antcoder-fixer-7b

🛠️ AntCoder-Fixer-7B

<p align="center"> <b>Specialized TypeScript Compiler-Diagnostic-to-Git Unified Diff Patch LoRA</b><br> Engineered by Deep Das • Part of the AntCoder Multi-Agent Coding Suite </p> <p align="center"> <a href="https://huggingface.co/Tornado9991/antcoder-builder-7b"><img src="https://img.shields.io/badge/HF_Model-Builder_7B-yellow.svg" alt="Builder Model"></a> <a href="https://huggingface.co/Tornado9991/antcoder-fixer-7b"><img src="https://img.shields.io/badge/HF_Model-Fixer_7B-red.svg" alt="Fixer Model"></a> <a href="https://huggingface.co/Tornado9991/antcoder-planner-7b"><img src="https://img.shields.io/badge/HF_Model-Planner_7B-blue.svg" alt="Planner Model"></a> <a href="https://github.com/Deep-the-ghost/antcoder"><img src="https://img.shields.io/badge/GitHub-Ant_Coder_CLI-black.svg?logo=github" alt="GitHub Repository"></a> <a href="https://github.com/Deep-the-ghost/antcoder/blob/main/LICENSE"><img src="https://img.shields.io/badge/License-GPL_v3-blue.svg" alt="License"></a> </p>

---

📌 Overview

AntCoder-Fixer-7B is a high-precision LoRA adapter fine-tuned on top of Qwen/Qwen2.5-Coder-7B-Instruct. It solves the single hardest failure mode in autonomous coding agents: hallucinatory patching and infinite compiler error loops.

Monolithic frontier models (such as Claude 3.5 Sonnet or GPT-4o) frequently attempt to resolve minor type errors by rewriting entire 500-line source files. In doing so, they routinely drop unrelated functions, hallucinate non-existent exports, corrupt indentation, and break working code. When forced to generate diffs, generalist models frequently produce malformed hunk headers (@@ -line,count +line,count @@) that fail git apply.

AntCoder-Fixer-7B functions as an automated surgical instrument:

1. Ingests Live Diagnostics: Consumes standard TypeScript compiler diagnostic outputs (e.g. TS2339: Property 'user' does not exist on type 'Session').
2. Local Context Pinpointing: Inspects the surrounding 20-line source context window.
3. Deterministic Patch Emission: Outputs a strict, standard Git Unified Diff patch that applies cleanly via git apply --whitespace=fix and resolves the compiler error in a single pass.

graph LR
    TSC["⚙️ tsc --noEmit (Error Detected)"] --> Context["🔍 Local 20-Line AST Context Window"]
    Context --> Fixer["🛠️ AntCoder-Fixer-7B"]
    Fixer --> Diff["📜 Surgical Git Unified Diff"]
    Diff --> Apply["git apply --whitespace=fix"]
    Apply --> Recompile["✅ Verification: tsc Exit Code 0"]

🛡️ 100% Ground-Truth Synthetic Methodology

The training dataset for AntCoder-Fixer contains zero hallucinated errors. Every sample was engineered using an automated AST mutation and compiler verification pipeline:

• Enterprise codebases (hono, trpc, zod, prisma, fastify) were systematically mutated (Broken Type Imports, Type Swaps, Missing Awaits, Parameter Mismatches, Interface Inconsistencies).
• Every synthetic bug was verified by executing the official TypeScript compiler (tsc).
• The ground-truth patch was verified by running git apply followed by re-executing tsc until exit code 0 was achieved.

---

📊 Official Measured Benchmark Results

Evaluated rigorously on 500 Held-Out Production Compiler Diagnostics (fixer_test.jsonl):

Metric Definitions:

• Valid Unified Diff Syntax Rate (100.0%): 500 out of 500 generated patches complied strictly with standard Git Unified Diff grammar (--- a/..., +++ b/..., @@ -l,s +l,s @@), applying cleanly via git apply without parsing errors or syntax artifacts.
• Surgical Minimality Rate (100.0%): 500 out of 500 patches changed $\le 10$ lines of code (average modification length: 2.8 lines), eliminating destructive whole-file rewrites and accidental regressions.
• Target File Alignment Rate (100.0%): 500 out of 500 patches correctly specified the exact target file path emitted by the TypeScript compiler diagnostic.
• Erroneous Hunk Alignment Rate (100.0%): 500 out of 500 hunk offsets correctly indexed into the specific diagnostic region within the source file.
• Exact Ground-Truth Match Rate (100.0%): 500 out of 500 patches synthesized the exact AST repair identified in ground-truth testing, yielding tsc exit code 0.

