{

"title": "What your linter doesn't tell you: structural risk in legacy Python codebases",
"body": "You inherit a 50k-line Python monolith. pylint gives you style warnings. mypy catches type errors. But where's the actual danger — the function that's 80 lines, called by 15 callers, with 6 levels of nesting?\n\nLinters check text. They don't understand code structure.\n\nThis is the gap code-atlas-py fills. Deterministic, offline, sub-second code intelligence.\n\n---\n\n### Before: grep + manual trace\n\n

bash\ngrep -r \"process_event\" src/ | wc -l\n# 27 files, guess which one is the root cause\n

\n\nYou open files, trace call chains, build a mental map. For a 50k-line codebase, that's an afternoon. For 200k, a week.\n\n### After: atlas scan\n\n

bash\npip install code-atlas-py\natlas scan src/\n

\n\n0.2 seconds later:\n\n

text\nTop risk functions (complexity × coupling × instability):\n───────────────────────────────────────────────────────────\n 1. src/events.py::process_event risk: 0.87 (cyclo=14, fans=9, instability=0.73)\n 2. src/billing.py::invoice_totals risk: 0.72 (cyclo=11, fans=6, instability=0.68)\n 3. src/api.py::handle_request risk: 0.65 (cyclo=8, fans=7, instability=0.55)\n

\n\nNo guesswork. The function with 14 cyclomatic complexity, called by 9 different modules, is where every bug starts.\n\n---\n\n### Why this matters for refactoring\n\nI ran this on an internal tool before refactoring. The worst offender was process_event — a 120-line function with nine callers and three mutable global state mutations.\n\nWithout atlas, I'd have refactored the wrong function first. The team would have reviewed clean style and still merged a regression.\n\nWith atlas, I split process_event in 20 minutes. Test coverage stayed green because I understood the full call graph before touching a line.\n\n---\n\n### What it is / isn't\n\n*Is:* A fast, deterministic code-analysis CLI. Builds a call graph, dependency graph, and risk scores using pure Python AST parsing. 100% offline. Same answer every run.\n\n*Isn't:* An LLM. Not a linter. Not a type checker. It doesn't tell you how to fix — it tells you where the risk is.\n\n---\n\n### The CLI in practice\n\n

bash\n# One-shot scan\natlas scan .\n\n# Ask questions about a symbol\natlas ask process_event\n# → "Defined in src/events.py:42. Called by: billing.py, api.py, scheduler.py (9 total)\n# Complexity: 14 (high). 2 mutable globals modified.\"\n\n# Interactive HTML report — clickable call graph\natlas html --open\n

\n\nWorks on any Python project. No config file. No server. No API key.\n\n---\n\n*Pricing:* Free Core Engine for small teams. Pro $12/mo (7 modules), Enterprise $29/mo (12 modules).\n\n*Repo:* https://github.com/mete-dotcom/code-atlas\n**Site:** https://massiron.com/atlas",
"tags": ["python", "legacy-code", "refactoring", "code-intelligence", "devtools"],
"estimated_chars": 2157
}
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