From 04d0819744afe8870eb36f1c92f9baddb18a490f Mon Sep 17 00:00:00 2001
From: anticafeformat-dev
 <249614758+anticafeformat-dev@users.noreply.github.com>
Date: Thu, 14 May 2026 13:18:34 +0000
Subject: [PATCH] fix(mcp): wrap tools/call result in spec-required content
 array
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`callTool` in `src/mcp/server.ts` returned the tool handler's payload
as the JSON-RPC `result` directly (e.g. `{user: {...}}` for
`get_current_user`). The MCP specification requires `tools/call` to
return:

```json
{
  "content": [{"type": "text", "text": "..."}],
  "isError": false   // optional, defaults to false
}
```

Strict MCP clients (e.g. Claude Code) ignore non-spec result shapes
and surface tool calls as `(completed with no output)` — silent
failure with no error to debug. Affects all 13 registered tools.

This patch wraps the handler's return value in the required envelope
at a single point (the central `callTool` method), so every tool gets
spec-compliant output without per-tool changes.

## Verification

stdin smoke test (`initialize` + `tools/call get_current_user`):

- Before:
  `{"result":{"user":{"id":1,"name":"Григорий",...}}}`
- After:
  `{"result":{"content":[{"type":"text","text":"{\"user\":{\"id\":1,...}}"}]}}`

Claude Code now displays the JSON payload to the model; previously
returned `(no output)`.
---
 src/mcp/server.ts | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/mcp/server.ts b/src/mcp/server.ts
index bcb0d09..84b62da 100644
--- a/src/mcp/server.ts
+++ b/src/mcp/server.ts
@@ -123,7 +123,9 @@ export class McpServer {
     }
     const args: unknown = record.arguments ?? {};
     const result: unknown = await tool.handler(args);
-    return result;
+    return {
+      content: [{ type: "text", text: JSON.stringify(result) }]
+    };
   }
 
   private sendResult(id: JsonRpcId, result: unknown): void {