metamask-integration/chain138-snap/docs/FEATURES.md

Chain 138 Snap — Features and RPC methods

This document lists every function and feature of the Snap, with parameters and response shapes. The Snap supports both blockchains: Chain 138 (DeFi Oracle Meta Mainnet) and ALL Mainnet (651940).

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Blockchains supported

Chain	Chain ID	Name	Use in Snap
Chain 138	138	DeFi Oracle Meta Mainnet	Primary; networks, config, market, swap, bridge
ALL Mainnet	651940	ALL Mainnet	Supported in networks, token list, optional chainId

All methods that accept an optional chainId default to 138 when omitted.

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Feature overview (visual)

┌─────────────────────────────────────────────────────────────────────────┐
│                     Chain 138 Snap (npm:chain138-snap)                  │
├─────────────────────────────────────────────────────────────────────────┤
│  Networks & config     │  get_networks, get_chain138_config,            │
│  (Chain 138 + ALL)     │  get_chain138_market_chains                    │
├─────────────────────────────────────────────────────────────────────────┤
│  Token list            │  get_token_list, get_token_list_url            │
│  (optional chainId)     │  (chainId: 138 or 651940)                     │
├─────────────────────────────────────────────────────────────────────────┤
│  Market data           │  get_market_summary, show_market_data          │
│  (USD prices)          │  (dialog: token symbols + prices)              │
├─────────────────────────────────────────────────────────────────────────┤
│  Bridge routes         │  get_bridge_routes, show_bridge_routes          │
│  (CCIP + Trustless)    │  (dialog: CCIP WETH9/WETH10 + Trustless Lockbox)│
├─────────────────────────────────────────────────────────────────────────┤
│  Swap quote            │  get_swap_quote, show_swap_quote               │
│  (Chain 138)           │  (tokenIn, tokenOut, amountIn → amountOut)      │
├─────────────────────────────────────────────────────────────────────────┤
│  Oracles & dynamic     │  get_oracles, show_dynamic_info                │
│  (API config)          │  (dialog: networks + token list URL)          │
├─────────────────────────────────────────────────────────────────────────┤
│  Test                  │  hello (returns greeting)                      │
└─────────────────────────────────────────────────────────────────────────┘

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RPC method matrix

Method	Chain 138	ALL (651940)	Requires apiBaseUrl / URL param	Shows dialog (UI)
hello	—	—	No	Yes (confirmation)
get_networks	✅	✅	apiBaseUrl or networksUrl	No
get_chain138_config	✅	—	apiBaseUrl or networksUrl	No
get_chain138_market_chains	✅	—	apiBaseUrl	No
get_token_list	✅	✅	apiBaseUrl or tokenListUrl	No
get_token_list_url	✅	✅	apiBaseUrl or tokenListUrl	No
get_oracles	✅	—	apiBaseUrl	No
show_dynamic_info	✅	✅	apiBaseUrl or networksUrl/tokenListUrl	Yes
get_market_summary	✅	✅	apiBaseUrl	No
show_market_data	✅	✅	apiBaseUrl	Yes
get_bridge_routes	✅	—	apiBaseUrl or bridgeListUrl	No
show_bridge_routes	✅	—	apiBaseUrl or bridgeListUrl	Yes
get_swap_quote	✅	—	apiBaseUrl + tokenIn, tokenOut, amountIn	No
show_swap_quote	✅	—	apiBaseUrl + tokenIn, tokenOut, amountIn	Yes

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Method reference by category

Test

Method	Params	Response	UI
hello	—	"Hello from Chain 138 Snap!"	Confirmation dialog

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Networks and chain config

Method	Params	Response shape
get_networks	apiBaseUrl or networksUrl	{ version?, networks: EIP-3085[] }
get_chain138_config	apiBaseUrl or networksUrl	Chain 138 params (chainId, chainName, rpcUrls, nativeCurrency, blockExplorerUrls, oracles)
get_chain138_market_chains	apiBaseUrl	[{ chainId, name, nativeToken, rpcUrl, explorerUrl }]

Visual (dialog): None for get_*; use show_dynamic_info for an in-Snap dialog with networks and token list URL.

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Token list

Method	Params	Response shape
get_token_list	apiBaseUrl or tokenListUrl, optional chainId (138 | 651940)	{ tokens: [{ symbol, name, address, ... }] } or API shape
get_token_list_url	Same	URL string or object with token list URL

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Oracles and dynamic info

Method	Params	Response / UI
get_oracles	apiBaseUrl	Oracles config from API
show_dynamic_info	apiBaseUrl or networksUrl / tokenListUrl	Dialog: networks summary and token list URL

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Market data (USD prices)

Method	Params	Response shape	UI
get_market_summary	apiBaseUrl, optional chainId (default 138)	{ tokens: [{ symbol, name, address, market?: { priceUsd, volume24h } }] }	No
show_market_data	Same	—	Dialog: "Market data (Chain 138)" with token symbols and USD prices

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Bridge routes (CCIP + Trustless)

Method	Params	Response shape	UI
get_bridge_routes	apiBaseUrl or bridgeListUrl	{ routes: { weth9?, weth10?, trustless? }, chain138Bridges: { weth9?, weth10?, trustless? } }	No
show_bridge_routes	Same	—	Dialog: CCIP (WETH9/WETH10) and Trustless (Lockbox on 138) routes to Ethereum Mainnet

The API or bridgeListUrl JSON may include:

• CCIP: routes.weth9, routes.weth10, chain138Bridges.weth9, chain138Bridges.weth10.
• Trustless: chain138Bridges.trustless (Lockbox on Chain 138), optional routes.trustless['Ethereum Mainnet (1)'] (Ethereum-side contract).

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Swap quote

Method	Params	Response shape	UI
get_swap_quote	apiBaseUrl, tokenIn, tokenOut, amountIn (raw string), optional chainId (default 138)	{ amountOut?, error?, poolAddress? }	No
show_swap_quote	Same	—	Dialog: In/Out amounts (raw)

---

Request flow (high level)

flowchart LR
  subgraph dApp
    A[dApp / Companion site]
  end
  subgraph Snap
    B[Chain 138 Snap]
  end
  subgraph API
    C[Token-aggregation API]
  end
  A -->|wallet_invokeSnap + apiBaseUrl / URL params| B
  B -->|GET /api/v1/networks etc.| C
  C -->|JSON| B
  B -->|result or snap_dialog| A

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Optional URL overrides

Instead of (or in addition to) apiBaseUrl, you can pass:

Param	Used by methods
networksUrl	get_networks, get_chain138_config
tokenListUrl	get_token_list, get_token_list_url
bridgeListUrl	get_bridge_routes, show_bridge_routes

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Screenshots and visuals (for maintainers)

To make the docs more visual, add screenshots under docs/images/ and link them here and in the README. Suggested captures:

Screenshot	Description
connect.png	Companion site Connect button and MetaMask install prompt
market-data-dialog.png	Snap dialog from show_market_data (Chain 138 tokens + prices)
bridge-routes-dialog.png	Snap dialog from show_bridge_routes (CCIP + Trustless routes)
swap-quote-dialog.png	Snap dialog from show_swap_quote
dynamic-info-dialog.png	Snap dialog from show_dynamic_info (networks + token list URL)

After adding images, link them in this section and in README.md.