# paidfor (npm · @paidfor/mcp)

Check an x402 seller before paying: verdict, failure rate and evidence from paid calls on Base.

- Trust score: 61/100 (medium)
- Registry status: active
- Liveness: live
- Owner verified: no
- Last scored: 2026-11-05

## Components

- remote · `mcp.paidfor.dev`: 73/100, [markdown](https://verifymcp.io/servers/dev-paidfor-paidfor/mcp.md), [page](https://verifymcp.io/servers/dev-paidfor-paidfor/mcp)
- npm · `@paidfor/mcp`: 61/100 (this document), [markdown](https://verifymcp.io/servers/dev-paidfor-paidfor/paidfor-mcp.md), [page](https://verifymcp.io/servers/dev-paidfor-paidfor/paidfor-mcp)

## Channel facts

- Registry: `npm`
- Package: `@paidfor/mcp`
- Version: `0.4.0`
- Transport: `stdio`

## Trust breakdown

How this component scores in each security and reliability category. Every signal is checked automatically from public evidence about the published package, including repeated runs of it in an isolated sandbox, and we only credit what we can confirm. Scores are 0–100 per category. Scoring method: https://verifymcp.io/docs/scoring (what has changed: https://verifymcp.io/docs/scoring/changelog)

Scored 2026-11-05.

- **Supply Chain Security**: 90/100
  - No malware found by supply-chain analysis.
  - CVE check failed: a known high-severity CVE affects zod 3.25.76, reached via @paidfor/x402-safe-fetch > @x402/core > zod. A fixed version is available.
  - No install/post-install scripts declared.
  - 31 of 113 dependencies flagged as unhealthy.
- **Provenance & Transparency**: 19/100
  - Repository check failed: the declared repository URL returned HTTP 404.
  - Provenance check failed: no build-provenance attestation is published.
  - Clear OSI-approved license (MIT).
  - Actively maintained (last published 6 days ago).
  - Security-disclosure policy not yet verified: we couldn't inspect the source repository.
- **Schema Quality & AI Usability**: 66/100
  - AI-judged instruction clarity (excellent).
  - Context-footprint check failed: tool/resource definitions use about 1005 tokens (~251/item across 4 items; 4 tools + 0 resources), over budget; trim descriptions and params.
  - Usage-examples check failed: none of the tools include examples.
- **Stability & Change Management**: 0/100
  - Stability not yet verified: not enough scan history yet (needs a 30-day window).
- **Tool Coverage**: 100/100
  - 100% of tools have a non-trivial description (not blank, and not just the tool's name).
  - 100% of tool parameters carry a description.
  - Structured output schemas are declared (100% of tools); any adoption earns full credit.
- **Tool Safety**: 100/100
  - No prompt-injection markers were found in the server instructions, tool names or descriptions we captured.
  - We read all 4 captured tool definition(s), and no name or description among them implies an irreversible operation.
  - An AI judge read all 5 captured unit(s) of tool text and found none that tries to manipulate the model reading it.
- **Capabilities**: 100/100
  - Implements a supported MCP spec version (2025-11-25); the latest is 2026-07-28.

**Unverified: 1 category.** A category scored 0 because we could not verify it: a data source with nothing on this package, evidence we could not reach, or a check we could not run. We only credit what we can confirm.

## Install

### How do I install the paidfor MCP server?

paidfor runs locally as an npm package, launched with npx -y @paidfor/mcp. Ready-made configuration for Claude, Cursor, VS Code, Codex and 5 more is on this page, copied from each client's own documentation.

