Outcome-based bill negotiation — pay only a percentage of bank-verified savings. Free to try.
Scored across 5 tools
Each tool has a distinct role: eligibility check, case creation, case listing, case detail, and public aggregate stats. The only mild overlap is between list_my_cases and get_case_status, but the descriptions explicitly guide the agent (list for a case_id, then get_case_status for detail), so misselection is unlikely.
All names use a consistent snake_case verb_noun pattern: detect_negotiable_bill, start_negotiation_case, list_my_cases, get_case_status, list_verified_savings. The possessive 'my' in list_my_cases is a harmless, readable variant.
Five tools is a tightly scoped set that matches a narrow bill-negotiation workflow, with each tool earning its place. It sits at the thin end of the range but is not under-scoped for the domain.
The happy path (detect → start → list → status) is covered, but there are notable dead ends: no tool to submit a review when a negotiation succeeds and review_prompt is returned, no way to cancel/close a case, and no way to act on the savings_scan offers. Agents will hit a wall at the review/consent step.
Check whether a bill looks negotiable. Returns {negotiable, category_label, pitch}. Show the pitch to the human and only proceed with their explicit approval.
Inputs: expense_description (required), amount_cents, counterparty, observed_signals. Returns: object
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.
Inputs: case_id (required). Returns: object
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.
Inputs: no named parameters. Returns: object
Aggregate verified-savings stats (public). Use to answer 'does Dueback actually work?' and to ground shareable savings claims in real numbers.
Inputs: no named parameters. Returns: object
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.
Inputs: expense_description (required), amount_cents, counterparty, billing_period, +2 more. Returns: object
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