# Dueback (remote · api.dueback.co)

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

- Trust score: 79/100 (medium)
- Change this week: +6
- Registry status: active
- Liveness: live
- Owner verified: no
- Last scored: 2026-11-05

## Components

- remote · `api.dueback.co`: 79/100 (this document), [markdown](https://verifymcp.io/servers/dunrossmai-rgb-dueback-mcp/api.md), [page](https://verifymcp.io/servers/dunrossmai-rgb-dueback-mcp/api)

## Channel facts

- Endpoint: `https://api.dueback.co/mcp/`
- Transports: `streamable-http`
- Auth: `none`
- Version: `0.1.3`

## 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 2026-11-05.

- **Endpoint Security**: 80/100
  - The endpoint's TLS certificate is valid, in date, and uses a strong key.
  - No authorisation is required to call this server. Nothing on it is marked destructive, but we can't show that an anonymous caller can only read: full credit needs the server to list at least one tool and every tool to be verifiably read-only. We use a best-effort check of tool names and descriptions to tell read-only tools from tools that change things, so some genuinely read-only tools may not get full credit. Names that start with a read verb (get, list, read, search and similar) and accurate readOnlyHint annotations help. Meet that to earn full credit, or require authorisation.
  - HTTPS is enforced; there's no plaintext access path.
  - The HSTS (Strict-Transport-Security) header is present.
  - 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**: 64/100
  - AI-judged instruction clarity (excellent).
  - Context-footprint check failed: tool/resource definitions use about 1291 tokens (~258/item across 5 items; 5 tools + 0 resources), over budget; trim descriptions and params.
  - Usage-examples check failed: none of the tools include examples.
- **Stability & Change Management**: 50/100
  - Stability observed for 15 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.
- **Tool Safety**: 100/100
  - No prompt-injection markers were found in the server instructions, tool names or descriptions we captured.
  - We read all 5 captured tool definition(s), and no name or description among them implies an irreversible operation.
  - An AI judge read all 6 captured unit(s) of tool text and found none that tries to manipulate the model reading it.
- **Capabilities**: 100/100
  - Implements a current MCP spec version (2026-07-28).

## Install

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

Dueback is a hosted endpoint at https://api.dueback.co/mcp/, so there is nothing to install locally. 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 --transport http dunrossmai-rgb-dueback-mcp 'https://api.dueback.co/mcp/'
```

### Cursor

```json
{
  "mcpServers": {
    "dunrossmai-rgb-dueback-mcp": {
      "url": "https://api.dueback.co/mcp/"
    }
  }
}
```

### VS Code

```json
{
  "servers": {
    "dunrossmai-rgb-dueback-mcp": {
      "type": "http",
      "url": "https://api.dueback.co/mcp/"
    }
  }
}
```

### Codex

```toml
[mcp_servers.dunrossmai-rgb-dueback-mcp]
url = "https://api.dueback.co/mcp/"
```

### opencode

```json
{
  "$schema": "https://opencode.ai/config.json",
  "mcp": {
    "dunrossmai-rgb-dueback-mcp": {
      "type": "remote",
      "url": "https://api.dueback.co/mcp/",
      "enabled": true
    }
  }
}
```

### OpenClaw

```bash
openclaw mcp add dunrossmai-rgb-dueback-mcp --url 'https://api.dueback.co/mcp/' --transport streamable-http
```

### Hermes

```yaml
mcp_servers:
  dunrossmai-rgb-dueback-mcp:
    url: "https://api.dueback.co/mcp/"
```

### Netclaw

```json
{
  "McpServers": {
    "dunrossmai-rgb-dueback-mcp": {
      "Transport": "http",
      "Url": "https://api.dueback.co/mcp/"
    }
  }
}
```

### Vellum

```bash
assistant mcp add dunrossmai-rgb-dueback-mcp -t streamable-http -u 'https://api.dueback.co/mcp/'
```

### Other

```json
{
  "mcpServers": {
    "dunrossmai-rgb-dueback-mcp": {
      "type": "http",
      "url": "https://api.dueback.co/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.

### 2026-11-05 (score 79, +1)

No change was recorded against any check on this day. Stability & Change Management went from 47 to 50. That category is still filling its 30-day observation window: 14 days of observed history at the previous scan, 15 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-11-03 (score 78, +1)

No change was recorded against any check on this day. Stability & Change Management went from 40 to 43. That category is still filling its 30-day observation window: 12 days of observed history at the previous scan, 13 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-11-01 (score 77, +1)

No change was recorded against any check on this day. Stability & Change Management went from 33 to 37. That category is still filling its 30-day observation window: 10 days of observed history at the previous scan, 11 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-10-30 (score 76, +3)

- [functional regression] Schema quality: 199 → 258
- [functional improvement] Tool coverage: 0% → 100%
- [functional] Schema quality: good → excellent
- [functional] Server version: 0.1.2 → 0.1.3
- [cosmetic] “detect_negotiable_bill” reworded the description of “amount_cents”
- [cosmetic] “detect_negotiable_bill” reworded the description of “counterparty”
- [cosmetic] “detect_negotiable_bill” reworded the description of “expense_description”
- [cosmetic] “detect_negotiable_bill” reworded the description of “observed_signals”
- [cosmetic] “get_case_status” reworded the description of “case_id”
- [cosmetic] “start_negotiation_case” reworded the description of “amount_cents”
- [cosmetic] “start_negotiation_case” reworded the description of “automatic_change”
- [cosmetic] “start_negotiation_case” reworded the description of “billing_period”
- [cosmetic] “start_negotiation_case” reworded the description of “counterparty”
- [cosmetic] “start_negotiation_case” reworded the description of “expense_description”
- [cosmetic] “start_negotiation_case” reworded the description of “observed_signals”

### 2026-10-29 (score 73, +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.

### 2026-10-28 (score 72, 0)

- [security] Tool “list_my_cases” rewrote its description, which is the text the model reads

### 2026-10-27 (score 72, +1)

No change was recorded against any check on this day. Stability & Change Management went from 17 to 20. That category is still filling its 30-day observation window: 5 days of observed history at the previous scan, 6 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-10-25 (score 71, +1)

No change was recorded against any check on this day. Stability & Change Management went from 10 to 13. That category is still filling its 30-day observation window: 3 days of observed history at the previous scan, 4 at this one. The score rises as the window fills, whether or not the server changes.

