# io.github.nexus-mcp-infra/useful-data-source-for-agents-doing-product-price-sdk (remote · useful-data-source-for-agents-production.up.railway.app)

Semantic product search over Singapore e-commerce, ranked by an auditable entropy-based value-score

- Trust score: 64/100 (medium)
- Change this week: +4
- Registry status: deprecated
- Liveness: live
- Owner verified: no
- Last scored: 2026-08-03

> **Deprecated**: this server is marked deprecated in the MCP registry.

## Components

- remote · `useful-data-source-for-agents-production.up.railway.app`: 64/100 (this document), [markdown](https://verifymcp.io/servers/nexus-mcp-infra-useful-data-source-for-agents-doing-product-price-sdk/useful-data-source-for-agents-production.md), [page](https://verifymcp.io/servers/nexus-mcp-infra-useful-data-source-for-agents-doing-product-price-sdk/useful-data-source-for-agents-production)

## Channel facts

- Endpoint: `https://useful-data-source-for-agents-production.up.railway.app/mcp`
- Transports: `streamable-http`
- Auth: `none`
- Version: `1.0.0`

## Trust breakdown

How this component scores in each security and reliability category. Every signal is checked automatically against the live server, 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 2026-08-03.

- **Endpoint Security**: 57/100
  - The endpoint's TLS certificate is valid, in date, and uses a strong key.
  - Authorisation not fully verified: no authorisation is required to call this server, and 2 tool(s) never declared a destructiveHint. The MCP spec treats an absent hint as destructive by default, so we cannot call this surface safe.
  - HTTPS is enforced; there's no plaintext access path.
  - HSTS check failed: the Strict-Transport-Security header is absent.
  - DNSSEC check failed: this domain isn't protected by DNSSEC.
- **Transport & Reachability**: 100/100
  - Verified streamable-http transport via a live MCP handshake.
- **Schema Quality & AI Usability**: 61/100
  - AI-judged instruction clarity (good).
  - Context-footprint check failed: tool/resource definitions use about 477 tokens (~238/item across 2 items; 2 tools + 0 resources), over budget; trim descriptions and params.
  - Usage-examples check failed: none of the tools include examples.
- **Stability & Change Management**: 27/100
  - Stability observed for 8 of 30 days with no destabilising changes; credit accrues until the full window elapses.
- **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.
- **Capabilities**: 100/100
  - Implements a supported MCP spec version (2025-11-25); the latest is 2026-07-28.

## Install

### Claude

```bash
claude mcp add --transport http nexus-mcp-infra-useful-data-source-for-agents-do https://useful-data-source-for-agents-production.up.railway.app/mcp
```

### Codex

```toml
[mcp_servers.nexus-mcp-infra-useful-data-source-for-agents-do]
url = "https://useful-data-source-for-agents-production.up.railway.app/mcp"
```

### opencode

```json
{
  "$schema": "https://opencode.ai/config.json",
  "mcp": {
    "nexus-mcp-infra-useful-data-source-for-agents-do": {
      "type": "remote",
      "url": "https://useful-data-source-for-agents-production.up.railway.app/mcp",
      "enabled": true
    }
  }
}
```

### OpenClaw

```bash
openclaw mcp add nexus-mcp-infra-useful-data-source-for-agents-do --url https://useful-data-source-for-agents-production.up.railway.app/mcp --transport streamable-http
```

### Hermes

```yaml
mcp_servers:
  nexus-mcp-infra-useful-data-source-for-agents-do:
    url: "https://useful-data-source-for-agents-production.up.railway.app/mcp"
```

### Other

```json
{
  "mcpServers": {
    "nexus-mcp-infra-useful-data-source-for-agents-do": {
      "type": "http",
      "url": "https://useful-data-source-for-agents-production.up.railway.app/mcp"
    }
  }
}
```

The mcpServers block is a cross-client convention. Remote transports vary, so check your client's docs.

