Skills/PyPI/mcp-server-for-ynab

mcp-server-for-ynab@0.4.0

CAUTION· not started

Publisher claims: "An AI-first MCP server for YNAB. Read-only by default, with reversible writes." Observed in sandbox: no network, touches nothing outside the project, writes no memory.

Registry PyPI (MCP server)Publisher hs737 · publishing for 78 daysInstalls 355Last detonated 5d ago
What would fix thisWatchDispute verdict

Coverage

Not started: dependency install failed; the server itself was not observed.
Tested
the dependency install step · every file read, file written and host contacted by what ran
Not tested
server startup · the tool list · tool behavior

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
YNAB_API_KEYConfiguration, not credentials: FASTMCP_HOST, FASTMCP_PORT, YNAB_HISTORY_PATH, YNAB_PLAN_ID
Where it talks to
no vendor host named in the codeAlso ynab.com, getpostman.com — not the publisher's domain; check what for before connecting.
What the honeypot saw
no credential files read · no network
What we could not test
server startup · the tool list · tool behavior

Connect it with a scoped credential, under the guard, and read the third-party hosts first. The code names ynab.com, getpostman.com as well as its own vendor. The guard injects YNAB_API_KEY only into requests to the host you bind (and its subdomains) and refuses the rest.

$vet-skills run --net declared -- uvx mcp-server-for-ynab

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; not started: dependency install failed; the server itself was not observed) on 2026-11-09 and scored it 78/100 (Caution). It is not known to be malicious, but it has behaviour or code a security policy should decide on before install. Notable findings: Access to sensitive file paths; Access to sensitive file paths; Access to sensitive file paths. Summary: no network, touches nothing outside the project, writes no memory.

Behavior trace

Honeypot run · 0 s · 2 scenarios · 0 deviations
t+CategoryObserved action
0.0sprocessno install scripts in bundle
0.2sprocessdependency install exit 1 ·
0.2sclaimednot started: dependency install failed (exit 1); the server itself was not observed
0.2sprocessscript backend runs setup only
0.2sprocessno install scripts to re-run

Static findings

HIGH
Access to sensitive file pathsscripts/live_write_sweep.py:362 · Access to sensitive file paths — SSH keys, AWS credentials, env files, or system filesprint("ERROR: YNAB_API_KEY is not set. Load your .env first.", file=sys.stderr)Fix: Stop enumerating or reading credential locations; take secrets from a declared environment variable the user sets on purpose.
AST05
MEDIUM
MCP server using network transport (SSE/HTTP)scripts/mcp_http_check.sh:59 · MCP server using network transport (SSE/HTTP) — data sent over network"$PYTHON" -m mcp_server_for_ynab.cli.main http --host "$HOST" --port "$PORT" > "$LOG" 2>&1 &Fix: Namespace tool names and keep tool descriptions literal; no instructions to the agent inside them.
AST04
MEDIUM
MCP server using network transport (SSE/HTTP)src/mcp_server_for_ynab/ynab_client/base.py:5 · MCP server using network transport (SSE/HTTP) — data sent over networkfrom mcp_server_for_ynab.http_client.client import YnabHttpClientFix: Namespace tool names and keep tool descriptions literal; no instructions to the agent inside them.
AST04
MEDIUM
npx invocation of non-well-known packagescripts/build_mcpb.py:58 · npx invocation of non-well-known package — may execute untrusted codeprint("ERROR: npx not found. Node is required to build the MCPB bundle.", file=sys.stderr)Fix: Pin versions and sources; vendor anything fetched at install time.
AST06
MEDIUM
Python subprocess execution detectedscripts/check_assets.py:61 · Python subprocess execution detectedresult = subprocess.run([sys.executable, "-c", script], capture_output=True, text=True, check=True, env=env)Fix: Build commands from fixed arguments, never from interpolated strings; prefer an API client over shelling out.
AST05
HIGH
Access to sensitive file pathsscripts/live_read_sweep.py:218 · Access to sensitive file paths — SSH keys, AWS credentials, env files, or system filesprint("ERROR: YNAB_API_KEY is not set. Load your .env first.", file=sys.stderr)Fix: Stop enumerating or reading credential locations; take secrets from a declared environment variable the user sets on purpose.
AST05
MEDIUM
Process kill commandscripts/mcp_http_check.sh:31 · Process kill command — agent can terminate processes[ -n "$SERVER_PID" ] && kill "$SERVER_PID" 2>/dev/nullFix: Build commands from fixed arguments; do not interpolate untrusted strings into a shell.
AST05
MEDIUM
MCP server using network transport (SSE/HTTP)src/mcp_server_for_ynab/server/context.py:19 · MCP server using network transport (SSE/HTTP) — data sent over networkfrom mcp_server_for_ynab.http_client.client import YnabHttpClientFix: Namespace tool names and keep tool descriptions literal; no instructions to the agent inside them.
AST04
MEDIUM
MCP server using network transport (SSE/HTTP)src/mcp_server_for_ynab/http_client/client.py:20 · MCP server using network transport (SSE/HTTP) — data sent over networkfrom mcp_server_for_ynab.http_client.rate_budget import RateBudgetFix: Namespace tool names and keep tool descriptions literal; no instructions to the agent inside them.
AST04
HIGH
Access to sensitive file pathssrc/mcp_server_for_ynab/config/settings.py:53 · Access to sensitive file paths — SSH keys, AWS credentials, env files, or system files# have no clone and so no .env.example to consult. Name the place theFix: Stop enumerating or reading credential locations; take secrets from a declared environment variable the user sets on purpose.
AST05
MEDIUM
MCP server using network transport (SSE/HTTP)src/mcp_server_for_ynab/http_client/__init__.py:1 · MCP server using network transport (SSE/HTTP) — data sent over networkfrom mcp_server_for_ynab.http_client.client import YnabHttpClientFix: Namespace tool names and keep tool descriptions literal; no instructions to the agent inside them.
AST04
MEDIUM
Python subprocess execution detectedscripts/build_mcpb.py:40 · Python subprocess execution detectedreturn subprocess.run(Fix: Build commands from fixed arguments, never from interpolated strings; prefer an API client over shelling out.
AST05
HIGH
Access to sensitive file pathsscripts/mcp_http_check.sh:54 · Access to sensitive file paths — SSH keys, AWS credentials, env files, or system filesecho "ERROR: YNAB_API_KEY is not set. Load your .env first." >&2Fix: Stop enumerating or reading credential locations; take secrets from a declared environment variable the user sets on purpose.
AST05

Cost to the agent

Instructions loaded
≈59 tok
1 file · 81 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 mcp-server-for-ynab@0.4.0 as of 5d ago. This is the package itself, not its dependencies.

What would make this Verified

2 points to 80 · weights: behavior 45%, static 25%, prompt 15%, publisher 15%
  1. Unclaimed publisher≈ +8 on the totalClaim hs737: a verified publisher gets +50 on publisher trust. It is free and usually instant with GitHub sign-in.
  2. 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.
  3. MCP server using network transport (SSE/HTTP)≈ +2 on the totalNamespace tool names and keep tool descriptions literal; no instructions to the agent inside them.
  4. npx invocation of non-well-known package≈ +2 on the totalPin versions and sources; vendor anything fetched at install time.
  5. Python subprocess execution detected≈ +2 on the totalBuild commands from fixed arguments, never from interpolated strings; prefer an API client over shelling out.
  6. Process kill command≈ +2 on the totalBuild commands from fixed arguments; do not interpolate untrusted strings into a shell.
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