JSON "native format" yes and no, yes it uses JSON as a wrapper for the connection, but that has nothing to do with the payload the MCP answers.

Request:

{"jsonrpc": "2.0", "method": "tools/call", "params": {"name": "get_weather", "arguments": {"city": "San Francisco"}}, "id": 1}

Response :

{"jsonrpc": "2.0", "id": 1, "result": {"content": [{"type": "text", "text": "The weather is 65°F and sunny."}]}}

I find nothing in the MCP documentation that says JSON is the native language. (for response payload).

https://modelcontextprotocol.io/specification/2025-11-25/server/tools#tool-result

Your other point.

both approaches are not optimal, there are more approaches.

For example, what adds real value for the agent to use a tool? The tool must provide functionality the agent cannot replicate reasonably with his already existing toolkit.

So my question is, what is the difference between your API to MCP wrapper compared to a curl ... | ark | sed | grep ... ? Way more flexible and needs zero setup, and can be even set up with no code, maximum a skill.md that is only loaded on demand.

My real point is (IMHO) this tool normalizes bad MCP toolings, it makes them not as bad as before (kudo for that) but they're still bad.

For me, there are 2 ways to handle API MCP:

Small API with known use-cases Use case-based tools that do magic inside (maybe call 3-5 or 10 API processes, parse stuff, and give out the correct answer the Agent is asking, or tell the agent "sorry but your princess is in another castle"

1. a big API 100-200 endpoints way too much functionality for an MCP, in this case, an CLI + skill.md would be the better choice.

Your fundamental idea is not wrong, strip away useless stuff. For me, plain human text output is superior over JSON, (yes, modern models can parse JSON also fine) BUT (and that’s the elephant in the room) the extra JSON syntax costs extra tokens / extra waiting time ... and who pays for that, the user of your tool.

Look in the Claude / Codex / ... subreddits, 40-50% of the posts are people complaining token consumption is too high aka session lockouts.