strict-development-rules

A set of coding and testing rules for the Gemini CLI project. It specifies how developers should write tests and verify changes.

In plain words
What is it for?
It guides asynchronous tests, React component tests, snapshot updates, and parameterized tests. It also sets rules for modifying or adding Gemini CLI code.
Why use it?
It reduces flaky tests, misleading warnings, and accidental changes hidden by poorly updated snapshots. It also keeps test code consistent across the project.

Command for Gemini CLI

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 commands/google-gemini/gemini-cli/strict-development-rules
Clone the repo
git clone --depth 1 https://github.com/google-gemini/gemini-cli

Made for: Gemini CLI.

Per session 0 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 2,023 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 1 finding. 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 $0.00000 $0.02023
Opus 5 $0.00000 $0.01012
Sonnet 5 $0.00000 $0.00405
Haiku 4.5 $0.00000 $0.00202

Measured yesterday against content hash 373969348168, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

strict-development-rules scanned grade A with 1 finding 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 yesterday.

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.

Runs shell commandslowCapability

Expected in a hook, worth knowing in a rule or an instructions file.

- Mock critical dependencies (`fs`, `os`, `child_process`) ONLY at the top of
Origin

Copies of this mod

2 near-identical copies found in the catalogue:

.gemini/commands/strict-development-rules.md · 159 lines

How it starts

The opening of the file, as written. The whole thing — 159 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Gemini CLI Strict Development Rules

These rules apply strictly to all code modifications and additions within the Gemini CLI project.

Testing Guidelines

  • Async/Await: Always use waitFor from packages/cli/src/test-utils/async.ts instead of vi.waitFor for all waitFor calls within packages/cli. NEVER use fixed waits (e.g., await delay(100)). Always use waitFor with a predicate to ensure tests are stable and fast. Using the wrong waitFor can result in flaky tests and act warnings.
  • React Testing: Use act to wrap all blocks in tests that change component state. Use render or renderWithProviders from packages/cli/src/test-utils/render.tsx instead of render from ink-testing-library directly. This prevents spurious act warnings. If test cases specify providers directly, consider whether the existing renderWithProviders should be modified.
  • Snapshots: Use toMatchSnapshot to verify that rendering works as expected rather than matching against the raw content of the output. When modifying snapshots, verify the changes are intentional and do not hide underlying bugs.
  • Parameterized Tests: Use parameterized tests where it reduces duplicated lines. Give the parameters explicit types to ensure the tests are type-safe.
  • Mocks Management:
    • Mock critical dependencies (fs, os, child_process) ONLY at the top of the file. Ideally, avoid mocking these dependencies altogether.
    • Reuse existing mocks and fakes rather than creating new ones.
    • Avoid mocking the file system whenever possible. If using the real file system is too difficult, consider writing an integration test instead.
    • Always call vi.restoreAllMocks() in afterEach to prevent test pollution.
    • Use vi.useFakeTimers() for tests involving time-based logic to avoid flakiness.
  • Typing in Tests: Avoid using any in tests; prefer proper types or unknown with narrowing.

React Guidelines (packages/cli)

Read the full file on GitHub · 159 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. yesterday First seen · 159 lines · 0 tokens per session scan A 373969348168

Subscribe to this mod's changes

strict-development-rules is a command published in the GitHub repository google-gemini/gemini-cli (106,749 stars, last pushed 2d ago), licensed Apache-2.0. It costs nothing until one of its globs matches a file; then it loads 2,023 tokens. A static security scan graded it A with 1 finding (runs shell commands). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.