buzz-sprig container does not include Goose binary but UI allows Goose harness selection for k3s agents

[DevmanushRaky]

Problem

When creating a k3s agent via the Buzz desktop app with "Goose" as the agent harness, the agent deploys successfully and the pod shows as Running, but the agent never sends text replies — only emoji reactions.

There is no warning in the UI about this. The failure is silent.

Root Cause

The buzz-sprig container image does not include the Goose binary.
BUZZ_ACP_AGENT_COMMAND is set to goose by the Goose harness, but goose does not exist inside the container.

Pod logs show:

agent failed to spawn: IO error: No such file or directory (os error 2)

Binaries available in buzz-sprig (/usr/local/bin/):

buzz, buzz-acp, buzz-agent, buzz-dev-mcp, sprig, sprig-entrypoint

Additionally, BUZZ_ACP_AGENT_COMMAND is a reserved env var and cannot be overridden via the desktop app environment variables UI — so there is no workaround from the UI side without recreating the agent.

Steps to Reproduce

1. Create a k3s agent from Buzz desktop app
2. Select Agent harness: Goose
3. Set Run on: kubernetes
4. Use image: ghcr.io/block/buzz-sprig@sha256:<digest>
5. Deploy the agent
6. Send a message to the agent — it reacts with emoji but never sends a text reply

Fix (workaround)

Use Buzz Agent harness instead of Goose — buzz-agent binary exists in the container and works correctly.

Expected Behavior

One of the following:

1. Remove Goose as a selectable harness option when Run on: kubernetes is selected, OR
2. Include Goose in the buzz-sprig container image, OR
3. Show a clear error in the UI when the selected agent command binary is not found in the container