midnight-cast

Read-only CLI and MCP server for the Midnight networks: network health, error decoding, transactions, contracts, DUST, and working code from Midnight's official examples. Think Foundry cast for Midnight, not a wallet or app scaffold.

npx midnight-cast@latest health preview
# or: npm i -g midnight-cast@latest && midnight-cast health preview

Preview needs nothing else. Preprod and mainnet go through Blockfrost and need a free project ID for each; see Quick start.

Note: midnight-cast also installs a short alias, mn, which runs the same commands. Other global CLIs (e.g. @mermaid-js/mermaid-cli, midnight-wallet-cli) install an mn too, so these docs, the hints and the JSON output always say midnight-cast.

midnight-cast health preview

Or step by step: midnight-cast ping preview && midnight-cast tip preview && midnight-cast versions preview

Requires Node.js 20+ (22+ recommended). Without Node.js, the release binaries install the same commands after checking the checksum:

curl -fsSL https://github.com/Kanasjnr/midnight-cast/releases/latest/download/install.sh | sh

On Windows, in PowerShell: irm https://github.com/Kanasjnr/midnight-cast/releases/latest/download/install.ps1 | iex. Where there's no curl, wget -qO- <same URL> | sh works too. Alpine needs libstdc++ and libgcc first (apk add libstdc++ libgcc). MIDNIGHT_CAST_VERSION=0.2.0 pins a release and MIDNIGHT_CAST_INSTALL_DIR picks the directory (default ~/.local/bin). Each archive carries build provenance: gh attestation verify <archive> --repo Kanasjnr/midnight-cast.

Key capabilities

• Read RPC, indexer, and proof-server health, and whether Midnight's own examples pass on the node a network runs
• Compare live stack signals and a project's Midnight packages with the support matrix
• Decode ledger, pallet, Substrate 1010, and JSON-RPC errors, and messages from current tooling and Blockfrost
• Check a network, proof server and wallet are ready before the first transaction (preflight)
• Inspect transactions, deployed contracts, DUST generation and DUST event streams
• Find working code in Midnight's official examples for a topic in your own words (examples)
• Serve all of it to AI agents as a read-only MCP server, with guidance for Claude Code, Codex, Gemini CLI, Cursor and others
• Query block headers and raw JSON-RPC without writing scripts
• Run without Node.js from a standalone binary

What it does

No wallet keys. No signing or proving.

Common workflows

Is the network healthy?

midnight-cast health preprod

Example output:

Network: preprod
Healthy: yes

Services:
  rpc: OK (668ms)
  indexer: OK (1215ms)
  proof-server: OK (1053ms) (optional) — version=8.1.0 (matches matrix 8.1.0)

Sync:
  RPC height:      2805470
  Indexer height:  2805468
  Delta:           2 (threshold 100)
  In sync:         yes

Why did my tx fail?

midnight-cast tx <hash> --network preprod
midnight-cast decode --raw "<wallet-or-node-error>"

Example output:

Type:     RegularTransaction
ID:       232830
Hash:     e5c86fcd43eb9707e8f23d940e59a6c12ca7ad3ca7e9d2f1232843cc62de1b8c
Block:    909000 (428660a6154a27cee57af3527cb3370ad3bbce94f461f433533b1413e24b71f4)
Protocol: 22000
Status:   PARTIAL_SUCCESS
Fees:     paid=1 estimated=1
Segments: 0:ok, 20003:ok, 35012:fail
Failure:  indexer v4 exposes segment success only (no failure reason)
Hint:     paste wallet/node error → midnight-cast decode --raw "<error>"
Actions:  ContractCall
DUST:     665110:DustSpendProcessed
          → midnight-cast dust-event 665110

Is my local stack aligned with the network?

midnight-cast versions preprod

Example output:

Checks:
  node: expected=>=1.0.400 live=1.0.400 → OK (recommended 1.0.400)
  runtimeSpec: expected=1000300 live=1000300 → OK (node runtime spec_version vs matrix)
  indexer-api: expected=v4 live=v4 → OK (from configured indexer URL path)
  protocolVersion: expected=1000300 live=1000300 → OK (RPC specVersion vs indexer latest block)
  proof-server: expected=8.1.0 live=8.1.0 → OK (GET /version on configured proof server URL)

Summary: live stack matches matrix checks ✓

Quick start

npm i -g midnight-cast          # or: npx midnight-cast …
midnight-cast config init                  # ~/.config/midnight-cast/config.toml
midnight-cast health preview
midnight-cast decode 170
midnight-cast examples "dust sponsorship"

Networks: preview, preprod, mainnet, local — use --network or MN_NETWORK.

Preprod and mainnet go through Blockfrost, since Midnight retired its hosted preprod and mainnet endpoints (mainnet on 30 September 2026, preprod on 9 October). Blockfrost project IDs are per network: create a free Midnight Preprod project, a Midnight Mainnet one, or both, on blockfrost.io, then:

export BLOCKFROST_PREPROD_PROJECT_ID=<your Midnight Preprod project ID>
export BLOCKFROST_MAINNET_PROJECT_ID=nightmainnet...
npx midnight-cast health preprod

Preview is still hosted by Midnight and needs no project ID. The project IDs are never printed. See docs/COMMANDS.md.

Debug ladder

When something breaks, run these in order:

1. midnight-cast health — ping + sync + versions in one shot (preflight --address <wallet> before a first transaction)
2. midnight-cast ping — services up?
3. midnight-cast tip — indexer synced?
4. midnight-cast versions — stack matches support matrix?
5. midnight-cast decode — what does the error mean?
6. midnight-cast tx — what happened on chain?

