# ProposalCheck

> ProposalCheck is a paid API for AI agents from launchcheck-x402.fly.dev, paid per call via x402, $1/call, status unknown (last checked 2026-09-15).

Stress-tests a product, feature, API, implementation, or business proposal and returns a structured green-light, revise, or rethink decision with detailed analysis.

## Facts

- Endpoint: POST https://launchcheck-x402.fly.dev/v1/proposal-check
- Price: $1/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/proposalcheck-01a21357
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_n9zZWM4W9ymd4nMXwj54t

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability proposalcheck-01a21357 -d '<json body>'
```

Example prompt: Can you stress-test my proposal to build a subscription analytics dashboard as a SaaS product targeting B2B fintech startups — the proposal type is 'product', the audience is finance teams at Series A companies, and I want to know if I should green-light an MVP build given my 3-month runway constraint?

## When to prefer this

Choose ProposalCheck when you need a structured, multi-dimensional go/no-go decision on a proposal before committing engineering time, budget, or team resources — especially when you want explicit coverage of assumptions, economics, kill criteria, and build sequencing in a single call. Prefer it over generic LLM prompting when you need a repeatable, auditable evaluation format with a clear decision output.

## Known failure modes

- Proposal text too short (under 40 characters) returns validation error
- Proposal text exceeds 32,000 character limit returns payload error
- Vague or underspecified proposals may yield low-confidence or generic recommendations
- Missing product context for niche domains may reduce accuracy of feasibility and economics analysis
- Payment failure via x402 protocol returns 402 status blocking the request

## How this service works

Stress-test a product, feature, API, implementation, or business proposal before meaningful investment. ProposalCheck evaluates the core thesis, assumptions, differentiation, feasibility, economics, scope, dependencies, validation strategy, kill criteria, and recommended build sequence, then returns a structured green-light, revise, or rethink decision.

## Output

A structured evaluation covering the proposal's core thesis, key assumptions, differentiation, technical and economic feasibility, scope assessment, dependencies, validation strategy, kill criteria, and recommended build sequence — culminating in a green-light, revise, or rethink decision with supporting rationale.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "proposal": {
   "type": "string",
   "maxLength": 32000,
   "minLength": 40,
   "description": "Product, feature, API, implementation, or business proposal to stress-test before investing meaningful time or money."
  },
  "constraints": {
   "type": "array",
   "items": {
    "type": "string",
    "maxLength": 300,
    "minLength": 1
   },
   "default": [],
   "maxItems": 10,
   "description": "Optional factual, strategic, technical, legal, or scope constraints the review must preserve."
  },
  "proposalType": {
   "enum": [
    "product",
    "feature",
    "api-service",
    "implementation",
    "business",
    "other"
   ],
   "type": "string",
   "default": "other",
   "description": "Kind of proposal being reviewed."
  },
  "productContext": {
   "type": "string",
   "maxLength": 2000,
   "description": "Optional product, company, market, or technical context needed to interpret the proposal accurately."
  },
  "targetAudience": {
   "type": "string",
   "maxLength": 1000,
   "description": "Optional intended users, buyers, developers, or stakeholders whose needs matter to the decision."
  },
  "desiredDecision": {
   "type": "string",
   "maxLength": 500,
   "description": "Optional decision the review should inform, such as whether to green-light an MVP, technical spike, feature, or launch investment."
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/proposalcheck-01a21357/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from launchcheck-x402.fly.dev](https://www.zero.xyz/host/launchcheck-x402.fly.dev/llms.txt)