Big Plan Files Crash Cursor

yaser_alnajjar · February 15, 2026, 12:10pm

Where does the bug appear (feature/product)?

Cursor IDE

Describe the Bug

Hi!

I have a large plan file in .cursor/plans/ directory:
Around 250K characters
Around 4500 lines

I’m unable to open the file because Cursor IDE crashes when I open the file (the window becomes unresponsive, and MacOS tells me that I can either keep waiting or close the application).

I’m assuming it’s related to the rendering functionality for plan files since it was slow, but now it just crashes when the plan file got larger.

Steps to Reproduce

Clone this repo and try to open this file in Cursor (it will render it automatically since it’s inside .cursor directory):

github.com/yaseralnajjar/sifr

.cursor/plans/sifr_compiler_architecture_fa3c10ee.plan.md

main

---
name: Sifr Compiler Architecture
overview: Build "sifr", a compiled programming language with Python syntax and enforced typing that emits Rust source code, compiled via rustc into native binaries. The compiler is built in Rust, forking ruff's parser/AST crates and adding type checking, IR, and Rust codegen phases. TypeScript-inspired type system features (union/intersection types, literal types, full control-flow-based type narrowing) are first-class citizens. The end goal is a language capable of building web applications and general-purpose programs.
todos:
  - id: fork-parser
    content: "milestone_core_language: Fork ruff parser/AST crates (python_ast, python_parser) into crates/ with sifr_ prefix. Use git deps for infrastructure crates (text_size, source_file, python_trivia, python_literal). Set up Cargo workspace."
    status: completed
  - id: strip-ast
    content: "milestone_core_language: Strip the forked AST to only the nodes needed for milestone_core_language (function def, if/elif/else, assign, ann_assign, return, expr, basic expressions, literals). Remove IPython, match, async, with, try, import, etc."
    status: completed
  - id: type-system
    content: "milestone_core_language: Build sifr_type_system crate -- Type enum (Int, Float, Bool, Str, None, Function, Any, Never), type inference from initializers, type checking (binary ops, comparisons, function calls), subtyping rules."
    status: completed
  - id: hir
    content: "milestone_core_language: Build sifr_hir crate -- Typed IR with resolved names and types on every node. Name resolution (scopes). Ownership tracking (move vs copy)."
    status: completed
  - id: codegen
    content: "milestone_core_language: Build sifr_codegen crate -- Walk HIR and emit Rust source code. Type mapping (int->i64, str->String, etc.). Generate Cargo.toml + main.rs. Handle print() as println! macro."
    status: completed
  - id: driver

This file has been truncated. show original

Expected Behavior

It should be rendered without an issue.

Screenshots / Screen Recordings

Operating System

MacOS

Version Information

Version: 2.4.37
VSCode Version: 1.105.1
Commit: 7b9c34466f5c119e93c3e654bb80fe9306b6cc70
Date: 2026-02-12T23:15:35.107Z
Build Type: Stable
Release Track: Default
Electron: 39.2.7
Chromium: 142.0.7444.235
Node.js: 22.21.1
V8: 14.2.231.21-electron.0
OS: Darwin arm64 25.2.0

Does this stop you from using Cursor

Yes - Cursor is unusable (plan mode)

deanrie · February 15, 2026, 4:10pm

Hey, thanks for the report.

A few plan rendering crashes in Plan mode were fixed in recent 2.4.x updates, but those fixes clearly don’t cover a file this large. 250,000 characters is way above what the current plan renderer can handle reliably.

For now, you can try a couple of workarounds:

Rename the file extension from .plan.md to just .md so Cursor won’t trigger the special plan rendering, and you should at least be able to read and edit the raw content
Going forward, try splitting big plans into smaller, more focused files to stay under the rendering limit

Let me know if the rename trick works for you, and I’ll pass it along to the team.

yaser_alnajjar · February 15, 2026, 4:56pm

The workaround works to rename the extension of the file, thanks Dean!

It would be good if the renderer can deal with larger files in future since sometimes it might be better to have one plan file top down for specific tasks.

system · March 9, 2026, 4:56pm

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