MCP catalogs

Progressive tool discovery

Exact arguments and input schemas for progressive tool discovery.

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arc_search_tools
arc_describe_tool
arc_call_tool

arc_search_tools

Find on-demand Arc tools by keyword; hits carry required arguments, and a clear winner is promoted into your direct tool list with its schema. Otherwise invoke a hit with arc_call_tool or inspect it with arc_describe_tool.

Argument	Required	Type	Description / schema default
`query`	yes	string	keyword or phrase matched against tool names and descriptions
`limit`	no	integer	max results (default 8, max 25)

Complete input schema

json

{
  "type": "object",
  "properties": {
    "query": {
      "type": "string",
      "description": "keyword or phrase matched against tool names and descriptions"
    },
    "limit": {
      "type": "integer",
      "description": "max results (default 8, max 25)"
    }
  },
  "required": [
    "query"
  ]
}

arc_describe_tool

Return one on-demand tool's full description and input schema; the described tool also joins your direct tool list.

Argument	Required	Type	Description / schema default
`name`	yes	string	exact tool name, e.g. 'arc_create_task'

Complete input schema

json

{
  "type": "object",
  "properties": {
    "name": {
      "type": "string",
      "description": "exact tool name, e.g. 'arc_create_task'"
    }
  },
  "required": [
    "name"
  ]
}

arc_call_tool

Invoke an on-demand tool found by arc_search_tools; arguments is that tool's input object. A successfully called tool joins your direct tool list.

Argument	Required	Type	Description / schema default
`name`	yes	string	exact tool name to invoke, e.g. 'arc_create_task'
`arguments`	no	object	argument object for that tool (omit if it takes none)

Complete input schema

json

{
  "type": "object",
  "properties": {
    "name": {
      "type": "string",
      "description": "exact tool name to invoke, e.g. 'arc_create_task'"
    },
    "arguments": {
      "type": "object",
      "description": "argument object for that tool (omit if it takes none)"
    }
  },
  "required": [
    "name"
  ]
}