Format massive JSON arrays into Markdown natively to avoid context blowouts

server/src/handlers/git.rs

@@ -27,7 +27,7 @@ impl McpTool for GetActiveWorktreeContextHandler {
         _state: Arc<MemoryState>,
     ) -> crate::error::Result<String> {
         let result =
-            tokio::task::spawn_blocking(move || -> crate::error::Result<serde_json::Value> {
+            tokio::task::spawn_blocking(move || -> crate::error::Result<String> {
                 let cwd = env::current_dir().map_err(|e| crate::error::AppError::Internal(format!("Failed to get current directory: {}", e)))?;
                 let repo = git2::Repository::discover(&cwd).map_err(|e| {
                     crate::error::AppError::Internal(format!("Not in a git repository: {}", e))
@@ -79,16 +79,34 @@ impl McpTool for GetActiveWorktreeContextHandler {
                     diff_output.push_str("\n... [Diff truncated due to size]");
                 }
 
-                Ok(json!({
-                    "branch": branch_name,
-                    "modified_files": files,
-                    "diff": diff_output
-                }))
+                let mut out = String::new();
+                out.push_str("## Active Worktree Context\n\n");
+                out.push_str(&format!("**Branch:** `{}`\n\n", branch_name));
+                
+                out.push_str("### Modified Files\n");
+                if files.is_empty() {
+                    out.push_str("No modified files.\n");
+                } else {
+                    for f in files {
+                        out.push_str(&format!("- `{}`\n", f));
+                    }
+                }
+                
+                out.push_str("\n### Diff\n");
+                if diff_output.is_empty() {
+                    out.push_str("No changes.\n");
+                } else {
+                    out.push_str("```diff\n");
+                    out.push_str(&diff_output);
+                    out.push_str("\n```\n");
+                }
+                
+                Ok(out)
             })
             .await
             .map_err(|e| crate::error::AppError::Internal(format!("Task panic: {}", e)))??;
 
-        Ok::<String, crate::error::AppError>(serde_yaml::to_string(&result)?)
+        Ok(result)
     }
 }
 
@@ -170,7 +188,25 @@ impl McpTool for QueryGitDiffsHandler {
             matches.extend(git_matches);
         }
 
-        Ok(serde_yaml::to_string(&matches)?)
+        let mut out = String::new();
+        out.push_str(&format!("## Git Diffs for `{}`\n\n", req.query));
+        for m in &matches {
+            if let Some(file) = m.get("file_path").and_then(|f| f.as_str()) {
+                let desc = m.get("description").and_then(|d| d.as_str()).unwrap_or("");
+                let commit = m.get("commit").and_then(|c| c.as_str()).unwrap_or("");
+                out.push_str(&format!("- **File:** `{}` | **Commit:** `{}`\n  - {}\n", file, commit, desc));
+            } else {
+                let commit = m.get("commit_id").and_then(|c| c.as_str()).unwrap_or("");
+                let author = m.get("author").and_then(|a| a.as_str()).unwrap_or("");
+                let msg = m.get("message").and_then(|m| m.as_str()).unwrap_or("");
+                out.push_str(&format!("- **Commit:** `{}` | **Author:** {}\n  - {}\n", commit, author, msg));
+            }
+        }
+        if matches.is_empty() {
+            out.push_str("No git diffs found.\n");
+        }
+
+        Ok(out)
     }
 }
 
@@ -193,10 +229,10 @@ mod tests {
             .map_err(|e| format!("Failed to get worktree context: {}", e))
             .unwrap();
 
-        let parsed: serde_json::Value = serde_yaml::from_str(&result).unwrap();
-        assert!(parsed.get("branch").is_some());
-        assert!(parsed.get("modified_files").is_some());
-        assert!(parsed.get("diff").is_some());
+        assert!(result.contains("## Active Worktree Context"));
+        assert!(result.contains("**Branch:**"));
+        assert!(result.contains("### Modified Files"));
+        assert!(result.contains("### Diff"));
     }
 
     #[tokio::test]
@@ -212,7 +248,6 @@ mod tests {
             .map_err(|e| format!("Failed to get worktree context: {}", e))
             .unwrap();
 
-        let parsed: serde_json::Value = serde_yaml::from_str(&result).unwrap();
-        assert!(parsed.get("branch").is_some() || parsed.is_object());
+        assert!(result.contains("## Active Worktree Context"));
     }
 }