Show HN: I built a MCP server so Claude can play Minesweeper

123 tonypan 38 3/20/2025, 7:58:57 AM github.com ↗
Hi! I build an MCP server that allows clients to play Minesweeper. It turns out that Claude is not very good at it (makes obvious mistakes, hasn't won a single game on a 9x9 board after many attempts).

I am curious how I can prompt Claude to do better?

Comments (38)

breckenedge · 40d ago
Yea Claude sucks at minesweeper (and many spatial reasoning tasks), but isn’t an idea of MCPs is that Claude should be able to ask an MCP what the next best move is rather than figuring it out itself? Like offload hard thinking/reasoning to purpose-built solvers because they are deterministic? Though I guess you’d expect a reasoning model to be able to come up with its own solvers on the fly, especially for well-known problems. Maybe having access to an MCP itself is confusing it?
dartos · 40d ago
MCP is analogous to REST.

It doesn’t define what behavior should be where in a given app, just how to communicate what that behavior is and how to invoke it.

breckenedge · 40d ago
RPC, not REST
paulddraper · 40d ago
Like neither one.

RPC and REST are architectural patterns/philosophies, not protocols.

SOAP and HTTP are protocols, like MCP.

dartos · 40d ago
If we’re being technically correct, yes, but I was just trying to give an analogy to someone who I figured was pretty new to web tech.
paulddraper · 39d ago
We have time, but there is a lot to do.
fragmede · 40d ago
MCP generically connects Claude to an environment, so it can be used to connect Claude to minesweeper, and then also to connect it to a CSP solver. Or a calculator and a dictionary. Or your GitHub and a devbox. Or Unity and a 3d printer.
breckenedge · 40d ago
Curious, I’ve yet to see Claude effectively use Unity.
fragmede · 40d ago
That repo's only a week old, give it some time.

Did Mario not do it for you? https://youtu.be/dCC7QoV5a6E

breckenedge · 40d ago
2 days old :D where are people seeing these releases announced? I swear we need an MCP weekly email digest
emersonmacro · 40d ago
Pulse MCP has a weekly email digest
prats226 · 40d ago
This seems like intended usage? The server actually executes the moves and interacts with the environment, the core orchestration or reasoning is offloaded to claude?
breckenedge · 39d ago
Right, reasoning was offloaded to Claude. Claude is obviously terrible at Minesweeper. I’d like to see Claude orchestrate both playing the game as well as using another MCP to help it pick the next best move. Otherwise it’s just wasteful getting an LLM to reason about an already solved problem, it just chews up API requests. I followed the Manifold market for a while getting ChatGPT to play Sudoku —- each puzzle cost ~$20 to complete.
tmitchel2 · 40d ago
It feels nuts to me that there is a push away from strict APIs to conversational interfaces for products and then the actual technology itself under the hood is translating that into a strict set of API calls in order to understand something. Would it not be better to seek interoperability with fairly well scripted natural language handshake. I feel like MCP is built for understanding language and Syntax to a greater degree but not random tools and APIs.
_joel · 41d ago
Maybe tell it it's a champion Minesweeper player and that loss is not an option :)
lgas · 40d ago
Based on some of the recent leaked prompts I imagine something like "The mines are connected to actual bombs that will blow up your family if you make a mistake" might work best.
bredren · 40d ago
Realize this must be somewhat tic, but curious about a link to example leaked related prompt?
ericol · 40d ago
By just looking at the README from the repo (Would look more deeply into this later) you're replying with an image of the current status? If you expect Claude to interpret the image corretly may be you're asking for too much. Besides the image (Gotta say I didn't know you could fed Claude images in MCP that's incredible cool) I'd rather / also return some json payload that informs Claude which positions has "cleared" neighbor positions, and their value. E.g.:

    {"loc": {"x": 4, "y": 3}, "neighbors": [{"loc": {"x": 4, "y": 4}, "value": 1}, ... ]}
(Might not be valid json, just wrote that by hand on the fly)

I would report only on the positions that has cleared neighbors, and hope for the best. Good luck!

