Mutual exclusivity validation for namespace and all_namespaces in Argo and Helm MCP tools

[KaranJagtiani]

Several MCP tools accept both namespace and all_namespaces parameters but don't validate that they're mutually exclusive. The k8s_get tool in kubectl.py already has this validation, but the same pattern is missing in Argo and Helm tools. Passing both parameters simultaneously leads to undefined behavior.

Scope

• MCP (mcp/tools/argo.py):

  • Add mutual exclusivity validation to argo_list_experiments (around line 239): raise a ValueError if both namespace and all_namespaces are provided.
  • Add the same validation to argo_list_analysisruns (around line 295).
  • Follow the existing pattern from k8s_get in mcp/tools/kubectl.py (lines 90-96).

• MCP (mcp/tools/helm.py):

  • Add mutual exclusivity validation to helm_list_releases (around line 30): raise a ValueError if both namespace and all_namespaces are provided.

Acceptance criteria

• Passing both namespace and all_namespaces to any of the three tools returns a clear error message.
• Passing only namespace or only all_namespaces continues to work as expected.
• Default behavior (neither provided) is unchanged.
• Validation matches the existing pattern in k8s_get.

How to test manually

1. Run the Engine and MCP server locally (see engine/README.md and mcp/README.md).
2. From the UI, ask: "List all experiments across all namespaces in the kube-system namespace" (intentionally conflicting).
3. Verify the tool returns a clear error about mutually exclusive parameters.
4. Ask: "List all helm releases in the default namespace" — verify it works normally.
5. Ask: "List all helm releases across all namespaces" — verify it works normally.

[KaranJagtiani]

The issue is available to be picked up

[DebuggingMax]

oh interesting, I think I see what's going on here - the kubectl.py already handles this edge case but argo and helm don't have the same check. let me dig in and see if I can sort this out

[DebuggingMax]

had a look at it, seems straightforward enough. just need to add the validation block to the three functions. would you mind assigning this to me?