E2E testing guidelines
Add a new EVM network to the @metamask/bridge-controller package in the MetaMask/core monorepo. Use when a task asks to register an EVM chain for Swaps or Bridge, extend ALLOWED_BRIDGE_CHAIN_IDS or DEFAULT_CHAIN_RANKING, add bridge chain constants and display names, define the chain's default swaps token, or expose a new bridge ChainId enum member.
Add a new EVM network to the unified Swaps and Bridge flow in MetaMask/metamask-mobile. Use when a task asks to consume a newly supported bridge-controller chain, add a Mobile bridge network label, configure its default destination token or stablecoin slippage, update bridgeConfigV2 rollout requirements, or validate that a new EVM network appears in Mobile's source and destination network pickers.
Wire a new or existing controller — whether imported from a `@metamask/*-controller` npm package or defined locally in the repo — into the MetaMask Mobile Engine or the MetaMask Extension background. Use this skill when: adding a controller to Engine or to the extension's messenger-client init, creating a controller init function or messenger, delegating actions/events between controllers, adding a controller to EngineState/Engine.context or to MESSENGER_FACTORIES and the MessengerClient union, or debugging a controller whose state never reaches Redux/the UI or resets on restart.
Detect, prevent, and fix flaky Jest unit tests in MetaMask Mobile before they reach CI. Use this skill when: reviewing a PR diff or changed test files for flakiness risk, fixing an intermittently failing Jest test, reproducing a flaky test locally, or auditing GitHub Actions history to rank historically flaky unit tests by failure rate.
Interactively break a perps product requirement into split, dispatch-ready technical tickets across MetaMask Core, its release, Mobile, and Extension. Use when a product manager (or a codebase-aware Claude acting for one) has a perps bug or feature and needs engineering-grade tickets, correctly routed now that @metamask/perps-controller is the Core source of truth. Triages where the change actually lives, emits only the applicable layer tickets with dependency links, and enforces token-efficient, signal-over-noise tickets agents can act on directly.
Pre-flight self-review gate for perps PRs. A perps dev runs it on their OWN PR to drive a looping double-agentic cross-review — two different model CLIs (Claude, Codex, Cursor) review independently because each catches different issues — until all APPROVE the same commit with zero findings. Reviewers are deliberately strict: every perps anti-pattern and every nit is a blocker. Loops fix → re-review until the PR meets perps standard, then says it is ready for an external human reviewer. Use for "review my perps PR", "cross review my perps branch", "is my perps PR ready", or self-review before requesting review. Self-gate: does not push, merge, or open the PR.
Interactively validate perps changes across local MetaMask Core, Mobile, and Extension checkouts. Use when a Core @metamask/perps-controller change must be checked in Mobile/Extension, or when a Mobile/Extension perps change needs parity validation in the other client. Defaults to current checkout as owner, yalc for Core package transport, read-only validation targets, and the smallest meaningful proof; asks the user only when required folders or proof level cannot be resolved.