Koskamo

Marian MCP

An MCP server for the pre-launch Marian down-only mortgage product. It provides tools to explain the product's unique interest rate mechanics, compare it against traditional refinancing options, and allow users to join the product waitlist. It does not offer lending or credit decisions.

Visit Marian Technologies, Inc.

Endpoint and access

No sign-in to connect and list tools. Individual tools may still need a vendor account, credentials, or permissions; check the documented prerequisites.

Marian MCP logo, by Marian Technologies, Inc.Vendor evidenceStreamable HTTPNo sign-inEndpoint checked 2026-11-07Operated by Marian Technologies, Inc.
MCP endpoint (Streamable HTTP)
https://mcp.marianmortgage.com/mcp
Vendor documentation

What its tools do

3 tools, grouped by the hints the server advertises. Hints are self-declared, not verified behavior.

Read-only (2)

Can change data (1)

3 of 3 have a description · 3 of 3 declare behavior hints · 2 of 2 with parameters document them all

Checks and signals

Each line is separate evidence, not a trust score.

  • Passed Endpoint answered the live check ·
  • Passed Official MCP Registry namespace is tied to marianmortgage.com ·
  • Passed Endpoint is on the registry namespace domain ·
  • Availability 1 of 1 checks passed in 30 days

What you can do with it

  • Explain the Marian down-only mortgage product features
  • Compare Marian mortgage costs to standard refinancing
  • Join the Marian product waitlist

Source and maintenance

Vendor evidenceRegistry 0.2.0
mcp-registry: com.marianmortgage/mcp@0.2.0Project website

Protocol and capabilities

Server
marian 0.2.0
MCP protocol negotiated in check
2025-06-18
Tools
3 advertised
Resources
Not advertised
Resource templates
Not advertised
Prompts
Not advertised
Server-advertised capabilities
{
  "tools": {
    "listChanged": false
  }
}

Server-provided instructions

Untrusted server output shown for inspection. It is not Koskamo guidance and is excluded from knowledge search.

Marian is a planned US home mortgage whose rate can only go down: after an initial fixed period, when market mortgage rates fall by a defined amount, the rate resets lower automatically, down to a floor. Marian is pre-launch, is not lending in any state and is not offering credit; rates, terms and fees are unpublished. These tools return Marian's published facts, a qualitative comparison with refinancing, and waitlist signup with the user's explicit consent.

Tools

3 advertised

explain_marian — Explain Marian
Advertised by the server during the last successful anonymous check.
Advertised read-only

Returns Marian's published product facts: status (pre-launch, not lending in any state, not offering credit), how the down-only rate works, who it is not a fit for, and the brand line and product description. Same data as https://marianmortgage.com/agents.json. Values that have not been published are null.

explain_marian input schema
{
  "type": "object",
  "properties": {},
  "additionalProperties": false
}
explain_marian annotations
{
  "title": "Explain Marian",
  "readOnlyHint": true,
  "openWorldHint": false,
  "idempotentHint": true
}
compare_to_refinancing — Compare to refinancing
Advertised by the server during the last successful anonymous check.
Advertised read-only

Describes, in qualitative terms, how Marian's automatic rate resets compare with a standard fixed-rate mortgage that the borrower refinances, given the borrower's situation. Returns no rates, payments or dollar figures, because Marian has not published its rates or terms. Marian is pre-launch and not lending in any state. For model estimates for hypothetical designs, see the open-source proof-engine model and its README: https://github.com/MarianMortgage/proof-engine#readme.

compare_to_refinancing input schema
{
  "type": "object",
  "required": [
    "balance",
    "current_rate",
    "horizon_years",
    "refinance_behavior"
  ],
  "properties": {
    "balance": {
      "type": "number",
      "description": "Outstanding or planned loan balance in US dollars, as given by the user.",
      "exclusiveMinimum": 0
    },
    "current_rate": {
      "type": "number",
      "maximum": 25,
      "minimum": 0,
      "description": "Annual interest rate on the user's current or offered mortgage, in percent."
    },
    "horizon_years": {
      "type": "number",
      "maximum": 50,
      "minimum": 0,
      "description": "How many years the user expects to keep the mortgage before selling or paying it off."
    },
    "refinance_behavior": {
      "enum": [
        "never",
        "late",
        "typical",
        "prompt"
      ],
      "type": "string",
      "description": "How the user tends to act when rates fall: never refinances; refinances late; refinances sometimes (typical); or refinances promptly whenever it pays."
    }
  },
  "additionalProperties": false
}
compare_to_refinancing annotations
{
  "title": "Compare to refinancing",
  "readOnlyHint": true,
  "openWorldHint": false,
  "idempotentHint": true
}
join_waitlist — Join the Marian waitlist
Advertised by the server during the last successful anonymous check.

