ToolTrust
C27/100
modelcontextprotocol

mcpb

mcp2.1.2

@modelcontextprotocol

Desktop Extensions: One-click local MCP server installation in desktop apps

By modelcontextprotocol | 15 findings | Scanned 6/15/2026 | tooltrust-scanner/v0.3.17 | 2.0k

1 Critical2 Low12 Info

Risk Summary

Needs Approval

Dep Visibility plus Excessive Permissions raises enough risk that this tool should not be auto-trusted.

Potential impact: This finding indicates the tool should be reviewed before it is trusted.

Recommended action: Keep this tool behind manual approval and avoid unattended runs until the risky capabilities are narrowed or removed.

Suggested policy: keep this tool behind manual approval, do not allow unattended runs, and re-scan after narrowing risky permissions.

Security Findings (15)

  • CriticalAS-006

    💻Arbitrary Code Execution

    heuristic signal

    execute_javascript:tool name or description implies arbitrary script/code execution (evaluate_script, execute javascript, etc.)

    Fix: This tool can execute arbitrary code or shell commands on the host system. Remove it unless strictly required. If kept: (1) restrict access to trusted users/agents only, (2) require human approval before each invocation (Claude Desktop: set approval_required: true; other clients: enable equivalent confirmation), (3) use the most restrictive sandbox or read-only mode available, and (4) never expose this tool to untrusted input sources.

  • LowAS-011

    ℹ️Missing Rate-Limit / Timeout ×2

    tool performs network or execution operations but declares no rate-limit, timeout, or retry configuration

    open_urlexecute_javascript

    Fix: Declare explicit rate-limit, timeout, and retry configuration for all network and execution tools. Implement exponential back-off and surface resource state to the calling agent.

  • InfoAS-002

    ⚠️Excessive Permissions ×2

    declared capabilities: network access

    open_url

    declared capabilities: code/command execution

    execute_javascript

    Fix: Tool requests broad permissions (exec/fs/network). Validate input parameters using Enums where possible, and restrict file system operations to explicit allowed directories.

  • InfoAS-014

    ℹ️Dependency Inventory Unavailable ×10

    Tool did not expose metadata.dependencies or repo_url, so supply-chain coverage is limited.

    open_urlget_current_tablist_tabsclose_tabswitch_to_tabreload_tabgo_backgo_forwardexecute_javascriptget_page_content

    Fix: Review and remediate the identified issue.

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$ curl -sfL https://raw.githubusercontent.com/AgentSafe-AI/tooltrust-scanner/main/install.sh | bash
$ tooltrust-scanner scan --server "npx -y mcpb"

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