feat(harness): expose TurnRunner inspection and cancel results

crates/tinyagents-harness/src/turn_runner/README.md

@@ -60,4 +60,28 @@ existing sinks. When one generation failure retires queued requests, the runner
 rewrites each classification message to match that request's queued failure
 message while preserving its class and details.
 
+`TurnQueueItem<P>` lets a host store its own queue wrapper while the runner and
+agent loop share the same `RunQueue` allocation. Implement the lossless request
+conversions on the host wrapper and select it as the runner's trailing
+queue-item type; the default remains `TurnRequest<P>`. Queue snapshots and
+`TurnHost::run` expose that exact queue item type, while dispatch converts the
+item back to its complete `TurnRequest<P>`.
+
+## Host inspection and cancellation
+
+`live_turns` returns identity-only `LiveTurn` records for primary and parallel
+turns tracked through cleanup, including turns already canceled or completing.
+Hosts can filter these records by `ScopeKey` and thread to prepare cancellation
+notes without receiving runner-owned tokens. Use
+`cancel_requests` to cancel matching turns and receive the request IDs it
+actually stopped; when an unscoped cancellation matches multiple turns, the
+primary request ID comes first, followed by parallel request IDs in
+lexicographic order. The existing `cancel` method remains a boolean wrapper
+for callers that only need to know whether anything matched.
+
+`queue_snapshot` copies the active primary queue without consuming it. Items
+are tagged by lane in Steer, Followup, Collect order, with FIFO order preserved
+within each lane. Hosts can render or classify pending work from the snapshot
+and still leave subsequent draining to the runner.
+
 Focused unit coverage lives in `mod_tests.rs` and `mod_api_tests.rs`.

crates/tinyagents-harness/src/turn_runner/mod.rs

@@ -13,8 +13,8 @@ pub(crate) use types::ActiveTurn;
 
 pub use types::{
     EventSink, FailureClassification, FailureClassifier, IngressDecision, IngressPolicy,
-    IngressStage, QueueDisposition, ReplyStore, RequeuePayload, ScopeKey, Summarizer,
-    TerminalEvent, TurnHost, TurnRequest, TurnResult, TurnRunner, TurnRunnerConfig,
+    IngressStage, LiveTurn, QueueDisposition, ReplyStore, RequeuePayload, ScopeKey, Summarizer,
+    TerminalEvent, TurnHost, TurnQueueItem, TurnRequest, TurnResult, TurnRunner, TurnRunnerConfig,
     TurnRunnerError, TurnSession, TurnSignal, WorkTracker, deterministic_reply_id,
 };