# BM25 Budget-Controlled Web Distillation (Context Trimmer)

> BM25 Budget-Controlled Web Distillation (Context Trimmer) is a paid API for AI agents from hn-pulse.agentdiet.dev, paid per call via MPP, $0.001/call, status unknown (last checked 2026-10-23).

Fetches and distills a URL or raw HTML into compact, token-budgeted agent-ready content using BM25 ranking and multiple output modes.

## Facts

- Endpoint: POST https://hn-pulse.agentdiet.dev/v1/context-trimmer?utm_source=zero.xyz
- Price: $0.001/call
- Payment: MPP
- Status: unknown
- Last checked: 2026-10-23
- Activations on Zero: 0
- Provider: hn-pulse.agentdiet.dev
- Website: https://hn-pulse.agentdiet.dev
- Canonical page: https://www.zero.xyz/c/hn-pulse-agentdiet-dev-bm25-budget-controlled-web-distillation-7750e6f0
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_qh8f6EsY71Op3FdAIuFAf

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 hn-pulse-agentdiet-dev-bm25-budget-controlled-web-distillation-7750e6f0 -d '<json body>'
```

Example prompt: Fetch the Stripe docs page at https://stripe.com/docs/payments and distill it in budget mode focused on 'webhook events', keeping it under 500 tokens so I can fit it in my context window.

## When to prefer this

Choose this endpoint when you need to reduce the token footprint of web content before feeding it to an LLM, especially when you have a strict context window or cost budget. The BM25 budget mode is uniquely useful when you want only the most query-relevant passages from a long page, not a generic summary. Prefer this over generic scrapers when ROI proof and token savings metrics are important for your agent's cost accounting.

## Known failure modes

- URL unreachable or returns non-200 — distillation fails with an error status
- HTML too short or empty — minimal or no compression achieved
- Token budget set below minimum (20) — validation error
- BM25 query not provided in budget mode — may fall back to generic distillation
- Rate limiting or payment failure — 402 response if payment not attached

## How this service works

Distill a URL or raw HTML payload with BM25 budget control (Live x402 v2, IETF MPP & MCP endpoint at https://hn-pulse.agentdiet.dev/v1/context-trimmer)

## Output

Returns a status field, distilled content (markdown text, structured JSON tables/metadata, skeleton outline, or BM25-ranked excerpt depending on mode), an roi_proof object showing raw vs distilled token counts, compression ratio, and estimated LLM cost saved, plus optional billing and cache hit/miss info.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "required": [
  "url"
 ],
 "properties": {
  "url": {
   "type": "string",
   "minLength": 1,
   "description": "Target webpage URL to fetch and distill (or builtin://stripe-docs)"
  },
  "html": {
   "type": "string",
   "description": "Optional raw HTML string to distill directly without fetching"
  },
  "mode": {
   "enum": [
    "markdown",
    "structured",
    "skeleton",
    "budget"
   ],
   "type": "string",
   "default": "markdown",
   "description": "Distillation mode"
  },
  "query": {
   "type": "string",
   "description": "BM25 focus query when mode=budget"
  },
  "max_tokens": {
   "type": "integer",
   "minimum": 20,
   "description": "Strict token budget ceiling when mode=budget"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "object",
 "required": [
  "status",
  "roi_proof",
  "data"
 ],
 "properties": {
  "data": {
   "type": "object",
   "description": "Distilled Markdown, structured JSON tables/metadata, skeleton outline, or BM25 budget excerpt."
  },
  "cache": {
   "type": "object",
   "properties": {
    "status": {
     "enum": [
      "HIT",
      "MISS"
     ],
     "type": "string"
    },
    "cache_key": {
     "type": "string"
    },
    "latency_ms": {
     "type": "number"
    }
   }
  },
  "status": {
   "type": "string",
   "description": "Execution status ('ok')"
  },
  "billing": {
   "type": "object",
   "properties": {
    "agent_id": {
     "type": "string"
    },
    "payment_method": {
     "type": "string"
    },
    "fee_charged_usd": {
     "type": "number"
    }
   }
  },
  "roi_proof": {
   "type": "object",
   "properties": {
    "raw_tokens": {
     "type": "integer"
    },
    "tokens_saved": {
     "type": "integer"
    },
    "roi_multiplier": {
     "type": "number"
    },
    "distilled_tokens": {
     "type": "integer"
    },
    "llm_cost_saved_usd": {
     "type": "number"
    },
    "compression_ratio_pct": {
     "type": "number"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/hn-pulse-agentdiet-dev-bm25-budget-controlled-web-distillation-7750e6f0/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from hn-pulse.agentdiet.dev](https://www.zero.xyz/host/hn-pulse.agentdiet.dev/llms.txt)