Atlas / MCP servers / jacck / Reasoner

ReasonerBLOCK

Name: Reasoner
Author: jacck

mcp/jacck/reasoner

MCP server by jacck · Audited 2026-10-05

⚑ Report / re-scan Source ↗

A systematic reasoning MCP server implementation for Claude Desktop with beam search and thought evaluation.

Verdict

BLOCK

Grade

Trust score

47 /100

Exposed tools

1 1r · 0w · 0d

Transport

sse · stdio

License

MIT

Stars

277

Overview

From the repository's own README, as read at the audited commit. Badges and raw HTML are left out.

A reasoning implementation for Claude Desktop that lets you use both Beam Search and Monte Carlo Tree Search (MCTS). tbh this started as a way to see if we could make Claude even better at complex problem-solving... turns out we definitely can.

Current Version:

v2.0.0

What's New:

Added 2 Experimental Reasoning Algorithms: - mcts-002-alpha - Uses the A Search Method along with an early alpha implementation of a Policy Simulation Layer - Also includes an early alpha implementation of Adaptive Exploration Simulator & Outcome Based Reasoning Simulator NOTE the implementation of these alpha simulators is not complete and is subject to change - `mcts-002alt-alpha` - Uses the Bidirectional Search Method along with an early alpha implementation of a Policy Simulation Layer - Also includes an early alpha implementation of Adaptive Exploration Simulator & Outcome Based Reasoning Simulator NOTE* the implementation of these alpha simulators is not complete and is subject to change

What happened to mcts-001-alpha and mcts-001alt-alpha?

Quite simply: It was useless and near similar to the base mcts method. After initial testing the results yielded in basic thought processes was near similar showing that simply adding policy simulation may not have an effect.

So why add Polciy Simulation Layer now?

Well i think its important to incorporate Policy AND Search in tandem as that is how most of the algorithms implement them.

Previous Versions:

v1.1.0

Added model control over search parameters: beamWidth - lets Claude adjust how many paths to track (1-10) numSimulations - fine-tune MCTS simulation count (1-150)

Features

Two search strategies that you can switch between:
Beam search (good for straightforward stuff)
MCTS (when stuff gets complex) with alpha variations (see above)
Tracks how good different reasoni

Read from source at commit d1e3696613e8OBSERVED · 2026-10-05

Connect

Built from this server's own package name, version and transport as found in its source — not copied from anyone's documentation, so it cannot drift against a page we do not control.

claude-code

claude mcp add mcp-reasoner -- npx -y [email protected]

claude-desktop

{
  "mcpServers": {
    "mcp-reasoner": {
      "command": "npx",
      "args": [
        "-y",
        "[email protected]"
      ]
    }
  }
}

Exposed tools (1)

1 read · 0 write · 0 destructive.

Tool	Risk	Description
`mcp-reasoner`	read	Advanced reasoning tool with multiple strategies including Beam Search and Monte Carlo Tree Search

Trust audit

BLOCKgrade F · trust 47/100 Do not install this without reading the findings. The audit found something that could harm you or your machine.

Layer	What it checks	Result
L0	Provenance & inventory	PASS
L1	Static analysis of the code	FAIL
L2	Instruction surface (what it tells the agent)	PASS
L3	Class-specific surface	PASS
L4	Behavioural (sandbox)	SKIPPED

What the source does

Filesystem: none-observed
Network: declared (5 observation(s))
Shell: declared (9 observation(s))
Dependencies: not all pinned
Secrets in source: none-found

Findings (25)

HIGHCode injection · code.eval_exec · CWE-78, CWE-94, CWE-95

node_modules/depd/index.js:425

var deprecatedfn = new Function('fn', 'log', 'deprecate', 'message', 'site',

Why it matters. evaluates text as code

Fix. remove; use a parser or a dispatch table

HIGHCode injection · code.eval_exec · CWE-78, CWE-94, CWE-95

node_modules/depd/index.js:427

'return function (' + args + ') {' +

Why it matters. evaluates text as code

Fix. remove; use a parser or a dispatch table

HIGHCode injection · code.eval_exec · CWE-78, CWE-94, CWE-95

node_modules/function-bind/implementation.js:74

bound = Function('binder', 'return function (' + joiny(boundArgs, ',') + '){ return binder.apply(this,arguments); }')(binder);

Why it matters. evaluates text as code

Fix. remove; use a parser or a dispatch table

HIGHCode injection · code.eval_exec · CWE-78, CWE-94, CWE-95

node_modules/shelljs/src/common.js:334

if (options.unix === false) { // this branch is for exec()

