Claude Code gateway compatibility guide changedllm-gateway-protocol
Nearest release: v2.1.283, published 5 hours before upstream edited the page. Shown because the two are within 24 hours of each other. Nothing here says the release caused the edit.
Upstream edited this page at 26 Sep 2026 00:30 UTC, give or take a minute or two: the time comes from Anthropic’s own sitemap rather than from a commit. This site recorded the change at 26 Sep 2026 00:37 UTC.
Upstream edited
Recorded here
Lines+4added
Lines−0removed
From line
61
where the diff opens
First seen
14 Aug 2026
this site's first read of the page
Recorded edits22to this page, all time
The whole hunk
from line 61, old and new numbered
/
from line 61
6161
6262Stream inference responses. Claude Code reads the stream as it arrives, so if your gateway buffers complete responses before relaying them, Claude Code stalls.
6363
64Deliver each response's full event sequence without dropping, duplicating, or reordering events. When an event references a content block whose `content_block_start` never arrived, or a block whose `content_block_stop` already arrived, Claude Code stops reading the stream at that event instead of applying it, so a duplicated `content_block_stop` can't run the same tool call twice. [The response above may be incomplete](/docs/en/errors#the-response-above-may-be-incomplete) describes what the user sees, under the `Part of the response never arrived` and `The response stream was malformed` variants.
65
66Relay each response through its final `message_delta` and `message_stop` events before ending the body. A body that ends after a `message_delta` carrying a `stop_reason`, with no content block still open and no content block event after that frame, counts as complete even when `message_stop` is missing. A body that your gateway ends cleanly any earlier, once a content block has started, is treated the same as a dropped connection: [Automatic retries](/docs/en/errors#automatic-retries) says when Claude Code re-issues the request, and [The response above may be incomplete](/docs/en/errors#the-response-above-may-be-incomplete) covers what it keeps once visible content has arrived. Claude Code keeps the `stop_reason` a `message_delta` delivers, so a later usage-only `message_delta` whose `delta` has `stop_reason: null` or no `stop_reason` key doesn't clear it.
67
6468When the client speaks the Amazon Bedrock format, relay the `InvokeModelWithResponseStream` response body and its `Content-Type: application/vnd.amazon.eventstream` header unmodified, and don't convert the stream to server-sent events. See [Streaming errors behind a gateway or proxy](/docs/en/amazon-bedrock#streaming-errors-behind-a-gateway-or-proxy).
6569
6670Forward keep-alive pings as well. On connections through `ANTHROPIC_BASE_URL` or `ANTHROPIC_AWS_BASE_URL`, Claude Code counts every byte your gateway relays, including SSE `ping` events and comment lines, and aborts a stream that goes silent for 300 seconds by default. The upstream's pings are the only traffic during long thinking pauses, so if your gateway strips or buffers them, Claude Code aborts the stream during those pauses; [Automatic retries](/docs/en/errors#automatic-retries) covers what an aborted stream reports based on how far the response had progressed. An upstream that sends no pings at all, such as Amazon Bedrock's binary event-stream, leaves those pauses with nothing to forward. When translating from such an upstream, emit your own `ping` events during silent gaps. Gateways reached through `ANTHROPIC_BEDROCK_BASE_URL`, `ANTHROPIC_VERTEX_BASE_URL`, or `ANTHROPIC_FOUNDRY_BASE_URL` aren't wrapped by this byte-level watchdog, even when they relay the Anthropic Messages format; there, a [5-minute idle timeout](/docs/en/env-vars) aborts a silent stream instead, and on `ANTHROPIC_BEDROCK_BASE_URL` connections you can add the byte watchdog with [`CLAUDE_ENABLE_BYTE_WATCHDOG_BEDROCK`](/docs/en/env-vars).
No line in this hunk matches that.