blockchain-core

blockchain-core is a skill for Claude Code, Codex from j4flmao/agent-skills. It costs 175 tokens per session (5,863 once invoked), scanned A, original, MIT.

A guide to the core software of a blockchain, including how nodes communicate, agree on blocks, store state, and process transactions. Consensus is the method nodes use to agree on the shared history.

In plain words
What is it for?
Use it to analyze or design consensus, peer-to-peer networking, mempools, state machines, node software, and blockchain data structures.
Why use it?
It helps reason about security, performance, finality, transaction pools, and the economic incentives behind a blockchain network.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it to analyze or design consensus, peer-to-peer networking, mempools, state machines, node software, and blockchain data structures.

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Install with agentmods
npx agentmods add skills/j4flmao/agent-skills/blockchain-core
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.

Any agent
npx skills add j4flmao/agent-skills --skill blockchain-core
Clone the repo
git clone --depth 1 https://github.com/j4flmao/agent-skills

Made for: Claude Code, Codex.

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 blockchain-core

README.md
[![agentmods](https://agentmods.dev/badge/skills/j4flmao/agent-skills/blockchain-core/github.svg)](https://agentmods.dev/skills/j4flmao/agent-skills/blockchain-core)
Your own site
<a href="https://agentmods.dev/skills/j4flmao/agent-skills/blockchain-core"><img src="https://agentmods.dev/badge/skills/j4flmao/agent-skills/blockchain-core/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 blockchain-core

Your own site · 80×15
<a href="https://agentmods.dev/skills/j4flmao/agent-skills/blockchain-core"><img src="https://agentmods.dev/badge/skills/j4flmao/agent-skills/blockchain-core.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 175 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 5,863 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • NVIDIA SkillSpector pass 7 Sept 2026
How audits are shown
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 5.1 $0.00175 $0.05863
Opus 5.5 $0.00070 $0.02345
Sonnet 5.5 $0.00035 $0.01173
Haiku 4.5 $0.00017 $0.00586

Measured today against content hash b1c9212169b7, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

blockchain-core 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 today.

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.

skills/blockchain/blockchain-core/SKILL.md · 544 lines

How it starts

The opening of the file, as written. The whole thing — 544 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Blockchain Core

Purpose

Guide core blockchain protocol engineering covering consensus mechanisms, state machine design, P2P networking, mempool architecture, MEV economics, and node implementation. This skill enables building and analyzing blockchain protocols from first principles.

Agent Protocol

Trigger

"blockchain core", "consensus mechanism", "proof of work", "proof of stake", "PoW", "PoS", "DAG consensus", "Avalanche consensus", "Snowman", "Hashgraph", "gas", "staking", "MEV", "miner extractable value", "PBS", "proposer builder separation", "MEV-Boost", "ePBS", "blockchain node", "C++ blockchain", "Go blockchain", "blockchain protocol", "mempool", "transaction pool", "block finality", "blockchain data structure", "merkle tree", "cryptography blockchain", "p2p blockchain", "blockchain state machine", "economic security", "fork choice rule", "finality gadget", "light client"

Input Context

  • Consensus family (Nakamoto/BFT/hybrid/DAG)
  • State machine model (UTXO/account/WASM)
  • Network topology (permissionless/permissioned/hybrid)
  • Performance requirements (TPS, finality time, node requirements)
  • Security model (adversary threshold, economic security assumptions)
  • Implementation language (Go/Rust/C++)

Output Artifact

Protocol architecture specification: consensus mechanism with fork choice rule, state machine design, network layer architecture, mempool policy, security analysis, implementation plan.

Response Format

  1. Architecture overview: consensus family + state model + network topology + finality model
  2. Key mechanisms: fork choice rule, block production, validation, finality
  3. State machine: UTXO or account model, state transition function, state storage
  4. Network layer: gossip protocol, peer discovery, block propagation
  5. Security & economics: adversary model, economic security, MEV exposure
  6. Implementation guidance: language choice, database backend, key data structures

Completion Criteria

  • Consensus mechanism specification includes: finality type, fork choice rule, adversary threshold
  • State machine design specifies state transition function and storage layout
  • Network layer defines gossip protocol and peer discovery mechanism
  • Security analysis covers: 51% attacks, long-range attacks, selfish mining, eclipse attacks
  • Implementation plan specifies: language, database, networking library, testing approach

Read the full file on GitHub · 544 lines

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. today Changed · -4 lines b1c9212169b7
  2. 1mo ago First seen · 548 lines · 175 tokens per session scan A d85ba34d3d7e

Subscribe to this mod's changes

blockchain-core is a skill published in the GitHub repository j4flmao/agent-skills (34 stars, last pushed today), licensed MIT. It adds 175 tokens to every session and 5,863 once invoked, about $0.0007 per session on Opus 5.5. 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 2026-09-03.

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