Record M2a limits, the accepted availability risk and three more measurements

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

docs/inference-contract.md

@@ -125,6 +125,23 @@ checkpoint at the end of the previous prompt. The cost is bounded by the thinkin
 answer, and it is paid once. The control run also shows that streamed deltas, concatenated, replay
 byte for byte.
 
+### (l) Closing the connection cancels generation
+
+Measured 2026-09-17: a streaming request was closed by the client while the model was thinking.
+`/slots` showed the slot idle 0.1 s later. A client that aborts frees the GPU.
+
+### (m) Exact token counts while streaming
+
+With `timings_per_token: true` every streamed chunk carries a `timings` object, including
+`predicted_n`, the number of tokens generated so far. A thinking cap can count real tokens.
+
+### (n) Tool-call arguments stream token by token
+
+Measured 2026-09-17: the model wrote a 1,500-word essay into a `write_file` call. 1,999 tokens over
+30 s arrived as 1,948 tool-call deltas, the longest gap between events was 0.33 s, and the
+concatenated `arguments` fragments were valid JSON. The server does not hold a tool call back
+until it parses, so a silence-based liveness limit is safe during long tool calls.
+
 ### (a) Throughput
 
 Method: timed requests, server-reported `timings`, thinking off. "At depth 32k" means a 2k-token