Why it matters. evaluates text as code

Fix. remove; use a parser or a dispatch table

HIGHSupply chain · supply.typosquat · CWE-829, CWE-1357

node_modules/iconv-lite/package.json

request ~ requests

Why it matters. dependency name one edit from a popular package

Fix. verify the package; likely typosquat

MEDIUMInformation disclosure · disclose.log_secret · CWE-209, CWE-532

node_modules/@types/node/url.d.ts:543

* console.log(myURL.password);

MEDIUMObfuscation / stealth · obf.zero_width · CWE-506, CWE-94

node_modules/iconv-lite/encodings/sbcs-data-generated.js:100

"chars": "€پ‚ƒ„...†‡ˆ‰ٹ‹Œچژڈگ‘’“”•–—کTMڑ›œں ،¢£¤¥¦§ ̈©ھ«¬® ̄°±23 ́μ¶· ̧1؛»1⁄41⁄23⁄4؟ہءآأؤإئابةتثجحخدذرزسشصض×طظعغـفقكàلâمنهوçèéêëىيîïًٌٍَôُِ÷ّùْûüے"

MEDIUMObfuscation / stealth · obf.zero_width · CWE-506, CWE-94

node_modules/iconv-lite/encodings/sbcs-data-generated.js:373

"chars": "«»...“”�•‘’� กขฃคฅฆงจฉชซฌญฎฏฐฑฒณดตถทธนบปผฝพฟภมยรฤลฦวศษสหฬอฮฯะัาําิีึืฺุู–—฿เแโใไๅๆ็่้๊๋์ํTM๏๐๑๒๓๔๕๖๗๘๙®©����"

LOWInventory / provenance · inv.hidden_file · CWE-1104

node_modules/.package-lock.json

.package-lock.json

Why it matters. hidden member outside the usual dotfiles

Fix. review its purpose

LOWInventory / provenance · inv.hidden_file · CWE-1104

node_modules/concat-map/.travis.yml

.travis.yml

Why it matters. hidden member outside the usual dotfiles

Fix. review its purpose

LOWInventory / provenance · inv.hidden_file · CWE-1104

node_modules/function-bind/.nycrc

.nycrc

Why it matters. hidden member outside the usual dotfiles

Fix. review its purpose

LOWInventory / provenance · inv.hidden_file · CWE-1104

node_modules/hasown/.nycrc

.nycrc

Why it matters. hidden member outside the usual dotfiles

Fix. review its purpose

LOWInventory / provenance · inv.hidden_file · CWE-1104

node_modules/is-core-module/.nycrc

.nycrc

Why it matters. hidden member outside the usual dotfiles

Fix. review its purpose

LOWCode injection · code.eval_exec · CWE-78, CWE-94, CWE-95

node_modules/resolve/test/list-exports/packages/tests/index.js:189

await Function('fixtureSpec', 'return import(fixtureSpec)')(fixtureSpec); // eslint-disable-line no-new-func

Why it matters. evaluates text as code

Fix. remove; use a parser or a dispatch table

LOWFilesystem / path · fs.traversal · CWE-22, CWE-59

node_modules/resolve/test/list-exports/packages/tests/fixtures/resolve-2/project/test/resolver/without_basedir/main.js:1

var resolve = require('../../../');

LOWFilesystem / path · fs.traversal · CWE-22, CWE-59

node_modules/resolve/test/list-exports/packages/tests/index.js:184

const fullFilename = fs.realpathSync(path.join(__dirname, `../../node_modules/@fixtures/${file.replace(/^\./, resultsNative.name)}`));

LOWFilesystem / path · fs.traversal · CWE-22, CWE-59

node_modules/resolve/test/resolver/multirepo/packages/package-a/index.js:9

var expected = path.join(__dirname, '../../node_modules/jquery/dist/jquery.js');

LOWFilesystem / path · fs.traversal · CWE-22, CWE-59

node_modules/resolve/test/resolver/multirepo/packages/package-a/index.js:19

assert.equal(resolve.sync('../../node_modules/jquery', { basedir: basedir, preserveSymlinks: false }), expected);

LOWFilesystem / path · fs.traversal · CWE-22, CWE-59

node_modules/resolve/test/resolver/multirepo/packages/package-a/index.js:33

assert.equal(resolve.sync('../../../../../node_modules/jquery', { basedir: basedir, preserveSymlinks: true }), expected);