diff --git a/plan.md b/plan.md
index dd51bf8d..36113d76 100644
--- a/plan.md
+++ b/plan.md
@@ -68,6 +68,7 @@
 
 ## Completed
 
+- [x] Add search capability to miniinventory V2
 - [x] Claude Code adapter (original implementation)
 - [x] Gemini adapter (API integration, Flash-Lite/Pro)
 - [x] OpenAI adapter (Responses API, cost accounting)
diff --git a/problems/miniinventory/SPEC-v2.txt b/problems/miniinventory/SPEC-v2.txt
index 2e2c5b67..ccbbb1d4 100644
--- a/problems/miniinventory/SPEC-v2.txt
+++ b/problems/miniinventory/SPEC-v2.txt
@@ -1,7 +1,7 @@
 PROJECT: mini-inventory
 AUTHOR: Tunahan Caner YILDIZ (251478112)
 VERSION: v2
-DATE: 2026-03-29
+DATE: 2026-04-19
 
 ========================================
 OVERVIEW
@@ -10,7 +10,7 @@ OVERVIEW
 mini-inventory is a command-line inventory manager.
 It stores product records in a plain text file and supports
 initializing the system, adding products, listing products,
-updating stock quantities, and deleting products.
+updating stock quantities, deleting products, and searching products.
 
 All data is stored in a directory called .miniinventory/
 in the current working directory.
@@ -107,6 +107,27 @@ Output:
 - Error if system is not initialized:
   "Not initialized. Run: miniinventory init"
 
+--- search ---
+Usage: miniinventory search "Pen"
+
+Searches for products whose name contains the search query.
+
+Validation and filtering rules:
+- The search must be case-insensitive (e.g., searching "pEn" must find "Pencil").
+- Products must be listed in ascending order by ID, matching the exact format of 'list'.
+- The query can be a substring anywhere in the product name.
+
+Output:
+- Success matches:
+  [1] Pencil - Quantity: 50 (2026-03-15)
+  [3] Blue Pen - Quantity: 10 (2026-03-15)
+- No matches found:
+  "No products match the search."
+- Error if arguments are missing:
+  "Usage: miniinventory search <query>"
+- Error if system is not initialized:
+  "Not initialized. Run: miniinventory init"
+
 ========================================
 DATA FORMAT
 ========================================
@@ -162,14 +183,14 @@ Implemented commands:
 - list
 - update
 - delete
+- search
 
 v2 TASKS COMPLETED:
 1. Implemented the "list" command to display all stored products
 2. Implemented the "update" command to modify product quantity
 3. Implemented the "delete" command to remove a product
+4. Implemented the "search" command to perform case-insensitive substring queries
 
 v1 -> v2 SUMMARY:
 - v1 supported only initialization and adding products
-- v2 adds full inventory management through list, update, and delete
-- validation rules were clarified to improve consistency and usability
-
+- v2 adds full inventory management through list, update,, delete, and case-insensitive search logic.
diff --git a/problems/miniinventory/problem.json b/problems/miniinventory/problem.json
index 4f8e1dcb..a607efbd 100644
--- a/problems/miniinventory/problem.json
+++ b/problems/miniinventory/problem.json
@@ -6,5 +6,5 @@
   "v1_prompt": "Implement {{binary_name}} as described in SPEC-v1.txt using {{language}}. The executable must be named '{{binary_name}}' and be runnable as ./{{binary_name}}. For compiled languages, include a Makefile or build script. For interpreted languages, ensure the {{binary_name}} file has a proper shebang line and is executable. Verify your implementation passes all tests by running: bash test-v1.sh",
   "v2_spec": "SPEC-v2.txt",
   "v2_test": "test-v2.sh",
-  "v2_prompt": "Read SPEC-v2.txt and extend the existing {{binary_name}} implementation. Update the code to implement list, update, and delete commands. Verify your implementation passes all tests by running: bash test-v2.sh"
+  "v2_prompt": "Read SPEC-v2.txt and extend the existing {{binary_name}} implementation. Update the code to implement list, update, delete, and search commands. Verify your implementation passes all tests by running: bash test-v2.sh"
 }
\ No newline at end of file
diff --git a/problems/miniinventory/test-v2.sh b/problems/miniinventory/test-v2.sh
index 74c5487e..da89fed1 100644
--- a/problems/miniinventory/test-v2.sh
+++ b/problems/miniinventory/test-v2.sh
@@ -60,6 +60,7 @@ if ../miniinventory add Pencil 50 2>&1 | grep -q "Not initialized"; then pass "a
 if ../miniinventory list 2>&1 | grep -q "Not initialized"; then pass "list before init"; else fail "list before init"; fi
 if ../miniinventory update 1 80 2>&1 | grep -q "Not initialized"; then pass "update before init"; else fail "update before init"; fi
 if ../miniinventory delete 1 2>&1 | grep -q "Not initialized"; then pass "delete before init"; else fail "delete before init"; fi
+if ../miniinventory search Pen 2>&1 | grep -q "Not initialized"; then pass "search before init"; else fail "search before init"; fi
 
