# `ClaudeAgentSDK.Query`
[🔗](https://github.com/nshkrdotcom/claude_agent_sdk/blob/v0.17.2/lib/claude_agent_sdk/query.ex#L1)

Handles querying Claude Code and processing responses.

This module is responsible for building the appropriate command-line arguments
for different types of Claude Code queries (new queries, continuations, and
resumptions) and delegating to the CLI streaming transport for execution.

All functions in this module return a Stream of `ClaudeAgentSDK.Message` structs.

## SDK MCP Server Support

When SDK MCP servers are detected in options, the query automatically uses
the Client GenServer (which supports bidirectional control protocol) instead
of the simpler CLI-only stream lane. This is transparent to the caller - you
still get the same Stream interface.

# `continue`

```elixir
@spec continue(String.t() | nil, ClaudeAgentSDK.Options.t()) ::
  Enumerable.t(ClaudeAgentSDK.Message.t())
```

Continues the most recent conversation.

## Parameters

- `prompt` - Optional additional prompt to send (string or nil)
- `options` - Configuration options (see `t:ClaudeAgentSDK.Options.t/0`)

## Returns

A stream of `t:ClaudeAgentSDK.Message.t/0` structs.

## Examples

    ClaudeAgentSDK.Query.continue("Add error handling", %ClaudeAgentSDK.Options{})

# `resume`

```elixir
@spec resume(String.t(), String.t() | nil, ClaudeAgentSDK.Options.t()) ::
  Enumerable.t(ClaudeAgentSDK.Message.t())
```

Resumes a specific conversation by session ID.

## Parameters

- `session_id` - The session ID to resume (string)
- `prompt` - Optional additional prompt to send (string or nil)
- `options` - Configuration options (see `t:ClaudeAgentSDK.Options.t/0`)

## Returns

A stream of `t:ClaudeAgentSDK.Message.t/0` structs.

## Examples

    ClaudeAgentSDK.Query.resume("session-123", "Add tests", %ClaudeAgentSDK.Options{})

# `run`

```elixir
@spec run(String.t() | Enumerable.t(), ClaudeAgentSDK.Options.t(), term() | nil) ::
  Enumerable.t(ClaudeAgentSDK.Message.t())
```

Runs a new query with the given prompt and options.

Automatically detects if SDK MCP servers are present in options and routes
to the appropriate backend:
- SDK MCP servers present → Uses Client GenServer (bidirectional control protocol)
- No SDK MCP servers → Uses CLI-only streaming transport (unidirectional)

## Parameters

- `prompt` - The prompt to send to Claude (string)
- `options` - Configuration options (see `t:ClaudeAgentSDK.Options.t/0`)

## Returns

A stream of `t:ClaudeAgentSDK.Message.t/0` structs.

## Examples

    # Simple query (no SDK MCP)
    ClaudeAgentSDK.Query.run("Write a hello world function", %ClaudeAgentSDK.Options{})

    # With SDK MCP servers (auto-uses Client)
    server = ClaudeAgentSDK.create_sdk_mcp_server(name: "math", tools: [Add])
    options = %Options{mcp_servers: %{"math" => server}}
    ClaudeAgentSDK.Query.run("What is 2+2?", options)

---

*Consult [api-reference.md](api-reference.md) for complete listing*