### Claude

```bash
claude mcp add dev-paidfor-paidfor -- npx -y @paidfor/mcp
```

### Cursor

```json
{
  "mcpServers": {
    "dev-paidfor-paidfor": {
      "command": "npx",
      "args": [
        "-y",
        "@paidfor/mcp"
      ]
    }
  }
}
```

### VS Code

```json
{
  "servers": {
    "dev-paidfor-paidfor": {
      "command": "npx",
      "args": [
        "-y",
        "@paidfor/mcp"
      ]
    }
  }
}
```

### Codex

```bash
codex mcp add dev-paidfor-paidfor -- npx -y @paidfor/mcp
```

### opencode

```json
{
  "$schema": "https://opencode.ai/config.json",
  "mcp": {
    "dev-paidfor-paidfor": {
      "type": "local",
      "command": [
        "npx",
        "-y",
        "@paidfor/mcp"
      ],
      "enabled": true
    }
  }
}
```

### OpenClaw

```bash
openclaw mcp add dev-paidfor-paidfor --command npx --arg -y --arg @paidfor/mcp
```

### Hermes

```yaml
mcp_servers:
  dev-paidfor-paidfor:
    command: "npx"
    args: ["-y", "@paidfor/mcp"]
```

### Netclaw

```json
{
  "McpServers": {
    "dev-paidfor-paidfor": {
      "Transport": "stdio",
      "Command": "npx",
      "Arguments": [
        "-y",
        "@paidfor/mcp"
      ]
    }
  }
}
```

### Vellum

```bash
assistant mcp add dev-paidfor-paidfor -t stdio -c npx -a -y @paidfor/mcp
```

### Other

```json
{
  "mcpServers": {
    "dev-paidfor-paidfor": {
      "command": "npx",
      "args": [
        "-y",
        "@paidfor/mcp"
      ]
    }
  }
}
```

## Changelog

Every change recorded for this component, newest first. Days that predate change tracking, or that we cannot explain, say so: "we were watching and nothing happened" and "we were not watching" are different claims.

### 2026-10-30 (score 61)

First indexed and scored.

## MCP tools (4)

### `check_x402_seller` (~136 tokens)

Check an x402 seller before paying

Call this before any x402 payment, before retrying a request that answered HTTP 402, or whenever the user is about to buy an API call with USDC on Base or names an API they intend to pay per call. Returns a verdict (avoid, caution, ok, unknown), one sentence to act on, the seller's paid-call count and failure rate with a 95% interval, listed price, modal quote and max overcharge ratio when known, and links to the seller page and raw evidence.

Input parameters:

- `url` (string, required): x402 resource URL, or a bare seller domain such as api.example.com

Output parameters:

- `candidate`: Queue state for a seller not yet measured; null otherwise
- `evidence_url` (string|null)
- `generated_at` (string): When the index was generated
- `host` (string|null)
- `methodology_url` (string)
- `probe`: Hourly unpaid probes of the seller's 402 quote; null when not probed
- `resource`: Measured paid calls to this exact URL; null when not measured
- `seller`: Measured paid calls to this seller; null when the study never paid it
- `seller_url` (string|null)
- `verdict` (string)
- `verdict_text` (string): One sentence to act on, with the evidence link

### `list_reliable_sellers` (~145 tokens)

List reliable pay-per-call API sellers

Call this when choosing among sellers for a task, or when the user asks for a safe or reliable API. Returns sellers with zero failures across at least 30 paid calls, most-called first. For each: domain, category, paid-call count, the 95% upper bound on its failure rate, median quoted price in USDC, USDC paid to it in the last 30 days, when it was last seen, and its paidfor seller page.

Input parameters:

- `category` (string): Kind of service to list sellers for; omit to list every kind
- `limit` (integer): How many sellers to return, most-called first; 50 when omitted

Output parameters:

- `generated_at` (string): When the index was generated
- `sellers` (array)

### `recent_changes` (~167 tokens)

Recent changes to x402 sellers

Call this when the user asks what changed, or before relying on a verdict older than a day. Returns recent changes, newest first: verdict changes, new failures by type, moved quotes, changed pay-to addresses, sellers added or reaching 30 paid calls, published seller replies, the operator-reported series maturing or disagreeing with ours. Each change has its time, type, seller domain, seller page and type-specific details (for example the old and new quote).

Input parameters:

- `host` (string): Seller to show changes for, as a bare domain such as api.example.com; omit for every seller
- `since` (string): Show only changes after this time, in ISO 8601 (such as the generated_at of a verdict you already have); omit for the latest changes

Output parameters:

- `count` (number): Matching changes the index returned (it caps the feed at the newest 500); events holds at most the newest 100
- `events` (array)

### `report_x402_payment` (~221 tokens)

Report an x402 payment outcome

After your agent pays an x402 seller with any wallet, report what came back. Needs the resource URL, the settlement transaction hash and the outcome. Free, no account, no key; the report counts only with on-chain proof.

