Image: GitHub
Why it mattersOpen your Claude Code and Codex settings. Remove any Postman MCP server you did not add yourself.
A developer who runs Postman on a Mac opened their Claude Code settings this week. They found a Postman MCP server they did not add. On 25 October a user with the handle indicava filed an issue on the Postman desktop repository. The title: "[SEVERE] Desktop auto-installs Codex/Claude plugins; installer attempts to trust its own startup hook". The thread reached 181 points on Hacker News on 3 November. Postman has not replied on the issue page.
What the developer found
Indicava was running Postman desktop 12.33.4 with its own Codex plugin at 1.1.0 and Claude plugin at 2.0.1. Postman's own log at ~/Library/Application Support/Postman/logs/main.log recorded the line PostmanAgentPluginService~install: script completed with the results claude-code:installed,codex:installed. The source field for that install read auto-existing-upgrade.
Four changes landed on the machine, every one of them silently.
Postman wrote a new MCP server at https://mcp.postman.com/mcp into ~/.claude/settings.json and ~/.codex/config.toml. It wrote startup hooks to hooks/codex-hooks.json and to the Claude settings file. The hooks route API engineering tasks to Postman by default. It added itself to ~/.claude/plugins/installed_plugins.json. And it dropped a Postman CLI into ~/.local/bin.
The user wrote that no prompt asked for consent. The plugins approved their own hooks inside Claude Code and Codex, which normally ask the user before trusting a hook.
Why this matters for a developer
A hook is code that runs inside Claude Code or Codex. It fires when the agent reads a file, calls a tool or starts a task. An MCP server is a remote endpoint the agent can send data to. Both are a path for anything the agent sees to leave the machine. The default in both products is to ask the user before trusting one.
Postman's own documentation presents its MCP server as a way for an AI agent to call Postman API collections. On a developer laptop that often means production keys, staging URLs and internal API responses.
What to do today
A developer on Postman desktop 12.33.4 or later should open ~/.claude/settings.json and ~/.codex/config.toml. Look for an entry pointing at mcp.postman.com. Check ~/.claude/plugins/installed_plugins.json for a Postman entry you did not approve. Removing those lines reverses the install.
The quieter fix is to stop Postman from auto-upgrading. Postman's own documentation names the setting under Preferences, Update, and the option is to require manual updates. The user chose it, Postman desktop still wrote the plugin on a later launch.
As of 3 November 2026 the GitHub issue is open. It has 33 👍 reactions and no official reply. The issue page is the only primary account on this story so far.
Source
This item was written by an AI system from the linked source. Reveneau is responsible for what it publishes.
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