Unclear The second condition is not identified, so setting the variable may not be enough on its own.
MCP servers are outside tools and services that Claude Code connects to. Some of them are reached over the web, using HTTP or SSE (a kind of streaming web connection). In a sandbox, which is a restricted environment that limits what Claude Code can reach, web traffic passes through a proxy that applies a network policy.
When the proxy refuses a connection, it answers with a 403 status (the web's "forbidden" code) and a message starting "request blocked" that says no rule or allowlist entry allows the host, or that the request was blocked by policy. Claude Code can now remember the host and port in that answer. When an MCP server reached over HTTP or SSE then fails with such a refusal, Claude Code skips retrying it if its address is https and uses a remembered host and port.
This only happens when both of these hold:
CLAUDE_CODE_MCP_NO_REDIAL_AFTER_POLICY_REFUSALis set to true- a second internal condition is also met
It stops sandboxed sessions from reconnecting again and again to MCP servers that the network policy has already blocked. Without the variable, Claude Code keeps retrying as before.
The second condition is not identified, so setting the variable may not be enough on its own.