smoke-tests

A guide for running VS Code smoke tests, which start a full VS Code instance and check complete user flows from beginning to end. It covers Electron, browser, and remote runs.

In plain words
What is it for?
Use it to run all smoke tests or selected suites, test packaged builds, run browser or remote checks, capture traces, or investigate flaky tests.
Why use it?
It helps verify that major workflows work in a real application environment and provides filtering, tracing, and repeat options for investigating failures.

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/microsoft/vscode/smoke-tests
Any agent
npx skills add microsoft/vscode --skill smoke-tests
Clone the repo
git clone --depth 1 https://github.com/microsoft/vscode

Made for: Claude Code, Codex.

Per session 50 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,322 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 $0.00050 $0.02322
Opus 5 $0.00025 $0.01161
Sonnet 5 $0.00010 $0.00464
Haiku 4.5 $0.00005 $0.00232

Measured 2d ago against content hash ed290f30a6dd, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

smoke-tests 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 2d 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.

.github/skills/smoke-tests/SKILL.md · 151 lines

How it starts

The opening of the file, as written. The whole thing — 151 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Running Smoke Tests

Smoke tests live in test/smoke/ and drive a full VS Code instance (Electron, web, or remote) through end-to-end user flows.

Scripts

  • npm run smoketest — compiles the smoke tests first (test/smoke), then runs them.
  • npm run smoketest-no-compile — runs the already-compiled smoke tests. CI uses this after an explicit compile step.

Both forward extra arguments after -- to the runner (test/smoke/test/index.js).

Common options

Option Description
-g <pattern> (alias -f) Grep filter on test/suite titles (mocha grep).
--build <path> Run against a packaged build instead of the compiled-from-source dev build.
--tracing Capture Playwright traces (and screenshots on failure).
--web Run the browser smoke tests instead of Electron.
--headless Headless browser (used with --web).
--remote Run the remote smoke tests.
# Run everything (Electron, from source)
npm run smoketest

# Run only a subset of suites by name, with tracing (replace <suite name> with your suite, e.g. "Agents Window")
npm run smoketest -- -g "<suite name>" --tracing

# Run against a packaged build (CI style)
npm run smoketest-no-compile -- --tracing --build "/path/to/VSCode-darwin-arm64/Code - OSS.app"

The -g pattern matches against test/suite titles. For example, -g "Agents Window" matches all three Agents Window suites (Agents Window, Agents Window (local AgentHost), and Agents Window (local AgentHost, SDK sandbox)); use whatever substring identifies the suite(s) you care about.

The runner exits non-zero if any test fails, so a 0 exit code means every selected test passed.

Temporarily looping a suite to hunt flaky CI tests

When a smoke test fails intermittently only in CI, a useful technique is to temporarily run the suspect suite many times in a row and fail on the first failure. This reproduces the flake under the real CI environment and captures its traces/screenshots, instead of waiting for it to recur naturally across unrelated PRs.

Read the full file on GitHub · 151 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. 2d ago First seen · 151 lines · 50 tokens per session scan A ed290f30a6dd

Subscribe to this mod's changes

smoke-tests is a skill published in the GitHub repository microsoft/vscode (190,384 stars, last pushed today), licensed MIT. It adds 50 tokens to every session and 2,322 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.