kortex AGENTS.md

Repository instructions for kortex, a project whose add-ons are shipped in formats for Claude Code, Codex, and Junie. It documents where skills, agents, manifests, marketplace indexes, and related files belong.

In plain words
What is it for?
It helps developers add or update skills and agents, maintain each host's manifest and marketplace entry, regenerate agent copies, and write request-matching skill descriptions.
Why use it?
It prevents changes from being made for only one host, which could leave the other versions out of sync. It also clarifies which files are shipped and which are only internal documentation.

Instructions file for CodexOpenCode

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 instructions/heapy/kortex/agents-md
Clone the repo
git clone --depth 1 https://github.com/Heapy/kortex

Made for: Codex, OpenCode.

Per session 1,306 This file is loaded in full into every session.
When invoked 1,306 The same file — it is already loaded in full.
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 $0.01306 $0.01306
Opus 5 $0.00653 $0.00653
Sonnet 5 $0.00261 $0.00261
Haiku 4.5 $0.00131 $0.00131

Measured yesterday against content hash 3975e7a21296, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

kortex AGENTS.md 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.

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.

AGENTS.md · 91 lines

How it starts

The opening of the file, as written. The whole thing — 91 lines — stays where its author put it; the contents beside it link to each section on GitHub.

kortex

One tree, three hosts. The same skills ship as Claude Code plugins, Codex plugins, and Junie extensions, so every change has to be made in each host's manifest, not just the one you are looking at.

Layout

Path What it is
plugins/<plugin>/skills/<skill>/SKILL.md the skill itself: YAML frontmatter (name, description) then the body
plugins/<plugin>/agents/<agent>.md a subagent: YAML frontmatter then the prompt; loaded by Claude Code and Junie
plugins/<plugin>/plugin.json portable Agent Plugins manifest; no host reads it yet
plugins/<plugin>/.claude-plugin/plugin.json Claude Code manifest
plugins/<plugin>/.codex-plugin/plugin.json Codex manifest
plugins/<plugin>/extension.json Junie manifest
.claude-plugin/marketplace.json Claude Code marketplace index
.junie-extension/marketplace.json Junie marketplace index
scripts/sync-agents.main.kts regenerates the Codex copy of every agent
docs/ field reports; not shipped with any plugin

A skill's description is what the host matches a user request against — write it as the set of phrases that should trigger it, not as a summary.

Specs

Two specifications govern the tree, and they split cleanly: one owns the skill, the other owns the directory around it.

Spec Owns Where
Agent Skills SKILL.md: frontmatter fields, name/description limits, scripts/, references/, assets/ https://agentskills.io/specification
Agent Plugins 1.0.0 the plugin directory: plugin.json in the plugin root, skills discovered at skills/, MCP at mcp.json https://github.com/agentplugins/agent-plugins-spec, spec/1.0.0.md, plugin.schema.json

Agent Plugins says nothing about SKILL.md — it delegates to Agent Skills. Constraints worth keeping in mind while editing: name must match the skill's directory name and is limited to lowercase alphanumerics and single hyphens; description is capped at 1024 characters; skills are found one level under skills/ and nowhere deeper.

Read the full file on GitHub · 91 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. yesterday First seen · 91 lines · 1,306 tokens per session scan A 3975e7a21296

Subscribe to this mod's changes

kortex AGENTS.md is an instructions file published in the GitHub repository Heapy/kortex (5 stars, last pushed 4d ago), licensed Apache-2.0. It adds 1,306 tokens to every session, about $0.0065 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.