Ars Contexta is a Claude Code plugin that creates a personalized knowledge system from a conversation about how someone thinks and works, using connected Markdown files, note-processing skills, hooks, navigation maps, and templates. It is for people who want an owned, persistent second brain tailored to their domain. The catalogue entries are its generated skills, hooks, agent, and plugin workflow.
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.
npx agentmods add skills/agenticnotetaking/arscontexta/add-domainnpx skills add agenticnotetaking/arscontexta --skill add-domaingit clone --depth 1 https://github.com/agenticnotetaking/arscontextaWrote 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.
[](https://agentmods.dev/skills/agenticnotetaking/arscontexta/add-domain)<a href="https://agentmods.dev/skills/agenticnotetaking/arscontexta/add-domain"><img src="https://agentmods.dev/badge/skills/agenticnotetaking/arscontexta/add-domain.svg" alt="Measured on agentmods" height="20"></a>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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5 | $0.00038 | $0.03516 |
| Opus 5 | $0.00019 | $0.01758 |
| Sonnet 5 | $0.00008 | $0.00703 |
| Haiku 4.5 | $0.00004 | $0.00352 |
Grade A, and why
add-domain 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 5d 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.
How it starts
The opening of the file, as written. The whole thing — 442 lines — stays where its author put it; the contents beside it link to each section on GitHub.
You are extending an existing knowledge system with a new domain. This is composition, not replacement. The new domain must coexist with existing domains while maintaining its own vocabulary, schema, and processing patterns. The shared graph (wiki links, hub MOC, description fields) connects everything.
Your Task
Add a new knowledge domain: $ARGUMENTS
Reference Files
Read these during derivation phases:
Composition rules:
${CLAUDE_PLUGIN_ROOT}/reference/derivation-validation.md-- Test 4 (Multi-Domain Composition) validates the pattern${CLAUDE_PLUGIN_ROOT}/reference/three-spaces.md-- three-space architecture (shared across domains)${CLAUDE_PLUGIN_ROOT}/reference/interaction-constraints.md-- coherence validation for domain config
Domain configuration:
${CLAUDE_PLUGIN_ROOT}/reference/vocabulary-transforms.md-- domain-native term mapping${CLAUDE_PLUGIN_ROOT}/reference/tradition-presets.md-- pre-validated domain configurations${CLAUDE_PLUGIN_ROOT}/reference/use-case-presets.md-- 3 presets with configurations${CLAUDE_PLUGIN_ROOT}/reference/dimension-claim-map.md-- research backing for dimension positions${CLAUDE_PLUGIN_ROOT}/reference/failure-modes.md-- domain vulnerability matrix
Validation:
${CLAUDE_PLUGIN_ROOT}/reference/kernel.yaml-- the 12 non-negotiable primitives${CLAUDE_PLUGIN_ROOT}/reference/validate-kernel.sh-- kernel validation script
PHASE 1: Scan Existing System
Automated. Understand what exists before adding to it.
1a. Read system configuration
Read ops/derivation.md for:
- Current dimension positions
- Vocabulary mapping
- Platform and automation level
- Active feature blocks
Read ops/config.yaml for live configuration values.
1b. Inventory existing domains
Identify all current knowledge domains:
- Primary notes folder and its domain vocabulary
- Any existing secondary domains (folders, templates, MOCs)
- Schema fields in use per domain
1c. Identify dimension types
What ships with it
1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
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.
- 5d ago First seen · 442 lines · 38 tokens per session scan A 5c9517f20916
add-domain is a skill published in the GitHub repository agenticnotetaking/arscontexta (3,486 stars, last pushed 6mo ago), licensed MIT. It adds 38 tokens to every session and 3,516 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.
Other skills, from other repositories
llm-wiki
Build and maintain an LLM-curated personal knowledge base — the "LLM Wiki" pattern from Andrej Karpathy's April 2026 gist. Use this skill whenever the user wants to ingest a source (paper, article, transcript, PDF, notes) into a persistent compounding knowledge base, ask a question against accumulated notes, lint or…
migrate
Scan the project and migrate existing documentation into OKF format. Use when the user wants to populate the knowledge base from existing docs, README, schemas, API specs, runbooks, or any structured project knowledge. Trigger on "migrate to okf", "populate the knowledge base", "scan my docs", "convert docs to okf"…
ingest
Create or update a single OKF concept file from raw input. Use when the user wants to document a specific table, metric, API, service, or concept in the knowledge base — even if they say "add this to the okf", "documenta essa tabela", "cria um conceito pra isso", "adiciona no knowledge base", "register this API", or…
claude-mega-brain
OKF knowledge navigation. ALWAYS use this skill the moment a block appears in session context — it means the project has documented concepts and you must consult them before answering questions about data, schemas, metrics, APIs, or systems. Also trigger when the user asks about a table, column, metric definition…
init
Initialize OKF knowledge base files in the current project. Use when the user wants to start documenting their project for claude-mega-brain, or when the user says "init mega brain", "setup the knowledge base", "cria o okf", "inicializa o mega brain", "quero usar o mega brain", "criar a estrutura do knowledge base"…
remember
Capture a durable learning into the personal Trove. Use when the user says remember this, note this, save to trove, add to my trove, or when a session surfaces a decision, gotcha, convention/preference, or external reference worth keeping. Writes one atomic entry file and updates INDEX.md.