Support MCP resources as a new context

ericdallo · ericdallo · commit 6de7a342d0a7 · 2025-08-04T22:38:55.000-03:00
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -2,6 +2,8 @@
 
 ## Unreleased
 
+- Support MCP resources as a new context.
+
 ## 0.14.4
 
 - Fix usage miscalculation.
diff --git a/README.md b/README.md
@@ -28,7 +28,7 @@ _Demo using [eca-vscode](https://github.com/editor-code-assistant/eca-vscode)_
 - :gear: **Single configuration**: Configure eca making it work the same in any editor via global or local configs.
 - :loop: **Chat** interface: ask questions, review code, work together to code.
 - :coffee: **Agentic**: let LLM work as an agent with its native tools and MCPs you can configure.
-- :syringe: **Context**: support: giving more details about your code to the LLM.
+- :syringe: **Context**: support: giving more details about your code to the LLM, including MCP resources and prompts.
 - :rocket: **Multi models**: OpenAI, Anthropic, Ollama local models, and custom user config models.
 
 ## Rationale 
diff --git a/docs/features.md b/docs/features.md
@@ -35,7 +35,7 @@ Provides access to run shell commands, useful to run build tools, tests, and oth
 
 ### Contexts
 
-User can include contexts to the chat, which can help LLM generate output with better quality.
+User can include contexts to the chat, including MCP resources, which can help LLM generate output with better quality.
 Here are the current supported contexts types:
 
 - `file`: a file in the workspace, server will pass its content to LLM (Supports optional line range).
diff --git a/docs/models.md b/docs/models.md
@@ -2,11 +2,11 @@
 
 ## Built-in providers and capabilities
 
-| model     | MCP / tools | MCP prompts | thinking/reasioning | prompt caching | web_search |
-|-----------|-------------|-------------|---------------------|----------------|------------|
-| OpenAI    | √           | √           | X                   | X              | √          |
-| Anthropic | √           | √           | X                   | √              | √          |
-| Ollama    | √           | √           | X                   | X              | X          |
+| model     | tools (MCP) | reasoning / thinking | prompt caching | web_search |
+|-----------|-------------|----------------------|----------------|------------|
+| OpenAI    | √           | √                    | √              | √          |
+| Anthropic | √           | √                    | √              | √          |
+| Ollama    | √           | √                    | X              | X          |
 
 ### OpenAI
 
diff --git a/docs/protocol.md b/docs/protocol.md
@@ -278,7 +278,7 @@ type ChatModel =
  */
 type OllamaRunningModel = string
 
-type ChatContext = FileContext | DirectoryContext | WebContext | RepoMapContext;
+type ChatContext = FileContext | DirectoryContext | WebContext | RepoMapContext | McpResourceContext;
 
