architecture

architecture is a skill for Claude Code from mirkosertic/MCPLuceneServer. It costs 36 tokens per session (1,564 once invoked), scanned A, original, Apache-2.0.

Technical documentation describing how a software system is structured and why it works that way. It covers components such as the Java SDK, Lucene search, and document crawling.

In plain words
What is it for?
Answer architecture questions, explain system internals, document processing patterns, and support planning for significant modifications.
Why use it?
It helps developers understand existing design decisions and internal processing before planning substantial changes.

Skill for Claude Code

Written for Claude Code: allowed-tools in frontmatter.

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 skills/mirkosertic/mcpluceneserver/architecture
Any agent
npx skills add mirkosertic/MCPLuceneServer --skill architecture
Clone the repo
git clone --depth 1 https://github.com/mirkosertic/MCPLuceneServer

Made for: Claude Code.

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 architecture

README.md
[![agentmods](https://agentmods.dev/badge/skills/mirkosertic/mcpluceneserver/architecture.svg)](https://agentmods.dev/skills/mirkosertic/mcpluceneserver/architecture)
Your own site
<a href="https://agentmods.dev/skills/mirkosertic/mcpluceneserver/architecture"><img src="https://agentmods.dev/badge/skills/mirkosertic/mcpluceneserver/architecture.svg" alt="Measured on agentmods" height="20"></a>
Per session 36 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,564 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 5.1 $0.00036 $0.01564
Opus 5 $0.00018 $0.00782
Sonnet 5 $0.00007 $0.00313
Haiku 4.5 $0.00004 $0.00156

Measured 6d ago against content hash 828dca1781c0, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

architecture 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 6d 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.

.claude/skills/architecture/SKILL.md · 152 lines

How it starts

The opening of the file, as written. The whole thing — 152 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Architecture Deep Dive

System Overview

┌─────────────────────────────────────────────────────┐
│           Claude Desktop / MCP Client               │
└────────────────┬────────────────────────────────────┘
                 │ STDIO Transport (JSON-RPC)
                 ▼
┌─────────────────────────────────────────────────────┐
│           MCP Java SDK (STDIO Transport)            │
│  ┌──────────────────────────────────────────────┐   │
│  │        LuceneSearchTools (MCP Tools)         │   │
│  └──────────────────────────────────────────────┘   │
└─────────┬───────────────────────────┬───────────────┘
          │                           │
          ▼                           ▼
┌──────────────────────┐    ┌──────────────────────┐
│  LuceneIndexService  │    │ DocumentCrawler      │
│  - Search & Index    │    │ Service              │
│  - NRT Manager       │    │ - File Discovery     │
│  - Admin Operations  │    │ - Content Extraction │
└──────────┬───────────┘    └──────────┬───────────┘
           │                           │
           ▼                           ▼
┌─────────────────────────────────────────────────────┐
│              Apache Lucene 10.3 + Apache Tika       │
└─────────────────────────────────────────────────────┘

Design Decisions

Why Plain Java (no Spring)?

  • Fast startup (~1 second) - critical for MCP subprocess
  • Smaller JAR (~45MB)
  • Direct control over lifecycle
  • Trade-off: Manual dependency wiring in LuceneserverApplication.java

Why STDIO Transport?

  • Required for Claude Desktop integration
  • No network security concerns
  • Consequence: Console logging MUST be disabled in production (deployed profile)

Why Multi-Analyzer Pipeline?

The server uses multiple analyzer chains optimized for different search patterns. Each document is indexed with several shadow fields, each using a different analyzer:

  • UnicodeNormalizingAnalyzer: Primary content field with NFKC normalization, diacritic folding, ligature expansion
  • ReverseUnicodeNormalizingAnalyzer: Reversed tokens for efficient leading wildcard queries (*vertrag)
  • OpenNLPLemmatizingAnalyzer: Dictionary-based lemmatization for German and English (handles irregular forms)
  • GermanTransliteratingAnalyzer: Maps ASCII digraphs to umlauts (Mueller→Müller)

Read the full file on GitHub · 152 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. 6d ago First seen · 152 lines · 36 tokens per session scan A 828dca1781c0

Subscribe to this mod's changes

architecture is a skill published in the GitHub repository mirkosertic/MCPLuceneServer (5 stars, last pushed yesterday), licensed Apache-2.0. It adds 36 tokens to every session and 1,564 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 2026-08-31.