mod-003b-docstring-must-use-raw-string-prefix

A documentation rule for Python model and method docstrings. It requires raw triple-double-quoted strings so backslashes used in LaTeX mathematics are preserved for Sphinx, a Python documentation generator.

In plain words
What is it for?
Use it when writing Python docstrings that contain LaTeX notation and are processed by Sphinx.
Why use it?
Without the raw-string prefix, Python may interpret LaTeX backslashes as escape sequences and the generated documentation can render incorrectly.

Cursor rule for Cursor

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add rules/nvidia/physicsnemo/mod-003b-docstring-must-use-raw-string-prefix
Clone the repo
git clone --depth 1 https://github.com/NVIDIA/physicsnemo

Made for: Cursor.

Per session 31 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 338 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00031 $0.00338
Opus 5 $0.00015 $0.00169
Sonnet 5 $0.00006 $0.00068
Haiku 4.5 $0.00003 $0.00034

Measured 3d ago against content hash 432c1fb1b648, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

mod-003b-docstring-must-use-raw-string-prefix scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 3d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

.cursor/rules/mod-003b-docstring-must-use-raw-string-prefix.mdc · 55 lines

What it actually says

When writing docstrings, rule MOD-003b must be followed. Explicitly reference "Following rule MOD-003b, which requires docstrings to be prefixed with r"""..." when explaining docstring format.

MOD-003b: Docstring must use raw string prefix r"""

Description:

Each docstring should be prefixed with r""" (not """ or '''). The r prefix creates a raw string that prevents Python from interpreting backslashes, which is essential for LaTeX math notation to render correctly in Sphinx documentation.

Rationale:

LaTeX commands in docstrings use backslashes (e.g., \math, \text). Without the raw string prefix, Python interprets these as escape sequences, breaking the documentation rendering.

Example:

class MyModel(Module):
    r"""
    A model with LaTeX notation.

    Parameters
    ----------
    dim : int
        Dimension :math:`D` of input features.
    """
    pass

Anti-pattern:

# WRONG: Using ''' instead of r"""
class MyModel(Module):
    '''
    A model with LaTeX notation.
    '''
    pass

# WRONG: Missing 'r' prefix
class MyModel(Module):
    """
    Parameters with shape :math:`(B, D)`  # Won't render correctly
    """
    pass
Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 3d ago First seen · 55 lines · 31 tokens per session scan A 432c1fb1b648

Subscribe to this mod's changes

mod-003b-docstring-must-use-raw-string-prefix is a cursor rule published in the GitHub repository NVIDIA/physicsnemo (3,211 stars, last pushed yesterday), licensed Apache-2.0. It adds 31 tokens to every session and 338 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.