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.
git clone --depth 1 https://github.com/onesimplecode/agent-engineering-standardsWrote 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/rules/onesimplecode/agent-engineering-standards/testing)<a href="https://agentmods.dev/rules/onesimplecode/agent-engineering-standards/testing"><img src="https://agentmods.dev/badge/rules/onesimplecode/agent-engineering-standards/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/rules/onesimplecode/agent-engineering-standards/testing"><img src="https://agentmods.dev/badge/rules/onesimplecode/agent-engineering-standards/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 | $0.00042 | $0.00587 |
| Opus 5.5 | $0.00017 | $0.00235 |
| Sonnet 5.5 | $0.00008 | $0.00117 |
| Haiku 4.5 | $0.00004 | $0.00059 |
Grade A, and why
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 — 33 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Testing
TR-TEST-001 — TDD required for core logic
Tests are written before or alongside core logic. Scaffolding may come first, but business logic should not be considered complete without tests.
TR-TEST-002 — Coverage targets by deployment tier
POC projects may use targeted coverage. Local Production targets at least 70 percent coverage. Cloud Production targets at least 90 percent coverage.
TR-TEST-004 — LLM regression benchmark on model switch
When switching or upgrading a runtime LLM, run a standard task set against the old and new models and record cost, latency, correctness, and schema validation deltas. See templates/llm-regression-benchmark.md.
TR-TEST-005 — LLM eval files co-located with agent modules
Each agent module that makes LLM calls should have a co-located tests/evals/test__eval.py file with golden cases, a score function, and an LLM_EVAL=true guard so evals do not run in the standard unit suite. See templates/llm-eval.md.
TR-TEST-006 — Post-write state change verification for agent actions
Agent actions that produce external side effects, such as writing files, updating records, sending messages, or calling tools, should be followed by a deterministic verification step that confirms the observable state changed as expected.
TR-TEST-007 — Agent security-property claims verified against ground truth, not self-report
A claim about an agent's own behavior — obtained only by asking the agent in conversation ("do you have tool X," "do you remember Y") — is not verification evidence for a security-relevant property: isolation between agents, a permission boundary, or memory/session scoping. An agent's self-report can produce a false pass when the question is answered by the wrong backend, a stale cache, or the agent's own (possibly incorrect) belief about its state, none of which is the property actually under test. Verify instead against the system's own ground truth — the target API's own list/read endpoint, a database row, a server log line — independent of what the agent under test reports. This is a security-property-specific instance of the general "verify before referencing" discipline (TR-GOV-001's single-source-of-truth cousin, applied to runtime claims rather than static code symbols): the authoritative source for whether an isolation boundary holds is the boundary's own enforcement point, never the agent's narration of it.
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 · 33 lines · 42 tokens per session scan A 708233689014
testing is a cursor rule published in the GitHub repository onesimplecode/agent-engineering-standards (3 stars, last pushed 1mo ago), licensed MIT. It adds 42 tokens to every session and 587 once invoked, about $0.0002 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.
Other cursor rules, from other repositories
workflow
BDD-style workflow, UI screenshots in the PR, HTTP OpenAPI, config schema and CLI packaging sync before lint, final checks, the comment on an issue a merge closes and the cleanup after the merge.
standard-backend-tests-redaction
This standard establishes best practices for writing backend tests using Jest in the Packmind monorepo. It focuses on clarity, maintainability, and consistency across test suites by emphasizing behavi... .
testing
Cursor rule "testing" from kanyun-inc/reskill, covering testing rules, testing philosophy, spec-driven tdd workflow, benefits of test-first approach and example: adding --dry-run option.
unit-tests-tdd
TDD for behavior changes; co-located tests; keep touched areas well covered.
every-error-regression-test
Mandatory regression test for every discovered defect or failure (non-negotiable).
moodle-phpunit-testing
Use when writing, running, or debugging PHPUnit tests for Moodle plugins or core. Covers advancedtestcase, resetAfterTest, data generators, mocking $DB, testing events/tasks/external functions, and CLI invocation.