project-context-primer

project-context-primer is a skill for Claude Code, Codex from omergocmen/vibe-coder-kit. It costs 58 tokens per session (1,160 once invoked), scanned A, original, MIT.

A project-startup routine that loads a codebase's recorded architecture decisions, conventions, known problems, and current status before coding begins.

In plain words
What is it for?
Use it at the start of a new conversation or agent session, when handing work to another agent, or when returning to a project after a long break.
Why use it?
It reduces the chance of making changes that conflict with earlier decisions or repeat known mistakes.

Skill for Claude CodeCodex

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/omergocmen/vibe-coder-kit/project-context-primer
Any agent
npx skills add omergocmen/vibe-coder-kit --skill project-context-primer
Clone the repo
git clone --depth 1 https://github.com/omergocmen/vibe-coder-kit

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 project-context-primer

README.md
[![agentmods](https://agentmods.dev/badge/skills/omergocmen/vibe-coder-kit/project-context-primer.svg)](https://agentmods.dev/skills/omergocmen/vibe-coder-kit/project-context-primer)
Your own site
<a href="https://agentmods.dev/skills/omergocmen/vibe-coder-kit/project-context-primer"><img src="https://agentmods.dev/badge/skills/omergocmen/vibe-coder-kit/project-context-primer.svg" alt="Measured on agentmods" height="20"></a>
Per session 58 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,160 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 $0.00058 $0.01160
Opus 5 $0.00029 $0.00580
Sonnet 5 $0.00012 $0.00232
Haiku 4.5 $0.00006 $0.00116

Measured 4d ago against content hash 5e9e7fbf93d5, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

project-context-primer 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 4d 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.

.agent/skills/project-context-primer/SKILL.md · 154 lines

How it starts

The opening of the file, as written. The whole thing — 154 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Project Context Primer Skill

When to Trigger

Always run first when:

  • Starting a new conversation about this project
  • A subagent is spawned to work on a module
  • Picking up work after a gap of more than a day
  • Someone says "can you help with this project?" without any context

Step-by-Step Process

1. Load the Knowledge Index

Read .agent/knowledge/INDEX.md first.

The INDEX.md file contains rows in this format:

| Date | Type | Topic (linked) | One-line summary |
  • Scan all rows for entries relevant to today's task
  • For each relevant row, follow the link and read the full .agent/knowledge/<slug>.md file
  • Pay special attention to entries of type decision and gotcha — these prevent the most costly mistakes
  • Extract the slug from the link: [topic](./auth/token-refresh.md) → slug is auth/token-refresh

If INDEX.md does not exist, output this exact warning and proceed:

⚠️ Knowledge base not initialized (.agent/knowledge/INDEX.md missing).
This means no architectural decisions, conventions, or gotchas have been recorded yet.
Action: Use the `knowledge-base-update` skill at the end of this session to start building it.

2. Load the Project README

Read README.md (or docs/README.md if present).

Extract and internalize:

  • What the project does (one sentence)
  • Tech stack (language, framework, major libraries)
  • How to run it locally
  • How to run tests

3. Load Active Task Context

Read the full file on GitHub · 154 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. 4d ago First seen · 154 lines · 58 tokens per session scan A 5e9e7fbf93d5

Subscribe to this mod's changes

project-context-primer is a skill published in the GitHub repository omergocmen/vibe-coder-kit (91 stars, last pushed 3mo ago), licensed MIT. It adds 58 tokens to every session and 1,160 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 2026-08-30.

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