Skills/npm/mcp

mcp@0.28.3

CAUTION· startup only

Publisher claims: "Shardflux MCP server (stdio): serverless VMs for your agent. Open a persistent workspace by key, run commands, edit files, use git, a browser and a desktop in it. Uses your scoped Shardflux API key." Observed in sandbox: no network, touches nothing outside the project, writes no memory.

Registry npm (MCP server)Publisher shardflux · publishing for 47 daysInstalls 6,711Last detonated 6 h ago
What would fix thisWatchDispute verdict

Coverage

Startup only; authenticated tool behavior not tested.
Tested
server startup over stdio (initialize sent) · every file read, file written and host contacted by what ran
Not tested
the tool list (the server exited before answering) · what the tools do when called with real credentials
Needs
SHARDFLUX_API_KEY — give it to the server where it runs, through vet-skills run --secrets, so the value never enters the server's environment. Never paste a credential into a chat, a ticket or a report.

What this means for the label: Caution here covers what ran. The server's tools were not exercised with a real credential, so nothing about their behavior is asserted; the credential summary below says what to do with that.

Before you give it your token

It will ask for
SHARDFLUX_API_KEYSHARDFLUX_SESSION_TOKENConfiguration, not credentials: CLAUDE_CODE_SESSION_ID, CLAUDE_PROJECT_DIR, PATHEXT, SHARDFLUX_AGENT_LABEL, SHARDFLUX_API_URL, SHARDFLUX_BASE_URL, SHARDFLUX_CLI, SHARDFLUX_CONFIG_DIR, SHARDFLUX_MCP_LOG_LEVEL, SHARDFLUX_MCP_TOOL_TIMEOUT_MS, SHARDFLUX_MCP_TOOLS, SHARDFLUX_PREWAKE, SHARDFLUX_TEMPLATE, SHARDFLUX_WAKE, SHARDFLUX_WAKE_TIMEOUT_MS, SHARDFLUX_WORKSPACE_KEY, SHARDFLUX_WORKSPACE_MODE
Where it talks to
shardflux.dev (its own)
What the honeypot saw
no credential files read · no network
What we could not test
the tool list (the server exited before answering) · what the tools do when called with real credentials

Connect it with a scoped credential, under the guard. It asks for SHARDFLUX_API_KEY, SHARDFLUX_SESSION_TOKEN and talks to shardflux.dev. Give the credential to the guard, not the server: the value never enters the server's environment and only travels to the host you bind. What the tools do with a real credential was not observed.

$vet-skills run --secrets SHARDFLUX_API_KEY=shardflux.dev,SHARDFLUX_SESSION_TOKEN=shardflux.dev -- npx -y @shardflux/mcp

Never paste a credential into a chat, a ticket or a report, including ours. How the guard holds it.

Is [email protected] safe to install?

KillerSkills ran it in the KillerSkills honeypot sandbox (2 scenarios; startup only; authenticated tool behavior not tested) on 2026-11-14 and scored it 75/100 (Caution). It is not known to be malicious, but it has behaviour or code a security policy should decide on before install. Notable findings: Prompting user to enter sensitive credentials; Access to sensitive file paths. Summary: no network, touches nothing outside the project, writes no memory.

Behavior trace

Honeypot run · 52 s · 2 scenarios · 0 deviations
t+CategoryObserved action
0.0sprocessno install scripts in bundle
12sprocessdependency install exit 0
32sprocessrelaunched with a decoy SHARDFLUX_API_KEY (tagged; nothing real)
52sclaimedstartup only: exited before answering, asking for SHARDFLUX_API_KEY (a decoy value was refused)
52sprocessscript backend runs setup only
52sprocessno install scripts to re-run