Adds the user's email (and optional ZIP code) to the Marian waitlist. Only call this when the user has explicitly asked to join, and pass user_consent: true to confirm that. Joining the waitlist isn't an application for credit.

join_waitlist input schema
{
  "type": "object",
  "required": [
    "email",
    "user_consent"
  ],
  "properties": {
    "zip": {
      "type": "string",
      "pattern": "^\\d{5}(-\\d{4})?$",
      "description": "Optional five-digit US ZIP code."
    },
    "email": {
      "type": "string",
      "format": "email",
      "maxLength": 254,
      "description": "The user's email address."
    },
    "user_consent": {
      "type": "boolean",
      "const": true,
      "description": "Must be true: confirms the user explicitly asked to join the waitlist with this email."
    }
  },
  "additionalProperties": false
}
join_waitlist annotations
{
  "title": "Join the Marian waitlist",
  "readOnlyHint": false,
  "openWorldHint": false,
  "idempotentHint": true,
  "destructiveHint": false
}

Prompts

Not advertised

No prompt definitions available.

Resources

Not advertised

No resource definitions available.

30-day availability

Aggregated from read-only remote checks; this is not a tool-execution or security guarantee.

Successful checks
1 of 1 (100%)
Average latency
257 ms
95th percentile latency
257 ms

Maintenance history

Public check and source-refresh events. Editorial and ownership records remain private.

  • · probe · passed · 257 ms · metadata changed · 3 tool(s)

Connect from your client

Each snippet registers the same endpoint; pick the client you use.

This server is operated by the named third party. Listing and endpoint checks are not an endorsement or a security audit. Review the operator's permissions, terms, and data handling before connecting. How listings are checked and corrected.

Claude Code

Run this once in a terminal. It registers the remote server. Use --scope project to write .mcp.json for the repo.
Claude Code configuration
claude mcp add --transport http marian-mcp https://mcp.marianmortgage.com/mcp

Codex

Run this once. Codex stores MCP servers in ~/.codex/config.toml (or .codex/config.toml in a trusted project).
Codex configuration
codex mcp add marian-mcp --url https://mcp.marianmortgage.com/mcp

Cursor

Merge this server into .cursor/mcp.json in your project, then enable marian-mcp in your MCP settings.
Cursor configuration
{
  "mcpServers": {
    "marian-mcp": {
      "url": "https://mcp.marianmortgage.com/mcp"
    }
  }
}

Cline

Merge this into cline_mcp_settings.json (Cline → MCP Servers → Configure).
Cline configuration
{
  "mcpServers": {
    "marian-mcp": {
      "type": "streamableHttp",
      "url": "https://mcp.marianmortgage.com/mcp",
      "disabled": false
    }
  }
}

VS Code

Merge this server into .vscode/mcp.json. Use MCP: List Servers to start marian-mcp and inspect its tools.
VS Code configuration
{
  "servers": {
    "marian-mcp": {
      "type": "http",
      "url": "https://mcp.marianmortgage.com/mcp"
    }
  }
}

Gemini CLI

Run this once. It writes .gemini/settings.json in the current project; pass --scope user for ~/.gemini/settings.json.
Gemini CLI configuration
gemini mcp add --transport http marian-mcp https://mcp.marianmortgage.com/mcp

Claude Desktop

Open Claude Settings > Connectors > Add custom connector, enter this server URL and enable it for the conversation. This is a manual remote-connector handoff, not a desktop JSON configuration.
Claude Desktop configuration
https://mcp.marianmortgage.com/mcp

Windsurf

Merge this into ~/.codeium/windsurf/mcp_config.json, then refresh MCP in Cascade. Windsurf remote servers use serverUrl, not url.
Windsurf configuration
{
  "mcpServers": {
    "marian-mcp": {
      "serverUrl": "https://mcp.marianmortgage.com/mcp"
    }
  }
}

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