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Alex
1 day ago

Nightfall blocked my Notion MCP write and I almost killed the gateway

#agents#tooling#mcp
Nightfall MCP Gateway
Govern Cursor and Claude Code MCP tool calls

been running Nightfall MCP Gateway in front of Cursor + Claude Code for about a week. $20/mo out of pocket until the team notices.

Tuesday it blocked notion.create_page mid-standup notes. fair. I had docs-path on allow and somehow still got 40 red denials in an hour because the agent kept probing notion.update_block.

turned the whole gateway off for 12 minutes. turned it back on. allowlisted only read tools after that.

anyone else running this without drowning in deny spam?

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  • Hao Ward

    Do not turn it off. I saw agent delete a Stripe refund helper once with green CI. Gateway stop that kind of thing.

    For Notion, did you set write tools to deny by default, or only allowlist read? Blast radius on create_page is already bad if it posts to wrong workspace.

    • Kai

      silent allowlist mismatch ate ~40 min of my friday.

      gateway ui said notion.search allow, cursor still got deny. tool name in the policy was Notion.search — casing. once i lowercased both sides the red spam dropped to like 3/hr.

      read-only allowlist is the only setup that doesn't make me want to deny:false at 11pm.

      • Jules Park

        repro'd the casing trap on win11 too. gateway allowlist had notion.Search, cursor sent notion.search. UI looked green, every call red.

        i started dumping tools/list JSON and diffing against the policy file before trusting the badge. took 2 minutes, saved another friday.

  • Wei Zhang

    Do not kill the gateway. I see this on MCP servers I maintain — client says connected, agent still probes write tools for an hour.

    For Notion I put deny-by-default on create_page / update_block / append_block_children. Only search + get_page on allow. Deny spam drops a lot after that.

    Also check stdio log for the exact tool name string. UI label and schema name are sometimes different.

  • Jonah

    same on nightfall + cursor this week

    blocked notion.update_block like 60+ times in one standup then i almost flipped deny:false

    kept it on. read tools only. $20/mo is cheaper than a wrong page in the company wiki

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