From 74e2b97b1bd9e474e356b7189bd4dccc01cae6f6 Mon Sep 17 00:00:00 2001
From: teamchong <25894545+teamchong@users.noreply.github.com>
Date: Thu, 18 Jun 2026 21:34:03 -0400
Subject: [PATCH] =?UTF-8?q?docs:=20exact-recall=20escape=20hatch=20?=
 =?UTF-8?q?=E2=80=94=20route=20byte-exact=20subtasks=20to=20a=20non-Fable?=
 =?UTF-8?q?=20subagent?=
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---
 README.md | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/README.md b/README.md
index fe4740e..e4a4890 100644
--- a/README.md
+++ b/README.md
@@ -65,6 +65,14 @@ came back **0/15** on Opus and 13/15 on Fable 5, and the failure mode is
 need back byte-exact (IDs, hashes, secrets, exact numbers) must stay text.
 Recent turns do; a dedicated verbatim-risk guard is not built yet.
 
+**Exact-recall escape hatch.** pxpipe only images Fable requests
+(`PXPIPE_MODELS=claude-fable-5`), so any subagent on a non-Fable model passes
+through as text. Route work that needs byte-exact values to one — globally with
+`CLAUDE_CODE_SUBAGENT_MODEL=claude-sonnet-4-6`, or per-agent with `model: sonnet`
+in the agent frontmatter. It reads from source (file/JSONL), not the imaged
+history. This covers exact-recall you route on purpose; it does **not** catch a
+silent misread you did not expect — that is the unbuilt guard above.
+
 **Does it break real work?** Parity in what we measured: a 10-instance
 SWE-bench Lite pilot (the easy subset) resolved **10/10 on both arms**,
 pxpipe ON at $27 vs OFF at $54 token-equivalent, and 19 SWE-bench Pro