FabTally Guard

FabTally Guard — MCP server

De-risk-a-dollar verification checks an AI agent runs before a costly action. Fronts the Guard HTTP API at https://guard.fabtally.com. Holds no private key.

Tools (all paid; a call with no payment returns the decoded x402 402 challenge)

Tool	Price	What it does
deps_check	$0.003	Vet a package before installing — OSV.dev CVEs, typosquat similarity, deprecation/yank, SPDX license, age/download signals + a plain-English risk verdict. Args: ecosystem (npm|pypi|crates), name, version?.
x402_preflight	$0.002	Verify another x402 endpoint before paying it — valid x402 v2 402 challenge? price/asset/network/payTo consistent with its /.well-known/x402? TLS/reachability/openapi? + the parsed price. Args: url.
json_repair	$0.002	Coerce near-miss LLM JSON to a JSON-Schema-conformant object (fences/commas/quotes/keys/literals/brackets, then type-coerce, defaults, drop extras) — or precise per-field errors. Args: json (string), schema.
url_read	$0.004	Fetch a public url → clean Markdown + token estimate for RAG. Respects robots.txt, public pages only, nothing stored. Args: url.

Every tool also accepts an optional x_payment (base64 x402 payload) that is forwarded as the X-PAYMENT header to settle the call and return the real result. Humans can instead prepay by card and use an X-FabTally-Key credit key against the HTTP API.

Transports

• stdio (portable): npx fabtally-guard-mcp (bin: fabtally-guard-mcp)
• streamable-http (hosted): https://guard.fabtally.com/mcp

Config: FABTALLY_GUARD_BASE (default https://guard.fabtally.com).

Read-only, keyless, stateless, descriptive. Operated by Sunstone Soft (fabtally.com). Not a security guarantee.