io.github.shigechika/mcp-stdio

What we checked

Six static checks, weighted by risk. Every result reflects only what could be observed in the published package and repository — never intent.

• Injection surface

  unscannable25% of grade

  Tool descriptions/manifest scanned for instruction-injection patterns (imperatives at the model, hidden text, 'ignore previous', data-exfil URLs).

  No tool descriptions, server instructions, prompts, or resources were fetched; nothing to scan for injection.

• Supply chain

  pass25% of grade

  Package provenance: namespace verification, repo linkage, maintainer count, account age, postinstall scripts, typosquat distance.

  repository linkage verified

• Credential hygiene

  warn15% of grade

  How the server takes secrets (env vs plaintext config vs hardcoded); secrets appearing in tool schemas.

  tests/test_relay.py: assigns a literal to secret (sess…ge (len 44)) — non-provider secret literal; prefer environment intake. Reads secrets from the environment (e.g. src/mcp_stdio/cli.py) — the recommended intake shape.

• Permission scope

  warn15% of grade

  Declared tools vs. breadth (filesystem, network, exec); flags shell-exec and unbounded filesystem access.

  discloses broad/destructive filesystem access: src/mcp_stdio/token_store.py: destructive filesystem call (shutil.rmtree/os.remove/etc.) Capability DISCLOSURE, not a verdict: static analysis sees the primitive is present and reachable, not whether its use is attacker-controlled.

• Version behavior

  fail10% of grade

  Diff of tool definitions between versions; new permissions or changed descriptions in a patch release (the postmark-mcp class).

  vs prior 0.43.4 (patch bump): new capability primitive(s) in source: http-client; new hardcoded outbound host/BCC destination(s): 127.0.0.1, a.com, api.example.com, attacker.example.com, auth.broken.com, auth.example.com, b.com, evil.example.net, ex.com, example.com, github.com, host, html.spec.whatwg.org, localhost., mcp.example.com, modelcontextprotocol.io, nonexistent.com, other.example.com, proxy.example.com, resource.example.com, user.

• Transport config

  warn10% of grade

  Remote servers: TLS and auth mode (none/token/OAuth). Local servers: whether the manifest indicates it phones home.

  manifest/source references heartbeat behavior — disclosure