diff --git a/docs/MIGRATION.md b/docs/MIGRATION.md
index 1761a32..02c64b8 100644
--- a/docs/MIGRATION.md
+++ b/docs/MIGRATION.md
@@ -149,4 +149,4 @@ agent, err := odek.New(odek.Config{
 
 ## Cache / cost budgets
 
-Cache usage fields come from the SDK (`Usage.Cache*`). Pin **go-llm-sdk v0.3.2+** so GPT-5.6 tools+reasoning stays on (`POST /v1/responses`) and cache-token parsing remains honest.
+Cache usage fields come from the SDK (`Usage.Cache*`). Pin **go-llm-sdk v0.3.3+** so GPT-5.6 tools+reasoning stays on (`POST /v1/responses`), cache-token parsing remains honest, and DeepSeek thinking-mode tool loops replay `reasoning_content` instead of dropping it (v0.3.2 and older lose the key on turns where the provider elided reasoning, and the loop 400s from then on).
diff --git a/docs/PROVIDERS.md b/docs/PROVIDERS.md
index eb0b6d0..0c8f434 100644
--- a/docs/PROVIDERS.md
+++ b/docs/PROVIDERS.md
@@ -47,6 +47,15 @@ actually reasons, and a reasoning summary is streamed back. `thinking=disabled`
 stays on Chat Completions with `reasoning_effort: none`. The same Responses
 route is used for GPT-5.4/5.5 when an explicit thinking level is set.
 
+**DeepSeek (`deepseek`, the default id):** thinking mode requires
+`reasoning_content` to be replayed on every assistant turn of a request that
+carries tools, including turns where the provider returned no reasoning of
+its own, which happens on some turns. With go-llm-sdk v0.3.3+ odek echoes the
+key on tool-carrying requests, so such a turn no longer serializes without it.
+On v0.3.2 and older the key is dropped when empty and a long tool loop dies
+mid-run with `400 ... The reasoning_content in the thinking mode must be
+passed back to the API`, then fails on every later request in that loop.
+
 ## odek knobs (not in the SDK)
 
 | Knob | Where |
diff --git a/go.mod b/go.mod
index 44408e7..09ec74a 100644
--- a/go.mod
+++ b/go.mod
@@ -11,4 +11,4 @@ require (
 
 require golang.org/x/sys v0.47.0
 
-require github.com/BackendStack21/go-llm-sdk v0.3.2
+require github.com/BackendStack21/go-llm-sdk v0.3.3
diff --git a/go.sum b/go.sum
index cb0c96c..f9c2e33 100644
--- a/go.sum
+++ b/go.sum
@@ -1,5 +1,7 @@
 github.com/BackendStack21/go-llm-sdk v0.3.2 h1:aUXa450t+eOtLmuNX6gOMSD4zZsGCKtaIaG1YDHmNxY=
 github.com/BackendStack21/go-llm-sdk v0.3.2/go.mod h1:Nhro6plQaVIIFajPhzp2dzz4rv4DFU/yXNEudChllyE=
+github.com/BackendStack21/go-llm-sdk v0.3.3 h1:JlMQL8K7W+BVe7zjhP7MMYK5VNqmK38QlDrFjA7Pp2c=
+github.com/BackendStack21/go-llm-sdk v0.3.3/go.mod h1:Nhro6plQaVIIFajPhzp2dzz4rv4DFU/yXNEudChllyE=
 github.com/BackendStack21/go-mcp v1.3.0 h1:55iJgiAgcptv+mQwWEHNaFqPJksPR6zn4beYjHk/Ea4=
 github.com/BackendStack21/go-mcp v1.3.0/go.mod h1:RKFw6nrl6ySQqqrR8KtG7HYZ/heyyjT8SjiEtlbTMY8=
 github.com/BackendStack21/go-vector v1.4.0 h1:Ssu5RDEt4Cr9A17/ogdfjeuaLFFNHASJBIEGpqKzAV0=