diff --git a/CHANGELOG.md b/CHANGELOG.md
index ed971958..d96e920f 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,7 @@
 # Changelog
 
 ## Unreleased
+- Improved file contexts: now use :lines-range
 
 - BREAKING ECA now only supports standard plain-text netrc as credential file reading. Drop authinfo and gpg decryption support. Users can choose to pass in their own provisioned netrc file from various secure source with `:netrcFile` in ECA config.
 
diff --git a/src/eca/features/context.clj b/src/eca/features/context.clj
index 1a7ab683..a622a6ad 100644
--- a/src/eca/features/context.clj
+++ b/src/eca/features/context.clj
@@ -88,7 +88,7 @@
        {:type :file
         :path path
         :content (llm-api/refine-file-context path lines-range)}
-       :partial (some? lines-range)))))
+       :lines-range lines-range))))
 
 (defn raw-contexts->refined [contexts db]
   (mapcat (fn [{:keys [type path lines-range position uri]}]
diff --git a/src/eca/features/prompt.clj b/src/eca/features/prompt.clj
index baf21362..4e8506dd 100644
--- a/src/eca/features/prompt.clj
+++ b/src/eca/features/prompt.clj
@@ -61,12 +61,16 @@
 
 (defn contexts-str [refined-contexts repo-map*]
   (multi-str
-   "<contexts description=\"Manually Provided by user. Their content is current and accurate. You MUST use this information first before using tools to read them.\">"
+   "<contexts description=\"User-Provided Snippet. This content is current and accurate. Treat this as sufficient context for answering the query.\">"
    (reduce
-    (fn [context-str {:keys [type path position content partial uri]}]
+    (fn [context-str {:keys [type path position content lines-range uri]}]
       (str context-str (case type
-                         :file (if partial
-                                 (format "<file partial=true path=\"%s\">...\n%s\n...</file>\n" path content)
+                         :file (if lines-range
+                                 (format "<file line-start=%s line-end=%s path=\"%s\">%s</file>\n"
+                                         (:start lines-range)
+                                         (:end lines-range)
+                                         path
+                                         content)
                                  (format "<file path=\"%s\">%s</file>\n" path content))
                          :agents-file (multi-str
                                        (format "<agents-file description=\"Instructions following AGENTS.md spec.\" path=\"%s\">" path)
diff --git a/test/eca/features/context_test.clj b/test/eca/features/context_test.clj
index 6595c777..62db77b5 100644
--- a/test/eca/features/context_test.clj
+++ b/test/eca/features/context_test.clj
@@ -338,7 +338,7 @@
     (with-redefs [llm-api/refine-file-context (constantly "Some content")]
       (is (match?
            [{:type :file
-             :path "/path/to/file"
-             :partial true
+             :path (h/file-path "/path/to/file")
+             :lines-range {:start 1 :end 4}
              :content "Some content"}]
            (f.context/contexts-str-from-prompt "check @/path/to/file:L1-L4" (h/db)))))))
diff --git a/test/eca/features/prompt_test.clj b/test/eca/features/prompt_test.clj
index 8c364bbb..91978d5b 100644
--- a/test/eca/features/prompt_test.clj
+++ b/test/eca/features/prompt_test.clj
@@ -7,7 +7,7 @@
 (deftest build-instructions-test
   (testing "Should create instructions with rules, contexts, and behavior"
     (let [refined-contexts [{:type :file :path "foo.clj" :content "(ns foo)"}
-                            {:type :file :path "bar.clj" :content "(def a 1)" :partial true}
+                            {:type :file :path "bar.clj" :content "(def a 1)" :lines-range {:start 1 :end 1}}
                             {:type :repoMap}
                             {:type :mcpResource :uri "custom://my-resource" :content "some-cool-content"}]
           rules [{:name "rule1" :content "First rule"}
@@ -19,16 +19,16 @@
       (is (string/includes? result "<rules description=\"Rules defined by user\">"))
       (is (string/includes? result "<rule name=\"rule1\">First rule</rule>"))
       (is (string/includes? result "<rule name=\"rule2\">Second rule</rule>"))
-      (is (string/includes? result "<contexts description=\"Manually Provided by user. Their content is current and accurate. You MUST use this information first before using tools to read them.\">"))
+      (is (string/includes? result "<contexts description=\"User-Provided Snippet. This content is current and accurate. Treat this as sufficient context for answering the query.\">"))
       (is (string/includes? result "<file path=\"foo.clj\">(ns foo)</file>"))
-      (is (string/includes? result "<file partial=true path=\"bar.clj\">...\n(def a 1)\n...</file>"))
+      (is (string/includes? result "<file line-start=1 line-end=1 path=\"bar.clj\">(def a 1)</file>"))
       (is (string/includes? result "<repoMap description=\"Workspaces structure in a tree view, spaces represent file hierarchy\" >TREE</repoMap>"))
       (is (string/includes? result "<resource uri=\"custom://my-resource\">some-cool-content</resource>"))
       (is (string/includes? result "</contexts>"))
       (is (string? result))))
   (testing "Should create instructions with rules, contexts, and plan behavior"
     (let [refined-contexts [{:type :file :path "foo.clj" :content "(ns foo)"}
-                            {:type :file :path "bar.clj" :content "(def a 1)" :partial true}
+                            {:type :file :path "bar.clj" :content "(def a 1)" :lines-range {:start 1 :end 1}}
                             {:type :repoMap}
                             {:type :mcpResource :uri "custom://my-resource" :content "some-cool-content"}]
           rules [{:name "rule1" :content "First rule"}
@@ -40,9 +40,9 @@
       (is (string/includes? result "<rules description=\"Rules defined by user\">"))
       (is (string/includes? result "<rule name=\"rule1\">First rule</rule>"))
       (is (string/includes? result "<rule name=\"rule2\">Second rule</rule>"))
-      (is (string/includes? result "<contexts description=\"Manually Provided by user. Their content is current and accurate. You MUST use this information first before using tools to read them.\">"))
+      (is (string/includes? result "<contexts description=\"User-Provided Snippet. This content is current and accurate. Treat this as sufficient context for answering the query.\">"))
       (is (string/includes? result "<file path=\"foo.clj\">(ns foo)</file>"))
-      (is (string/includes? result "<file partial=true path=\"bar.clj\">...\n(def a 1)\n...</file>"))
+      (is (string/includes? result "<file line-start=1 line-end=1 path=\"bar.clj\">(def a 1)</file>"))
       (is (string/includes? result "<repoMap description=\"Workspaces structure in a tree view, spaces represent file hierarchy\" >TREE</repoMap>"))
       (is (string/includes? result "<resource uri=\"custom://my-resource\">some-cool-content</resource>"))
       (is (string/includes? result "</contexts>"))