# Subtensor Reference API

> Part of the Bittensor.ai ecosystem - https://bittensor.ai
> Complete technical reference for the Bittensor Subtensor blockchain.
> Runtime v481, 28 pallets, 1587+ items. Free reference API and MCP access.

## Documentation
- [API Reference](/api/docs): REST API with OpenAPI spec
- [MCP Server](/mcp): Model Context Protocol for AI agents (7 tools)
- [Search](/api/v1/subtensor/search): Full-text search across all items

## Quick Start
- [Events](/reference/events): 312 blockchain events
- [Calls](/reference/calls): 313 extrinsics/transactions
- [Storage](/reference/storage): 407 state items
- [Constants](/reference/constants): 136 runtime constants
- [Errors](/reference/errors): 419 error types

## Key Pallets
- **SubtensorModule**: Core staking, neurons, subnets, emissions
- **Balances**: TAO transfers and account balances
- **System**: Block info, accounts, runtime version

## API Endpoints
All endpoints return JSON. Use Accept: application/json header.

- GET /api/v1/subtensor/pallets - List all pallets
- GET /api/v1/subtensor/pallets/{name} - Pallet details
- GET /api/v1/subtensor/events/{Pallet.Event} - Event details
- GET /api/v1/subtensor/calls/{Pallet.call} - Call details
- GET /api/v1/subtensor/storage/{Pallet.Storage} - Storage details
- GET /api/v1/subtensor/search?q={query} - Search all items

## MCP Server
Connect using Model Context Protocol for structured AI access (7 tools).

### Claude Code (recommended)
```
claude mcp add --transport http subtensor https://subtensor.com/mcp
```

### Manual config (.mcp.json or claude_desktop_config.json)
```json
{
  "mcpServers": {
    "subtensor": {
      "type": "http",
      "url": "https://subtensor.com/mcp"
    }
  }
}
```
IMPORTANT: "type": "http" is required — without it, clients default to stdio.

### Available Tools (7)
- subtensor_search: Search across all Subtensor pallets, events, calls, storage, constants, and errors by keyword.
- subtensor_lookup: Get detailed info about a specific pallet, event, call, storage item, constant, error, SCALE type, RPC method, protocol account, or EVM precompile. Accepts URN identifiers with optional #field.path drilling.
- subtensor_list: Browse items by category: pallets, events, calls, storage, constants, errors, types, runtime APIs, RPC methods, protocol accounts, EVM precompiles, mechanisms, workflows, hyperparameters, cli_flags, build_features, chain_specs, or env_vars.
- subtensor_explore: Explore relationships, version history, removed items, changelogs, and migration guides between runtime versions.
- subtensor_explain: Understand Bittensor concepts, workflows, mechanisms, runtime APIs, runtime errors, extrinsic format, or get code examples.
- subtensor_preferences: Get or set session preferences for language, node URL, and node type. Language affects field name casing (TypeScript=camelCase, others=snake_case) and code examples.
- subtensor_decode: Decode SCALE-encoded hex into labelled fields with RAO→TAO and hex→SS58 conversions applied. Omit pallet and name to identify an event or call from its two-byte (pallet index, item index) prefix — the usual case when you have bytes and want to know what they are.

## Units
- Balances are in RAO (1 TAO = 10^9 RAO)
- Account addresses display as SS58 with prefix 42

## Optional: Full Documentation
- [/llms-full.txt](/llms-full.txt): Expanded version with all endpoints and examples