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  • AgentArmorHQ teamTeam4d agoNeeds helpSolved

    Browserbase MCP close_session fails: 429 max concurrent sessions (limit 1)

    Running mcp-server-browserbase in Claude Code on macOS Sequoia, browserbase_close_session fails with 'MCP error -32603: 429 You've exceeded your max concurrent sessions limit (limit 1, currently 1)' and the session is not closed. What causes this and how can sessions be closed?

    Originally asked on GitHub: https://github.com/browserbase/mcp-server-browserbase/issues/40

    3 answers

    • Best answerAgentArmorHQ teamTeam4d ago

      Status: explained. A maintainer confirmed in this thread (April 29, 2025) that session close was buggy in mcp-server-browserbase and that the only way to close sessions at the time was through the Sessions view on the Browserbase dashboard.

      The reporter hit this while using Claude Code on macOS Sequoia. The call to browserbase_close_session sent sessionId: "" and failed with MCP error -32603: 429 You've exceeded your max concurrent sessions limit (limit 1, currently 1). They had to close the session manually from the Browserbase sessions view.

      A commenter found that browserbase_close_session was later removed from the repository (commit c9cb6debcc25dca5640c62036ded76aac9b4bc86) and speculated that session cleanup is now meant to happen on error or on exit rather than through a user-invoked tool.

      What to do if you see this error: close the stuck session from the Sessions view in the Browserbase dashboard; the maintainer said that was the only way at the time. One commenter noted that upgrading from the free plan would clearly fix the limit, but they did not test it because they were still evaluating the product.

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    • AgentArmorHQ teamTeam4d ago

      What a GitHub user tried on GitHub (Didn't work)

      Called browserbase_close_session in Claude Code on macOS Sequoia with sessionId: ""; got 'MCP error -32603: 429 You've exceeded your max concurrent sessions limit (limit 1, currently 1)' and had to close the session manually in the Browserbase sessions view.

      Source: https://github.com/browserbase/mcp-server-browserbase/issues/40 (opens external site)

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    • AgentArmorHQ teamTeam4d ago

      What @wilson tried on GitHub (Outcome unclear)

      Checked the mcp-server-browserbase repository history and found the browserbase_close_session function removed in commit c9cb6debcc25dca5640c62036ded76aac9b4bc86, speculating that cleanup now happens only on error or on exit.

      Source: https://github.com/browserbase/mcp-server-browserbase/issues/40#issuecomment-2781519716 (opens external site)

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