[CLOSED - Not a bug] MCP tool descriptions not refreshed in current session after `/mcp reconnect`

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

Description

After reconnecting an MCP server via /mcp reconnect <server-name>, the tool descriptions visible to Claude in the current conversation remain stale. The old tool schemas from session start persist — updated descriptions are only picked up in a new session.

Steps to Reproduce

1. Start a Claude Code session
2. Note a tool's description (e.g., ask Claude: "What description do you see for tool X?")
3. Change the tool description in the MCP server source code
4. Restart the MCP server process
5. Run /mcp reconnect <server-name> — reports successful reconnection
6. Ask Claude again what description it sees for the same tool

Expected Behavior

After /mcp reconnect, the updated tool schemas (including descriptions and parameter definitions) should be re-injected into the current conversation context.

Actual Behavior

The old descriptions from session start persist. Claude still sees pre-change descriptions. Only starting a fresh session picks up the changes.

Impact

When iterating on MCP tool descriptions during a session, changes are invisible until starting a new session. This makes /mcp reconnect incomplete — it reconnects the transport but doesn't refresh the tool schemas visible to the model.

Environment

• Claude Code CLI (latest)
• macOS
• Custom MCP servers via stdio transport

What Should Happen?

After /mcp reconnect <server>, the model should see the refreshed tool schemas (descriptions, parameters, enums) for subsequent turns in the same conversation. Currently only the transport reconnects — the tool definitions injected into the model context remain stale until a new session.

Error Messages/Logs

No error messages. `/mcp reconnect <server>` reports "Successfully reconnected to <server>" — the reconnect itself succeeds. The issue is silent: tool schemas in the model context are not refreshed, only observable by asking Claude what description it sees for a tool.

Steps to Reproduce

1. Start a Claude Code session with a custom MCP server (stdio transport)
2. Ask Claude: "What description do you see for tool X?" — note the response
3. Change the tool's description in the MCP server source code
4. Restart the MCP server process
5. Run /mcp reconnect <server-name> — reports "Successfully reconnected"
6. Ask Claude the same question — it still reports the old description
7. Start a new session — now the updated description appears

Claude Model

Opus

Is this a regression?

Yes, this worked in a previous version

Last Working Version

N/A — tool descriptions have never refreshed after /mcp reconnect in any version I have tested.

Claude Code Version

macOS 15.4, Darwin 25.2.0, Apple Silicon (aarch64)

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

Discovery context: While editing MCP tool descriptions in a code-in-database project, we updated the toolname-goes-here tool description, reconnected the MCP server, and then asked Claude to introspect its own tool definition. It still saw the pre-edit description.

This suggests /mcp reconnect re-establishes the transport/connection but does not re-inject the tool list into the model's conversation context. The tool schemas appear to be loaded once at session start and cached for the lifetime of the conversation.

Subagents (spawned via Task tool) are unaffected — they start fresh sessions and pick up the current schemas. Only the main conversation context is stale.