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/skills/happier-testing/SKILL.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/skills/happier-dev/happier/happier-testing)<a href="https://agentmods.dev/skills/happier-dev/happier/happier-testing"><img src="https://agentmods.dev/badge/skills/happier-dev/happier/happier-testing/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/skills/happier-dev/happier/happier-testing"><img src="https://agentmods.dev/badge/skills/happier-dev/happier/happier-testing.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector pass
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 | $0.00052 | $0.03115 |
| Opus 5.5 | $0.00021 | $0.01246 |
| Sonnet 5.5 | $0.00010 | $0.00623 |
| Haiku 4.5 | $0.00005 | $0.00312 |
Grade A, and why
happier-testing 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 24d 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 — 161 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Happier Testing And TDD
Use this skill whenever work adds, changes, reviews, deletes, or audits tests, fixtures, testkits, lane wiring, or validation behavior. It is the single test-quality owner; CI failure collection remains in .agents/skills/happier-ci-stabilize.
Goal
Apply strict RED-GREEN-REFACTOR while following Happier-specific lane, fixture, and rerun rules so changes do not silently drift until a late pipeline sweep.
Workflow
- Inventory first
- Search for existing tests by symbol, route, command, feature id, config key, component name, or error code.
- Map the affected lane(s) and any shared/package-local harnesses the change can invalidate before editing code.
- Name the observable contract or material risk the test must distinguish before writing it.
- For user-visible or environment-dependent work, define the composed live recipe before implementation: exact entry point, provider/account/state, actions, expected outcome, recovery path, and build/bundle/runtime identity that will prove the result.
- Update the most relevant existing test first when possible.
- Consolidate overlapping tests instead of stacking new ones on top.
- Classify failures correctly
production defect: runtime behavior is wrongstale test or expectation: assertions/fixtures assume an obsolete contractharness or mock defect: helpers/mocks/testkit do not represent real runtime wiringrelease-control or setup defect: workflow admission, permissions, generated prerequisites, or configuration are wrongexternal service or configuration defect: an external dependency, credential, account, or published state is unavailable or invalidresource or timeout defect: the owning resource budget, cleanup, runner, or lifecycle bound is wronginconclusive: available evidence cannot yet identify the owning class
- RED
- Write or update the smallest relevant test first.
- Run only the smallest relevant slice and confirm it fails because the intended behavior is missing or wrong, not because of setup, fixtures, mocks, wording, syntax, or an unrelated error.
What ships with it
1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
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.
- 24d ago Changed · +16 lines · +20 tokens per session 3c3f1e20289f
- 1mo ago Changed 80325a71176b
- 1mo ago Changed 2a94e625aef0
- 1mo ago Changed · +1 lines 6646c74aa80c
- 1mo ago Changed · +7 lines 4bed6340e89b
- 1mo ago Changed 95a3c24e87f0
- 1mo ago First seen · 137 lines · 32 tokens per session scan A 90a848f1b743
happier-testing is a skill published in the GitHub repository happier-dev/happier (2,072 stars, last pushed yesterday), licensed MIT. It adds 52 tokens to every session and 3,115 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 2026-09-03.
Other skills, from other repositories
cmux-testing
Choose scoped cmux verification, add behavioral tests, and validate Swift test targets and wiring. Use when adding tests or deciding what local/CI evidence a change needs.
tdd
Test-first at pre-agreed seams — one test, one implementation, tracer-bullet red/green; independent expected values; substitutions only at the seam's boundary class; launch Phase 4 reference.
adk-go-self-review
Review an ADK Go change the way a maintainer will — a fresh-context pass over the whole diff, five lenses (correctness and tests, scope, simplicity, style, adk-python parity), and the mutation check that proves your tests pin the change. Use before opening a PR, before any later push that changes code, and when asked…
cmux-test-bisect
Find when and why tests broke on main: bisect a Swift package suite on CI across old commits, read the failure matrix, and decide per test whether the test went stale or the code regressed. Use when a suite is red on main, when PR CI only ran filtered tests and the full suite has drifted, or when asked which PR broke…
tdd-ask-help
Interactive AI Guide and Navigator for the TDD-Spec SDLC ecosystem. Diagnoses current project phase, recommends next actions, routes scenarios, and explains skill purposes.
tdd-explore-ideas
Systematic codebase exploration, architectural critique, and 5-step Idea Assessment with TDD hypothesis verification for Phase 0.