## 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.

### 2026-08-03 (score 64, +1)

No change was recorded against any check on this day. Stability & Change Management went from 23 to 27. That category is still filling its 30-day observation window: 7 days of observed history at the previous scan, 8 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-07-31 (score 63, +1)

- [functional] We updated how we score, so this day's move reflects our rubric, not a change to the server

### 2026-07-30 (score 62, 0)

- [functional] We updated how we score, so this day's move reflects our rubric, not a change to the server

### 2026-07-29 (score 62, +1)

No change was recorded against any check on this day. Stability & Change Management went from 7 to 10. That category is still filling its 30-day observation window: 2 days of observed history at the previous scan, 3 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-07-28 (score 61, +1)

- [functional improvement] Tool “nexus_useful_data_source_for_agents_doing_prod_fetch_buywhere_vendor_price_distribution” now declares an output schema
- [functional improvement] Tool “nexus_useful_data_source_for_agents_doing_prod_rank_buywhere_products_by_value_score” now declares an output schema
- [functional] First check of Tool coverage: 100

### 2026-07-27 (score 60, 0)

- [functional] We updated how we score, so this day's move reflects our rubric, not a change to the server

### 2026-07-26 (score 60)

First indexed and scored.

## MCP tools (2)

### `nexus_useful_data_source_for_agents_doing_prod_rank_buywhere_products_by_value_score` (~281 tokens)

Searches the BuyWhere Singapore catalogue for products matching a natural-language query and returns them ranked by an auditable value-score derived from Shannon entropy of cross-vendor price variance, causal reliability, and price rank. Use this when an agent needs ranked product recommendations for a Singapore market query with auditable justification per product. Do NOT use for real-time stock ticker data, non-SGD markets, or exact product ID lookup (use fetch_buywhere_vendor_price_distribution for that). Requires a valid api_key (same as X-API-Key) and an x402 payment.

Input parameters:

- `api_key` (string, required): API key required for this paid operation -- same secret configured as X-API-Key on the REST endpoints (BUYWHERE_API_KEYS). Payment (x402) alone is not sufficient; both gates must pass.
- `limit` (number): Maximum number of ranked products to return. Higher values increase latency. Recommended 5-20 for agent consumption.
- `min_value_score` (number): Minimum composite value-score [0.0, 1.0] a product must have to be included. Products below this threshold are excluded before ranking.
- `query` (string, required): Natural-language product description, e.g. 'noise-cancelling wireless headphones under SGD 300'. Must be in English.

### `nexus_useful_data_source_for_agents_doing_prod_fetch_buywhere_vendor_price_distribution` (~196 tokens)

Given a BuyWhere product identifier, returns the full cross-vendor price distribution in SGD along with the Shannon entropy of that distribution and the coefficient of variation. Use this when an agent already knows the product and needs to audit price fairness or detect outlier vendor pricing. Do NOT use as a discovery tool — it requires a known BuyWhere product_id from rank_buywhere_products_by_value_score. Requires a valid api_key (same as X-API-Key) and an x402 payment.

Input parameters:

- `api_key` (string, required): API key required for this paid operation -- same secret configured as X-API-Key on the REST endpoints (BUYWHERE_API_KEYS). Payment (x402) alone is not sufficient; both gates must pass.
- `product_id` (string, required): BuyWhere internal product identifier as returned by rank_buywhere_products_by_value_score. Format: alphanumeric string.

## Diagnostics

Captured diagnostic sections: TLS, DNSSEC, Authorisation, Transports. The full working is on the page: https://verifymcp.io/servers/nexus-mcp-infra-useful-data-source-for-agents-doing-product-price-sdk/useful-data-source-for-agents-production#diagnostics

## Score history

- 2026-08-03: 64
- 2026-08-02: 63
- 2026-08-01: 63
- 2026-07-31: 63
- 2026-07-30: 62
- 2026-07-29: 62
- 2026-07-28: 61
- 2026-07-27: 60
- 2026-07-26: 60

## Links

- Remote endpoint: https://useful-data-source-for-agents-production.up.railway.app/mcp
- Repository: https://github.com/nexus-mcp-infra/useful-data-source-for-agents-doing-product-price-sdk
- Changelog RSS feed: https://verifymcp.io/servers/nexus-mcp-infra-useful-data-source-for-agents-doing-product-price-sdk/useful-data-source-for-agents-production/changelog.xml
- Changelog JSON feed: https://verifymcp.io/servers/nexus-mcp-infra-useful-data-source-for-agents-doing-product-price-sdk/useful-data-source-for-agents-production/changelog.json
- HTML version of this page: https://verifymcp.io/servers/nexus-mcp-infra-useful-data-source-for-agents-doing-product-price-sdk/useful-data-source-for-agents-production