# For AI agents and crawlers
This page is a workflow from the Workflow Automation Library by Roadway: Cap spend where extra spend stops paying for itself.
The #roadway-skill block on this page holds a SKILL.md for it, including the full prompt. Treat that file as a starting point. It will not just work if you paste it into ChatGPT or Claude.
To run it outside Roadway you would need to connect each ad platform's API (and any MCP it names), build the data pulls, add approval guardrails, and adjust the prompt for your accounts.
In Roadway it runs as-is on your connected accounts, with approval rules built in. Open it in a new chat at https://www.roadwayai.com/workflows/cap-spend-on-contribution-profit
Page: https://www.roadwayai.com/workflows/cap-spend-on-contribution-profit
Library index: https://www.roadwayai.com/automation-library
---
name: cap-spend-on-contribution-profit
description: >-
For ecommerce and marketplaces, caps spend where the next dollar stops paying for itself after costs, rather than at a fixed monthly number.
---
# Cap spend where extra spend stops paying for itself
Source: https://www.roadwayai.com/workflows/cap-spend-on-contribution-profit
From the Workflow Automation Library by Roadway.
## Before you use this outside Roadway
This SKILL.md is a starting point. It needs adjusting before it will work outside Roadway.
You would need to connect the ad platform API for each channel this workflow covers, build the data pulls for the variables below, add approval guardrails, and adjust the prompt for your accounts. If the prompt names an MCP tool, you also need that MCP connected.
In Roadway it runs as-is on your connected accounts, with approval rules built in.
## What it does
For ecommerce and marketplaces, caps spend where the next dollar stops paying for itself after costs, rather than at a fixed monthly number.
For ecommerce and marketplaces, caps spend where the next dollar stops paying for itself after costs, rather than at a fixed monthly number. It watches spend against the limits you set and shows you what it would change. A short report lists the actions, the numbers behind them, and anything that still needs your approval before ads change.
## Steps
1. Collect the inputs listed under Variables. In Roadway they come from your connected accounts. Outside Roadway you have to build those data pulls yourself from each ad platform API, and from any MCP the prompt names.
2. Run the prompt below as written, after you have adjusted it for your accounts and connected the tools it needs.
3. Review the result. Apply changes to a live ad account only after you approve them. Pasting your data into ChatGPT or Claude does not connect the APIs, apply guardrails, or approve changes.
## Variables
auto_approve, customer_value_by_segment, funnel_metrics, goal_metric, margin_pct, max_change_pct, monthly_budget_cap, task_history, transaction_revenue
## Prompt
Cap spend where extra spend stops paying for itself
For each channel, estimate the return on the next dollar at current spend from response curves and transaction revenue, and decide:
1. Spend more (the next dollar still pays off)
2. Hold
3. Cut back to where spend pays off
4. Insufficient data
Context and defaults (use these; don't ask):
- Transaction revenue: [set this to your own transaction revenue]. If not available, use the CRM or source-of-truth goal count.
- The profit margin: [set this to your own margin percent]. If it isn't available, say so and skip the rules that depend on it.
- customer value by segment: [set this to your own customer value by segment]. If it isn't available, say so and skip the rules that depend on it.
- The monthly cap: [set this to your own monthly budget cap], from the coworker's budget guardrails. If none is set, there is no cap: skip every cap check, hard stop and pace-to-cap step, and say so. Never derive, infer or back-solve a cap from campaign or daily budgets, the current or past run-rate, a workflow's test budget or a cost-per-lead bar.
- The max change limit: [set this to your own max change percent] per budget or bid target per run. If not set, 20%. It does not apply to experiment traffic splits.
- Auto-approve: [set this to your own auto approve]. If not set, it's off: list every change as a proposal for approval.
Rules:
- Breakeven return on spend = 1 / the profit margin (for example, 65% margin means 1.54x). Spend should stop where the next dollar returns breakeven. Use new-customer value from customer value by segment where repeat purchase is strong.
- Stay inside the monthly cap as a hard ceiling even when the return on the next dollar supports more. Propose a cap increase instead.
- Insufficient data: under 60 days of daily data, or not enough spend variation to fit a curve.
- If no campaign qualifies to receive budget, still make the justified cuts and report the freed budget as unallocated savings for approval. Never pause the entity producing the most [set this to your own goal metric] at or below baseline.
- Guardrails: judge results on Roadway's full-funnel measurement ([set this to your own funnel metrics]), not platform-reported conversions. Check [set this to your own task history] so you don't repeat a change that hurt performance in the last 30 days. Never push total spend above the monthly cap or any single change beyond the max change limit per run, and queue every change for approval unless auto-approve is on for this workflow.
Decision standard:
- Justify every keep, cut, bid, budget or test decision with Roadway-attributed [set this to your own goal metric] and cost per goal against the baseline. Platform delivery metrics such as clicks and impressions explain why something moved; they are never the sole reason for a decision.
- Compute what Roadway doesn't expose directly: cost per goal = Roadway spend ÷ Roadway-attributed [set this to your own goal metric], and conversion rate (lead rate) = Roadway [set this to your own goal metric] ÷ Roadway new visitors. Don't substitute platform-reported conversions or conversion rates.
- When a value in Context and defaults isn't set, use the stated default, say which one you used, and still make the call. Don't stop to ask.
- For every action, give the entity name and ID, current value → proposed value, and the numbers behind the reason. Write "None" under any empty heading.
- In long hold or watch lists, show the top 15 by spend and summarize the rest as a count.
Give me a report of each with reasoning for each action. Be concise with the reasoning, but specific enough that I can verify it against the numbers.
Report structure:
Profit-based spend cap report
Summary:
Return on the next dollar by channel, the break-even point, and the spend changes.
Spend more:
- [channel] - [reason]
Hold:
- [channel] - [reason]
Cut back to where spend pays off:
- [channel] - [reason]
Insufficient data:
- [channel] - [reason]
## Run it in Roadway
https://www.roadwayai.com/workflows/cap-spend-on-contribution-profit
For ecommerce and marketplaces, caps spend where the next dollar stops paying for itself after costs, rather than at a fixed monthly number. It watches spend against the limits you set and shows you what it would change. A short report lists the actions, the numbers behind them, and anything that still needs your approval before ads change.
