[Feature]: Support adding prompts when using cli-mode instead of acp

[Inrego]

Problem

With the announced upcoming change in usage from Anthropic, any agent SDK and claude -p usage will be drawn from a given api budget instead of from the subscription usage.

I imagine this will affect kandev greatly, and possibly the only solution to keep using kandev with claude subscription will be using cli mode.

Proposed solution

Better support for cli mode, allowing the initial task prompt to be injected into claude cli sessions.

Affected area

agentctl

Who needs this?

Individual developer

Target workflow

I think it's self explanatory.

Alternatives considered

Another consideration could be finding workarounds like https://github.com/smithersai/claude-p
But in the end, it circumvents the ToS and may result in a ban. Also, it might be a cat and mouse game with Anthropic.

Acceptance criteria

Ideally full feature parity between ACP and CLI mode

Risks and constraints

No response

References

No response

Before submitting

• I checked existing issues and did not find this request already tracked.
• This request describes user value, not only an implementation detail.

[carlosflorencio]

Yeah we thought about improving the CLI passthrough experience in the past. Namely add support for:

• drag and drop files into the cli (inserts the file path as stdin)
• insert file/diff comments as stdin text
• insert the first task prompt as stdin
• etc

I guess we'll need to prioritize to have them before the new claude credit system starts 💪

Thanks for the suggestion tho.

[Inrego]

I'm not sure if any special handling of plan mode needs to be done when using CLI sessions. Related issue: #930