diff --git a/CHANGELOG.md b/CHANGELOG.md
index cc48c3797..7e03c422f 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,9 +2,11 @@
 
 ## Unreleased
 
+- `variantsByModel` entries now support an optional `:api` filter (string or vector) to restrict variant matching by provider API type.
 - Custom commands and skills now expose `:arguments` metadata inferred from their content. Previously they always reported empty arguments.
 - Native `skill-create`, `plugin-install`, and `plugin-uninstall` commands now declare `:required true` on their arguments in the command listing.
-- - Fix documentation link in `--help` output
+- Fix documentation link in `--help` output.
+- Add built-in variants for `deepseek-v4-pro` (`none`, `high`, `max`).
 
 ## 0.131.1
 
diff --git a/docs/config.json b/docs/config.json
index 5204393bf..fbd86c19c 100644
--- a/docs/config.json
+++ b/docs/config.json
@@ -475,6 +475,17 @@
           "items": {
             "type": "string"
           }
+        },
+        "api": {
+          "type": [
+            "string",
+            "array"
+          ],
+          "description": "Restrict variants to the given API type(s). String for exact match, array for any-of. Absent = match all.",
+          "markdownDescription": "Restrict variants to the given API type(s). String for exact match, array for any-of. Absent = match all.",
+          "items": {
+            "type": "string"
+          }
         }
       },
       "additionalProperties": false
diff --git a/docs/config/variants.md b/docs/config/variants.md
index 5e9ed3464..b941ea567 100644
--- a/docs/config/variants.md
+++ b/docs/config/variants.md
@@ -35,6 +35,16 @@ ECA ships with built-in variants for some known models via the `variantsByModel`
     | `high`     | `{"reasoning": {"effort": "high", "summary": "auto"}}` |
     | `xhigh`    | `{"reasoning": {"effort": "xhigh", "summary": "auto"}}` |
 
+=== "DeepSeek"
+
+    Applies to models matching `deepseek-v4-pro`. Only for providers using the `openai-chat` API.
+
+    | Variant    | Payload |
+    | ---------- | ------- |
+    | `none`     | `{"thinking": {"type": "disabled"}}` |
+    | `high`     | `{"reasoning_effort": "high"}` |
+    | `max`      | `{"reasoning_effort": "max"}}` |
+
 ## Custom Variants
 
 You can define your own variants per model under `providers.<provider>.models.<model>.variants`. Custom variants are merged with built-in ones — if names clash, your definition wins.
diff --git a/src/eca/config.clj b/src/eca/config.clj
index b677da5b5..b9f241289 100644
--- a/src/eca/config.clj
+++ b/src/eca/config.clj
@@ -72,6 +72,11 @@
    "xhigh" {:output_config {:effort "xhigh"} :thinking {:type "adaptive" :display "summarized"}}
    "max" {:output_config {:effort "max"} :thinking {:type "adaptive" :display "summarized"}}})
 
+(def ^:private deepseek-variants
+  {"none" {:thinking {:type "disabled"}}
+   "high" {:reasoning_effort "high"}
+   "max" {:reasoning_effort "max"}})
+
 (def ^:private initial-config*
   {:providers {"openai" {:api "openai-responses"
                          :url "${env:OPENAI_API_URL:https://api.openai.com}"
@@ -188,7 +193,9 @@
    :variantsByModel {".*sonnet[-._]4[-._]6|opus[-._]4[-._][56]" {:variants anthropic-variants}
                      ".*opus[-._]4[-._]7" {:variants anthropic-v2-variants}
                      ".*gpt[-._]5(?:[-._](?:2|4|5)(?!\\d)|[-._]3[-._]codex)" {:variants openai-variants
-                                                                            :excludeProviders ["github-copilot"]}}
+                                                                              :excludeProviders ["github-copilot"]}
+                     ".*deepseek[-._]v4[-._]pro" {:variants deepseek-variants
+                                                  :api "openai-chat"}}
    :mcpTimeoutSeconds 60
    :lspTimeoutSeconds 30
    :streamIdleTimeoutSeconds 120
@@ -243,10 +250,16 @@
    A variant set to {} is removed from the result, allowing users to disable
    built-in variants."
   [config provider model-name user-variants]
-  (let [builtin (when model-name
-                  (some (fn [[pattern-str {:keys [variants excludeProviders]}]]
+  (let [provider-api (get-in config [:providers provider :api])
+        api-match? (fn [api config-val]
+                     (cond (sequential? config-val) (some #{api} config-val)
+                           config-val (= api config-val)
+                           :else true))
+        builtin (when model-name
+                  (some (fn [[pattern-str {:keys [variants excludeProviders api]}]]
                           (when (and (regex-matches? pattern-str model-name)
-                                     (not (some #{provider} excludeProviders)))
+                                     (not (some #{provider} excludeProviders))
+                                     (api-match? provider-api api))
                             variants))
                         (:variantsByModel config)))
         merged (cond