# FactReason (remote · www.factreason.com)

Check exact npm/PyPI upgrades for evidence-backed breaking changes; query APIs and components.

- Trust score: 69/100 (medium)
- Registry status: active
- Liveness: live
- Owner verified: no
- Last scored: 2026-08-17

## Components

- remote · `www.factreason.com`: 69/100 (this document), [markdown](https://verifymcp.io/servers/factreason-factreason/www.md), [page](https://verifymcp.io/servers/factreason-factreason/www)

## Channel facts

- Endpoint: `https://www.factreason.com/mcp`
- Transports: `streamable-http`
- Auth: `none`
- Version: `2.0.4`

## 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 2026-08-17.

- **Endpoint Security**: 74/100
  - The endpoint's TLS certificate is valid, in date, and uses a strong key.
  - No authorisation is required to call this server. Every tool declares its destructiveHint and none is destructive, so open access doesn't expose one.
  - 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**: 75/100
  - AI-judged instruction clarity (excellent).
  - Context-footprint check failed: tool/resource definitions use about 1425 tokens (~142/item across 10 items; 10 tools + 0 resources), over budget; trim descriptions and params.
  - Usage-examples check failed: none of the tools include examples.
- **Stability & Change Management**: 10/100
  - Stability observed for 3 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**: 60/100
  - Spec-recency check failed: implements MCP spec 2025-06-18; the latest is 2026-07-28.

## Install

### Claude

```bash
claude mcp add --transport http factreason-factreason https://www.factreason.com/mcp
```

### Codex

```toml
[mcp_servers.factreason-factreason]
url = "https://www.factreason.com/mcp"
```

### opencode

```json
{
  "$schema": "https://opencode.ai/config.json",
  "mcp": {
    "factreason-factreason": {
      "type": "remote",
      "url": "https://www.factreason.com/mcp",
      "enabled": true
    }
  }
}
```

### OpenClaw

```bash
openclaw mcp add factreason-factreason --url https://www.factreason.com/mcp --transport streamable-http
```

