Backend

Detection — At the start of every invocation, before taking any action, determine which backend to use:

If the user passed --backend pup anywhere in their invocation → use pup mode immediately, regardless of whether MCP tools are present. Skip steps 2–4.
Check whether MCP tools are present in your active tool list. The canonical signal is whether a tool named get_llmobs_experiment_summary (with or without the mcp__datadog-llmo-mcp__ prefix) appears in your available tools.
If MCP tools are present → use MCP mode throughout. Tool name binding: note the exact name under which get_llmobs_experiment_summary appears in your active tool list and use that exact name (prefixed or unprefixed) for every MCP tool call this invocation. All other experiment tools follow the same naming convention.
If MCP tools are absent → check whether pup is executable: run pup --version via Bash. A JSON response containing "version" confirms pup is available.
If pup responds → use pup mode throughout. Translate every MCP tool call to its pup equivalent using the Tool Reference appendix at the bottom of this file.
If neither is available → stop and tell the user:

"Neither the Datadog MCP server nor the pup CLI is available. Connect the MCP server (claude mcp add --scope user --transport http datadog-llmo-mcp 'https://mcp.datadoghq.com/api/unstable/mcp-server/mcp?toolsets=llmobs') or install pup."

--backend pup is accepted anywhere in the invocation arguments and is stripped before passing remaining args to the skill logic.

pup invocation rules:

Invoke via Bash: pup llm-obs <subcommand> [flags]
pup always outputs JSON. Parse directly — no content-block unwrapping (unlike MCP results, which may wrap JSON in [{"type": "text", "text": "<json>"}]).
If pup returns an auth error, tell the user to run pup auth login and stop.
Parallelization: issue multiple Bash tool calls in a single message (one pup command per call).

agent-observability-experiment-analyzer