TensorFeed x402 Base Reader
ai.tensorfeedPublished by tensorfeed.aiv0.2.1Updated Oct 24, 2026
Read-only Base mainnet reader. Verifies x402 payment settlements + AFTA federation status.
The publisher's own server: TensorFeed
Overview
A read-only Base mainnet reader that lets an assistant verify x402 USDC payment settlements on-chain, parse publisher x402 manifests, and check AFTA federation.
- What you can do
- Read Base chain state: ETH and USDC balances, latest block number, transaction receipts, read-only contract calls, and recent USDC transfers for an address. Verify x402 payments: check that a transaction's USDC Transfer event matches an expected recipient and amount, and list USDC payments sent to a merchant address. Inspect x402 endpoints: fetch a domain's well-known x402 manifest, probe a URL for a canonical paid 402 response, and decode a base64 X-PAYMENT header offline. Query TensorFeed surfaces: AFTA federation status and member list, TensorFeed wallet payment lookup, and publisher uptime health.
- When to use it
- Use it when an assistant needs to independently confirm that an x402 payment actually settled on Base instead of trusting a merchant's receipt, or to audit a publisher's x402 manifest and endpoint before paying. It suits read-only verification workflows where no wallet or signing is wanted.
- Requirements
- Runs locally via npx from the npm package, so Node.js is needed. It defaults to the public Base RPC endpoint; optionally set TENSORFEED_RPC_URL to an allowlisted Alchemy or Infura endpoint for higher rate limits. Network access to Base and to probed domains is required. No account or private key is needed.
Installation
In SourceWeft
- Open TensorFeed x402 Base Reader in the dashboard and add it to a workspace.
- Enable the server for the chats that should use its tools.
Desktop only via STDIO. STDIO servers start a local process, so they need the SourceWeft desktop host.
Other MCP clients
Follow the launch instructions in the repository.
README
@tensorfeed/x402-base-mcp
Read-only MCP server for verifying x402 USDC settlements on Base mainnet. Drop it into any MCP-compatible agent (Claude Desktop, Claude Code, Cursor, ChatGPT) to independently audit x402 payment receipts on-chain, parse publisher .well-known/x402 manifests, and check AFTA federation status. No private keys, no signing, no broadcasts.
Relationship to Coinbase Base MCP
Coinbase shipped Base MCP (the official mcp.base.org server, launched May 2026) as the transact-side MCP: it connects an agent to a Base Account and lets the agent propose swaps, transfers, and x402 payments that the user approves in-wallet.
This package, @tensorfeed/x402-base-mcp, is the verify-side MCP. Once an x402 payment has been made (by Base MCP, by a server-side @coinbase/x402 middleware, or by any other x402 client), this server lets the calling agent independently check the on-chain settlement, parse the publisher's /.well-known/x402 manifest, and audit the receipt. Read-only chain visibility, no wallet.
The two are complementary, not competing. Use Base MCP to pay. Use this MCP to verify.
Why a separate verify MCP
x402 is a payment protocol where agents pay merchants in USDC on Base for paid API responses. When an agent receives a payment receipt back, it has two options for confirming that the settlement actually happened the way the receipt claims:
- Trust the merchant
- Read the on-chain Transfer event itself
Most existing EVM MCP servers either require a private key (so the agent can also send transactions, which is operationally risky and unnecessary for verification), or are generic multi-chain readers that don't speak x402. This server is the read-only, x402-aware option. Drop it into a Claude Desktop or Claude Code session and any agent can verify x402 payments without operating a wallet.
The TensorFeed-flavor tools (verify_afta_federation, tf_payment_lookup) compose the same primitives against TF's canonical surfaces and demonstrate the pattern. Use them or ignore them; the generic tools work fine on their own.
Installation
Claude Desktop
Add to claude_desktop_config.json:
Claude Code
Optional: bring your own RPC
The server defaults to the public Base RPC (https://mainnet.base.org), which is fine for casual use. For heavier workloads, set an Alchemy or Infura URL via TENSORFEED_RPC_URL. The URL must match the allowlist in src/rpc/allowlist.ts; anything else falls back to the public endpoint and logs a warning to stderr.
Affiliate links if you don't already have an account:
- Alchemy: https://www.alchemy.com/
- Infura: https://www.infura.io/
Tools
Generic Base reads
x402-native verification
TensorFeed flavor
Examples
Verify an x402 settlement (works on TensorFeed's first canonical V2 payment):
Inspect a publisher's x402 manifest:
Check AFTA certification:
Threat model
Read-only chain-visibility MCP. The full picture is in SECURITY.md; the short version:
- No private keys, no signing, no broadcasts. The server cannot move funds.
- Input validators on every tool reject malformed inputs (bad checksums, malformed hashes, URL-shaped domains, private/loopback hostnames).
- Output sanitization strips C0/C1 control characters and zero-width / direction-override marks from every string returned to the calling agent.
- External strings carry an
_origin: "external"marker so the calling agent knows the value came from a third party. - 50 KB response cap on serialized tool output; oversized responses collapse to a structured stub.
- RPC allowlist limits self-hosters to known endpoints; arbitrary URLs are rejected and fall back to public Base RPC.
- No telemetry, no phone-home, no analytics.
- Provenance: npm releases are published via GitHub Actions OIDC with cryptographic provenance attestations. Verify with
npm audit signatures.
Report security issues to [email protected]. Please do not file a public issue or CVE for an unfixed vulnerability.
License
MIT
Related
- Coinbase Base MCP - the official transact-side MCP for Base. Pair with this package for a full pay + verify loop: Base MCP signs the x402 payment, this package independently confirms the settlement on-chain.
- @tensorfeed/mcp-server - companion package, the TensorFeed data MCP (news, status, models, benchmarks, premium endpoints). Complementary role: this server verifies x402 payments on-chain; mcp-server wraps the TF data API as MCP tools.
- TensorFeed - AI ecosystem data layer
- TensorFeed developers - free + premium API for AI agents
- Agent Fair-Trade Agreement (AFTA) - open standard for honest agent commerce
- x402 spec - the payment protocol this MCP verifies
Source: README.md at commit 7653522
Tools
0Version history
1- v0.2.1LatestSep 16, 2026
Score
50% of the applicable checks met
How complete this listing is, computed from the registry entry, the endpoint and public sources. Not a rating of the server and not a statement that it is safe or working today: reachability is a dated check, and no installs or reviews go into the score.
- Reached in the last 30 days25 pts
Keep the endpoint answering the MCP handshake; SourceWeft probes it every 30 days.
- Auth declared10 pts
Declare the credential headers in the registry entry, or keep the endpoint answering the probe so its auth can be classified.
- Tools listed15 pts
Answer tools/list without a credential, or ship a package that starts in a sandbox without one.
- DescriptionRequired15 pts
- Logo10 pts
- Documentation15 pts
- License10 pts
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TensorFeed
ai.tensorfeedOfficial publisher
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Remote MCP endpoint offering real-time data feeds to AI agents, with premium tools paid for by USDC micropayments on Base.