cortex-prompt

cortex-prompt is a skill for Claude Code from tonone-ai/tonone. It costs 55 tokens per session (2,225 once invoked), scanned A, original, MIT.

A prompt-package builder for AI systems that creates the instructions, examples, output format, edge-case rules, and evaluation criteria. A prompt is the text that tells an AI model what to do and how to respond.

In plain words
What is it for?
Use it to write or improve system prompts, add few-shot examples, define structured outputs, handle unusual inputs, and set criteria for judging responses.
Why use it?
It replaces scattered prompt-writing guidance with a complete package that can be used and tested. It also checks existing prompts, AI providers, and evaluation tools in the project.

Skill for Claude Code

Written for Claude Code: allowed-tools in frontmatter. Also seen: names the TodoWrite tool; mentions Claude Code.

Part of the engineering-team plugin — 80 skills shipped together

Good fit Use it to write or improve system prompts, add few-shot examples, define structured outputs, handle unusual inputs, and set criteria for judging responses.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/tonone-ai/tonone/cortex-prompt
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 tonone-ai/tonone --skill cortex-prompt
Clone the repo
git clone --depth 1 https://github.com/tonone-ai/tonone

Made for: Claude Code.

Or install engineering-team, the plugin that ships this one along with the rest of its 80 skills.

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 cortex-prompt

README.md
[![agentmods](https://agentmods.dev/badge/skills/tonone-ai/tonone/cortex-prompt/github.svg)](https://agentmods.dev/skills/tonone-ai/tonone/cortex-prompt)
Your own site
<a href="https://agentmods.dev/skills/tonone-ai/tonone/cortex-prompt"><img src="https://agentmods.dev/badge/skills/tonone-ai/tonone/cortex-prompt/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 cortex-prompt

Your own site · 80×15
<a href="https://agentmods.dev/skills/tonone-ai/tonone/cortex-prompt"><img src="https://agentmods.dev/badge/skills/tonone-ai/tonone/cortex-prompt.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 55 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,225 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 $0.00055 $0.02225
Opus 5.5 $0.00022 $0.00890
Sonnet 5.5 $0.00011 $0.00445
Haiku 4.5 $0.00006 $0.00222

Measured 17d ago against content hash 0cc41f9d9ceb, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

cortex-prompt 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 17d 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.

bundle/engineering-team/skills/cortex-prompt/SKILL.md · 247 lines

How it starts

The opening of the file, as written. The whole thing — 247 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Build a Production-Ready Prompt

You are Cortex — the ML/AI engineer on the Engineering Team. Given a task description, produce the complete prompt package: system prompt, user template, few-shot examples, output schema, edge case handling, and eval criteria. Write the artifact — don't coach the human to write it.

Follow the output format defined in docs/output-kit.md — 40-line CLI max, box-drawing skeleton, unified severity indicators, compressed prose.

Step 0: Scan for Context

Before asking anything, check what already exists:

# Existing prompts
find . -type f -name "system.txt" -o -name "system_prompt*" -o -name "*prompt*.txt" -o -name "*prompt*.yaml" 2>/dev/null | head -10
grep -rl "SYSTEM_PROMPT\|system_message\|system.*prompt" --include="*.py" --include="*.ts" --include="*.js" . 2>/dev/null | head -10

# LLM provider and SDK
cat requirements.txt 2>/dev/null | grep -iE "anthropic|openai|google-generativeai|cohere|langchain|llamaindex"
cat pyproject.toml 2>/dev/null | grep -iE "anthropic|openai|google-generativeai|cohere"
cat package.json 2>/dev/null | grep -iE "anthropic|openai|@google"

# Existing eval or test infrastructure
find . -type d -name "evals" -o -name "prompts" 2>/dev/null

Note: existing prompt patterns, provider, versioning conventions.

Step 1: Clarify the Task (Minimal)

Understand the task before writing the prompt. If the user hasn't provided this, ask once — don't iterate:

  1. What does the LLM need to do? (classify, extract, summarize, generate, transform, converse)
  2. What are 3–5 example input/output pairs? Real examples beat abstract descriptions.
  3. What does failure look like? (wrong format, hallucination, refusal, verbosity, wrong answer)
  4. What's the volume and latency budget? (determines model tier — Haiku vs Sonnet vs Opus)

If the user can't provide examples, generate plausible ones and validate before proceeding.

Step 2: Select the Model Tier

Pick the cheapest model that can reliably do the task:

Read the full file on GitHub · 247 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. 17d ago First seen · 247 lines · 55 tokens per session scan A 0cc41f9d9ceb

Subscribe to this mod's changes

cortex-prompt is a skill published in the GitHub repository tonone-ai/tonone (76 stars, last pushed 9d ago), licensed MIT. It adds 55 tokens to every session and 2,225 once invoked, about $0.0002 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 2026-09-27.

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