langchain-best-practices

langchain-best-practices is a cursor rule for Cursor from tutumomo/MCP-civil-tools. It costs 103 tokens per session, scanned A, original, no licence file.

A set of LangChain coding guidelines that applies to Python files when enabled. LangChain is a software framework for building applications with language models.

In plain words
What is it for?
Guiding work in Python files that use LangChain.
Why use it?
It provides project-specific guidance for LangChain code. The description does not include the actual guidelines.

Cursor rule for Cursor

Written for Cursor: installed under .cursor/.

Good fit Guiding work in Python files that use LangChain.

Compare 6 cursor rules from other repositories ↓
Install with agentmods
npx agentmods add rules/tutumomo/mcp-civil-tools/langchain-best-practices
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.

Clone the repo
git clone --depth 1 https://github.com/tutumomo/MCP-civil-tools

Made for: Cursor.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for langchain-best-practices

README.md
[![agentmods](https://agentmods.dev/badge/rules/tutumomo/mcp-civil-tools/langchain-best-practices/github.svg)](https://agentmods.dev/rules/tutumomo/mcp-civil-tools/langchain-best-practices)
Your own site
<a href="https://agentmods.dev/rules/tutumomo/mcp-civil-tools/langchain-best-practices"><img src="https://agentmods.dev/badge/rules/tutumomo/mcp-civil-tools/langchain-best-practices/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for langchain-best-practices

Your own site · 80×15
<a href="https://agentmods.dev/rules/tutumomo/mcp-civil-tools/langchain-best-practices"><img src="https://agentmods.dev/badge/rules/tutumomo/mcp-civil-tools/langchain-best-practices.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 103 This file is loaded in full into every session.
When invoked 103 The same file — it is already loaded in full.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin unknown 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 5.1 $0.00103 $0.00103
Opus 5 $0.00051 $0.00051
Sonnet 5 $0.00021 $0.00021
Haiku 4.5 $0.00010 $0.00010

Measured 11d ago against content hash d392b90c63bb, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

langchain-best-practices 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 11d 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/langchain-best-practices.mdc · 19 lines

The source is not reproduced here

No licence file

A repository with no LICENSE is all rights reserved by default, so the body is not copied here. The metadata, the measurements and the link are.

Read it on GitHub

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. 11d ago First seen · 19 lines · 103 tokens per session scan A d392b90c63bb

Subscribe to this mod's changes

langchain-best-practices is a cursor rule published in the GitHub repository tutumomo/MCP-civil-tools (3 stars, last pushed 7mo ago), with no licence file. It adds 103 tokens to every session, about $0.0005 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 2026-08-31.