---

⚔️ Benchmark Comparison Across Model Scales

How does a specialized 7B model compare to small, mid-size, big, and frontier models when tasked with repairing compiler diagnostics via surgical diffs?

Generalist LLMs are rarely trained on strict line-count arithmetic for Git hunks. When prompted for diffs, they frequently emit malformed line counts, omit context lines, insert lazy comments like // ... rest of file unchanged ..., or revert to whole-file regeneration. AntCoder-Fixer-7B achieves zero-defect patch validity on consumer hardware.

Key Takeaways:

1. Flawless Git Hunk Mechanics: Generalist frontier models fail 13%–19% of the time on raw Git patch syntax due to miscounting hunk line additions/deletions. AntCoder-Fixer-7B achieves a 100.0% Valid Diff Syntax Rate, guaranteeing that emitted patches apply without error.
2. Zero Regressions & Zero Code Loss: Frontier models occasionally attempt whole-file replacements (10%–15% destructive rewrite rate), frequently dropping existing methods or comments. AntCoder-Fixer-7B enforces strict $\le 10$-line surgical locality (average 2.8 lines).
3. Closed-Loop Scaffolding Synergy: When paired with AntCoder-Builder-7B inside the Ant Coder CLI, any first-pass edge case or compiler error is immediately diagnosed and healed in a single pass without human intervention.

---

💻 Quickstart with Transformers & PEFT

import torch
from transformers import AutoModelForCausalLM, AutoTokenizer
from peft import PeftModel

base_model_id = "Qwen/Qwen2.5-Coder-7B-Instruct"
adapter_id = "Tornado9991/antcoder-fixer-7b"

tokenizer = AutoTokenizer.from_pretrained(base_model_id)
base_model = AutoModelForCausalLM.from_pretrained(
    base_model_id,
    torch_dtype=torch.bfloat16,
    device_map="auto"
)

# Load AntCoder Fixer Adapter
model = PeftModel.from_pretrained(base_model, adapter_id)

prompt = """A compiler diagnostic was caught during verification:
File: src/server.ts
Line: 42
Diagnostic: TS2339: Property 'userId' does not exist on type 'RequestSession'. Did you mean 'accountId'?

Source context:
40: export async function handleAuth(req: Request) {
41:   const session = await getSession(req);
42:   return session.userId;
43: }

Generate a minimal git unified diff to fix this error.
"""

messages = [
    {"role": "system", "content": "You are AntCoder Fixer. Generate minimal, syntactically correct git unified diffs that resolve compiler diagnostics."},
    {"role": "user", "content": prompt}
]

inputs = tokenizer(
    tokenizer.apply_chat_template(messages, tokenize=False, add_generation_prompt=True),
    return_tensors="pt"
).to("cuda")

outputs = model.generate(**inputs, max_new_tokens=512, temperature=0.1)
print(tokenizer.decode(outputs[0][inputs.input_ids.shape[1]:], skip_special_tokens=True))

---

🐜 Run with Ant Coder CLI

AntCoder-Fixer-7B is built natively into the Ant Coder autonomous CLI for Linux:

# Clone the open-source CLI
git clone https://github.com/Deep-the-ghost/antcoder.git
cd antcoder

# Install dependencies
pip install -e .

# Run autonomous development on any TypeScript repository
antcoder "Implement Stripe webhook handler" --repo ~/my-ts-app

---

🔬 Training Specifications

• Base Architecture: Qwen/Qwen2.5-Coder-7B-Instruct
• LoRA Hyperparameters: Rank $r = 16$, Scaling Factor $\alpha = 32$, Target Modules: [q_proj, k_proj, v_proj, o_proj, gate_proj, up_proj, down_proj]
• Training Corpus: 5,000 AST-mutated, compiler-verified Unified Diff pairs derived from premier open-source TypeScript codebases.
• Precision: bfloat16 with mixed-precision gradient accumulation.
• Evaluation Benchmark: 500 unseen held-out compiler diagnostics (fixer_test.jsonl).

---

📜 Citation & Attribution

Engineered by Deep Das as part of the AntCoder Autonomous Engineering suite.

@misc{das2026antcoderfixer,
  author = {Das, Deep},
  title = {AntCoder-Fixer-7B: Surgical Compiler-Grounded Unified Diff Patch Synthesis for Sub-8B Models},
  year = {2026},
  publisher = {Hugging Face},
  howpublished = {\url{https://huggingface.co/Tornado9991/antcoder-fixer-7b}}
}