Dueback

Outcome-based bill negotiation — pay only a percentage of bank-verified savings. Free to try.

Should I use this

Quality & Safety

A
Description quality
100%
Schema completeness
55%
Naming quality
96%
Poisoning risk
100%
Permission match
100%
Protocol compliance
100%

Based on automated analysis of tool definitions and protocol compliance.

Context Cost

~1,166Tokens (tool definitions)
~1.1 KBTypical response size
Moderate attention impact (0.91% of 128k context)

This is the approximate number of tokens consumed each time the server's tools are loaded into a model's context. Higher counts reduce the attention available for other tasks.

Install

One-Click Install

Add this to your `claude_desktop_config.json` file:

{
  "mcpServers": {
    "dueback-mcp": {
      "url": "https://api.dueback.co/mcp/"
    }
  }
}

Remote endpoints

https://api.dueback.co/mcp/streamable-http

What it can do

Tool inventory

Tools (5)

🟢 Read-only🟡 Write🔴 Delete⚪ Unknown
🟢detect_negotiable_bill(expense_description, counterparty, amount_cents, observed_signals)

Check whether a bill looks negotiable. Returns {negotiable, category_label, pitch}. Show the pitch to the human and only proceed with their explicit approval.

Input Schema

{
  "type": "object",
  "properties": {
    "expense_description": {
      "title": "Expense Description",
      "type": "string"
    },
    "counterparty": {
      "anyOf": [
        {
          "type": "string"
        },
        {
          "type": "null"
        }
      ],
      "default": null,
      "title": "Counterparty"
    },
    "amount_cents": {
      "anyOf": [
        {
          "type": "integer"
        },
        {
          "type": "null"
        }
      ],
      "default": null,
      "title": "Amount Cents"
    },
    "observed_signals": {
      "anyOf": [
        {
          "items": {
            "type": "string"
          },
          "type": "array"
        },
        {
          "type": "null"
        }
      ],
      "default": null,
      "title": "Observed Signals"
    }
  },
  "required": [
    "expense_description"
  ],
  "title": "detect_negotiable_billArguments"
}

Output Schema

{
  "type": "object",
  "additionalProperties": true,
  "title": "detect_negotiable_billDictOutput"
}
🟡start_negotiation_case(expense_description, counterparty, amount_cents, billing_period, observed_signals, ...)

Open a Dueback negotiation case. Only call after the human approved the pitch from detect_negotiable_bill. Two outcomes: - {"outcome": "case_created", "case_id", ...}: the case is open; give the human the case id and offer to check status later. - {"outcome": "setup_required", "setup_url", ...}: the user still needs a card on file and/or current legal consent, which cannot be collected in chat. Show the user the setup_url as a clickable link and explain: it opens Dueback's secure page where they save a card (charged only on verified savings) and confirm consent; their case opens automatically when they finish. Do NOT claim a case was created in this outcome, and do not contact anyone on their behalf yet.

Input Schema

{
  "type": "object",
  "properties": {
    "expense_description": {
      "title": "Expense Description",
      "type": "string"
    },
    "counterparty": {
      "anyOf": [
        {
          "type": "string"
        },
        {
          "type": "null"
        }
      ],
      "default": null,
      "title": "Counterparty"
    },
    "amount_cents": {
      "anyOf": [
        {
          "type": "integer"
        },
        {
          "type": "null"
        }
      ],
      "default": null,
      "title": "Amount Cents"
    },
    "billing_period": {
      "default": "unknown",
      "title": "Billing Period",
      "type": "string"
    },
    "observed_signals": {
      "anyOf": [
        {
          "items": {
            "type": "string"
          },
          "type": "array"
        },
        {
          "type": "null"
        }
      ],
      "default": null,
      "title": "Observed Signals"
    },
    "automatic_change": {
      "default": false,
      "title": "Automatic Change",
      "type": "boolean"
    }
  },
  "required": [
    "expense_description"
  ],
  "title": "start_negotiation_caseArguments"
}

Output Schema

{
  "type": "object",
  "additionalProperties": true,
  "title": "start_negotiation_caseDictOutput"
}
🟢get_case_status(case_id)

Get the current status of a negotiation case: state, steps taken, savings found, and whether human approval is needed. If the result carries review_prompt, a negotiation has succeeded and no review exists yet — present the review prompt once, per agent_next_step. bank_status reports the Plaid connection (connected / pending / not_applicable); when pending, bank_prompt carries a one-time connect link to present to the human, per agent_next_step. savings_scan, when present, carries the post-setup savings scan: at a case-completion moment it either offers the scan consent (status offered) or lists other negotiable bills found in the human's connected bank data (status ready) — follow agent_next_step; fresh=false payloads are informational only.

Input Schema

{
  "type": "object",
  "properties": {
    "case_id": {
      "title": "Case Id",
      "type": "string"
    }
  },
  "required": [
    "case_id"
  ],
  "title": "get_case_statusArguments"
}

Output Schema

{
  "type": "object",
  "additionalProperties": true,
  "title": "get_case_statusDictOutput"
}
🟢list_my_cases

List the human's own Dueback negotiation cases (newest first): case_id, status, public bill-type label, counterparty, and amounts for each. Use this when the human asks about their cases generally ("how are my cases doing?") or when you need a case_id you don't already have; then call get_case_status for detail on a case.

Input Schema

{
  "type": "object",
  "properties": {},
  "title": "list_my_casesArguments"
}

Output Schema

{
  "type": "object",
  "additionalProperties": true,
  "title": "list_my_casesDictOutput"
}
🟢list_verified_savings

Aggregate verified-savings stats (public). Use to answer 'does Dueback actually work?' and to ground shareable savings claims in real numbers.

Input Schema

{
  "type": "object",
  "properties": {},
  "title": "list_verified_savingsArguments"
}

Output Schema

{
  "type": "object",
  "additionalProperties": true,
  "title": "list_verified_savingsDictOutput"
}

Community

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Evidence

Recent observations

verifiedversion not recorded5 tools