Improve in-flight cancel latency via run abort signal propagation

docs/api/PROTOCOL.md

@@ -700,6 +700,7 @@ Cancel the current agent operation.
 
 Used by the web dashboard/chat stop button and channel-level `/stop` / `/cancel` command fast-paths.
 Cancellation is best-effort and stops at the next agent/tool-loop safe point.
+Flynn now propagates a run-level abort signal into model/tool execution, so providers/tools that honor `AbortSignal` typically stop promptly instead of waiting for request/tool timeouts.
 
 ### Node Methods
 

docs/api/TOOLS.md

@@ -68,6 +68,8 @@ export interface ToolExecutionContext {
 }
 ```
 
+`signal` is wired to run-level cancellation (`agent.cancel`, `/stop`, `/cancel`) and tool timeout. Tools should honor it for fast cooperative aborts.
+
 ### ToolResult
 
 ```typescript