feat(ollama): enforce JSON logits & add nvim_buffer edit action

- Added format parameter to Ollama generate for JSON logit enforcement.

- Implemented safe edit action in nvim_buffer MCP tool to replace raw Lua.

nvim-core/src/lib.rs

@@ -1088,16 +1088,17 @@ pub async fn run_mcp_loop(app_name: &str, app_version: &str) {
                                         "properties": {
                                             "action": {
                                                 "type": "string",
-                                                "enum": ["get_active", "read", "open", "create_scratch", "save", "reload", "close", "list", "search"],
+                                                "enum": ["get_active", "read", "open", "create_scratch", "save", "reload", "close", "list", "search", "edit"],
                                                 "description": "Action to perform on the buffer"
                                             },
-                                            "file": { "type": "string", "description": "Target file path (for open, read, search)" },
+                                            "file": { "type": "string", "description": "Target file path (for open, read, search, edit)" },
                                             "buf_id": { "type": "integer", "description": "Buffer ID (for close, reload, or split)" },
                                             "content": { "type": "string", "description": "Initial text content (for create_scratch)" },
                                             "name": { "type": "string", "description": "Buffer display name (for create_scratch)" },
                                             "filetype": { "type": "string", "description": "Filetype syntax (for open, create_scratch)" },
-                                            "start_line": { "type": "integer", "description": "1-indexed start line (for read)" },
-                                            "end_line": { "type": "integer", "description": "1-indexed end line (for read)" },
+                                            "start_line": { "type": "integer", "description": "1-indexed start line (for read, edit)" },
+                                            "end_line": { "type": "integer", "description": "1-indexed end line (for read, edit)" },
+                                            "replacement_content": { "type": "string", "description": "New content for the specified line range (for edit)" },
                                             "pattern": { "type": "string", "description": "Regex or substring pattern to search for (for search)" },
                                             "force": { "type": "boolean", "description": "Force reload or close (for reload, close)" }
                                         },
@@ -1324,6 +1325,47 @@ pub async fn run_mcp_loop(app_name: &str, app_version: &str) {
                                     execute_nvim_lua_with_args(code, vec![args_rmp])
                                 )
                             }
+                            "edit" => {
+                                let args_rmp = json_to_rmpv(args);
+                                let code = "
+                                    local args = ...
+                                    local file = args.file
+                                    if not file or file == '' or file == vim.NIL then
+                                        error(\"Missing 'file'\")
+                                    end
+                                    local start_line = tonumber(args.start_line)
+                                    if not start_line then
+                                        error(\"Missing 'start_line'\")
+                                    end
+                                    local end_line = tonumber(args.end_line)
+                                    if not end_line then
+                                        error(\"Missing 'end_line'\")
+                                    end
+                                    local content = args.replacement_content
+                                    if not content or content == vim.NIL then
+                                        error(\"Missing 'replacement_content'\")
+                                    end
+                                    
+                                    local bufnr = vim.fn.bufnr(file, true)
+                                    if vim.fn.bufloaded(bufnr) == 0 then
+                                        vim.fn.bufload(bufnr)
+                                    end
+                                    
+                                    local lines = vim.split(content, '\\n', { plain = true })
+                                    vim.api.nvim_buf_set_lines(bufnr, start_line - 1, end_line, false, lines)
+                                    
+                                    local win = vim.fn.bufwinid(bufnr)
+                                    if win ~= -1 then
+                                        pcall(vim.api.nvim_win_set_cursor, win, {start_line, 0})
+                                    end
+                                    
+                                    return 'Successfully edited lines ' .. tostring(start_line) .. ' to ' .. tostring(end_line) .. ' in ' .. file
+                                ";
+                                handle_lua_result!(
+                                    id,
+                                    execute_nvim_lua_with_args(code, vec![args_rmp])
+                                )
+                            }
                             "open" => {
                                 let args_rmp = json_to_rmpv(args);
                                 let code = "

server/src/handlers/graph.rs

@@ -824,7 +824,7 @@ impl McpTool for CondenseEntityHandler {
                     req.entity_name,
                     unique_obs.join("\n- ")
                 );
-                if let Ok(summary) = state.ollama.generate(&prompt, None, None).await {
+                if let Ok(summary) = state.ollama.generate(&prompt, None, None, None).await {
                     let lines: Vec<String> = summary
                         .lines()
                         .map(|l| l.trim().trim_start_matches('-').trim().to_string())

server/src/handlers/meta.rs

@@ -33,7 +33,7 @@ impl McpTool for LogErrorFixHandler {
             );
             if let Ok(summary) = state
                 .ollama
-                .generate(&prompt, Some(&state.ollama.reasoning_model), None)
+                .generate(&prompt, Some(&state.ollama.reasoning_model), None, None)
                 .await
             {
                 let clean = summary.trim();
@@ -207,7 +207,7 @@ impl McpTool for LogCodeChangeHandler {
                 "Summarize in 1 concise sentence the architectural impact of changing file '{}': {}",
                 req.file_path, description
             );
-            if let Ok(summary) = state.ollama.generate(&prompt, None, None).await {
+            if let Ok(summary) = state.ollama.generate(&prompt, None, None, None).await {
                 let clean = summary.trim();
                 if !clean.is_empty() {
                     description = format!("{} (AI Summary: {})", description, clean);

server/src/handlers/workspaces.rs

@@ -359,7 +359,7 @@ impl McpTool for SemanticCodeSearchHandler {
             );
             if let Ok(summary) = state
                 .ollama
-                .generate(&prompt, None, Some("Respond clearly and concisely."))
+                .generate(&prompt, None, Some("Respond clearly and concisely."), None)
                 .await
             {
                 out.push_str("\n\n--- Local GraphRAG Summary ---\n");

server/src/lib.rs

@@ -308,6 +308,7 @@ pub async fn memory_consolidation_worker(state: Arc<MemoryState>) {
                 &prompt,
                 None,
                 Some("You are a helpful JSON-only data deduplication assistant. Output only JSON."),
+                Some("json"),
             )
             .await
         {

server/src/ollama.rs

@@ -27,6 +27,8 @@ struct GenerateRequest<'a> {
     options: Option<serde_json::Value>,
     #[serde(skip_serializing_if = "Option::is_none")]
     keep_alive: Option<&'a str>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    format: Option<&'a str>,
 }
 
 #[derive(Deserialize)]
@@ -113,6 +115,7 @@ impl OllamaClient {
         prompt: &str,
         model_override: Option<&str>,
         system: Option<&str>,
+        format: Option<&str>,
     ) -> Result<String, AppError> {
         let model = model_override.unwrap_or(&self.coder_model);
         let url = format!("{}/api/generate", self.base_url.trim_end_matches('/'));
@@ -128,6 +131,7 @@ impl OllamaClient {
                 "num_predict": 4096 // Give reasoning models plenty of output room
             })),
             keep_alive: Some("1h"),
+            format,
         };
 
         let res = self
@@ -172,6 +176,7 @@ impl OllamaClient {
                 "num_predict": 1024
             })),
             keep_alive: Some("1h"),
+            format: None,
         };
 
         let res = self