Common one-liners

midnight-cast health preprod --json
midnight-cast ping preprod
midnight-cast versions preprod
midnight-cast decode --raw "1010: Invalid Transaction: Custom error: 186"
midnight-cast decode 179 --network preview          # ledger map stamped per network
midnight-cast tx <hash> --network preprod           # status, fees, segments; links dust-event ids
midnight-cast block 909000 preprod                  # header at height (+ hash)
midnight-cast dust-events --from 565900 --limit 10 --network preprod
midnight-cast rpc chain_getHeader --json
midnight-cast versions preprod --fail-on-mismatch   # CI; local Midnight packages (either npm scope) vs matrix pins
midnight-cast preflight preprod --address mn_addr_preprod1…   # ready for a first transaction?
midnight-cast contract <address> preprod            # latest action, circuit, deploy block, balances
midnight-cast examples "send shielded tokens"       # working code from Midnight's official examples
midnight-cast explain sync                          # why a first wallet sync takes so long

Using with AI agents

An agent working on a Midnight project needs to know what the network is doing right now, what an error means, and what working code looks like. midnight-cast answers all three from live data and Midnight's own sources, in a form an agent can parse, and its MCP server can't change anything.

It sits next to two other sources an agent may already have. The Kapa answer engine answers questions from Midnight's documentation and examples. Midnight Expert gives agents skills and MCP tools for writing and verifying Compact and SDK code. midnight-cast is the part neither covers: the live state of preview, preprod and mainnet, the meaning of a specific error code on the ledger the network runs, whether a project's versions match the network, and which of Midnight's official examples shows a pattern.

The JSON contract

Add --json to any command for one stable envelope: ok, data, a structured error with a kind and hint, any warnings, and next, the follow-up commands an expert would run. midnight-cast explain --json describes every command, option, exit code and error kind in one call, and schemas/ has a JSON Schema for each command's output. Exit codes are 0 for success, 1 for a failed check and 2 for a usage error. See JSON output.

midnight-cast decode --raw "1010: Invalid Transaction: Custom error: 186" --json
midnight-cast explain --json

The MCP server

Agents that speak MCP can use midnight-cast directly: midnight-cast mcp runs an MCP server on stdio with 14 tools, health, preflight, ping, tip, versions, block, tx, dust_event, dust_events, contract, dust_status, decode, explain and examples, each returning the same envelope. For example, in Claude Code:

claude mcp add --transport stdio midnight-cast -- npx -y midnight-cast mcp

A sandbox or CI image without Node.js can run the same server from the standalone binary: midnight-cast mcp.

What an agent can and can't do with it

• Every MCP tool only reads, and each is marked read-only to the client. None signs or submits a transaction, and none needs a wallet, a key or a seed. The CLI's rpc command, which passes any JSON-RPC method to a node, isn't an MCP tool.
• MIDNIGHT_CAST_NETWORKS limits which networks the model may query, for example preview,preprod.
• Tools that reach a network are rate limited, 30 calls a minute by default (MIDNIGHT_CAST_MAX_CALLS_PER_MINUTE), so a looping agent can't exhaust public endpoints or a Blockfrost plan.
• The only secrets it holds are optional Blockfrost project IDs for preprod and mainnet. They're sent only to Blockfrost and redacted from every response, so the model never sees them.
• decode, explain and examples work offline from data bundled with the release.

Guidance, skill and plugin

To teach a coding agent when and how to use midnight-cast, add the guidance to your project: midnight-cast agents init --write appends a marked section to AGENTS.md (read by Codex, Cursor, Copilot, Gemini CLI, Windsurf, Aider and others; use --file CLAUDE.md for Claude Code), or install the portable skill with npx skills add Kanasjnr/midnight-cast --skill midnight-cast. The snippets are in docs/agents.

In Claude Code, one plugin installs the skill, the MCP server and a /midnight-cast:diagnose <network> [tx or error] command. When the plugin is enabled, Claude Code asks for optional Blockfrost project IDs for preprod and mainnet and keeps them in secure storage; left empty, an exported BLOCKFROST_PREPROD_PROJECT_ID or BLOCKFROST_MAINNET_PROJECT_ID is used. If you added the server with claude mcp add before, remove it with claude mcp remove midnight-cast so only the plugin's server runs:

claude plugin marketplace add Kanasjnr/midnight-cast
claude plugin install midnight-cast@midnight-cast

docs/MCP.md has the setup for Codex, Gemini CLI, Cursor, VS Code and others, the network allow-list, and how the Blockfrost project ID stays out of the model's sight.

Community & support

midnight-cast decode --raw "…" auto-detects 1010 envelopes, Custom(N), ledger error names, pallet module errors, and JSON-RPC codes from one pasted error. Use --network so the ledger map matches preview vs preprod. Pallet Transaction hints point to inner Custom(N), and codes 179–181 show grouped transcript context. For missing codes or protocol questions, use Discord and the Midnight docs.

Documentation

• Workflows — scenario guides with sample output
• Command reference — command-by-command reference with examples
• Docs index

Cast ↔ midnight-cast

cast block  →  midnight-cast block latest | midnight-cast block <height>
cast rpc    →  midnight-cast rpc
cast logs   →  midnight-cast dust-events
cast 4byte  →  midnight-cast decode
cast send   →  wallet / Lace (not midnight-cast)
doctor      →  midnight-cast health

Development

git clone https://github.com/Kanasjnr/midnight-cast.git
cd midnight-cast && npm install && npm run build
npm link                        # global midnight-cast
npm run cli -- decode 170       # without link
npm test
BLOCKFROST_PREPROD_PROJECT_ID=<id> INTEGRATION=1 npm run test:integration   # live tests; mainnet ones also need BLOCKFROST_MAINNET_PROJECT_ID

License

Apache-2.0