Static findings

CRITICAL
Prompting user to enter sensitive credentialsdist/server.js:1491 · Prompting user to enter sensitive credentials — social engineering… a secure entry page on your computer. Give the returned URL to your user: they enter the password there and it goes directly to the encrypted store. Use site_logins_list to see …Fix: Stop enumerating or reading credential locations; take secrets from a declared environment variable the user sets on purpose.
AST03
MEDIUM
File type combined with upload actiondist/server.js:2131 · File type combined with upload action — agent may exfiltrate local data files…mands, services). Give either recipe (the document) or file (a template.yaml or .json path inside this server’s working directory). A file entry may name a local `from` path (a file, or a folder copied as a tar) relative to the template fi…Fix: Remove the call, or declare the host in frontmatter and explain in the README what is sent and why.
AST07
MEDIUM
npx invocation of non-well-known packagedist/move-to-cloud.js:89 · npx invocation of non-well-known package — may execute untrusted codeconst npx = onPath('npx', env, platform) ?? beside;Fix: Pin versions and sources; vendor anything fetched at install time.
AST06
MEDIUM
npx invocation of non-well-known packagedist/server.js:1130 · npx invocation of non-well-known package — may execute untrusted code… UTF-8 text (${ref.content_type})`}: ${hosted ? `read it with the local server (npx @shardflux/mcp), whose ${tool} save_to writes it to a file on your computer${tool === 'brain_rea…Fix: Pin versions and sources; vendor anything fetched at install time.
AST06
MEDIUM
npx invocation of non-well-known packagedist/server.js:1062 · npx invocation of non-well-known package — may execute untrusted codethrow new ToolError('invalid_arguments', 'files are read from your computer: attach them with the local server (npx @shardflux/mcp).');Fix: Pin versions and sources; vendor anything fetched at install time.
AST06
LOW
Unpinned dependencydist/move-to-cloud.js:319 · Unpinned dependencynote = `The shard command on this computer (${cli.command}) is older than CLI 0.19.0, so this move runs the latest CLI through npx. \`npm i -g shardflux@latest\` updates it.`;Fix: Pin the exact version (`[email protected]`, `==1.2.3`) so every install gets the bytes that were reviewed.
AST06
MEDIUM
npx invocation of non-well-known packagedist/move-to-cloud.js:15 · npx invocation of non-well-known package — may execute untrusted code* The CLI: $SHARDFLUX_CLI (an executable), else `shard` on PATH, else `npx -y @shardflux/cli@latest`. A `shard` on PATHFix: Pin versions and sources; vendor anything fetched at install time.
AST06
MEDIUM
npx invocation of non-well-known packagedist/server.js:631 · npx invocation of non-well-known package — may execute untrusted code… and plan upgrades, spend alerts and audit export are done with the shard CLI: `npx @shardflux/cli@latest --help`.', 'For setup, run `npx @shardflux/cli@latest setup --guide`: y…Fix: Pin versions and sources; vendor anything fetched at install time.
AST06
MEDIUM
npx invocation of non-well-known packagedist/move-to-cloud.d.ts:28 · npx invocation of non-well-known package — may execute untrusted code/** `npx -y @shardflux/cli@latest`: npx on PATH, else the one next to this Node.js. */Fix: Pin versions and sources; vendor anything fetched at install time.
AST06
HIGH
Access to sensitive file pathsdist/board.js:245 · Access to sensitive file paths — SSH keys, AWS credentials, env files, or system files…s device helper to find existing credentials in its normal environment, project .env files, vault references and CLI logins, then transfer them directly to their ma…Fix: Stop enumerating or reading credential locations; take secrets from a declared environment variable the user sets on purpose.
AST05
MEDIUM
npx invocation of non-well-known packagedist/server.js:632 · npx invocation of non-well-known package — may execute untrusted code…h the shard CLI: `npx @shardflux/cli@latest --help`.', 'For setup, run `npx @shardflux/cli@latest setup --guide`: you run permitted commands; your user answers multiple-choice q…Fix: Pin versions and sources; vendor anything fetched at install time.
AST06
MEDIUM
npx invocation of non-well-known packagedist/move-to-cloud.js:90 · npx invocation of non-well-known package — may execute untrusted codereturn npx ? { command: npx, args: ['-y', NPX_PACKAGE], source: 'npx' } : null;Fix: Pin versions and sources; vendor anything fetched at install time.
AST06
MEDIUM
npx invocation of non-well-known packagedist/move-to-cloud.js:86 · npx invocation of non-well-known package — may execute untrusted code/** `npx -y @shardflux/cli@latest`: npx on PATH, else the one next to this Node.js. */Fix: Pin versions and sources; vendor anything fetched at install time.
AST06
LOW
Refusal suppressionCHANGELOG.md:192 · Refusal suppression — attempting to prevent safety responses · informational: not an instruction file- `orchestrator_say` (0.23.0+, SDK 0.30.0): never refused for how many inputs wait (no more 429Fix: Remove the text that addresses the agent rather than the reader; describe behavior, do not instruct.
AST01
MEDIUM
npx invocation of non-well-known packagedist/server.js:2149 · npx invocation of non-well-known package — may execute untrusted codethrow new ToolError('invalid_arguments', 'build.files entries carry their content inline or reference an upload; a local `from` path needs the local server (npx @shardflux/mcp).');Fix: Pin versions and sources; vendor anything fetched at install time.
AST06

Cost to the agent

Instructions loaded
≈84 tok
1 file · 31 in bundle
Tool list per prompt
≈0 tok
0 tools · 0 per tool
Handshake
no reply
launch to tools/list, stdio
Undocumented tools
0
description under 20 chars · avg 0

Tokens estimated at four characters each. The tool list is re-read by the agent on every turn, so it is the number to compare between servers that do the same job: ranked across the index.

Known vulnerabilities

No advisories in OSV for @shardflux/mcp@0.28.3 as of 2 h ago. This is the package itself, not its dependencies.

What would make this Verified

5 points to 80 · weights: behavior 45%, static 25%, prompt 15%, publisher 15%
  1. Prompting user to enter sensitive credentials≈ +9 on the totalStop enumerating or reading credential locations; take secrets from a declared environment variable the user sets on purpose.
  2. Unclaimed publisher≈ +8 on the totalClaim shardflux: a verified publisher gets +50 on publisher trust. It is free and usually instant with GitHub sign-in.
  3. Access to sensitive file paths≈ +4 on the totalStop enumerating or reading credential locations; take secrets from a declared environment variable the user sets on purpose.
  4. File type combined with upload action≈ +2 on the totalRemove the call, or declare the host in frontmatter and explain in the README what is sent and why.
  5. npx invocation of non-well-known package≈ +2 on the totalPin versions and sources; vendor anything fetched at install time.
  6. Unpinned dependencies≈ +1 on the totalPin exact versions (and ideally hashes) in package.json, requirements or the install script so the bundle cannot change under you.
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