Browser Compatibility
Agentable tools work in all major browsers via native support or automatic polyfill.
How compatibility works
The Agentable snippet checks for navigator.modelContext on load. If it's not available natively, it automatically loads the WebMCP polyfill from unpkg.com before registering your tools.
// Simplified snippet logic
if (!navigator.modelContext) {
await loadPolyfill() // loads WebMCP polyfill
}
// Register tools...This means you don't need to do anything — compatibility is handled automatically.
Browser support
| Browser | Native WebMCP | Polyfill fallback |
|---|---|---|
| Chrome | Partial | ✓ |
| Firefox | — | ✓ |
| Safari | — | ✓ |
| Edge | Partial | ✓ |
| Brave | Partial | ✓ |
| Opera | Partial | ✓ |
| Mobile Chrome | — | ✓ |
| Mobile Safari | — | ✓ |
"Partial" means the browser has some modelContext support but may not implement the full spec. The polyfill fills any gaps.
AI agent compatibility
AI agents that support WebMCP natively query navigator.modelContext.tools directly. Agents that don't yet support WebMCP will not call your tools — but as the standard matures, more agents will adopt it.
Current agents with known WebMCP support: Claude (via browser use), others in development.
Polyfill loading
The polyfill is loaded automatically from a CDN. If it fails to load, the snippet logs a warning and continues — native WebMCP still functions where available.