Connector loads only 5 of 10 tools from self-hosted MCP server — confirmed server returns all 10 via raw curl

### What happened?

MCP server URL or name: https://mcp-gads.consultoria-ia-marketing.com/mcp
How are you connecting to this server? Custom connector URL entered manually (claude.ai connector settings)
Where does the issue occur? After connecting successfully — tools list is incomplete in the chat session, not a connection failure
When did you last reproduce this? 2026-06-17
Reference ID (ofid_): N/A — connection succeeds, this is not an auth/connect failure
Summary:

Self-hosted MCP server (FastMCP-based, Python, reports as google_ads_mcp v1.28.0 in its initialize response) exposes 10 tools via tools/list. The claude.ai connector consistently loads only 5 of them in chat sessions, even after multiple disconnect/reconnect cycles and a full restart of the server container. Verified independently via raw curl against the MCP endpoint (manual initialize → session ID → tools/list) that the server itself returns all 10 tools correctly with valid schemas.

Tools loaded by the connector (5): gads_create_ad_group, gads_get_campaign_detail, gads_update_campaign, gads_list_ads, gads_list_keywords
Tools NOT loaded, despite server exposing them (5): gads_create_campaign, gads_create_keyword, gads_create_responsive_search_ad, gads_update_ad_group, gads_list_campaigns

### What did you expect to happen?

What should happen: All 10 tools the server reports in tools/list should be available to load in the chat session.
What happened instead: Only 5 tools loaded, reproducibly, across multiple reconnects and a server restart.
Possible relevant detail: the server's initialize capabilities declare "tools":{"listChanged":false}. This may cause a caching layer between claude.ai and the server to treat the tool list as immutable from first connection, never refreshing even as the actual tool count grows.
Verification performed: direct curl to /mcp confirms 10/10 tools returned by the server; confirmed single container/replica (no stale instance behind the same domain); disconnect/reconnect of the connector produced a fresh session (different internal naming) but same 5/10 result; tool descriptions for the loaded 5 did refresh content (multi-line docstrings appeared post-reconnect), indicating some live communication occurred, yet the missing 5 never appeared.

### Steps to reproduce

Steps to reproduce:
Connect a custom MCP connector pointing at a FastMCP server exposing 10+ tools
In a chat session, search/load tools from that connector
Observe only a subset loads, while a direct curl tools/list call against the same server endpoint returns the full set

### Area

MCP Connector (adding/managing servers)

### MCP Server (if applicable)

https://mcp-gads.consultoria-ia-marketing.com/mcp

### Error messages or logs

```shell

```

### Additional context

_No response_

Start by reproducing the custom connector against the referenced FastMCP endpoint and compare its loaded tools with a manual initialize followed by tools/list via curl. Inspect the connector's handling of the initialize tools.listChanged capability and tool-list refresh behavior. Done means all 10 server-reported tools are available in the chat session after connecting or reconnecting.

Scritto dal modello di indicizzazione a partire dal testo della issue.