docs: update human and LLM docs and enhance tool/list schemas with actionable next steps

server/src/handlers/notes.rs

@@ -27,7 +27,7 @@ impl McpTool for StickyNotesHandler {
         match req.action {
             StickyNoteAction::Add => {
                 let content = req.content.ok_or_else(|| {
-                    crate::error::AppError::Internal("content is required for 'add' action".to_string())
+                    crate::error::AppError::Internal("Missing required parameter 'content' for action 'add'. Next step: Provide non-empty 'content' string in request and retry.".to_string())
                 })?;
                 let now = crate::handlers::utils::now_secs();
                 let expires_at = if let Some(ttl) = req.ttl_seconds {
@@ -64,7 +64,7 @@ impl McpTool for StickyNotesHandler {
             }
             StickyNoteAction::Delete => {
                 let idx = req.index.ok_or_else(|| {
-                    crate::error::AppError::Internal("index is required for 'delete' action".to_string())
+                    crate::error::AppError::Internal("Missing required parameter 'index' for action 'delete'. Next step: Provide 1-based sticky note 'index' integer in request and retry.".to_string())
                 })?;
                 let mut success = false;
                 state.code.sticky.modify(|notes| {
@@ -77,7 +77,7 @@ impl McpTool for StickyNotesHandler {
                     Ok("Sticky note deleted.".to_string())
                 } else {
                     Err(crate::error::AppError::Internal(
-                        "Invalid sticky note index.".to_string(),
+                        "Invalid sticky note index. Next step: Call sticky_notes with action='read' to view active notes and valid 1-based indices, then retry.".to_string(),
                     ))
                 }
             }
@@ -236,7 +236,7 @@ impl McpTool for HandoffMemosHandler {
         match req.action {
             HandoffMemoAction::Leave => {
                 let content = req.content.ok_or_else(|| {
-                    crate::error::AppError::Internal("content is required for 'leave' action".to_string())
+                    crate::error::AppError::Internal("Missing required parameter 'content' for action 'leave'. Next step: Provide non-empty 'content' string in request and retry.".to_string())
                 })?;
                 let ns = req.namespace.unwrap_or_else(|| crate::models::default_namespace());
                 state.telemetry.handoff_memos.modify(|memos| {