DMontgomery40/mcp-3D-printer-server vmain@a6cd596

Tool/prompt/resource text is free of hidden instructions that could hijack the agent.

Tool inputs are constrained (additionalProperties:false), so unexpected arguments can't be smuggled in.

Every consecutive version pair is diffed for new injection markers or destructive scope — a risky diff anywhere in history is a rug-pull (fail, durable); benign description drift warns.

Tool and prompt definitions stay fixed during a session — they don't change after a few calls, which is how runtime-gated rug-pulls slip past one-time review.

No over-broad or destructive tools (arbitrary shell, bulk-delete) that warrant human approval.

Untrusted tool input reaching a shell yields remote code execution. How many servers fail this?

Fix: Never pass tool arguments to a shell; use argv arrays with shell disabled.

Naive path checks let tools read/write outside intended directories (EscapeRoute-class).

Fix: Resolve to a canonical path and verify containment; reject ../ and symlinks.

Fetching tool-supplied URLs can pivot into internal networks and metadata services.

Fix: Allow-list destinations; reject arbitrary/loopback/link-local URLs.

A SECURITY.md gives a private path to report vulnerabilities.

Fix: Add SECURITY.md with a disclosure contact and process.

eval()/exec()/Function() on tool-derived strings allows arbitrary code execution.

pickle/yaml.load/etc. on untrusted data can execute code.

Hardcoded keys/tokens in published source are live credentials an attacker can use.

Reading secrets from env/secret stores avoids hardcoding them.

Runtime dependencies (parsed from the lockfile) are scanned against OSV.dev for published CVEs. Advisory: flagged dependencies lower the score but don't hard-cap it, since transitive reachability is unproven.

A lockfile makes installs reproducible and resistant to silent dependency swaps.

Unmaintained servers don't receive security fixes.

Archived repositories will never be patched.

A clear license is required for legal enterprise use.

A small, capped nudge from stars/downloads — widely-used servers get more eyes on bugs. It can never offset a real security failure.

Binding 0.0.0.0 or exposing debug inspectors widens the attack surface.

Fix: Bind to 127.0.0.1 by default; never ship open debug endpoints.

The client's token is never forwarded to downstream APIs — the server obtains its own, correctly-scoped credential instead.

HTTP endpoints reject requests carrying an unlisted Origin, so a malicious web page can't drive the server through the user's browser.

A container/sandbox image limits blast radius; a server that runs natively has full host access.