Testing & Quality skills

Browse reusable Agent Skills, each with a clear purpose and practical guidance.

analyzing-experiment-query-performance

Pull and interpret production experiment query-performance data from the staff-only `/api/debug_ch_queries` endpoints backing the `/instance/query_performance` scene: slowest experiment queries, precompute read/build health, and preaggregation cache footprint. Covers prod-US and prod-EU via a `query_performance:read` personal API key, all query params, and response field semantics (exception codes, exposure paths, precompute skip reasons, job states). Use when investigating slow or failing experiment queries, precompute regressions, 307/159/241 errors, preaggregation table growth, or when asked how experiment query performance or the precompute rollout is doing in production.

35.56k repo starsObserved in 3 repos
Testing & Quality
GitHub

check-posthog-loading

Inspect how the PostHog JavaScript SDK is loaded across a list of URLs. Use to confirm consistent installation across pages, find pages missing the snippet, detect mismatched API keys or hosts between pages, and verify the load method (head snippet vs deferred vs array.js).

35.56k repo starsObserved in 3 repos
Testing & Quality
GitHub

clickhouse-autoresearch-campaign

Run a ClickHouse query optimization campaign on one git branch using pi-autoresearch, dynamic lanes and hypotheses, baseline result capture, correctness checks, and stagnation-aware lane/campaign review.

35.56k repo starsObserved in 3 repos
Testing & Quality
GitHub

debugging-local-task-agent-runs

Debug the output of local PostHog task runs — the wizard cloud-run path that executes inside a Docker sandbox under the local Temporal `process-task` workflow (the wizard that integrates PostHog, then the coding agent that commits and opens the PR). Use when a local run looks stuck, failed, or silent, or when you need to read the wizard or agent logs. Covers the `.env.local` keys + `ai_features` intent required for cloud runs locally, finding the task UUID (docker ps, temporal CLI, Temporal UI at localhost:8081), tailing live logs inside the sandbox container (`/tmp/posthog-wizard.log`, `/tmp/agent-server.log`), and reading the durable per-run console log from object storage after the sandbox is torn down. Trigger terms: task-sandbox, run_wizard, agent-server, process-task, SANDBOX_PROVIDER, LLM_GATEWAY, cloud_run, posthog-wizard.log.

35.56k repo starsObserved in 3 repos
Testing & Quality
GitHub

fixing-flaky-tests

Guides an agent through reproducing, root-causing, fixing, and validating flaky tests in the PostHog monorepo. Use when a test fails intermittently in CI but passes on rerun or locally, when `hogli ci:insights` or the debugging-ci-failures skill classifies a failure as a flaky test, when given a GitHub Actions URL for a flaky job, or when asked to deflake, stabilize, or fix a flaky Jest, pytest, or Playwright test. Core discipline: reproduce locally before changing anything, fix the root cause (never mask it with sleeps, retries, or bigger timeouts), and prove the fix with an N-run validation loop sized to the observed failure rate.

35.56k repo starsObserved in 3 repos
Testing & Quality
GitHub

optimizing-clickhouse-and-hogql-queries

Workflow for optimizing ClickHouse and HogQL queries. Use when a HogQL query, query runner, insight, or report is too slow; when a hand-written ClickHouse query (via `sync_execute` or in a migration) is too slow; when ClickHouse times out or hits memory limits; when investigating a slow `system.query_log` row; or when reviewing a proposed HogQL printer change for performance. Covers extracting the ClickHouse SQL, common smells (`FROM ... FINAL`, `JSONExtract` over properties, missing skip indexes, self-joins, CTE blow-up), measuring against a real cluster, and applying the fix at the right layer (printer, query runner, or migration). Does NOT cover Postgres / Django ORM / app-database queries; those need pganalyze and the Postgres section of `query-performance-optimization.md`.

35.56k repo starsObserved in 3 repos
Testing & Quality
GitHub

qa-team

Multi-agent QA review team for code changes. This skill should be used when the user asks to "review my code", "run QA", "qa-team", "review this branch", "code review", "check my changes", or wants a comprehensive multi-perspective code review of the current branch's changes. Spawns parallel specialist agents (security, database, reliability, compatibility, data integrity, performance, frontend, copy) that independently review the diff and produce a converged report. Also includes two generalist reviewers for convergence validation.

35.56k repo starsObserved in 3 repos
Testing & Quality
GitHub

query-clickhouse-via-metabase

Run ClickHouse `system.query_log` analysis via the internal Metabase API. Use when investigating slow queries, materialization candidates, per-team query performance, ClickHouse cost or memory issues, or any system.query_log question. Covers prod-us and prod-eu, SSO-gated cookie auth via `hogli`, and ready-to-run query patterns.

35.56k repo starsObserved in 3 repos
Testing & Quality
GitHub

querying-local-postgres

Run read-only SQL against the local Postgres app database (SELECT, EXPLAIN, EXPLAIN ANALYZE on SELECT). Default local URL postgres://posthog:posthog@localhost:5432/posthog; else DATABASE_URL. Use when querying the local DB, inspecting tables, debugging data, or analyzing query plans. Mutations are strictly forbidden.

35.56k repo starsObserved in 3 repos
Testing & Quality
GitHub

simulate-new-user

Send synthetic first-time-visitor traffic to a URL and confirm that PostHog $pageview events fire. Use when a customer wants to verify that anonymous visitor tracking works, after deploying instrumentation changes, or when debugging "events not arriving" reports.

35.56k repo starsObserved in 3 repos
Testing & Quality
GitHub