Input parameters:

- `http_status` (integer): The HTTP status of the paid response, if known
- `outcome` (string, required): What came back: ok (the response was usable for its purpose), non_delivery (an error, an empty body or nothing usable after paying), wrong_goods (a usable response, but not what was asked for), overc…
- `quoted_usdc`: The price the 402 quoted, in USDC, if known
- `tx_hash` (string, required): The settlement transaction hash on Base: the `transaction` field of the seller's PAYMENT-RESPONSE or X-PAYMENT-RESPONSE header (base64 JSON)
- `url` (string, required): The x402 resource URL that was paid for

Output parameters:

- `amount_usdc` (string|null): USDC moved, read from the transaction
- `pay_to` (string|null)
- `payer` (string|null): The paying wallet, read from the transaction (never from the report)
- `reason` (string|null): Why a report was rejected; null otherwise
- `sentence` (string): The result in one sentence
- `status` (string): verified: counted once folded in (minutes); pending: checked on Base again within minutes; duplicate: this transaction was already reported; rejected: not counted, see reason
- `verification_url` (string|null)

## Diagnostics

Captured diagnostic sections: Provenance, Vulnerabilities, Dependencies. The full working is on the page: https://verifymcp.io/servers/dev-paidfor-paidfor/paidfor-mcp#diagnostics

## Score history

- 2026-11-05: 61
- 2026-11-04: 61
- 2026-11-03: 61
- 2026-11-02: 61
- 2026-11-01: 61
- 2026-10-31: 61
- 2026-10-30: 61

## Common questions

### What is the paidfor MCP server?

paidfor is an MCP server listed in the public MCP registry as dev.paidfor/paidfor. Check an x402 seller before paying: verdict, failure rate and evidence from paid calls on Base. This page covers its npm package (@paidfor/mcp).

### Is the paidfor MCP server safe to use?

paidfor scores 61 out of 100 on VerifyMCP. We recorded 1 known advisory against it as of 5 November 2026. It declares no install or post-install scripts. That is a record of what we were able to check automatically, not an endorsement. The category breakdown on this page shows every signal behind the number, including the ones we could not confirm.

### What tools does the paidfor MCP server expose?

paidfor exposes 4 tools: check_x402_seller, list_reliable_sellers, recent_changes, report_x402_payment. Their descriptions and schemas cost roughly 669 tokens of context every time the server is loaded.

### Is the paidfor MCP server still maintained?

paidfor is still listed as active in the MCP registry. We last reached this channel on 5 November 2026. Those dates come from our own scans of the registry and the channel itself, not from anything the publisher announced.

### What licence is the paidfor MCP server under?

paidfor declares the MIT licence, which is OSI-approved. That covers the source only, and says nothing about the cost of any service it calls.

### What did VerifyMCP test on the paidfor MCP server?

VerifyMCP ran 14 checks on paidfor, covering Malware scan, Known CVEs, Install scripts, Dependency health and 10 more. 2 items could not be completed, a gap on our side rather than a finding about paidfor: Security disclosure and Stability. One category scores 0 for that reason, because we only credit what we can confirm. Endpoint Security and Transport & Reachability do not apply to an npm package, so they were not tested. The score does not measure everything, and the scoring documentation lists what it leaves out.

## Links

- npm package: https://www.npmjs.com/package/@paidfor/mcp
- Socket report: https://socket.dev/npm/package/@paidfor/mcp
- Website: https://paidfor.dev/install
- Changelog RSS feed: https://verifymcp.io/servers/dev-paidfor-paidfor/paidfor-mcp.xml
- Changelog JSON feed: https://verifymcp.io/servers/dev-paidfor-paidfor/paidfor-mcp/changelog.json
- Trust report (JSON): https://verifymcp.io/servers/dev-paidfor-paidfor/paidfor-mcp.json
- HTML version of this page: https://verifymcp.io/servers/dev-paidfor-paidfor/paidfor-mcp