API Reference

Reference for the 7 MCP tools exposed by the Nella MCP server.

Tool Categories

Context Tools

Tool	Description
nella_get_context	Read the current session context, trust metadata, and heartbeat challenge.
nella_add_assumption	Record an assumption about the codebase.
nella_check_assumptions	Review valid and invalidated assumptions.
nella_check_dependencies	Detect dependency drift since the last snapshot.

See Context Tools for the grouped context workflow.

Indexing Tools

Tool	Description
nella_index	Build or refresh the workspace index used for search.
nella_search	Search the indexed workspace with hybrid, semantic, or lexical retrieval.

Trust Chain Tool

Tool	Description
nella_heartbeat	Verify trust-chain continuity using the current challenge value.

Setup

Start the local MCP server with either of these entry points:

npx -y @getnella/mcp --workspace /path/to/project
# or
nella mcp --workspace /path/to/project

Claude Desktop config

{
  "mcpServers": {
    "nella": {
      "command": "npx",
      "args": ["-y", "@getnella/mcp", "-w", "/path/to/project"]
    }
  }
}

Behavior Notes

• nella_search.filePattern is a case-insensitive substring filter on indexed file paths. It does not support glob syntax.
• nella_search.language is forwarded as a file-type filter. Language names like typescript and raw extensions like ts both work.
• nella_add_assumption.relatedFiles accepts exact paths or glob patterns because the underlying assumption tracker matches them with minimatch.
• nella_check_assumptions sets isError: true when assumptions were invalidated.
• nella_check_dependencies sets isError: true when dependency changes are detected.
• nella_get_context includes the session trust token, integrity guidance, and the current heartbeat challenge.

Tool Selection Guide

If you want to…	Use
Index the workspace for search	nella_index
Find code or docs in the indexed workspace	nella_search
Review the current session and trust metadata	nella_get_context
Record a working assumption	nella_add_assumption
Check whether assumptions still hold	nella_check_assumptions
Detect dependency drift	nella_check_dependencies
Continue the challenge-response trust chain	nella_heartbeat