generation and keyword extraction. The memory will be associated with the agent_id for isolated retrieval.",
+            "description": "Store a memory with automatic embedding generation and keyword extraction. Near-duplicate memories for the same agent are deduplicated automatically by similarity, with metadata merged and timestamps refreshed.",
             "inputSchema": {
                 "type": "object",
                 "properties": {
@@ -41,7 +41,7 @@ pub fn get_tool_definitions() -> Vec<Value> {
         }),
         json!({
             "name": "batch_store",
-            "description": "Store multiple memories with automatic embedding generation and keyword extraction. Accepts 1-50 entries and stores them atomically in a single transaction.",
+            "description": "Store multiple memories with automatic embedding generation and keyword extraction. Accepts 1-50 entries, stores them atomically in a single transaction, and applies the same automatic deduplication rules as single-store.",
             "inputSchema": {
                 "type": "object",
                 "properties": {

src/tools/store.rs

@@ -60,20 +60,26 @@ pub async fn execute(state: &Arc<AppState>, arguments: Value) -> Result<String>
             &keywords,
             metadata,
             expires_at.clone(),
+            state.config.dedup.threshold,
         )
         .await
         .context("Failed to store memory")?;
 
-    info!("Memory stored with ID: {}", id);
+    info!(
+        "Memory {} with ID: {}",
+        if id.deduplicated { "deduplicated" } else { "stored" },
+        id.id
+    );
 
     Ok(serde_json::json!({
         "success": true,
-        "id": id.to_string(),
+        "id": id.id.to_string(),
         "agent_id": agent_id,
+        "deduplicated": id.deduplicated,
         "keywords": keywords,
         "embedding_dimension": embedding.len(),
         "ttl": ttl,
-        "expires_at": expires_at.as_ref().map(|ts| ts.to_rfc3339())
+        "expires_at": id.expires_at.as_ref().map(|ts| ts.to_rfc3339())
     })
     .to_string())
 }

tests/e2e_mcp.rs

@@ -1242,5 +1242,224 @@ async fn e2e_existing_store_unchanged() -> anyhow::Result<()> {
     .await;
 