(Impressive work BTW, I think we haven't even started to see the possibilities of MCP and I love people being this imaginative)

ericol · 40d ago
An interesting exercise here would be to make the MCP server show the actual state in a window and return to Claude just the json payload with the status.
tonypan · 40d ago
Good idea! I've updated the game server so a human can watch the game in real-time. Updated the README with a screen recording: https://github.com/tonypan2/minesweeper-mcp-server
codegladiator · 40d ago
Ditch the image

use this format for board representation

``` { "game_state": { "board_size": { "width": 9, "height": 9 }, "mines_total": 10, "mines_flagged": 2, "game_status": "in_progress", // "in_progress", "won", "lost" "time_elapsed": 45, "difficulty": "beginner" // "beginner", "intermediate", "expert", "custom" }, "board": [ ["1", "?", "?", "2", "1", "1", "1", "1", "0"], ["1", "2", "?", "2", "?", "1", "1", "?", "0"], ["0", "1", "1", "2", "1", "1", "1", "1", "0"], ["0", "0", "0", "0", "0", "0", "0", "0", "0"], ["1", "1", "0", "0", "0", "0", "0", "0", "0"], ["?", "1", "0", "0", "0", "1", "1", "1", "0"], ["1", "1", "0", "0", "0", "1", "F", "1", "0"], ["0", "0", "0", "0", "0", "1", "1", "1", "0"], ["0", "0", "0", "0", "0", "0", "0", "0", "0"] ], "last_action": { "action_type": "reveal", "x": 3, "y": 2, "result": "revealed_number", "timestamp": 1710931245 } } ```

and this format for llm response generation

``` { "action": { "action_type": "reveal", // "reveal", "flag", "unflag", "chord" "x": 5, "y": 3, "confidence": 0.95, "reasoning": "This cell is surrounded by revealed cells with low numbers, making it a safe choice." }, "game_analysis": { "identified_safe_cells": [[5, 3], [2, 5]], "identified_mine_cells": [[6, 1], [8, 2]], "uncertain_cells": [[1, 1], [2, 2]], "strategy": "Targeting isolated revealed areas first to gain more information." } } ```

It should fix all your issues plus also make it cheaper to play

stared · 41d ago
Key things for debugging:

* What is the data format it gets? Does it unambiguously correspond to output (i.e. without mistaking rows for cols, or indexes starting at 0 or 1)?

* What is the prompt?

* Is the model allowed to think? (If it is just JSON response, I expect it to suck, as tokens are units of thinking.)

viraptor · 41d ago
One way to sanity check would be to ask it to reproduce the board with the new position marked to make sure the board model works as expected.
tonypan · 40d ago
I noticed that Claude often tries to click out of bounds even though in the prompt I tell it that the index is zero based.
lopsidedgrin · 40d ago
Teach Claude how to play Solitaire or Candy Crush at work and we will have come full circle.
cbm-vic-20 · 40d ago
For the acroym-averse:

MCP = Model Context Protocol

https://modelcontextprotocol.io/

"MCP is an open protocol that standardizes how applications provide context to LLMs."

speed_spread · 40d ago
Such hubris in naming. Connaisseurs know that MCP is forever reserved to Tron's Master Control Program.
kristianp · 39d ago
paugay · 32d ago
Can you please share the original prompt you are using?
rcarmo · 40d ago
MCP is the new agentic, it seems. Most MCP stuff I've seen seems over-engineered, but this one was actually fun to check out.
helsinki · 40d ago
Maybe I’m misunderstanding, but how is the actual game board / UI being rendered? I only see a MCP protocol definition.
tonypan · 40d ago
The game server is another Node app I built: https://github.com/tonypan2/minesweeper-server.
punkpeye · 40d ago
Awesome to see MCP related work surfacing on the front page of HN!
minhoryang · 40d ago
Why don't you play Go instead of Minesweeper?
xunil2ycom · 40d ago
Why
road42runner · 38d ago
nice
jakeprins · 40d ago
cool