diff --git a/context.lua b/context.lua
index 00222a1..01ea1ee 100644
--- a/context.lua
+++ b/context.lua
@@ -136,6 +136,22 @@ end
 --     model (user → assistant → user → assistant), no strict-template breakage.
 --
 -- The system prompt is NOT stored in self.turns per §6.
+-- Phase 4: [background] block composer. Memory items from memory.jsonl
+-- are stored on self.memory_items (loaded by repl.lua at startup) and
+-- rendered as a dim-styled suffix on the system prompt. Suppressed when
+-- norris_active to avoid stacking large background contexts in
+-- per-iteration broker calls (R-C1 review fold-in). Cap honored via
+-- inject_max_chars argument from the caller (already truncated by repl).
+local function compose_background(items)
+    if not items or #items == 0 then return "" end
+    local lines = { "", "", "[background] (memory.jsonl; manage via :memory)" }
+    for _, it in ipairs(items) do
+        lines[#lines + 1] =
+            ("- (%s) %s"):format(it.kind or "?", (it.content or ""):gsub("\n", " "))
+    end
+    return table.concat(lines, "\n")
+end
+
 -- Phase 3: NORRIS MODE suffix appended to the system prompt when
 -- self.norris_active. Carries self.norris_goal so eviction of the
 -- user's "[norris] goal: ..." turn doesn't lose the anchor.
@@ -165,6 +181,12 @@ message if they declined.]]
 
 function Context:to_messages()
     local sys_content = self.system_prompt
+    -- Phase 4 [background] memory block. Suppressed during Norris (R-C1
+    -- — avoid ~16K of redundant tokens per planning iteration).
+    if not self.norris_active then
+        sys_content = sys_content .. compose_background(self.memory_items)
+    end
+    -- Phase 3 NORRIS MODE suffix. Last block so its instructions dominate.
     if self.norris_active and self.norris_goal then
         sys_content = sys_content
             .. string.format(NORRIS_SUFFIX_TEMPLATE, self.norris_goal)