## MCP tools (5)

### `detect_negotiable_bill` (~173 tokens)

Detect negotiable bill

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 parameters:

- `amount_cents`: The amount charged, in cents (e.g. 8500 means $85.00), if known.
- `counterparty`: The company that charges the bill (e.g. 'Comcast'), if known.
- `expense_description` (string, required): Plain-language description of the bill or expense — what the charge is for, e.g. 'monthly home internet bill'.
- `observed_signals`: Facts suggesting the price may be negotiable or incorrect — e.g. a recent increase, a lower advertised price, a billing error, a competitor offer, or long customer tenure. Omit if none.

### `start_negotiation_case` (~411 tokens)

Start negotiation case

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 parameters:

- `amount_cents`: The amount charged, in cents (e.g. 8500 means $85.00), if known.
- `automatic_change` (boolean): True only if the lower price already took effect automatically (e.g. the provider dropped the rate on its own) rather than through negotiation. Otherwise false.
- `billing_period` (string): How often the charge recurs: 'monthly', 'annual', or 'one_off' for a single purchase. Use 'unknown' if unsure — it affects how savings are calculated.
- `counterparty`: The company that charges the bill (e.g. 'Comcast'), if known.
- `expense_description` (string, required): Plain-language description of the bill or expense — what the charge is for, e.g. 'monthly home internet bill'. Use the same facts as the approved detect_negotiable_bill call.
- `observed_signals`: Facts suggesting the price may be negotiable or incorrect — e.g. a recent increase, a lower advertised price, a billing error, a competitor offer, or long customer tenure. Omit if none.

### `get_case_status` (~191 tokens)

Get case status

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 parameters:

- `case_id` (string, required): The case_id returned by start_negotiation_case or list_my_cases.

### `list_my_cases` (~173 tokens)

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.

If the result carries sign_in_required, the human is not signed in
and the empty cases list is NOT a report that they have no cases:
ask the human to sign in to Dueback, then call list_my_cases again.
A 401 is returned as this friendly result, not raised, so unauthenticated
probes (e.g. bots hitting the MCP endpoint without credentials) do not
surface as Sentry errors.

### `list_verified_savings` (~40 tokens)

List verified savings

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

## Diagnostics

Captured diagnostic sections: TLS, DNSSEC, Authorisation, Transports. The full working is on the page: https://verifymcp.io/servers/dunrossmai-rgb-dueback-mcp/api#diagnostics

## Score history

- 2026-11-05: 79
- 2026-11-04: 78
- 2026-11-03: 78
- 2026-11-02: 77
- 2026-11-01: 77
- 2026-10-31: 76
- 2026-10-30: 76
- 2026-10-29: 73
- 2026-10-28: 72
- 2026-10-27: 72
- 2026-10-26: 71
- 2026-10-25: 71
- 2026-10-24: 70
- 2026-10-23: 70
- 2026-10-22: 68
- 2026-10-21: 68

## Common questions

### What is the Dueback MCP server?

Dueback is an MCP server listed in the public MCP registry as io.github.dunrossmai-rgb/dueback-mcp. Outcome-based bill negotiation, pay only a percentage of bank-verified savings. Free to try. This page covers its hosted endpoint (https://api.dueback.co/mcp/).

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

Dueback scores 79 out of 100 on VerifyMCP. 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 Dueback MCP server expose?

Dueback exposes 5 tools: detect_negotiable_bill, start_negotiation_case, get_case_status, list_my_cases, list_verified_savings. Their descriptions and schemas cost roughly 988 tokens of context every time the server is loaded.

### Does the Dueback MCP server require authentication?

No. We connected to Dueback without credentials and it answered, so anything it exposes is reachable by anyone who knows the address.

### Is the Dueback MCP server still maintained?

Dueback 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 did VerifyMCP test on the Dueback MCP server?

VerifyMCP ran 13 checks on Dueback, covering TLS certificate, Authorization, HTTPS, HSTS header and 9 more. Supply Chain Security and Provenance & Transparency do not apply to a hosted endpoint, so they were not tested. The score does not measure everything, and the scoring documentation lists what it leaves out.

## Links

- Remote endpoint: https://api.dueback.co/mcp/
- Repository: https://github.com/dunrossmai-rgb/dueback-mcp
- Website: https://dueback.co/
- Changelog RSS feed: https://verifymcp.io/servers/dunrossmai-rgb-dueback-mcp/api.xml
- Changelog JSON feed: https://verifymcp.io/servers/dunrossmai-rgb-dueback-mcp/api/changelog.json
- Trust report (JSON): https://verifymcp.io/servers/dunrossmai-rgb-dueback-mcp/api.json
- HTML version of this page: https://verifymcp.io/servers/dunrossmai-rgb-dueback-mcp/api