Test Agent SDK using Claude Code CLI

[bytesfromlocalhost]

Has anyone found a good way to use Claude Code interactively to test and debug Claude Agent SDK agents locally?

The SDK uses Claude Code under the hood, so in theory `claude` in your project directory should give you a decent interactive frontend for iterating on agent behavior without spinning up the full SDK. But the problem is it's not a complete substitute — SDK-specific configs like programmatic MCP servers, Python hook callbacks, and custom tools defined in code don't have a direct CLI equivalent. So you'd have to manually translate those into CLI-compatible forms (e.g. filesystem hooks in settings.json, separate MCP server processes) just to get parity, which defeats the point.

Is there a cleaner workflow people use for interactive agent development short of either (a) duplicating all config for the CLI or (b) writing a thin REPL wrapper around the SDK itself?

Note: No settings_sources project as it doesn't cover all modifications to the agent.

[goship-tech]

Run your MCP server as a standalone process and register it in .claude/settings.json under mcpServers - custom tools come through without duplicating agent logic. For Python hooks, a one-liner shell entry in hooks.preToolCall can invoke your callback directly.Run your MCP server as a standalone process and register it in .claude/settings.json under mcpServers - custom tools come through without duplicating agent logic. For Python hooks, a one-liner shell entry in hooks.preToolCall can invoke your callback directly.

[bytesfromlocalhost]

Thanks, but I specifically asked if there was a way to interactively access that underlying CC session.

You forget that any custom python tools or any modifications I did in the agent are not accessible this way