Getting it into your agent
This one installs as part of its plugin. Adding the marketplace and installing the plugin brings it with everything else the plugin ships.
/plugin marketplace add Tiltely/lens/plugin install lensWrote 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/tiltely/lens/tdd)<a href="https://agentmods.dev/skills/tiltely/lens/tdd"><img src="https://agentmods.dev/badge/skills/tiltely/lens/tdd/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/tiltely/lens/tdd"><img src="https://agentmods.dev/badge/skills/tiltely/lens/tdd.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 | $0.00086 | $0.01758 |
| Opus 5.5 | $0.00034 | $0.00703 |
| Sonnet 5.5 | $0.00017 | $0.00352 |
| Haiku 4.5 | $0.00009 | $0.00176 |
Grade A, and why
tdd 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 — 131 lines — stays where its author put it; the contents beside it link to each section on GitHub.
The Lens of TDD
Read first: ${CLAUDE_PLUGIN_ROOT}/core/protocol.md and ${CLAUDE_PLUGIN_ROOT}/core/dossier.md. Dossier rules: read it, skip answered questions WITH skip lines, append your outputs.
Division of labor: if a TDD process skill is available in the session (e.g. superpowers:test-driven-development), it governs the red-green-refactor loop. This lens governs judgment — which tests deserve to exist and what they must pin down. They compose; this lens never overrides process discipline.
Mode selection
- Explicit argument wins ("audit" / "design").
- Otherwise infer: planning/writing tests → design; reviewing tests that already exist → audit. Confirm your inference in one line.
Question battery — design mode
Tier 1 — framing (always)
- State the behavior under test as one sentence in DOMAIN language — "rejects expired tokens", "splits the bill evenly among present members". If you cannot phrase it without naming functions, mocks, or internals, you are about to test implementation, not behavior. Rephrase before continuing.
- The deletion test: if this test never existed, what bug would reach production undetected? If the honest answer is "none", the test is theater — do not write it.
Tier 2 — per proposed test
- What is the ONE reason this test can fail? (Many reasons → bad alarm, split it. Zero reasons → decoration, delete it. Exactly one → a test.)
- Red-phase honesty: will you SEE it fail first, and fail for the RIGHT reason? A test that passes on first run has verified nothing — including itself.
- What does the assertion actually pin? Distinguish:
- outcome assertions (returned value, persisted state, emitted event) — strong
- interaction assertions (mock called with X) — weak; justified ONLY when the interaction IS the contract (e.g., "charges Stripe exactly once")
- Boundaries, with criterio: list the edges (empty, one, many, duplicate, malformed, concurrent, unauthorized) — then say which you will NOT test and WHY. Knowing what not to test is the skill; "all of them" is not an answer.
- Stack-conditional:
nestjs-api→ what is the unit/e2e split here? What deserves the real database and what tolerates a mock — and does any mock re-implement query logic (red flag)?nextjs-web/expo-mobile→ does the test exercise what the USER does (render, interact, observe) rather than component internals/state shape?
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 · 131 lines · 86 tokens per session scan A 10a31403845c
tdd is a skill published in the GitHub repository Tiltely/lens (5 stars, last pushed 2mo ago), licensed MIT. It adds 86 tokens to every session and 1,758 once invoked, about $0.0003 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 2026-08-31.
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