README: embed main-stream + subagent plots

README.md

@@ -136,6 +136,32 @@ Across **all** requests (main + sub-agent inner = 37,766 requests):
 | OSL (tokens)                 |      224 |      478 |    1,150 |    1,907 |    5,461 |      530 |
 | Top entries/trace            |      115 |        — |        — |      678 |    1,141 |      231 |
 
+## Plots
+
+### Main-agent stream
+
+Histograms across all 21,566 main-agent turns (sub-agent groups skipped).
+Same view as the [no-subagents sibling](https://huggingface.co/datasets/semianalysisai/cc-traces-weka-no-subagents-051826) — the two datasets share an identical main-agent stream.
+
+![Main-stream distributions — log x](plots/distributions_log.png)
+![Main-stream distributions — linear x](plots/distributions_linear.png)
+
+### Sub-agent fan-out analysis
+
+Histograms across all 618 sub-agent groups (and their 16,200 inner requests). Companion to the main-stream plots — answers questions about how often sub-agents are spawned, how deep their tool-loops go, how long they take, and how much intra-group prefix cache reuse exists.
+
+![Sub-agent distributions — log x](plots/subagent_distributions_log.png)
+![Sub-agent distributions — linear x](plots/subagent_distributions_linear.png)
+
+Six panels:
+
+1. **Sub-agent groups per trace** — distribution of how many distinct sub-agent invocations each session spawns
+2. **Inner requests per group** — depth of each sub-agent's tool-use loop
+3. **Group wall-clock duration** — first→last inner span (seconds)
+4. **Group total tokens** — `Σ(in + out)` across each group's inner requests
+5. **Inner-request ISL** — per-call input length INSIDE sub-agent loops (smaller than main-agent turns because sub-agents work on focused sub-problems with trimmed context)
+6. **Intra-group cache hit rate** — for each non-first inner request, fraction of `hash_ids` already seen in earlier inners of the SAME group. Captures how much KV-cache reuse a local prefix cache would get out of a sub-agent's tool-use loop (typically high — sub-agents iterate on a stable prompt)
+
 ## Model composition
 
 | model | requests (main + subagent inner) |