diff --git a/4-Infrastructure/infra/ene-session-sync/sql/ene_chat_schema.sql b/4-Infrastructure/infra/ene-session-sync/sql/ene_chat_schema.sql
new file mode 100644
index 00000000..374f6f63
--- /dev/null
+++ b/4-Infrastructure/infra/ene-session-sync/sql/ene_chat_schema.sql
@@ -0,0 +1,86 @@
+-- Canonical ENE chat/session sync schema
+--
+-- This schema is consumed by:
+-- - 4-Infrastructure/infra/ene-session-sync (Rust)
+--
+-- Policy:
+-- - treat this file as the canonical DDL source for these tables
+-- - code should not embed divergent CREATE TABLE strings
+
+CREATE SCHEMA IF NOT EXISTS ene;
+
+-- Optional extension (non-fatal if unavailable).
+CREATE EXTENSION IF NOT EXISTS vector;
+
+CREATE TABLE IF NOT EXISTS ene.chat_sessions (
+    session_id              TEXT PRIMARY KEY,
+    title                   TEXT,
+    agent                   TEXT,
+    model                   TEXT,
+    workspace_fingerprint   TEXT,
+    workspace_root          TEXT,
+    fork_parent_session_id  TEXT,
+    compaction_count        INTEGER     NOT NULL DEFAULT 0,
+    compaction_summary      TEXT,
+    message_count           INTEGER     NOT NULL DEFAULT 0,
+    token_input_total       BIGINT      NOT NULL DEFAULT 0,
+    token_output_total      BIGINT      NOT NULL DEFAULT 0,
+    created_at_ms           BIGINT      NOT NULL,
+    updated_at_ms           BIGINT      NOT NULL,
+    first_message_at_ms     BIGINT,
+    last_message_at_ms      BIGINT,
+    embedding               vector(768),
+    meta                    JSONB       NOT NULL DEFAULT '{}',
+    receipt                 TEXT,
+    updated_at              TIMESTAMPTZ NOT NULL DEFAULT now()
+);
+
+CREATE TABLE IF NOT EXISTS ene.chat_messages (
+    id                    BIGSERIAL   PRIMARY KEY,
+    session_id            TEXT        NOT NULL REFERENCES ene.chat_sessions(session_id) ON DELETE CASCADE,
+    message_index         INTEGER     NOT NULL,
+    role                  TEXT        NOT NULL,
+    blocks                JSONB       NOT NULL,
+    text_content          TEXT,
+    token_input           BIGINT      NOT NULL DEFAULT 0,
+    token_output          BIGINT      NOT NULL DEFAULT 0,
+    token_cache_creation  BIGINT      NOT NULL DEFAULT 0,
+    token_cache_read      BIGINT      NOT NULL DEFAULT 0,
+    tool_calls            JSONB       NOT NULL DEFAULT '[]',
+    embedding             vector(768),
+    receipt_hash          TEXT,
+    created_at_ms         BIGINT      NOT NULL,
+    created_at            TIMESTAMPTZ NOT NULL DEFAULT now(),
+    UNIQUE(session_id, message_index)
+);
+
+CREATE TABLE IF NOT EXISTS ene.ingestion_receipts (
+    receipt_id    UUID        PRIMARY KEY DEFAULT gen_random_uuid(),
+    shim_name     TEXT        NOT NULL,
+    status        TEXT        NOT NULL DEFAULT 'pending',
+    sha256        TEXT        NOT NULL,
+    record_count  BIGINT      NOT NULL DEFAULT 0,
+    source_path   TEXT        NOT NULL,
+    meta          JSONB       NOT NULL DEFAULT '{}',
+    created_at    TIMESTAMPTZ NOT NULL DEFAULT now()
+);
+
+-- Idempotent migration helpers.
+ALTER TABLE ene.chat_sessions ADD COLUMN IF NOT EXISTS title TEXT;
+ALTER TABLE ene.chat_sessions ADD COLUMN IF NOT EXISTS agent TEXT;
+ALTER TABLE ene.chat_sessions ADD COLUMN IF NOT EXISTS model TEXT;
+
+CREATE INDEX IF NOT EXISTS idx_chat_sessions_updated
+    ON ene.chat_sessions(updated_at_ms DESC);
+CREATE INDEX IF NOT EXISTS idx_chat_sessions_workspace
+    ON ene.chat_sessions(workspace_fingerprint);
+CREATE INDEX IF NOT EXISTS idx_chat_messages_session_order
+    ON ene.chat_messages(session_id, message_index);
+CREATE INDEX IF NOT EXISTS idx_chat_messages_receipt
+    ON ene.chat_messages(receipt_hash);
+
+-- Optional indexes (non-fatal if missing language config).
+CREATE INDEX IF NOT EXISTS idx_chat_messages_text_search
+    ON ene.chat_messages USING GIN(to_tsvector('english', COALESCE(text_content, '')));
+CREATE INDEX IF NOT EXISTS idx_chat_messages_tool_search
+    ON ene.chat_messages USING GIN(tool_calls jsonb_path_ops);