### Hermes

```yaml
mcp_servers:
  factreason-factreason:
    url: "https://www.factreason.com/mcp"
```

### Other

```json
{
  "mcpServers": {
    "factreason-factreason": {
      "type": "http",
      "url": "https://www.factreason.com/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.

### 2026-08-16 (score 69, 0)

- [security] The server rewrote its instructions, which are the text every model session reads
- [security] Tool “factreason_component_spec” rewrote its description, which is the text the model reads
- [security] Tool “factreason_integration_brief” rewrote its description, which is the text the model reads
- [security] Tool “factreason_package_upgrade_advisory” rewrote its description, which is the text the model reads
- [functional regression] Schema quality: 124 → 142
- [functional] Server version: 2.0.3 → 2.0.4
- [functional] Server version: 2.0.2 → 2.0.3
- [cosmetic] “factreason_component_spec” added an optional parameter “responseFormat”
- [cosmetic] “factreason_integration_brief” added an optional parameter “responseFormat”
- [cosmetic] “factreason_package_upgrade_advisory” added an optional parameter “responseFormat”

### 2026-08-15 (score 69, +1)

- [functional improvement] Stability: unverified → 0.03

### 2026-08-14 (score 68)

First indexed and scored.

## MCP tools (10)

### `factreason_package_upgrade_advisory` (~226 tokens)

Compare two exact published npm or PyPI versions and return publisher-declared registry metadata changes, including yanks, exports, module format, runtime floors, peers, and licences, with before/after evidence. Set responseFormat="compact" for tokenizer-measured context savings; the backward-compatible default is "full". This is a read-only metered lookup; misses are never billed and API keys receive a daily free allowance. Use it for package metadata; use factreason_api_breaking_changes for a third-party HTTP API, and consult changelogs for behavioural changes.

Input parameters:

- `from` (string, required): Exact currently installed version, e.g. "4.1.2"
- `name` (string, required): Exact package name, e.g. "chalk" or "urllib3"
- `registry` (string, required): Registry containing both package versions
- `responseFormat` (string): Use compact to remove repeated prose and fields while retaining evidence; full preserves the legacy response contract
- `to` (string, required): Exact target version, e.g. "5.0.0"

Output parameters:

- `advisories` (array)
- `advisoryCount` (number)
- `billed` (boolean)
- `breakingCount` (number)
- `found` (boolean)
- `fromVersion` (string)
- `message` (string)
- `packageName` (string)
- `scope` (string)
- `toVersion` (string)
- `tokenMetrics` (object)

### `factreason_api_breaking_changes` (~121 tokens)

Temporarily unavailable for third-party APIs while stored comparisons are revalidated; calls return an unbilled status and alternatives. When restored, this compares optional from/to API versions and returns removed endpoints, parameter changes, and migration notes. Use factreason_package_upgrade_advisory for npm or PyPI packages.

Input parameters:

- `fromVersion` (string): Optional exact version currently targeted
- `service` (string, required): Third-party API service, e.g. "Stripe" or "OpenAI"
- `toVersion` (string): Optional exact version being evaluated

Output parameters:

- `alternatives` (array)
- `billed` (boolean)
- `changeCount` (number)
- `changes` (array)
- `found` (boolean)
- `meaning` (string)
- `message` (string)
- `service` (string)
- `suggestion` (string)

### `factreason_api_schema` (~112 tokens)

Search exact request and response schemas for third-party API endpoints. Pass service alone to list its indexed endpoints, add query to narrow by path or operation, or use query alone across services; returns matches or nearest services. Uses metered access and does not modify source data. Prefer factreason_integration_brief for one callable request.

Input parameters:

- `query` (string): Optional endpoint path or operation, e.g. "payment_intents"
- `service` (string): Optional service filter, e.g. "Stripe"

Output parameters:

- `found` (boolean)
- `hint` (string)
- `message` (string)
- `nearestServices` (array)
- `results` (array)
- `totalMatched` (number)

### `factreason_integration_brief` (~151 tokens)

Compile one callable third-party API brief: base URL, auth scheme, required parameters and types, request body, and documented response codes. Service is required and endpoint optionally narrows the operation. Set responseFormat="compact" for tokenizer-measured context savings; the backward-compatible default returns the full brief plus compact form. Uses metered access. Prefer factreason_api_schema when exploring multiple endpoints.

Input parameters:

- `endpoint` (string): Optional path or operation fragment used to select one call
- `responseFormat` (string): Use compact for the callable facts only; full preserves the legacy brief response
- `service` (string, required): Third-party API service, e.g. "Stripe" or "Twilio"

Output parameters:

- `billed` (boolean)
- `brief` (object)
- `compact` (string)
- `found` (boolean)
- `hint` (string)
- `message` (string)
- `nearestServices` (array)
