# FixLedger Post-Cutoff SDK Delta Oracle

> FixLedger Post-Cutoff SDK Delta Oracle is a paid API for AI agents from fixledger-iota.vercel.app, paid per call via x402, $0.003/call, status unknown (last checked 2026-11-01).

Returns a structured migration spec or active model/pricing matrix for a specified post-cutoff topic key, unlocked via micropayment.

## Facts

- Endpoint: POST https://fixledger-iota.vercel.app/api/x402/delta?utm_source=zero.xyz
- Price: $0.003/call
- Payment: x402
- Status: unknown
- Last checked: 2026-11-01
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/fixledger-post-cutoff-sdk-delta-oracle-3da70134
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_M5e8GeEbgXiwynhx63MBT

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 fixledger-post-cutoff-sdk-delta-oracle-3da70134 -d '<json body>'
```

Example prompt: Can you pull the verified post-cutoff delta for 'nextjs:v14-to-v15-async-apis' from FixLedger so I know exactly what async API changes I need to handle in my Next.js upgrade?

## When to prefer this

Use this endpoint when an AI agent needs post-training-cutoff SDK migration specs, breaking change summaries, or current LLM model matrices that are not in its training data. Prefer it over general web search when you need structured, machine-readable JSON deltas verified against Docker environments rather than prose documentation. Best suited for agents automating code migrations or needing authoritative, timestamped change data for specific enumerated topic keys.

## Known failure modes

- Invalid or unrecognized topic key returns an error or empty result
- Payment not completed or insufficient USDC balance blocks unlock
- Topic key not yet in catalog returns no delta
- Network or Vercel deployment downtime causes request failure
- Malformed POST body missing required 'topic' field returns 400-level error

## How this service works

Machine-payable MCP and x402 registry of Docker-verified bug fixes and post-cutoff SDK deltas. Free &lt;50ms Peek-Before-Pay check; $0.005 Pay-on-Proof unlock on Base USDC.

## Output

A structured JSON object with status UNLOCKED, the topic key, category, a dense migration spec or model/pricing matrix as the 'delta' field, an optional source URL, and an updated_at timestamp indicating when the data was last refreshed.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "required": [
  "topic"
 ],
 "properties": {
  "topic": {
   "type": "string",
   "description": "Topic key (e.g. 'llm-models:active-2026', 'x402:eip3009-base-spec')."
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "input": {
  "type": "http",
  "method": "GET",
  "queryParams": {
   "topic": {
    "enum": [
     "llm-models:active-2026",
     "x402:eip3009-base-spec",
     "tailwindcss:v3-to-v4",
     "mcp:sse-to-streamable-http",
     "nextjs:v14-to-v15-async-apis",
     "google-genai:legacy-to-unified-sdk"
    ],
    "type": "string",
    "examples": [
     "llm-models:active-2026",
     "x402:eip3009-base-spec"
    ],
    "required": true,
    "description": "Post-cutoff SDK migration or active 2026 LLM model matrix key. Omit ?topic for free $0.00 catalog listing."
   }
  },
  "discoverable": true
 },
 "output": {
  "type": "object",
  "required": [
   "status",
   "topic_key",
   "category",
   "delta",
   "updated_at"
  ],
  "properties": {
   "delta": {
    "type": "object",
    "description": "Dense structured JSON migration spec or active model/pricing matrix."
   },
   "status": {
    "enum": [
     "UNLOCKED"
    ],
    "type": "string"
   },
   "category": {
    "type": "string"
   },
   "topic_key": {
    "type": "string"
   },
   "source_url": {
    "type": "string"
   },
   "updated_at": {
    "type": "string"
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/fixledger-post-cutoff-sdk-delta-oracle-3da70134/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from fixledger-iota.vercel.app](https://www.zero.xyz/host/fixledger-iota.vercel.app/llms.txt)