knowledge-extraction

knowledge-extraction is a skill for Claude Code, Codex from kitchen-engineer42/joharnessburg. It costs 84 tokens per session (1,849 once invoked), scanned A, original, MIT.

A knowledge-processing phase that turns text chunks into structured entries matching a project's schema. It uses multiple workers and combines their results into a canonical state for later rewriting.

In plain words
What is it for?
Use it after a chunking phase to extract project knowledge from chunk files, record the results as events, and prepare them for the knowledge-rewrite phase.
Why use it?
It makes extracting facts from a large collection of documents manageable and consistent, instead of processing the whole corpus in one pass.

Skill for Claude CodeCodex

Installs and runs on its own, but its text points at files inside its plugin — anything it tells you to read at a ${CLAUDE_PLUGIN_ROOT} path is only there once the plugin is installed. Installing the plugin gets both.

Part of the john plugin — 28 skills, 5 commands, 5 agents, 3 hooks shipped together

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/kitchen-engineer42/joharnessburg/knowledge-extraction
Any agent
npx skills add kitchen-engineer42/joharnessburg --skill knowledge-extraction
Clone the repo
git clone --depth 1 https://github.com/kitchen-engineer42/joharnessburg

Made for: Claude Code, Codex.

Or install john, the plugin that ships this one along with the rest of its 28 skills, 5 commands, 5 agents, 3 hooks.

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 knowledge-extraction

README.md
[![agentmods](https://agentmods.dev/badge/skills/kitchen-engineer42/joharnessburg/knowledge-extraction.svg)](https://agentmods.dev/skills/kitchen-engineer42/joharnessburg/knowledge-extraction)
Your own site
<a href="https://agentmods.dev/skills/kitchen-engineer42/joharnessburg/knowledge-extraction"><img src="https://agentmods.dev/badge/skills/kitchen-engineer42/joharnessburg/knowledge-extraction.svg" alt="Measured on agentmods" height="20"></a>
Per session 84 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,849 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 $0.00084 $0.01849
Opus 5 $0.00042 $0.00924
Sonnet 5 $0.00017 $0.00370
Haiku 4.5 $0.00008 $0.00185

Measured 5d ago against content hash 826cb56a9f85, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-05, from the pricing page.

Security

Grade A, and why

knowledge-extraction 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.

plugins/joharnessburg/skills/knowledge-extraction/SKILL.md · 112 lines

How it starts

The opening of the file, as written. The whole thing — 112 lines — stays where its author put it; the contents beside it link to each section on GitHub.

knowledge-extraction

The phase where chunks become entries. This is where the vertical axis of John's matrix earns its keep — hundreds of subagents in parallel, each processing one chunk, each emitting events the reducer folds into canonical state. Without subagent fan-out, this phase doesn't scale.

Where the work happens

  • Inputs: <project>/.john/chunks/<chunk-id>.md + <project>/.john/chunks/chunks_index.json (from [[chunking]])
  • Schema reference: PLAN.md app-type definition section (per [[schema-design]])
  • Outputs: subagents emit to <project>/.john/events/extract/<chunk-id>/<subagent-id>-*.json (one file per event; exact event shapes and filename suffixes are in the knowledge-extractor agent definition); reducer (${CLAUDE_PLUGIN_ROOT}/scripts/reduce_events.py extract) folds to <project>/.john/checkpoints/extract/state.json; canonical state then drives [[knowledge-rewrite]].

The MECE sweep

Extract "everything there is" OR "everything needed for what" — which one depends on the project's intent. Decide that early and let it shape the sweep.

  • Comprehensive sweep: "extract everything there is in this corpus that matches the schema." Right for encyclopedic projects, regulations, broad knowledge bases.
  • Goal-directed sweep: "extract everything needed to answer X." Right for narrow apps where coverage outside the goal is wasteful.

Either way, MECE applies to coverage within the chosen scope: don't extract the same entry twice; don't leave the scope partially covered. Dedup across chunks happens later, in the rewrite phase (see [[knowledge-rewrite]]'s two-tier dedup) — the shipped reducer folds events without deduplicating; your job is to give that pipeline good raw events.

Fan-out per chunk

For each chunk, dispatch a subagent. Brief them comprehensively (per [[subagent-dispatch]]'s checklist):

  1. Project intent (from PLAN.md top).
  2. The chunk they're processing — the chunk file path or contents.
  3. The schema reference — what an entry looks like, what fields, what cross-link semantics.
  4. The event log target — where to write events (<project>/.john/events/extract/<chunk-id>/).
  5. What to return — a one-line digest. No raw extracted content in the digest; that's in the event log.
  6. What NOT to do — don't write canonical state directly; don't ask the user; don't try to dedupe across chunks (the reducer does that).

Read the full file on GitHub · 112 lines

Files

What ships with it

3 files 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.

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. 5d ago First seen · 112 lines · 84 tokens per session scan A 826cb56a9f85

Subscribe to this mod's changes

knowledge-extraction is a skill published in the GitHub repository kitchen-engineer42/joharnessburg (9 stars, last pushed 1mo ago), licensed MIT. It adds 84 tokens to every session and 1,849 once invoked, about $0.0004 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.

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