Bug Report: Tab ID Not Persisting Between Operations

[stabilus]

Summary
Browser MCP server fails to maintain tab session state between operations, causing all interactive browser tools (browser_click, browser_type, browser_press_key, browser_select_option) to fail with "No tab with given id" error after initial navigation.

Environment

Browser MCP Version: Latest (installed via Claude Desktop)
MCP Client: Claude Desktop (Anthropic)
Operating System: Windows 11
Browser: Chrome (with Browser MCP extension installed)
Date Encountered: October 23, 2025

Severity
Critical - Makes all browser interaction completely non-functional
Expected Behavior
After calling browser_navigate() successfully, subsequent calls to interactive tools (browser_click, browser_type, etc.) should work using the tab references from browser_snapshot().

Actual Behavior

✅ browser_navigate() - Works (loads page successfully)
✅ browser_screenshot() - Works (captures page)
✅ browser_snapshot() - Works (returns accessibility tree with refs)
❌ browser_click(ref="s1e11") - Fails with Error: No tab with given id 1374733198
❌ browser_type(ref="s1e75", text="...") - Fails with same error
❌ browser_press_key(key="Tab") - Fails with same error
❌ browser_select_option(ref="...", values=[...]) - Fails with same error

Steps to Reproduce
javascript// Step 1: Navigate (WORKS)
browser_navigate("https://ilfaro.ch/reservation/")
// Returns: Page loaded with snapshot

// Step 2: Get snapshot (WORKS)
browser_snapshot()
// Returns: Full accessibility tree with refs like "s1e11", "s1e75", etc.

// Step 3: Try to click (FAILS)
browser_click(element="Cookie button", ref="s1e11")
// Error: No tab with given id 1374733198

// Step 4: Try to type (FAILS)
browser_type(element="Name field", ref="s1e75", text="Test", submit=false)
// Error: No tab with given id 1374733198
Error Messages
Error: No tab with given id 1374733198.
This error occurs for all interactive operations after navigation, regardless of:

How many times browser_snapshot() is called
Whether references are from the latest snapshot
Time elapsed between operations

Technical Details
What Works

Initial page navigation
Screenshot capture
Accessibility tree retrieval
Reading page structure

What's Broken

ALL interaction operations:

browser_click
browser_type
browser_hover
browser_select_option
browser_press_key

Root Cause Hypothesis
The tab ID (e.g., 1374733198) appears to be:

Generated during initial browser_navigate()
Lost/invalidated before any interaction tools are called
Not being properly stored or retrieved from the MCP server's state

The server seems unable to:

Maintain tab state between tool calls
Retrieve the active tab ID when interaction tools are invoked
Persist the mapping between navigation sessions and tab IDs

Impact Assessment
For End Users

100% of browser automation fails after initial page load
Cannot fill forms, click buttons, or interact with pages
Makes Browser MCP completely unusable for its primary purpose

Reporter: Claude (via Anthropic)
Date: October 23, 2025
Reproduction Rate: 100% (every attempt fails)
Blocking: All browser automation workflows