Add machine info to prompt Environment Context section

Rename the "Project Environment Context" heading to "Environment Context"
and add OS, default shell, username and home directory. These help with
shell command syntax and path resolution and aren't reliably inferable by
the model. Values are read from the host running ECA.

Author: ericdallo

CHANGELOG.md

@@ -2,7 +2,8 @@
 
 ## Unreleased
 
-- Prompt now renders context as labeled `## Static Contexts` and `## Dynamic Contexts` sections, with Project Environment Context no longer wedged between them.
+- Prompt now renders context as labeled `## Static Contexts` and `## Dynamic Contexts` sections, with Environment Context no longer wedged between them.
+- System prompt's Environment Context section now includes OS, default shell, username and home directory.
 
 ## 0.136.1
 

resources/prompts/additional_system_info.md

@@ -1,5 +1,9 @@
-## Project Environment Context
+## Environment Context
 
+OS: {{osName}}
+Default shell: {{shell}}
+User: {{userName}}
+Home directory: {{homeDir}}
 Workspaces: {{workspaceRoots}}
 
 **Path Resolution & Context:**

src/eca/features/prompt.clj

@@ -99,6 +99,10 @@
   ([all-tools chat-id db]
    (merge
     {:workspaceRoots (shared/workspaces-as-str db)
+     :osName (str (System/getProperty "os.name") " " (System/getProperty "os.version"))
+     :shell (or (System/getenv "SHELL") (System/getenv "ComSpec"))
+     :userName (System/getProperty "user.name")
+     :homeDir (System/getProperty "user.home")
      :isSubagent (boolean (get-in db [:chats chat-id :subagent]))}
     (reduce
      (fn [m tool]

test/eca/features/prompt_test.clj

@@ -164,12 +164,12 @@
     (is (= "static" (prompt/instructions->str {:static "static" :dynamic nil})))))
 
 (deftest build-instructions-context-sections-ordering-test
-  (testing "Static contexts are labeled and rendered after Project Environment Context"
+  (testing "Static contexts are labeled and rendered after Environment Context"
     (let [refined-contexts [{:type :file :path "foo.clj" :content "(ns foo)"}]
           {:keys [static]} (build-instructions refined-contexts [] [] [] (delay "TREE") "code" {} nil [] (h/db))]
       (is (string/includes? static "## Static Contexts"))
-      (is (string/includes? static "## Project Environment Context"))
-      (is (< (string/index-of static "## Project Environment Context")
+      (is (string/includes? static "## Environment Context"))
+      (is (< (string/index-of static "## Environment Context")
              (string/index-of static "## Static Contexts")))))
   (testing "Static contexts come before Dynamic contexts in the flattened prompt"
     (let [refined-contexts [{:type :file :path "foo.clj" :content "(ns foo)"}