The tabnas agent tooling: an MCP server (stdio) and the unified tabnas CLI, two thin front-ends over one core so they cannot disagree — for the same request, the CLI's --json output and the MCP tool result are byte-identical.

Six tools only: parse, validate_grammar, explain_parse_error, test_grammar, list_plugins, describe_plugin. Five resources: the serialized-grammar schema, the diagnostic schema, the error-code registry, the plugin descriptors, and the engine's divergence record — all bundled, generated copies of the fleet's contract files.

Install

npm install -g @tabnas/mcp     # the `tabnas` CLI
npx --yes @tabnas/mcp          # run the MCP server (stdio)

CLI

tabnas parse    [file|-] [--grammar g.json] [--json]
tabnas validate --grammar g.json [--json]
tabnas diagnose [file|-] [--grammar g.json] [--json]
tabnas test     --spec fixtures.tsv [--grammar g.json] [--json]
tabnas plugins  [name] [--json]
tabnas mcp                                        # run the MCP server (stdio)

Exit codes: 0 success, 1 the operation said no (parse failure, invalid grammar, fixture failures, unknown plugin), 2 usage error. tabnas --help has the details. The CLI never touches the network. tabnas mcp runs the stdio MCP server (the entry the skills package's mcp.json invokes as npx --yes @tabnas/mcp@<x.y.z> mcp).

Serialized grammars and their options are validated before use by a firewall that rejects a prototype-pollution key (__proto__, constructor, prototype) anywhere in the tree, a ref key, a non-builtin function reference, a plugins key, and grammars over 5000 rules: a grammar is data, never code.

Full documentation: github.com/tabnas/mcp.