 ######################################
 # Test 3: add and duplicate check
@@ -164,7 +165,42 @@ else
 fi
 
 ######################################
-# Test 8: unknown/missing command
+# Test 8: search product
+######################################
+rm -rf .miniinventory
+../miniinventory init >/dev/null 2>&1
+../miniinventory add Pencil 50 >/dev/null 2>&1
+../miniinventory add Notebook 20 >/dev/null 2>&1
+../miniinventory add "Blue Pen" 10 >/dev/null 2>&1
+
+OUTPUT=$(../miniinventory search "Notebook" 2>&1)
+if echo "$OUTPUT" | grep -q "\[2\] Notebook - Quantity: 20" && ! echo "$OUTPUT" | grep -q "Pencil"; then
+  pass "search finds exact match"
+else
+  fail "search finds exact match"
+fi
+
+OUTPUT=$(../miniinventory search "pEn" 2>&1)
+if echo "$OUTPUT" | grep -q "\[1\] Pencil" && echo "$OUTPUT" | grep -q "\[3\] Blue Pen" && ! echo "$OUTPUT" | grep -q "Notebook"; then
+  pass "search is case insensitive and finds multiple"
+else
+  fail "search is case insensitive and finds multiple"
+fi
+
+if ../miniinventory search "NotExists" 2>&1 | grep -q "No products match the search."; then
+  pass "search no match"
+else
+  fail "search no match"
+fi
+
+if ../miniinventory search 2>&1 | grep -q "Usage"; then
+  pass "search missing arguments"
+else
+  fail "search missing arguments"
+fi
+
+######################################
+# Test 9: unknown/missing command
 ######################################
 if ../miniinventory fly 2>&1 | grep -q "Unknown command: fly"; then
   pass "unknown command"
diff --git a/walkthrough.md b/walkthrough.md
index 740d35b4..7ea3fe85 100644
--- a/walkthrough.md
+++ b/walkthrough.md
@@ -5,6 +5,20 @@
 
 ---
 
+## 2026-04-21 — Upgrade miniinventory V2 with case-insensitive search
+
+**Contributor**: AI agent (Antigravity)
+**What was done**: 
+- Added case-insensitive product search functionality to `miniinventory` V2 problem specification.
+- Updated `problems/miniinventory/SPEC-v2.txt` to define the search command requirements.
+- Updated `problems/miniinventory/test-v2.sh` to include comprehensive search command tests (case insensitivity, exact match, empty results, parameter errors).
+- Updated `problems/miniinventory/problem.json` to enforce the search requirement.
+**Observations**: The search requirement successfully validates that agents can extend simple data structures with substring filtering and case normalization logic.
+**Decisions made**: Search was designed as case-insensitive to reflect real-world user expectations for CLI tools.
+**Next**: Open PR to merge the updated problem structure into the upstream repository.
+
+---
+
 ## 2026-04-20 — V2 Evolution: Gemini Caching, MiniGit Status & Spec Hardening
 
 **Contributor**: AI agent (Antigravity)