Update README.md

README.md

@@ -38,14 +38,41 @@ print(obs.code_snippet)
 - `POST /mcp` – minimal MCP endpoint
 
 ## Tasks
-
-| Difficulty | Bug Type |
-|------------|----------|
-| easy | Missing null check |
-| medium | Inefficient loop |
-| hard | Division by zero |
-| harder | Race condition (missing lock) |
-| hardest | Potential deadlock |
+Easy (null‑checks, simple logic errors)
+#	Bug ID	Description	How to inject
+1	null_check	Missing if key in dict: guard	AST: remove if‑statement
+2	simple_typo	Variable name misspelled (users → usres)	AST: rename variable
+3	string_index	Indexing string with wrong index (off‑by‑one)	AST: change constant in index
+4	default_value	Not providing a default in dict.get()	AST: replace dict[key] with dict.get(key) … but wrongly
+5	empty_return	Function returns None in a branch that should return something	AST: insert return None or delete a return
+Medium (off‑by‑one, loop logic, simple arithmetic)
+#	Bug ID	Description	How to inject
+6	off_by_one	range(x) → range(1, x-1) (skips first and last)	AST: modify range args
+7	loop_skip	for i in range(len(arr)): missing last element because of off‑by‑one	AST: change range length
+8	sign_error	sum += item replaced with sum -= item	AST: swap Add/Sub
+9	swap_args	Calling a function with arguments swapped	AST: swap arg order
+10	uninitialised_var	Using a variable before assignment in a loop	AST: remove assignment line
+Hard (division‑by‑zero, floating‑point, edge‑case handling)
+#	Bug ID	Description	How to inject
+11	division_by_zero_empty	Missing check for empty list before averaging	AST: remove the if not data: guard
+12	division_by_zero_zero	Integer division where denominator can be zero	AST: remove a denominator‑checking statement
+13	float_precision	Using integer division // instead of / for average	AST: change operator
+14	abs_usage	Forgetting abs() when comparing differences	AST: remove abs() call
+15	round_error	Rounding too early causing precision loss	AST: insert round() incorrectly
+Harder (race conditions, missing atomic operations)
+#	Bug ID	Description	How to inject
+16	missing_lock	Shared counter accessed without a lock	Template: remove with lock: from code
+17	double_lock	Acquiring the same lock twice (deadlock risk)	Template: add extra lock.acquire()
+18	global_nonatomic	Compound assignment x = x + 1 instead of atomic +=	AST: modify assignment node
+19	thread_safe_list	Appending to a list from multiple threads without lock	Template: remove lock around list operation
+20	volatile_read	Reading a shared flag outside a lock	Template: remove synchronization block
+Hardest (deadlock, ordering, complex concurrency)
+#	Bug ID	Description	How to inject
+21	deadlock_order	Lock A then lock B in one thread, opposite in another	Template: swap lock acquisition order
+22	nested_lock_timeout	Not using a timeout when acquiring locks, causing hang	Template: replace acquire() with acquire(blocking=True) without timeout
+23	fork_join	Starting threads and not waiting for them to finish (missing join())	AST: remove thread.join()
+24	mutex_release	Releasing a mutex in one thread that was locked by another	Template: wrong release logic
+25	race_on_init	Initializing a shared resource after threads have started	Template: move initialization after thread creation
 
 ## Deployment