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.
npx skills add lugassawan/swe-workbench --skill principle-testinggit clone --depth 1 https://github.com/lugassawan/swe-workbenchWrote 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/lugassawan/swe-workbench/principle-testing)<a href="https://agentmods.dev/skills/lugassawan/swe-workbench/principle-testing"><img src="https://agentmods.dev/badge/skills/lugassawan/swe-workbench/principle-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/lugassawan/swe-workbench/principle-testing"><img src="https://agentmods.dev/badge/skills/lugassawan/swe-workbench/principle-testing.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 | $0.00098 | $0.01443 |
| Opus 5.5 | $0.00039 | $0.00577 |
| Sonnet 5.5 | $0.00020 | $0.00289 |
| Haiku 4.5 | $0.00010 | $0.00144 |
Grade A, and why
principle-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 1mo 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 — 111 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Testing Strategy and Architecture
Strategy and architecture, not the red-green-refactor discipline. For that, see swe-workbench:principle-tdd.
The pyramid
Three tiers, wide base up: unit → integration → e2e. Baseline ratio: ~70% unit, ~20% integration, ~10% e2e — adjust toward more integration for infrastructure-heavy systems, more e2e for UI-heavy products.
Inverting the pyramid (heavy e2e, thin unit) produces a slow, brittle suite — e2e tests amplify flakiness and punish every external dependency.
- Unit — one class or function, no I/O, milliseconds.
- Integration — two or more collaborators, real infrastructure (DB, message bus), seconds.
- e2e — full stack through the UI or API gateway; minutes.
Prefer more granular tests. One integration test that exercises a migration is worth more than five e2e tests covering the same path.
Test doubles
Five kinds (Meszaros's xUnit Patterns taxonomy). State-based: Stub, Fake. Behavior-verification: Spy, Mock. Dummy is a degenerate no-op.
| Double | What it does | When to use |
|---|---|---|
| Dummy | Passed but never called | Satisfying required params |
| Stub | Returns canned responses | Isolating the path under test |
| Fake | Working implementation (e.g. in-memory DB) | Fast integration tests |
| Spy | Records calls for post-hoc assertion | Verifying interactions |
| Mock | Pre-programmed expectations; fails on violation | Strict boundary contracts |
Mock only at trust boundaries: network, clock, filesystem, random, external services. The seam is domain ↔ infrastructure (Clean Architecture's dependency rule). Everything inside the domain is instantiated for real.
If a collaborator is hard to instantiate, that is a design signal — recommend a refactor, not a mock.
Coverage vs confidence
Line coverage is a metric, not a quality signal. 90% coverage with assertions only on getters is worthless; 60% coverage with well-targeted branch assertions is not.
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.
- 1mo ago First seen · 111 lines · 98 tokens per session scan A 6d7215f8e514
principle-testing is a skill published in the GitHub repository lugassawan/swe-workbench (3 stars, last pushed 2d ago), licensed MIT. It adds 98 tokens to every session and 1,443 once invoked, about $0.0004 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.
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