 /**
  * Context related to a file in the workspace
@@ -328,7 +328,39 @@ interface WebContext {
  */
 interface RepoMapContext {
     type: 'repoMap'; 
- }
+}
+
+/***
+ * A MCP resource available from a MCP server.
+ */
+interface McpResourceContext {
+    type: 'mcpResource';
+    
+   /** 
+    * The URI of the resource like file://foo/bar.clj
+    */
+    uri: string;
+
+    /** 
+     * The name of the resource.
+     */
+    name: string;
+    
+    /** 
+     * The description of the resource.
+     */
+    description: string;
+    
+    /** 
+     * The mimeType of the resource like `text/markdown`.
+     */
+    mimeType: string;
+    
+    /** 
+     * The server name of this MCP resource.
+     */
+    server: string;
+}
 ```
 
 _Response:_
diff --git a/src/eca/features/chat.clj b/src/eca/features/chat.clj
@@ -18,9 +18,9 @@
 
 (def ^:private logger-tag "[CHAT]")
 
-(defn ^:private raw-contexts->refined [contexts]
-  (mapcat (fn [{:keys [type path lines-range]}]
-            (case type
+(defn ^:private raw-contexts->refined [contexts db]
+  (mapcat (fn [{:keys [type path lines-range uri]}]
+            (case (name type)
               "file" [{:type :file
                        :path path
                        :partial (boolean lines-range)
@@ -32,7 +32,13 @@
                                         {:type :file
                                          :path filename
                                          :content (llm-api/refine-file-context filename nil)}))))
-              "repoMap" [{:type :repoMap}]))
+              "repoMap" [{:type :repoMap}]
+              "mcpResource" (mapv
+                              (fn [{:keys [text]}]
+                                {:type :mcpResource
+                                 :uri uri
+                                 :content text})
+                              (:contents (f.mcp/get-resource! uri db)))))
           contexts))
 
 (defn default-model [db config]
@@ -138,7 +144,7 @@
   (let [db @db*
         manual-approval? (get-in config [:toolCall :manualApproval] false)
         rules (f.rules/all config (:workspace-folders db))
-        refined-contexts (raw-contexts->refined contexts)
+        refined-contexts (raw-contexts->refined contexts db)
         repo-map* (delay (f.index/repo-map db {:as-string? true}))
         instructions (f.prompt/build-instructions refined-contexts rules repo-map* (or behavior (:chat-default-behavior db)))
         past-messages (get-in db [:chats chat-id :messages] [])
@@ -362,16 +368,18 @@
                                      (take 200) ;; for performance, user can always make query specific for better results.
                                      (map (fn [file-or-dir]
                                             {:type (if (fs/directory? file-or-dir)
-                                                     "directory"
-                                                     "file")
+                                                     :directory
+                                                     :file)
                                              :path (str (fs/canonicalize file-or-dir))})))
                                     (:workspace-folders @db*))
-        root-dirs (mapv (fn [{:keys [uri]}] {:type "directory"
+        root-dirs (mapv (fn [{:keys [uri]}] {:type :directory
                                              :path (shared/uri->filename uri)})
                         (:workspace-folders @db*))
-        all-contexts (concat [{:type "repoMap"}]
+        mcp-resources (mapv #(assoc % :type :mcpResource) (f.mcp/all-resources @db*))
+        all-contexts (concat [{:type :repoMap}]
                              root-dirs
-                             all-subfiles-and-dirs)]
+                             all-subfiles-and-dirs
+                             mcp-resources)]
     {:chat-id chat-id
      :contexts (set/difference (set all-contexts)
                                (set contexts))}))
diff --git a/src/eca/features/prompt.clj b/src/eca/features/prompt.clj
@@ -31,12 +31,13 @@
    ""
    "<contexts>"
    (reduce
-    (fn [context-str {:keys [type path content partial]}]
+    (fn [context-str {:keys [type path content partial uri]}]
       (str context-str (case type
                          :file (if partial
                                  (format "<file partial=true path=\"%s\">...\n%s\n...</file>\n" path content)
                                  (format "<file path=\"%s\">%s</file>\n" path content))
-                         :repoMap (format "<repoMap description=\"Workspaces structure in a tree view, spaces represent file hierarchy\" >%s</repoMap>" @repo-map*)
+                         :repoMap (format "<repoMap description=\"Workspaces structure in a tree view, spaces represent file hierarchy\" >%s</repoMap>\n" @repo-map*)
+                         :mcpResource (format "<resource uri=\"%s\">%s</resource>\n" uri content)
                          "")))
     ""
     refined-contexts)
diff --git a/src/eca/features/tools/mcp.clj b/src/eca/features/tools/mcp.clj
@@ -18,8 +18,12 @@
     McpSchema$Prompt
     McpSchema$PromptArgument
     McpSchema$PromptMessage
+    McpSchema$ReadResourceRequest
+    McpSchema$Resource
+    McpSchema$ResourceContents
     McpSchema$Root
     McpSchema$TextContent
+    McpSchema$TextResourceContents
     McpSchema$Tool
     McpTransport]
    [java.time Duration]
