evo-parallel-index-building

evo-parallel-index-building is a skill for Claude Code, Codex from OpenLAIR/OpenSkill. It costs 52 tokens per session (429 once invoked), scanned A, original, Apache-2.0.

A parallel text-index builder that creates a TF-IDF inverted index using a MapReduce-style process. An inverted index maps words to the documents that contain them so searches can find matches quickly.

In plain words
What is it for?
Use it to split documents into chunks, calculate word statistics, merge worker results, and build a searchable TF-IDF index.
Why use it?
It divides index construction into worker tasks and combines their results, reducing the need to build a large index in one process. It reports timing and basic index size information.

Skill for Claude CodeCodex

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

Good fit Use it to split documents into chunks, calculate word statistics, merge worker results, and build a searchable TF-IDF index.

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Install with agentmods
npx agentmods add skills/openlair/openskill/evo-parallel-index-building
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 OpenLAIR/OpenSkill --skill evo-parallel-index-building
Clone the repo
git clone --depth 1 https://github.com/OpenLAIR/OpenSkill

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 evo-parallel-index-building

README.md
[![agentmods](https://agentmods.dev/badge/skills/openlair/openskill/evo-parallel-index-building/github.svg)](https://agentmods.dev/skills/openlair/openskill/evo-parallel-index-building)
Your own site
<a href="https://agentmods.dev/skills/openlair/openskill/evo-parallel-index-building"><img src="https://agentmods.dev/badge/skills/openlair/openskill/evo-parallel-index-building/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 evo-parallel-index-building

Your own site · 80×15
<a href="https://agentmods.dev/skills/openlair/openskill/evo-parallel-index-building"><img src="https://agentmods.dev/badge/skills/openlair/openskill/evo-parallel-index-building.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 52 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 429 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.
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 $0.00052 $0.00429
Opus 5 $0.00026 $0.00215
Sonnet 5 $0.00010 $0.00086
Haiku 4.5 $0.00005 $0.00043

Measured yesterday against content hash 9da6b52bf085, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade A, and why

evo-parallel-index-building 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 yesterday.

The scan reads SKILL.md. This mod also ships 1 executable file (scripts/utils.py), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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.

tasks-evolved/parallel-tfidf-search/environment/skills/evo-parallel-index-building/SKILL.md · 47 lines

What it actually says

Parallel TF-IDF Index Building

Overview

Parallelizes TF-IDF index construction using MapReduce:

  1. Chunk: Split documents into chunks
  2. Map: Workers compute local TF and DF per chunk
  3. Reduce: Merge partial results (Counter.update for DF, dict.update for TF)
  4. Finalize: Compute IDF and TF-IDF scores, build inverted index

Key Formulas (matching sequential.py)

  • TF(t,d) = count(t in d) / total_tokens(d)
  • IDF(t) = log(N / df(t)) + 1
  • TF-IDF = TF * IDF
  • Posting lists sorted by score descending

Usage

import sys
sys.path.insert(0, '/app/environment/skills/evo-parallel-index-building/scripts')
from utils import (
    chunk_documents,
    map_index_chunk,
    merge_partial_results,
    finalize_tfidf_scores,
    build_tfidf_index_parallel,
    tokenize,
    compute_term_frequencies
)

# Build index
index_dict, elapsed, num_docs, vocab_size = build_tfidf_index_parallel(
    documents, num_workers=4, chunk_size=500
)

Functions

  • chunk_documents(documents, chunk_size=500) - Split docs into (doc_id, text) chunks
  • map_index_chunk(chunk) - Worker: compute local TF dict and DF Counter
  • merge_partial_results(partial_results) - Merge all local TF/DF/vocab
  • finalize_tfidf_scores(all_doc_tf, global_df, vocabulary, num_documents) - Compute IDF and build inverted index
  • build_tfidf_index_parallel(documents, num_workers=None, chunk_size=500) - Full pipeline
Files

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.

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. yesterday First seen · 47 lines · 52 tokens per session scan A 9da6b52bf085

Subscribe to this mod's changes

evo-parallel-index-building is a skill published in the GitHub repository OpenLAIR/OpenSkill (90 stars, last pushed 2d ago), licensed Apache-2.0. It adds 52 tokens to every session and 429 once invoked, about $0.0003 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 2026-09-11.