---
name: underground.substratesymposium.com
description: underground.substratesymposium.com exposes a single endpoint that returns the full buy catalog for the Underground Substrate Symposium marketplace, including all districts, shops, pricing models, product counts, and navigation links to per-shop product indexes. It serves as the discovery layer before any deeper shop or product-level queries.
host: underground.substratesymposium.com
---

# underground.substratesymposium.com

This host is the catalog entry point for the Underground Substrate Symposium, a marketplace organized into districts and shops. It serves agents that need to enumerate available vendors, understand pricing models, or obtain the URLs required to query individual shop inventories. It does not itself serve product-level data; it provides the map to find it.

## When to use this host

Use this host when an agent needs to discover what shops or districts exist within the Underground Substrate Symposium marketplace, retrieve pricing model metadata, or obtain product_index_url values for downstream shop queries. Do not use it to fetch individual product listings or product details — those require calling the per-shop product_index_url endpoints returned in the catalog response. If the agent already knows the specific shop endpoint it needs, skip this host and query that endpoint directly.

## Capabilities

### Marketplace Discovery

Returns the top-level catalog of the Underground Substrate Symposium, giving agents a complete picture of districts, shops, pricing structures, and navigation links needed to proceed to individual shop endpoints.

- **`fetch-underground-catalog`** — Returns the full Underground Substrate Symposium buy catalog, including all districts, shops, pricing models, product counts, and neighbor navigation links.

## Skill reference

### `fetch-underground-catalog`

**Underground Catalog** — Returns the full Underground Substrate Symposium buy catalog, including all districts, shops, pricing models, product counts, and neighbor navigation links.

*Use when:* Use when an agent needs to discover available shops, districts, pricing models, or product index URLs within the Underground Substrate Symposium marketplace before navigating to individual shop endpoints.

*Not for:* Do not use to fetch individual shop products or product details; use the per-shop product_index_url endpoints instead.

**Returns:** Returns a place metadata object and an array of districts, each containing shop slugs, pricing models, product counts, neighbor links, and product index URLs across 26 shops in 7 neighborhoods.

**Example:** `GET https://underground.substratesymposium.com/buy/catalog`

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