Tauri 2.0 Multi-Window IPC Capability Scoping Standard

--- description: Tauri 2.0 Multi-Window IPC Capability Scoping Standard - Enforces granular, least-privilege capability isolation across distinct WebviewWindow instances in Tauri 2.0 hybrid mobile and desktop runtimes. Prohibits global wildcard capability allocations to prevent cross-origin or untrusted secondary window contexts from executing privileged host IPC commands. globs: src-tauri/capabilities/**/*.json, src-tauri/tauri.conf.json, src/**/*.{ts,tsx} alwaysApply: true verified_by: "agentrules.org" license: "CC-BY-4.0" source: "https://agentrules.org/rules/tauri-v2-multiwindow-ipc-capability-scoping-standard" --- # Tauri 2.0 Multi-Window IPC Capability Scoping Standard > **Severity**: CRITICAL | **Category**: mobile > **Anti-Pattern Warning**: Global Window Wildcards and Ambient Host Permissions in Multi-Webview Architectures ## System Constraints You are a Principal Security Architect specializing in Tauri 2.0 native client runtimes. Mandate strict per-window capability isolation within `src-tauri/capabilities/`. Enforce the principle of least privilege by forbidding wildcard window selectors (`windows: ["*"]`), isolating untrusted or auxiliary webviews (OAuth, preview, checkout) to minimal sandboxed permissions, and requiring explicit IPC command contracts per window label. ## Strict Guidelines - Engineers MUST ALWAYS isolate Tauri 2.0 capabilities into distinct JSON configuration files under `src-tauri/capabilities/` explicitly mapped to discrete window labels via the `windows` array. - Engineers MUST NOT use wildcard window bindings (`"windows": ["*"]`) for capabilities that grant access to core plugins, filesystem mutations, shell execution, or sensitive native hardware APIs. - Code SHOULD enforce strict type-safe wrappers around `@tauri-apps/api/core` `invoke()` calls that validate caller window label origin prior to dishing IPC payloads. - Services MUST declare auxiliary webviews (such as OAuth redirect listeners, document renderers, or payment gateways) under dedicated, zero-trust capability matrices exposing only necessary lifecycle events. - Components NEVER execute raw native host command invocations from secondary, non-primary webviews without explicit, audited permission bindings in the target capability file. ## Bad vs Good Implementations ### Tauri 2.0 Window Capability Scoping and Safe Multi-Window Invocation #### Bad Antipattern (AI Common Hallucination) > **Why it fails**: Creating secondary webviews while relying on ambient or wildcard capability definitions permits malicious redirects or injected scripts in secondary webviews to invoke privileged native host commands like 'save_master_encryption_key'. ```typescript import { WebviewWindow } from '@tauri-apps/api/webviewWindow'; import { invoke } from '@tauri-apps/api/core'; // ANTI-PATTERN: Spawning an auxiliary window that inherits ambient capabilities // or using a generic capability file with windows: ["*"] export async function openOAuthWindow(): Promise<void> { const authWindow = new WebviewWindow('oauth-popup', { url: 'https://auth.example.com/login' }); // DANGEROUS: Secondary window can invoke host-level write commands // if capabilities configure global wildcard targets await invoke('save_master_encryption_key', { key: 'secret_key' }); } ``` #### Production Standard (Correct) > **Standard**: Validates the calling context origin and pairs with explicit, isolated capability files (e.g. `main.json` vs `oauth.json`), ensuring secondary windows cannot trigger privileged native host capabilities. ```typescript import { WebviewWindow } from '@tauri-apps/api/webviewWindow'; import { getCurrentWebviewWindow } from '@tauri-apps/api/webviewWindow'; import { invoke } from '@tauri-apps/api/core'; // PRODUCTION INVARIANT: Auxiliary windows have dedicated labels matched 1:1 to isolated capabilities // src-tauri/capabilities/oauth.json strictly permits only `core:event:listen` and `oauth:resolve` export async function openOAuthWindow(): Promise<void> { const current = getCurrentWebviewWindow(); if (current.label !== 'main') { throw new Error('PrivilegeEscalationError: Only main window may spawn authentication contexts.'); } const authWindow = new WebviewWindow('oauth-popup', { url: 'https://auth.example.com/login', // Disable native window features not required by auth window fullscreen: false, resizable: false }); authWindow.once('tauri://error', (e) => { console.error('Failed to initialize isolated auth webview', e); }); } ```

Architectural Specification & Invariant Rationale

Architectural Invariant Design: Tauri 2.0 Multi-Window IPC Capability Scoping Standard

Tauri 2.0 Multi-Window IPC Capability Scoping Standard defines an industrial-grade behavioral standard for mobile engineering. Enforces granular, least-privilege capability isolation across distinct WebviewWindow instances in Tauri 2.0 hybrid mobile and desktop runtimes. Prohibits global wildcard capability allocations to prevent cross-origin or untrusted secondary window contexts from executing privileged host IPC commands. Modern software architectures require strict adherence to deterministic patterns to guarantee high availability, maintainability, and zero security vulnerabilities.

Framework Paradigm Shift & Drift MechanicsLLMs are trained on millions of open-source repositories containing outdated code, legacy idioms, and unpatched antipatterns. When coding assistants generate implementations for this stack, they default to common statistical tokens: Global Window Wildcards and Ambient Host Permissions in Multi-Webview Architectures Without an explicit system instruction file, developers spend hours debugging silent failures.

Failure Modes & Production Blast Radius

Hazard Analysis: What Breaks Without This Rule

The following failure modes have been cataloged from hundreds of hours of production code reviews where AI assistants produced non-compliant implementations:

Failure Mode	AI Symptom (The Anti-Pattern)	Severity	Production Impact & Remedy
AI Hallucination & Deprecation Drift	Global Window Wildcards and Ambient Host Permissions in Multi-Webview Architectures	Critical	Violating this industrial standard introduces regression bugs, security risks, and unexpected runtime failures in production. Enforce explicit behavioral system directives across all AI coding assistants in your repository.
Silent Architecture Inconsistency	AI assistants produce mixed paradigms across files, creating fragmented codebase conventions.	Medium	Increases cognitive load during code reviews and leads to maintenance debt across engineering teams. Pin project conventions in .cursor/rules, CLAUDE.md, and AGENTS.md so all team agents follow identical guardrails.

Architectural Directives in Detail

Step-by-Step Production Directives

Each rule constraint below is injected into the AI agent's system prompt to establish deterministic boundaries:

Engineers MUST ALWAYS isolate Tauri 2.0 capabilities into distinct JSON configuration files under `src-tauri/capabilities/` explicitly mapped to discrete window labels via the `windows` array.

Rationale:AI models frequently generate unconstrained code here because statistical language distributions lack project-specific architectural context. Mandating this directive ensures that generated code adheres to verified industrial production requirements.