api_security

Security rules for building APIs in Web3 applications, which are applications that interact with blockchain networks. They focus on protecting sensitive operations, data, and digital assets.

In plain words
What is it for?
Use them when designing or reviewing Web3 API endpoints, access controls, data handling, and asset-related operations.
Why use it?
They help prevent API weaknesses that could expose information, allow unauthorised actions, or put assets at risk.

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/0xjcf/mcp_codeanalysis/api_security
Clone the repo
git clone --depth 1 https://github.com/0xjcf/MCP_CodeAnalysis

Made for: Cursor.

Per session 1,905 This file is loaded in full into every session.
When invoked 1,905 The same file — it is already loaded in full.
Security scan A 0 findings. Scan, not verified.
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 $0.01905 $0.01905
Opus 5 $0.00953 $0.00953
Sonnet 5 $0.00381 $0.00381
Haiku 4.5 $0.00191 $0.00191

Measured 2d ago against content hash 1bbb331ddb90, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

api_security 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 2d 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/web3_security/api_security.mdc · 262 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. 2d ago First seen · 262 lines · 1,905 tokens per session scan A 1bbb331ddb90

Subscribe to this mod's changes

api_security is a cursor rule published in the GitHub repository 0xjcf/MCP_CodeAnalysis (7 stars, last pushed 7mo ago), with no licence file. It adds 1,905 tokens to every session, about $0.0095 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.