use_subagent tool broken in --tui mode

[MikaelUlvesjo]

Checks

• I have searched github.com/aws/amazon-q-developer-cli/issues and there are no duplicates of my issue
• I have run q doctor in the affected terminal session
• I have run q restart and replicated the issue again

Operating system

Linux 5.15.0-168-generic - Ubuntu 22.04.5 LTS

Expected behaviour

When running kiro-cli chat --tui with an agent that has subagents configured
(via toolsSettings.subagent.availableAgents), the use_subagent tool should
accept ListAgents and InvokeSubagents commands as documented and as they
work in non-TUI mode.

Actual behaviour

The TUI mode rejects both commands with a schema validation error:

Failed to parse the tool use: The tool input does not match the tool schema:
unknown variant ListAgents, expected list_agents or invoke_subagents

Using the snake_case variants partially works — list_agents succeeds but
invoke_subagents fails with:

Failed to parse the tool use: The tool input does not match the tool schema:
missing field subagents

Steps to reproduce

1. Create an orchestrator agent (~/.kiro/agents/my-orchestrator.json):
   • "tools": ["use_subagent"]
   • "toolsSettings": { "subagent": { "availableAgents": ["my-worker"] } }
2. Create a worker agent (~/.kiro/agents/my-worker.json)
3. Ensure kiro-cli settings chat.enableSubagent true
4. Start with TUI: kiro-cli chat --tui --agent my-orchestrator
5. Ask something that triggers subagent delegation
6. Observe the enum parse error
7. Restart without --tui: kiro-cli chat --agent my-orchestrator
8. Same request works correctly

Environment

<This will be visible to anyone. Do not include personal or sensitive information>

[q-details]
version = "1.28.1"
hash = "fc92565d6f51c1708e92500b2b2bcc4a424f5705"
date = "2026-03-21T05:18:11.590914Z (2d ago)"
variant = "minimal"

[system-info]
chip = "Intel(R) Xeon(R) Gold 6338 CPU @ 2.00GHz"
total-cores = 8
memory = "62.79 GB"

[system-info.os.linux]
kernel_version = "5.15.0-168-generic"
id = "ubuntu"
name = "Ubuntu"
pretty_name = "Ubuntu 22.04.5 LTS"
version_id = "22.04"
version = "22.04.5 LTS (Jammy Jellyfish)"

[environment]
cwd = "/local/workspace/pas-nonfunctional-tests"
cli-path = "/local/workspace/pas-nonfunctional-tests"
os = "Linux"
shell-path = "/usr/bin/bash"
shell-version = "5.1.16"
install-method = "unknown"

[env-vars]
DISPLAY = ":1"
PATH = "/home/USER/.local/bin:/usr/local/bin"
Q_SET_PARENT_CHECK = "1"
SHELL = "/bin/bash"
TERM = "xterm-256color"
XDG_CURRENT_DESKTOP = "MATE"

[TrevorBurnham]

You should report kiro-cli issues in the Kiro repo: https://github.com/kirodotdev/Kiro/issues Did you follow a link to this repo from somewhere?

[MikaelUlvesjo]

I used Kiro-cli '/issue' and that opened a issue in this repo.
But with a search in the kiro repo I found this issue: kirodotdev/Kiro#6644 so I will not write a new one.

[TrevorBurnham]

I used Kiro-cli '/issue' and that opened a issue in this repo.

FYI the /issue command was updated to point to the new repo in kiro-cli v1.23.0, which was released in December.