HTTP 429 rate limit

[dawtips]

I've seen this over the past few days. Just a single call, without any others over the past 1-12 hours, gets rate limited. This is with Claude Managed Agents.

Request:
{
"evaluated_permission": "allow",
"id": "...",
"input": {
"query": "Dynamics 365 Sales standard entities lead opportunity quote quotedetail product pricelevel territory account contact"
},
"mcp_server_name": "microsoft-learn",
"name": "microsoft_docs_search",
"processed_at": "2026-04-14T15:20:16.555Z",
"type": "agent.mcp_tool_use"
}

Response:
{
"content": [
{
"text": "HTTP 429",
"type": "text"
}
],
"id": "...",
"is_error": true,
"mcp_tool_use_id": "sevt_018ryBGvo3d1SXeVuUwxXcvj",
"processed_at": "2026-04-14T15:20:17.472Z",
"type": "agent.mcp_tool_result"
}

[TianqiZhang]

@dawtips thanks for reporting this, we are aware of the rate limiting issue with Claude and are working on the mitigation. The root cause is that Claude.ai is using a single outbound IP for all the MCP calls coming out of the managed agents, so it's very easy to trigger our throttling rules.

[Wixee]

Hi @dawtips, could you please help confirm if the issue persists?

[dawtips]

Doesn't look like it. Many calls were 429ing just on init and some when calling a search function.

Session	When	Result
cold #1	t+4.0 min	mcp_init_429
cold #2	t+5.5 min	mcp_init_429
cold #3	t+8.1 min	mcp_init_429
cold #4	t+16.3 min	init OK, tool call 429
cold #5	t+21.4 min	mcp_init_429
cold #6	t+22.7 min	mcp_init_429
cold #7	t+26.7 min	mcp_init_429
cold #8	t+28.9 min	mcp_init_429
cold #9	t+29.1 min	mcp_init_429
cold #10	t+29.8 min	mcp_init_429