Agent skill · data analytics · github
phoenix-cli
Debug LLM applications using the Phoenix CLI. Fetch traces, analyze errors, structure trace review with open coding and axial coding, inspect datasets, review experiments, query annotation configs, and use the GraphQL API. Use whenever the user is analyzing traces or spans, investigating LLM/agent failures, deciding what to do after instrumenting an app, building failure taxonomies, choosing what evals to write, or asking "what's going wrong", "what kinds of mistakes", or "where do I focus" — even without naming a technique.
Why this skill is useful
Provides specific commands and workflows for debugging LLM applications that the AI wouldn't generate on its own.
What it needs
Requires @arizeai/phoenix-cli, jq, node installed locally. About 8k tokens when loaded. Last updated 2026-08-07. 37,534 stars on the source repository.
What this skill does
Phoenix CLI Invocation The CLI uses singular resource commands with subcommands like list and get: Setup Always use --format raw --no-progress when piping to jq. Quick Reference Task Files ---- ----- Look at sampled traces, spans, or sessions and write specific notes about what went wrong (no taxonomy yet) references/open-coding Group those notes into a structured failure taxonomy and quantify what matters references/axial-coding Both stages tag every artifact with one shared coding annotation identifier (descriptive shape, e.g. coding-run:chatbot-context-loss-2026-05-06) so the run is queryable, reversible, and viewable as a unit. Pass --identifier <value> explicitly on every px call — shell inheritance is unreliable across agent harnesses. Open coding writes notes via px ... add-note and records a small local JSONL sidecar at .px/coding/<sanitized-identifier>.jsonl; axial coding reads that sidecar as the deterministic handoff and records labels in .px/coding/<sanitized-identifier>-axial.jsonl. Pick the identifier once per run (see references/open-coding.md), then share the Phoenix UI link from the wrap-up section. Revert is opt-in and runs three identifier-bound DELETEs only after explicit user confirmation. Workflow term vs. server annotation name. The skill prose calls this value the coding annotation identifier (shell-variable hint: CODINGANNOTATIONIDENTIFIER). The server-side annotation NAME used for the UI filter is unchanged — codingsessionid — for data compatibility with rows already written by previous runs. Don't try to rename the server-side annotation; treat the asymmetry as load-bearing. Workflows "What do I do after instrumenting?" / "Where do I focus?" / "What's going wrong?" open-coding → axial-coding → build evals for the top categories. …
How to use it
Reference it in AdaL, Claude Code, Cursor or any coding agent — nothing to install:
@skills github/phoenix-cli