Before your agent buys, it asks: will this work?

Your agent never needs this website

• Discover: server.json (the MCP Registry listing file), /.well-known/mcp.json, llms.txt, OpenAPI 3.1
• Connect: one MCP endpoint (Streamable HTTP) or plain HTTP; no key needed to start
• Identify anything: identify_product takes URLs, model numbers, SKUs, UPCs or descriptions
• Decide: check_compatibility, validate_purchase_plan, fix_purchase_plan
• Pay per request: x402 (USDC on Base) or prepaid credits; 402 responses say how
• Retry safely: every error carries code, retryable and retry_after_seconds
• Close the loop: report_outcome and signed webhooks when a record behind a decision changes

// MCP: https://tetheredtrust.com/mcp
tools/call identify_product
{"product": "https://www.sanus.com/en_US/products/tv-mounts/vlt7/"}

→ {"status": "verified",
   "standards": {"provides": [{"id": "vesa:400x300", ...}]},
   "limits": {"needs": {"weight-lb": {"max": 150},
                        "screen-size-in": {"min": 42, "max": 90}}},
   "evidence": [{"level": "reviewed_source", "url": "..."}]}

tools/call check_compatibility
{"existing": "TCL 65QM8K", "candidate": "Sanus VLT7"}

→ {"decision": "supported",
   "checks": [{"rule": "vesa", "ok": true},
              {"rule": "limit:weight-lb", "ok": true}],
   "receipt": {"id": "rcpt_…"}}

validate_purchase_plan

Send the setup and the cart. Get one decision your agent can act on: supported, conditional, incompatible or insufficient_evidence, plus:

• A result for every part, with sources
• Limits across the whole configuration: memory slots, total capacity, M.2 slots
• Adapters and hubs the plan still needs
• Substitutions for parts that won't work
• The exact questions blocking a decision, and which field answers each
• A signed receipt, and a recheck before ordering

Build a plan in the console

POST https://tetheredtrust.com/v1/plan
{"setup": [{"text": "Lenovo ThinkPad T480",
            "config": {"memory_modules": [{"capacity_gb": 8}]}}],
 "purchase": [{"text": "Crucial CT16G4SFRA32A", "quantity": 2}]}

→ {"decision": "incompatible",
   "summary": "ThinkPad T480 has 2 slots and 1 already
     in use, so 2 more won't fit. Set
     config.replace_memory if the new modules
     replace the installed ones.",
   "results": [{"name": "16GB DDR4-3200 SODIMM",
                "decision": "supported", ...}],
   "system_checks": [{"rule": "memory_slots",
                      "ok": false, ...}],
   "questions": [], "receipt": {"id": "rcpt_…"},
   "plan_id": "plan_…"}

MCP, HTTP, SDKs and a sandbox

One MCP server with 18 tools, the same operations over HTTP (OpenAPI 3.1), copy-paste JavaScript and Python clients, and a sandbox with documented scenarios that never charges.

https://tetheredtrust.com/mcp

• how_it_works How Tethered Trust works
• list_coverage List coverage
• check_cart_before_checkout Check a cart before checkout
• enrich_catalog Enrich a product catalog
• identify_product Identify any product
• list_standards List the standards vocabulary
• resolve_product Look up a product
• validate_purchase_plan Validate a purchase plan
• fix_purchase_plan Fix a purchase plan
• plan_upgrade Plan an upgrade
• identify_from_photo Read a model number from a photo
• recheck_plan Recheck a saved plan
• check_batch Check many pairs
• check_compatibility Check compatibility
• find_parts Find parts that fit
• check_fit Check physical fit
• verify_receipt Verify a receipt
• report_outcome Report what happened

Connect your agent

import { TetheredTrust } from
  "https://tetheredtrust.com/sdk/tethered-trust.mjs";

const tt = new TetheredTrust({ sandbox: true });
const plan = await tt.validatePlan({
  purchase: ["ASUS TUF GAMING B650-PLUS WIFI",
             "AMD Ryzen 7 7800X3D",
             "Noctua NH-D15 G2"]
});
// plan.decision === "supported"