     assert!(result["success"].as_bool().unwrap_or(false));
+    assert_eq!(result["deduplicated"].as_bool(), Some(false));
+    Ok(())
+}
+
+
+// =============================================================================
+// Deduplication Tests (Issue #14)
+// =============================================================================
+
+#[tokio::test]
+async fn e2e_store_deduplicates_and_merges_metadata() -> anyhow::Result<()> {
+    let base = base_url();
+    let client = reqwest::Client::builder()
+        .timeout(Duration::from_secs(20))
+        .build()
+        .expect("reqwest client");
+
+    ensure_schema().await;
+    wait_until_ready(&client, &base).await;
+
+    let agent = format!("dedup_{}", uuid::Uuid::new_v4());
+    let content = format!("Dedup fact {} prefers concise replies", uuid::Uuid::new_v4());
+    let _ = call_tool(
+        &client,
+        &base,
+        "purge",
+        json!({ "agent_id": agent.clone(), "confirm": true }),
+    )
+    .await;
+
+    let first = call_tool(&client, &base, "store", json!({
+        "agent_id": agent.clone(),
+        "content": content.clone(),
+        "metadata": {
+            "source": "first",
+            "keep": true,
+            "override": "old"
+        }
+    }))
+    .await;
+
+    assert_eq!(first["deduplicated"].as_bool(), Some(false));
+
+    let first_query = call_tool(&client, &base, "query", json!({
+        "agent_id": agent.clone(),
+        "query": content.clone(),
+        "limit": 5,
+        "threshold": 0.0
+    }))
+    .await;
+    let first_created_at = first_query["results"]
+        .as_array()
+        .and_then(|items| items.first())
+        .and_then(|item| item.get("created_at"))
+        .and_then(Value::as_str)
+        .expect("first created_at")
+        .to_string();
+
+    tokio::time::sleep(Duration::from_millis(1100)).await;
+
+    let second = call_tool(&client, &base, "store", json!({
+        "agent_id": agent.clone(),
+        "content": content.clone(),
+        "metadata": {
+            "override": "new",
+            "second": true
+        }
+    }))
+    .await;
+
+    assert_eq!(second["deduplicated"].as_bool(), Some(true));
+    assert_eq!(second["id"], first["id"]);
+
+    let query = call_tool(&client, &base, "query", json!({
+        "agent_id": agent.clone(),
+        "query": content.clone(),
+        "limit": 5,
+        "threshold": 0.0
+    }))
+    .await;
+
+    assert_eq!(query["count"].as_u64(), Some(1));
+    let stored = query["results"]
+        .as_array()
+        .and_then(|items| items.first())
+        .expect("dedup query result");
+
+    assert_eq!(stored["metadata"]["source"], "first");
+    assert_eq!(stored["metadata"]["keep"], true);
+    assert_eq!(stored["metadata"]["override"], "new");
+    assert_eq!(stored["metadata"]["second"], true);
+
+    let second_created_at = stored["created_at"]
+        .as_str()
+        .expect("second created_at");
+    assert!(
+        second_created_at > first_created_at.as_str(),
+        "deduplicated write should refresh created_at"
+    );
+
+    let _ = call_tool(
+        &client,
+        &base,
+        "purge",
+        json!({ "agent_id": agent, "confirm": true }),
+    )
+    .await;
+
+    Ok(())
+}
+
+#[tokio::test]
+async fn e2e_store_dedup_is_agent_scoped() -> anyhow::Result<()> {
+    let base = base_url();
+    let client = reqwest::Client::builder()
+        .timeout(Duration::from_secs(20))
+        .build()
+        .expect("reqwest client");
+
+    ensure_schema().await;
+    wait_until_ready(&client, &base).await;
+
+    let agent_a = format!("dedup_scope_a_{}", uuid::Uuid::new_v4());
+    let agent_b = format!("dedup_scope_b_{}", uuid::Uuid::new_v4());
+    let content = format!("Shared cross-agent fact {}", uuid::Uuid::new_v4());
+
+    let _ = call_tool(&client, &base, "purge", json!({ "agent_id": agent_a.clone(), "confirm": true })).await;
+    let _ = call_tool(&client, &base, "purge", json!({ "agent_id": agent_b.clone(), "confirm": true })).await;
+
+    let first = call_tool(&client, &base, "store", json!({
+        "agent_id": agent_a.clone(),
+        "content": content.clone()
+    }))
+    .await;
+    let second = call_tool(&client, &base, "store", json!({
+        "agent_id": agent_b.clone(),
+        "content": content.clone()
+    }))
+    .await;
+
+    assert_eq!(first["deduplicated"].as_bool(), Some(false));
+    assert_eq!(second["deduplicated"].as_bool(), Some(false));
+    assert_ne!(first["id"], second["id"]);
+
+    let _ = call_tool(&client, &base, "purge", json!({ "agent_id": agent_a, "confirm": true })).await;
+    let _ = call_tool(&client, &base, "purge", json!({ "agent_id": agent_b, "confirm": true })).await;
+
+    Ok(())
+}
+
+#[tokio::test]
+async fn e2e_batch_store_deduplicates_within_batch() -> anyhow::Result<()> {
+    let base = base_url();
+    let client = reqwest::Client::builder()
+        .timeout(Duration::from_secs(20))
+        .build()
+        .expect("reqwest client");
+
+    ensure_schema().await;
+    wait_until_ready(&client, &base).await;
+
+    let agent = format!("batch_dedup_{}", uuid::Uuid::new_v4());
+    let content = format!("Batch dedup fact {}", uuid::Uuid::new_v4());
+    let _ = call_tool(
+        &client,
+        &base,
+        "purge",
+        json!({ "agent_id": agent.clone(), "confirm": true }),
+    )
+    .await;
+
+    let result = call_tool(&client, &base, "batch_store", json!({
+        "agent_id": agent.clone(),
+        "entries": [
+            {
+                "content": content.clone(),
+                "metadata": { "source": "first", "keep": "yes" }
+            },
+            {
+                "content": content.clone(),
+                "metadata": { "source": "second", "merged": "yes" }
+            }
+        ]
+    }))
+    .await;
+
+    let results = result["results"].as_array().expect("batch results");
+    assert_eq!(result["count"].as_u64(), Some(2));
+    assert_eq!(results[0]["deduplicated"].as_bool(), Some(false));
+    assert_eq!(results[0]["status"], "stored");
+    assert_eq!(results[1]["deduplicated"].as_bool(), Some(true));
+    assert_eq!(results[1]["status"], "deduplicated");
+    assert_eq!(results[0]["id"], results[1]["id"]);
+
+    let query = call_tool(&client, &base, "query", json!({
+        "agent_id": agent.clone(),
+        "query": content.clone(),
+        "limit": 5,
+        "threshold": 0.0
+    }))
+    .await;
+
+    assert_eq!(query["count"].as_u64(), Some(1));
+    let stored = query["results"]
+        .as_array()
+        .and_then(|items| items.first())
+        .expect("batch dedup query result");
+    assert_eq!(stored["metadata"]["source"], "second");
+    assert_eq!(stored["metadata"]["keep"], "yes");
+    assert_eq!(stored["metadata"]["merged"], "yes");
+
+    let _ = call_tool(
+        &client,
+        &base,
+        "purge",
+        json!({ "agent_id": agent, "confirm": true }),
+    )
+    .await;
+
     Ok(())
 }