# Services from modell.halowerk.com on Zero

> modell.halowerk.com serves 11 paid API services for AI agents, indexed by Zero. Each is callable per call with payment handled by Zero.

Canonical page: https://www.zero.xyz/host/modell.halowerk.com
Live health (JSON, refreshed every minute): https://www.zero.xyz/host/modell.halowerk.com/health.json

## Services

- [modell.halowerk.com Output Validator](https://www.zero.xyz/c/modell-halowerk-com-output-validator-4863f9da/llms.txt): $0.002/call via x402. Validates LLM output against a JSON Schema (Draft 2020-12 or draft-07), reporting each violation with its JSON path, the broken rule, and a fix suggestion, while also unwrapping code-fenced or prose-wrapped model responses before validation.
- [Halowerk Modell Drift Check](https://www.zero.xyz/c/halowerk-modell-drift-check-2aabdf36/llms.txt): $0.003/call via x402. Compares reference and current sample sets feature-by-feature, returning PSI, Jensen-Shannon divergence, and KS statistics to detect data drift in ML pipelines.
- [modell.halowerk.com Trace Grade](https://www.zero.xyz/c/modell-halowerk-com-trace-grade-da9ca18d/llms.txt): $0.002/call via x402. Analyzes an AI agent run's step trace to produce a scored quality report detecting loops, failure streaks, wasted calls, and per-step cost attribution.
- [modell.halowerk.com LLM Cost Estimator](https://www.zero.xyz/c/modell-halowerk-com-llm-cost-estimator-fb352155/llms.txt): $0.002/call via x402. Estimates the total API cost for a given LLM call by computing input, output, cache-read, and cache-write costs across models based on text or token counts.
- [OpenAPI 3.x Document Validator](https://www.zero.xyz/c/openapi-3-x-document-validator-78c92fa2/llms.txt): $0.002/call via x402. Validates an OpenAPI 3.x document and reports structural errors that would prevent a machine consumer from parsing or using it correctly.
- [Tool Argument Validator](https://www.zero.xyz/c/tool-argument-validator-34f104b3/llms.txt): $0.002/call via x402. Validates tool call arguments against a JSON Schema and flags semantic anomalies like placeholder values, suspicious numbers, destructive flags, and checksum failures.
- [Halowerk Context Planner](https://www.zero.xyz/c/halowerk-context-planner-c5cd093d/llms.txt): $0.002/call via x402. Plans how to split a long text into chunks that fit a language model's context window, accounting for system prompt, expected answer, and a safety margin, with optional overlap between chunks.
- [OpenAPI to MCP Tool Converter](https://www.zero.xyz/c/openapi-to-mcp-tool-converter-7b6fac71/llms.txt): $0.002/call via x402. Converts an OpenAPI 3.x document into a set of MCP tool definitions, merging path/query/header parameters and request body into a single flat input schema per operation with inline-expanded $refs.
- [Halowerk Model Router](https://www.zero.xyz/c/halowerk-model-router-900489ec/llms.txt): $0.002/call via x402. Scores every catalogue LLM against a given task and returns a ranked shortlist with per-model cost estimates, sub-scores, and exclusion reasons for models that can't fit the input.
- [Halowerk LLM Catalog](https://www.zero.xyz/c/halowerk-llm-catalog-c2b9ec54/llms.txt): $0.005/call via x402. Returns a filterable comparison table of language models with pricing (input, output, cache per million tokens), context window, max output length, batch discounts, and capability tags, each row timestamped for freshness.
- [Tool Compatibility Checker (modell.halowerk.com)](https://www.zero.xyz/c/tool-compatibility-checker-modell-halowerk-com-92f97d9a/llms.txt): $0.002/call via x402. Compares a producer tool's output schema against a consumer tool's input schema to determine whether they can be chained, reporting exact matches, synonym-based renames, and missing required fields.

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

- [Zero catalog index](https://www.zero.xyz/llms.txt)