FinalMix3

A multi-task code reinforcement-learning mixture in the verl RL prompt format: one code-generation split plus a suite of auxiliary code-understanding tasks, so the same corpus drives three training regimes.

It is OctoReasoner/FinalMix2 with three changes: every row now carries one uniform prompt format, the auxiliary mix is rebalanced by ability, and four defects where a prompt contradicted the grader that scores it are repaired. The rows themselves are otherwise the same problems, with the same rule-verifiable rewards.

Splits

Split	Rows	Contents	Use
train_no_aux	9,693	code generation only (9,693 rows)	RL on code generation alone
train_aux_cascade	25,318	all 15,625 auxiliary rows first, then the 9,693 code rows	cascade / curriculum RL (aux → code)
train_aux_multitask	25,318	the same rows, interleaved	mixed multi-task RL
validation	481	held-out code-generation problems	held-out code generation, for in-training validation
test	175	LiveCodeBench-v6 problems	LiveCodeBench-v6, repaired (see below)

Prompt format

Every row — code generation and auxiliary alike — is exactly two turns: a system turn that is byte-identical across the whole dataset, and a user turn that opens with an [INSTRUCTION] block naming the task and its answer format, and closes with a one-line reminder of that format.

system: You are an expert coding professional. You are given a self-contained
        code-related task instruction, ... Failure to follow this format will result
        in immediate task failure. Do not output any other text after your final answer.

user:   [INSTRUCTION]
        Predict the big-O time complexity of the code below.
        Reply in the format \boxed{X}, where X is the complexity in standard big-O
        notation, e.g. \boxed{O(1)}, \boxed{O(n)}, ... Write exponents as **.
        [/INSTRUCTION]

        [CODE] ... [/CODE]

        Remember to reply with your answer within \boxed{...}. Any other format will
        be immediately rejected.

This replaces FinalMix2's 25 per-family system prompts and its two rival code-fencing conventions. Answers are extracted last-wins (the last fenced python block, the last \boxed{...}, or a JSON object with the named key), so reasoning before the answer is free. The reminder's wording follows how each row is graded, not how it looks.

Auxiliary tasks

15,625 rows across 24 abilities. FinalMix2 budgeted its auxiliary mix per source family (14 of them) while ability (24 values) was never a stratification key, so rare abilities inside large families were crushed — code_io_output_from_input_mcq held 4 rows. FinalMix3 rebalances with a floor of 400 and a cap of 1,200 per ability: short abilities are topped back up from OctoReasoner/CodeAuxTasks (candidates must clear the same length, language and near-duplicate gates the mix used), and over-cap abilities are trimmed keeping the most distinctive rows. The spread across abilities falls from 549x to 5.6x.

ability	rows
code_io_input_from_output_mcq	1,200
code_from_space_complexity_mcq	1,200
coderpile_retrieval	1,200
pick_codes_similar_to_reference	1,200
predict_cwe_from_code_mcq	1,020
code_change_localization	836
code_from_time_complexity_mcq	829
code_cputime_ranking	817
variable_output_tracing	735
code_io_output_from_input_direct	707
code_memory_ranking	593
code_compile_status_prediction	583
localize_callable_from_cwe_mcq	552
localize_callable_from_cwe_direct	498
predict_cwe_from_code_catalog	400
code_io_input_output_pairs_mcq	400
time_complexity_from_code_mcq	400
code_io_input_from_output_direct	400
time_complexity_from_code_direct	400
space_complexity_from_code_mcq	400
space_complexity_from_code_direct	400
code_verifiable_instruction_following_generation	387
code_io_output_from_input_mcq	252
code_verifiable_instruction_following_edit	216

Code split

Source	Rows	Share
code_primeintellect	5,241	54.1%
code_contests_o	2,538	26.2%
code_taco	1,721	17.8%
code_lcbv5	193	2.0%

Repairs carried over FinalMix2

Each of these is a case where the shipped prompt or ground truth contradicted the grader, so a correct answer could not score:

1. pick_codes_similar_to_reference asked for a clustering (\boxed{(1, 2, 4), (3)}) while the gold is the flat list of positions equivalent to the reference and the scorer compares the set of integers in the answer — obeying the prompt scored 0.
2. predict_cwe_from_code_mcq capped answers at option E while every row offers six options; F was the single most common gold answer.
3. Multi-letter CWE answers are compared by string equality, so the required alphabetical ordering is stated again (it had been dropped in an earlier rewrite).
4. LiveCodeBench-v6 (test): 63 of 175 rows are functional problems whose ground truth carried no fn_name, so the checker graded them as stdin/stdout and the class Solution answer the prompt asks for scored 0 on every case. fn_name is now set from the starter signature and the expected outputs are canonicalised to what the fn-call harness prints. Scored end to end through the real reward path: 0/63 before, 63/63 after.

One row (vartrace_2327) was dropped: it asks for the final value of a variable it never names, and unlike the 16 similar rows it cannot be reconstructed.

Schema

Unchanged from FinalMix2:

Field	Type	Notes
data_source	string	routes the reward function
prompt	list of {role, content}	system + user, as above
ability	string	task category
reward_model	struct {style, extraction_method, ground_truth, key}	scoring spec
extra_info	struct {id, lower_pass_rate, upper_pass_rate}	per-example metadata

Code-generation rows are scored by executing the model's program against hidden tests in a sandbox; auxiliary rows by rule-based extraction against ground_truth.

Reproduction

python tasks/stratify_aux.py  --src FinalMix2/data       --out FinalMix2-strat/data \
                              --floor 400 --cap 1200
python tasks/unify_prompts.py --src FinalMix2-strat/data --out FinalMix3/data
python tasks/verify_unified_prompts.py --src FinalMix2-strat/data --out FinalMix3/data

The verifier checks every row: two turns with the byte-identical system prompt, one [INSTRUCTION] block carrying the ability's defined text, a reminder matching how the row is graded, the task content preserved verbatim from FinalMix2, and data_source / ability / reward_model / extra_info and row order otherwise untouched.