calva-backseat-driver: Skill for Claude Code

.github/skills/e2e-testing/SKILL.md

e2e-testing is a skill for Claude Code, Codex from BetterThanTomorrow/calva-backseat-driver. It costs 66 tokens per session (1,612 once invoked), scanned A, original, MIT.

A guide for writing and debugging end-to-end tests for Backseat Driver. End-to-end tests check a complete system, including the VS Code extension, its server, network connection, tools, and commands.

In plain words
What is it for?
Writing or changing tests in the e2e-test-ws workspace, adding MCP test scenarios, checking MCP behavior, and diagnosing test failures.
Why use it?
It helps test changes across the whole system instead of checking isolated parts. It also provides ways to investigate failures and inspect detailed test output.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

This is BetterThanTomorrow/calva-backseat-driver's own configuration. It tells Claude Code and Codex how to work on calva-backseat-driver itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything calva-backseat-driver configures →

Reuse

Borrowing it

Nothing to install: this file belongs to BetterThanTomorrow/calva-backseat-driver. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file
curl -O https://raw.githubusercontent.com/BetterThanTomorrow/calva-backseat-driver/master/.github/skills/e2e-testing/SKILL.md
Clone the repo
git clone --depth 1 https://github.com/BetterThanTomorrow/calva-backseat-driver

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 e2e-testing

README.md
[![agentmods](https://agentmods.dev/badge/skills/betterthantomorrow/calva-backseat-driver/e2e-testing.svg)](https://agentmods.dev/skills/betterthantomorrow/calva-backseat-driver/e2e-testing)
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<a href="https://agentmods.dev/skills/betterthantomorrow/calva-backseat-driver/e2e-testing"><img src="https://agentmods.dev/badge/skills/betterthantomorrow/calva-backseat-driver/e2e-testing.svg" alt="Measured on agentmods" height="20"></a>
Per session 66 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,612 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
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 5.1 $0.00066 $0.01612
Opus 5 $0.00033 $0.00806
Sonnet 5 $0.00013 $0.00322
Haiku 4.5 $0.00007 $0.00161

Measured 7d ago against content hash 2751017f4f6f, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-07, from the pricing page.

Security

Grade A, and why

e2e-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 7d 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/e2e-testing/SKILL.md · 163 lines

How it starts

The opening of the file, as written. The whole thing — 163 lines — stays where its author put it; the contents beside it link to each section on GitHub.

E2E Testing — Backseat Driver

E2e tests run inside a VS Code Extension Host via Joyride. They exercise the full stack: extension activation, MCP server lifecycle, TCP socket communication, tool invocation, and VS Code command registration. Together with the bd-tester agent (which uses the MCP protocol for its test harness) in the example/test project inside the dev Extension Host, the e2e suite provides full coverage of the MCP server and tools.

When verifying a change that affects MCP behavior, use the bd-tester agent in the dev Extension Host to specifically exercise the changed functionality, and often run its full protocol as a regression check.

Running Tests

bb run-e2e-tests-ws
  • Output summary prints to stdout
  • Detailed output: .tmp/e2e-output.log — read this file for diagnostics
  • Do not pipe or redirect the command

Test Infrastructure

File Layout

e2e-test-ws/.joyride/src/
├── e2e/
│   ├── test_runner.cljs    # Discovery, ordering, execution
│   ├── macros.cljs         # deftest-async macro
│   ├── utils.cljs          # wait-for+ polling utility
│   ├── mcp_helpers.cljs    # Shared MCP session/request helpers
│   ├── db.cljs             # Test state atom (pass/fail/error counts)
│   └── baldr.cljs          # ANSI color reporter
└── tests/
    └── mcp/
        ├── a_activation_test.cljs   # Pre-activation assertions (runs first)
        ├── output_log_test.cljs     # Datalog query tests
        └── server_test.cljs         # Server lifecycle, tools, resources, skills

Test Runner Mechanics

test_runner.cljs discovers *_test.cljs files, converts to namespace symbols, and sorts alphabetically. All namespaces run sequentially within one Extension Host session.

VS Code extension activation is irreversible within a session. Tests that must run before activation use an a_ filename prefix to sort first (e.g., a_activation_test.cljs).

A minimum assertion threshold (currently 2) catches silent failures where tests appear to pass but produce no assertions.

Read the full file on GitHub · 163 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. 7d ago First seen · 163 lines · 66 tokens per session scan A 2751017f4f6f

Subscribe to this mod's changes

e2e-testing is a skill published in the GitHub repository BetterThanTomorrow/calva-backseat-driver (64 stars, last pushed 9d ago), licensed MIT. It adds 66 tokens to every session and 1,612 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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