diff --git a/packages/coding-agent/CHANGELOG.md b/packages/coding-agent/CHANGELOG.md
index a8b4ea02..1fcde0b7 100644
--- a/packages/coding-agent/CHANGELOG.md
+++ b/packages/coding-agent/CHANGELOG.md
@@ -9,7 +9,7 @@
 
 ### Fixed
 
-- Fixed HTTP timeout setting not being respected for non-Codex providers (e.g., llama.cpp via OpenAI-compatible API). The `httpIdleTimeoutMs` setting (set via `/settings` HTTP timeout) now applies as the default SDK request timeout for all providers that support it, not just OpenAI Codex Responses. Disabling the timeout (HTTP timeout = false) now correctly disables SDK timeouts for all supported providers ([#5294](https://github.com/earendil-works/pi/issues/5294)).
+- Fixed HTTP timeout setting not being respected for non-Codex providers (e.g., llama.cpp via OpenAI-compatible API). The `httpIdleTimeoutMs` setting (set via `/settings` HTTP timeout) now applies as the default SDK request timeout for all providers that support it, not just OpenAI Codex Responses. Disabling the timeout (HTTP timeout = false) now correctly disables SDK timeouts for all supported providers by sending a maximum int32 value (effectively infinite) instead of 0, since SDKs treat timeout=0 as an immediate timeout ([#5294](https://github.com/earendil-works/pi/issues/5294)).
 - Fixed opening and listing very large JSONL session files by reading session entries line-by-line instead of materializing the full file as one string ([#5231](https://github.com/earendil-works/pi/issues/5231)).
 
 ## [0.78.0] - 2026-05-29
diff --git a/packages/coding-agent/src/core/sdk.ts b/packages/coding-agent/src/core/sdk.ts
index 417e8a11..7a1c922b 100644
--- a/packages/coding-agent/src/core/sdk.ts
+++ b/packages/coding-agent/src/core/sdk.ts
@@ -342,8 +342,11 @@ export async function createAgentSession(options: CreateAgentSessionOptions = {}
 				throw new Error(auth.error);
 			}
 			const providerRetrySettings = settingsManager.getProviderRetrySettings();
-			const timeoutMs =
-				options?.timeoutMs ?? providerRetrySettings.timeoutMs ?? settingsManager.getHttpIdleTimeoutMs();
+			const httpIdleTimeoutMs = settingsManager.getHttpIdleTimeoutMs();
+			// SDKs treat timeout=0 as 0ms (immediate timeout), not "no timeout".
+			// Use max int32 to effectively disable the timeout.
+			const effectiveTimeoutMs = httpIdleTimeoutMs === 0 ? 2147483647 : httpIdleTimeoutMs;
+			const timeoutMs = options?.timeoutMs ?? providerRetrySettings.timeoutMs ?? effectiveTimeoutMs;
 			const websocketConnectTimeoutMs =
 				options?.websocketConnectTimeoutMs ?? settingsManager.getWebSocketConnectTimeoutMs();
 			const attributionHeaders = getAttributionHeaders(model, settingsManager, options?.sessionId);