building

building is a skill for Claude Code, Codex from nearform/lastlight. It costs 52 tokens per session (1,694 once invoked), scanned A, original, MIT.

A build-and-check routine for code changes in an existing repository. It detects the package manager, installs dependencies, and runs tests, linting, and type checks.

In plain words
What is it for?
Use it to install a project, implement or fix code, review someone else’s change, and run the checks needed before delivery.
Why use it?
It gives changes a consistent verification process and helps catch failures before they are treated as complete. It also encourages test-first development when implementing code.

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/nearform/lastlight/building
Any agent
npx skills add nearform/lastlight --skill building
Clone the repo
git clone --depth 1 https://github.com/nearform/lastlight

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 building

README.md
[![agentmods](https://agentmods.dev/badge/skills/nearform/lastlight/building.svg)](https://agentmods.dev/skills/nearform/lastlight/building)
Your own site
<a href="https://agentmods.dev/skills/nearform/lastlight/building"><img src="https://agentmods.dev/badge/skills/nearform/lastlight/building.svg" alt="Measured on agentmods" height="20"></a>
Per session 52 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,694 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 $0.00052 $0.01694
Opus 5 $0.00026 $0.00847
Sonnet 5 $0.00010 $0.00339
Haiku 4.5 $0.00005 $0.00169

Measured 4d ago against content hash a37005811d8f, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

building 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.

apps/server/skills/building/SKILL.md · 136 lines

How it starts

The opening of the file, as written. The whole thing — 136 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Building

How to install, build, test, and gate a change in the sandbox. The same discipline whether you're implementing a feature, fixing review feedback, or verifying someone else's PR.

Workspace & git

The harness pre-cloned the repo; your cwd is the repo root (or a <repo>/ subdirectory — check with ls -la). Git is configured for clone/fetch/pull and local commits. If auth fails after ~1 hour, call the github_refresh_git_auth MCP tool. Suppress noise where it helps: git clone --quiet, CI=true.

Getting work onto the branch is not a git operation: a commit built by git here is unsigned and a repo that requires signed commits blocks it permanently, so a phase that publishes does it with github_publish rather than git push. Your prompt says whether yours publishes and with what arguments.

A new file cannot be published executable. GitHub builds the commit from paths and contents, with no file mode, so a new 100755 file is refused and nothing is published. Adding a script is the case you will hit: leave it non-executable (no chmod +x) and invoke it through its interpreter — bash scripts/verify.sh, python scripts/check.py — in the docs, the CI workflow and anywhere else that calls it. Symlinks, submodule pointers and a mode change on an existing file are refused too, and those need a human.

Install-first

node_modules (and any other dependency dir) is always absent on arrival — by design, not a blocker. Installing is the first step, not a reason to skip verification. Detect the package manager from the lockfile and use the frozen/CI variant:

  • package-lock.jsonnpm ci
  • pnpm-lock.yamlcorepack pnpm install --frozen-lockfile
  • yarn.lockcorepack yarn install --frozen-lockfile

Node is available via fnm + corepack; the egress allowlist permits the public package registries, so install works. For a monorepo, install at the root, then operate on the changed package. For non-Node repos, use the ecosystem's equivalent (pip install, cargo build, go mod download, …) read from the project's manifest.

Read the full file on GitHub · 136 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 · 136 lines · 52 tokens per session scan A a37005811d8f

Subscribe to this mod's changes

building is a skill published in the GitHub repository nearform/lastlight (22 stars, last pushed 8d ago), licensed MIT. It adds 52 tokens to every session and 1,694 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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