techstack

A project guide for learning how a codebase is organised, which tools it uses, and how to get started with it.

In plain words
What is it for?
It helps with setup, project commands, testing, GitHub CLI tasks, and understanding the project structure.
Why use it?
It gives coding agents the project-specific context needed to make changes without first exploring the repository from scratch.

Agent

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 agents/posthog/posthog.com/techstack
Clone the repo
git clone --depth 1 https://github.com/PostHog/posthog.com
Per session 0 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 1,153 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 1 finding. Scan, not verified.
Origin unknown 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 $0.00000 $0.01153
Opus 5 $0.00000 $0.00576
Sonnet 5 $0.00000 $0.00231
Haiku 4.5 $0.00000 $0.00115

Measured yesterday against content hash 392cd713f1db, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

techstack scanned grade A with 1 finding 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.

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

`gh` has no command for attaching an image to a PR body, which every visual PR needs. If you have your own skill or tooling for that, use it. Otherwise see the `curl` fallback in [browser screenshots](browser-screenshots
agents/techstack.md · 117 lines

The source is not reproduced here

No licence file

A repository with no LICENSE is all rights reserved by default, so the body is not copied here. The metadata, the measurements and the link are.

Read it on GitHub

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 · 117 lines · 0 tokens per session scan A 392cd713f1db

Subscribe to this mod's changes

techstack is an agent published in the GitHub repository PostHog/posthog.com (1,131 stars, last pushed 2d ago), with no licence file. It costs nothing until one of its globs matches a file; then it loads 1,153 tokens. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.