- `service` (string)
- `tokenMetrics` (object)

### `factreason_discover_api` (~96 tokens)

Find third-party APIs for a capability when the provider is unknown. Supply a concise capability such as "sms" or "manage DNS"; returns ranked services, example endpoints, and a next step. Uses metered access. When the provider is already known, call factreason_integration_brief instead.

Input parameters:

- `capability` (string, required): Capability to search for, e.g. "send an SMS" or "charge a card"

Output parameters:

- `billed` (boolean)
- `capability` (string)
- `count` (number)
- `found` (boolean)
- `hint` (string)
- `message` (string)
- `nextStep` (string)
- `results` (array)

### `factreason_create_topup_link` (~113 tokens)

Create a Stripe Checkout URL for adding prepaid credit to the calling Bearer API key. This creates an external checkout session but does not charge a card. You CANNOT COMPLETE THE PAYMENT YOURSELF, so return the URL to a human, and credit is applied only after they complete payment. Use after HTTP 402 or when balance is low; the tool itself is not metered.

Input parameters:

- `amountUsd` (number, required): Credit amount in USD; common blocks are 10, 50, and 200

Output parameters:

- `amountUsd` (number)
- `balanceUrl` (string)
- `checkoutUrl` (string)
- `createKeyUrl` (string)
- `created` (boolean)
- `error` (string)
- `instructions` (string)

### `factreason_component_spec` (~160 tokens)

Look up electronics component pin assignments, voltage range, package, and alternatives. Pass exact partNumber for one component or query for a capability search; partNumber takes precedence if both are supplied. For exact lookups, set responseFormat="compact" for tokenizer-measured context savings; the backward-compatible default is "full". Uses metered access and returns matches or suggestions. Confirm critical values against the manufacturer datasheet.

Input parameters:

- `partNumber` (string): Exact part number, e.g. "STM32F401RE"
- `query` (string): Free-text capability search, e.g. "3.3V ARM MCU with SPI"
- `responseFormat` (string): Use compact for an exact part lookup; full preserves the legacy data response

Output parameters:

- `compact` (string)
- `data` (object)
- `found` (boolean)
- `hint` (string)
- `message` (string)
- `nearestMatches` (array)
- `partNumber` (string)
- `provenance` (object)
- `qualityScore` (number)
- `results` (array)
- `tokenMetrics` (object)
- `totalMatched` (number)

### `factreason_deprecation_scan` (~110 tokens)

Scan publisher specifications for deprecated endpoints or parameters, sunset dates, and replacement operations. Omit filters for the catalogue-wide view, pass service to limit one API, and add endpoints to check selected paths. Uses metered access when findings exist. Use factreason_api_breaking_changes for broader version-to-version changes.

Input parameters:

- `endpoints` (array): Optional endpoint paths to check within the selected service
- `service` (string): Optional service filter, e.g. "Stripe" or "Twilio"

Output parameters:

- `count` (number)
- `found` (boolean)
- `message` (string)
- `results` (array)

### `factreason_auth_playbook` (~99 tokens)

Get publisher-declared authentication schemes, scopes, rate-limit headers, and error codes for one third-party API. Returns a structured playbook or nearest service suggestions, and marks undocumented details as unstated rather than guessing. Uses metered access. Prefer factreason_integration_brief when assembling a complete API call.

Input parameters:

- `service` (string, required): Third-party API service, e.g. "Stripe", "Twilio", or "Cloudflare"

Output parameters:

- `compact` (object)
- `found` (boolean)
- `message` (string)
- `nearestServices` (array)
- `playbook` (object)

### `factreason_subscribe_spec_changes` (~131 tokens)

Create a persistent specification watch for one service; a Bearer API key is required and each key may hold up to 50 watches. Without webhookUrl, read future events from the polling endpoint; with a public HTTP(S) URL, FactReason sends signed POST callbacks after later spec changes. Duplicate or unsafe webhook registrations are rejected. This does not ingest a specification immediately.

Input parameters:

- `serviceName` (string, required): Service name to watch, e.g. "Stripe" or "SendGrid"
- `webhookUrl` (string): Optional public HTTP(S) URL for signed change callbacks; omit to poll

Output parameters:

- `error` (string)
- `success` (boolean)
- `watch` (object)

## Diagnostics

Captured diagnostic sections: TLS, DNSSEC, Authorisation, Transports. The full working is on the page: https://verifymcp.io/servers/factreason-factreason/www#diagnostics

## Score history

- 2026-08-17: 69
- 2026-08-16: 69
- 2026-08-15: 69
- 2026-08-14: 68

## Links

- Remote endpoint: https://www.factreason.com/mcp
- Repository: https://github.com/factreason/factreason
- Website: https://factreason.com/
- Changelog RSS feed: https://verifymcp.io/servers/factreason-factreason/www.xml
- Changelog JSON feed: https://verifymcp.io/servers/factreason-factreason/www.json
- HTML version of this page: https://verifymcp.io/servers/factreason-factreason/www