@@ -74,6 +78,8 @@
    :command (:command server-config)
    :args (:args server-config)
    :tools (get-in db [:mcp-clients mcp-name :tools])
+   :prompts (get-in db [:mcp-clients mcp-name :prompts])
+   :resources (get-in db [:mcp-clients mcp-name :resources])
    :status status})
 
 (defn ^:private ->content [^McpSchema$Content content-client]
@@ -82,6 +88,16 @@
             :text (.text ^McpSchema$TextContent content-client)}
     nil))
 
+(defn ^:private ->resource-content [^McpSchema$ResourceContents resource-content-client]
+  (cond
+    (instance? McpSchema$TextResourceContents resource-content-client)
+    {:type :text
+     :uri (.uri resource-content-client)
+     :text (.text ^McpSchema$TextResourceContents resource-content-client)}
+
+    :else
+    nil))
+
 (defn ^:private list-server-tools [^ObjectMapper obj-mapper ^McpSyncClient client]
   (mapv (fn [^McpSchema$Tool tool-client]
           {:name (.name tool-client)
@@ -102,6 +118,25 @@
                             (.arguments prompt-client))})
         (.prompts (.listPrompts client))))
 
+(defn ^:private list-server-resources [^McpSyncClient client]
+  (try
+    (mapv (fn [^McpSchema$Resource resource-client]
+            {:uri (.uri resource-client)
+             :name (.name resource-client)
+             :description (.description resource-client)
+             :mime-type (.mimeType resource-client)})
+          (.resources (.listResources client)))
+    (catch Exception e
+      (logger/debug logger-tag "Could not list resources:" (.getMessage e))
+      [])))
+
+(defn ^:private mcp-client-from-db [pred db]
+  (->> (vals (:mcp-clients db))
+       (keep (fn [{:keys [client resources]}]
+               (when (some pred resources)
+                 client)))
+       first))
+
 (defn ^:private initialize-server! [name db* config on-server-updated]
   (let [db @db*
         workspaces (:workspace-folders @db*)
@@ -117,6 +152,7 @@
         (.initialize client)
         (swap! db* assoc-in [:mcp-clients name :tools] (list-server-tools obj-mapper client))
         (swap! db* assoc-in [:mcp-clients name :prompts] (list-server-prompts client))
+        (swap! db* assoc-in [:mcp-clients name :resources] (list-server-resources client))
         (on-server-updated (->server name server-config :running @db*)))
       (catch Exception e
         (logger/warn logger-tag (format "Could not initialize MCP server %s. Error: %s" name (.getMessage e)))
@@ -156,11 +192,7 @@
         (:mcp-clients db)))
 
 (defn call-tool! [^String name ^Map arguments db]
-  (let [mcp-client (->> (vals (:mcp-clients db))
-                        (keep (fn [{:keys [client tools]}]
-                                (when (some #(= name (:name %)) tools)
-                                  client)))
-                        first)
+  (let [mcp-client (mcp-client-from-db #(= name (:name %)) db)
         result (try
                  (let [result (.callTool ^McpSyncClient mcp-client
                                          (McpSchema$CallToolRequest. name arguments))]
@@ -179,12 +211,14 @@
                   (mapv #(assoc % :server (name server-name)) prompts)))
         (:mcp-clients db)))
 
+(defn all-resources [db]
+  (into []
+        (mapcat (fn [[server-name {:keys [resources]}]]
+                  (mapv #(assoc % :server (name server-name)) resources)))
+        (:mcp-clients db)))
+
 (defn get-prompt! [^String name ^Map arguments db]
-  (let [mcp-client (->> (vals (:mcp-clients db))
-                        (keep (fn [{:keys [client prompts]}]
-                                (when (some #(= name (:name %)) prompts)
-                                  client)))
-                        first)
+  (let [mcp-client (mcp-client-from-db #(= name (:name %)) db)
         prompt (.getPrompt ^McpSyncClient mcp-client (McpSchema$GetPromptRequest. name arguments))
         result {:description (.description prompt)
                 :messages (mapv (fn [^McpSchema$PromptMessage message]
@@ -194,8 +228,14 @@
     (logger/debug logger-tag "Prompt result:" result)
     result))
 
+(defn get-resource! [^String uri db]
+  (let [mcp-client (mcp-client-from-db #(= uri (:uri %)) db)
+        resource (.readResource ^McpSyncClient mcp-client (McpSchema$ReadResourceRequest. uri))
+        result {:contents (mapv ->resource-content (.contents resource))}]
+    (logger/debug logger-tag "Resource result:" result)
+    result))
+
 (defn shutdown! [db*]
-  (doseq [[_name {:keys [_client]}] (:mcp-clients @db*)]
-    ;; TODO NoClassDefFound being thrown for some reason
-    #_(.closeGracefully ^McpSyncClient client))
+  (doseq [[_name {:keys [client]}] (:mcp-clients @db*)]
+    (.closeGracefully ^McpSyncClient client))
   (swap! db* assoc :mcp-clients {}))
diff --git a/test/eca/features/prompt_test.clj b/test/eca/features/prompt_test.clj
@@ -8,7 +8,8 @@
   (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 :repoMap :path nil :content nil}]
+                            {:type :repoMap}
+                            {:type :mcpResource :uri "custom://my-resource" :content "some-cool-content"}]
           rules [{:name "rule1" :content "First rule"}
                  {:name "rule2" :content "Second rule"}]
           fake-repo-map (delay "TREE")
@@ -22,5 +23,6 @@
       (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 "<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)))))
