Happier is an open-source, end-to-end encrypted client that lets people run AI coding-agent sessions on a computer and continue controlling them from a phone, browser, or desktop app. It is for developers who use agents such as Claude Code, Codex, Gemini, or OpenCode across multiple devices, with self-hosting available. The catalogue entries are add-ons for configuring or extending this client and its supported coding-agent workflows.
Borrowing it
Nothing to install: this file belongs to happier-dev/happier. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/happier-dev/happier/dev/AGENTS.mdgit clone --depth 1 https://github.com/happier-dev/happierWrote 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.
[](https://agentmods.dev/instructions/happier-dev/happier/agents-md)<a href="https://agentmods.dev/instructions/happier-dev/happier/agents-md"><img src="https://agentmods.dev/badge/instructions/happier-dev/happier/agents-md/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.
<a href="https://agentmods.dev/instructions/happier-dev/happier/agents-md"><img src="https://agentmods.dev/badge/instructions/happier-dev/happier/agents-md.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.10542 | $0.10542 |
| Opus 5.5 | $0.04217 | $0.04217 |
| Sonnet 5.5 | $0.02108 | $0.02108 |
| Haiku 4.5 | $0.01054 | $0.01054 |
Grade A, and why
happier 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 14d 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.
How it starts
The opening of the file, as written. The whole thing — 350 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Agent Constitution
This file is the canonical cross-tool constitution for this repository.
What Happier is
Happier is a cross-device client and companion for coding agents. Think of it as what you would get if Claude Desktop, Codex App, Cursor Glass and Conductor were merged into one open-source app.
Agent sessions run on computers, VPSs and dev boxes users control. Happier can connect to one or many of these machines and lets users monitor, steer, approve, review, resume and continue their sessions from a phone, browser or desktop.
People drive agents through Happier all day. It should feel warm, fluid, blazing-fast and delightful to use.
We love ambitious product ideas and simple systems. Do not preserve complexity because it already exists or introduce machinery because it looks architecturally impressive. Understand the real constraint, intent and requirements. Do not overcomplicate the implementation or invent hard requirements for speculative, unreachable or low-impact edge cases. New guarantees and machinery must be justified by an explicit requirement, released contract, reproduced failure or reachable material risk.
Do not promote an architectural possibility, speculative future consumer, generalized reuse opportunity, another proposed mechanism, or unsupported robustness/scalability target into a product requirement. Offline behavior, unattended execution, exact ordering or freshness, failover, trust models, and fixed capacity limits are path-specific contracts; establish each from current product evidence, a released security or compatibility obligation, or explicit approval.
Cross-device reachability, execution placement, state ownership, persistence, availability, and consistency are separate contracts. A feature being available on several clients or scoped to an Account establishes neither a server-side source of truth nor a multi-writer problem. Add shared materialization or cross-machine coordination only for a named current flow that cannot be served by reaching the canonical authority through existing transport.
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.
- 14d ago Changed · +15 tokens per session 283c565a0dea
- 20d ago Changed · +2 lines · +100 tokens per session 5d0d14315aef
- 1mo ago Changed · +5 lines · +492 tokens per session 214822ab5d97
- 1mo ago Changed · +101 tokens per session 0380be279eca
- 1mo ago Changed · +3 lines · +182 tokens per session ef2859fd9ca9
- 1mo ago Changed · +44 tokens per session d6959416bf11
- 1mo ago First seen · 340 lines · 9,608 tokens per session scan A 84f9011f4fd6
happier AGENTS.md is an instructions file published in the GitHub repository happier-dev/happier (2,072 stars, last pushed yesterday), licensed MIT. It adds 10,542 tokens to every session, about $0.0422 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 2026-08-30.
Other instructions, from other repositories
vscode buildNext.instructions.md
Working notes and architecture documentation for the new esbuild-based build system in build/next. Use when making changes to the new build pipeline (transpile/bundle commands, NLS plugin, source-map handling, resource copying, or self-hosting watch tasks).
next.js AGENTS.md
AGENTS.md instructions for vercel/next.js, covering next.js development guide, codebase structure, monorepo overview, core package: packages/next and other important packages.
vscode oss-third-party-notices.instructions.md
Instructions for microsoft/vscode, covering vs code oss third-party-notices pipeline, architecture, pipeline flow in ci, cache eligibility and rollout and applying the notice (cutover).
langchain AGENTS.md
AGENTS.md instructions for langchain-ai/langchain, covering global development guidelines for the langchain monorepo, corridor security analysis, project architecture and context, monorepo structure and development tools & commands.
vscode copilot-instructions.md
Copilot instructions for microsoft/vscode, covering vs code copilot instructions, project overview, root folders, core architecture (src/ folder) and built-in extensions (extensions/ folder).
deno copilot-instructions.md
Copilot instructions for denoland/deno, covering deno development guide for github copilot, network access, high level overview, key directories and key files to understand first.