Antithesis Logs Explorer

Skill version: 2026-09-08 2e4a837

Purpose and Goal

Search across all timelines in an Antithesis test run to find events, correlate property failures, and answer temporal questions about ordering and causation — cascade elimination, fault correlation, root cause hypothesis testing, and any "if X happened before Y" query.

The Logs Explorer is distinct from the per-example log viewer used in triage. The triage log viewer shows one timeline centered on one event. The Logs Explorer searches across ALL timelines in a run, supports temporal queries (preceded by, not preceded by, followed by, not followed by), and visualizes results on a multiverse map.

When to Use

• Investigating whether a property failure is independent or a cascade from an earlier failure
• Counting how many independent occurrences of a failure exist across timelines
• Correlating failures with fault injection events
• Comparing failure patterns between backend configurations
• Identifying timeline clusters where failures co-occur

Prerequisites

• DO NOT PROCEED if snouty is not installed. See https://raw.githubusercontent.com/antithesishq/snouty/refs/heads/main/README.md for installation options.
• DO NOT PROCEED if agent-browser is not installed. See https://raw.githubusercontent.com/vercel-labs/agent-browser/refs/heads/main/README.md for installation options.
• DO NOT PROCEED if agent-browser is older than version v0.23.4. You can upgrade with agent-browser upgrade.
• DO NOT PROCEED if jq is not installed. See https://jqlang.org/download/ for installation options.
• python3 (>= 3.10, stdlib only) for assets/build-url.py.
• A completed Antithesis run. If you don't have a specific run URL, use the antithesis-triage skill's run discovery workflow to find one first.
• agent-browser installed and authenticated to the Antithesis tenant

Key Concepts

• Temporal query: Search for event X that is (or is not) preceded by or followed by event Y. Used to filter out cascade failures.
• Multiverse map: Visualization of the timeline tree. Failures appear as dots. Clusters of dots on related timelines suggest a shared root cause.
• Independent cluster count: The number of distinct timeline branches where a failure appears. "8 failures in 2 clusters" is much more informative than just "8 failures" — it tells you how many independent reproductions exist.
• Session ID: Each run has a unique session ID that scopes all queries. Queries against the wrong session return no results. The session ID is embedded in the encoded search URL parameter.

Important: Field Names

The Logs Explorer uses singular field names, not plural:

• assertion.message — the property/assertion name (NOT assertions.message)
• assertion.status — passing or failing (NOT assertions.status)
• general.output_text — log output text

The assertion.status field requires the matches operator, not contains. Other text fields use contains.

Session Setup

Use agent-browser with the shared Antithesis authentication:

SESSION="logs-explorer-$(date +%s)-$$"
agent-browser --session "$SESSION" --session-name antithesis --profile antithesis --args "--no-sandbox"

Launching the Logs Explorer

There are three ways to reach the Logs Explorer with the correct run selected:

Method 1: From a triage report (preferred)

Navigate to the triage report first, then extract the "Explore logs" link. This is the most reliable method because the link contains the correct session ID already encoded in the URL.

agent-browser --session "$SESSION" eval \
  "document.querySelector('a.an-button[href*=\"/search\"]').href"

Navigate to the returned URL. This automatically sets the correct session/run.

The URL will have the form:

https://{tenant}.antithesis.com/search?search=v5v{base64_encoded_query}

The v5v prefix is a version marker. The base64 payload contains the query JSON including the session ID (s field). See references/query-builder.md for the full query JSON format.

Method 2: From the Logs Explorer directly

The Logs Explorer page has a "Show me logs from" dropdown at the top (div.select_container.event_search_run_selector). Click it to see a list of recent runs with their name, status (In progress / Completed / Incomplete), and timestamp. Select the run you want.

If a run you expect to see is missing, refresh the page.

Method 3: From the sidebar

Click "Logs explorer" in the left sidebar navigation. This goes directly to https://{tenant}.antithesis.com/search with no run pre-selected. Then use the "Show me logs from" dropdown to choose a run.

agent-browser --session "$SESSION" open "https://{tenant}.antithesis.com/search"

Important: Always ensure the correct run is selected before searching. Each run has its own session ID — queries against the wrong session return no results. The selected run is shown in the dropdown at the top of the page.

Reference Files

URL Construction (preferred) and Runtime Injection

This skill ships two assets. Pick the one that fits the step you're on:

• assets/build-url.py — standalone Python CLI. Builds and decodes Logs Explorer URLs without any browser. Use this any time you just need a URL (e.g. to hand to agent-browser open or to paste into a browser). No injection, no DOM, no session needed.

  python3 assets/build-url.py failure \
    --session-id "$SESSION_ID" \
    --property "my-failing-property" \
    --tenant "{tenant}.antithesis.com"
  

  See references/query-builder.md for all subcommands (failure, not-preceded-by, not-followed-by, custom, decode).

• assets/antithesis-query-logs.js — in-page runtime. Inject this on the Logs Explorer page only when you need to interact with the page: click Search, wait for results, read counts/result rows, switch to the Map view, etc. Pure URL construction does not need the runtime.

  cat assets/antithesis-query-logs.js \
    | agent-browser --session "$SESSION" eval --stdin
  

  The runtime registers window.__antithesisQueryLogs. If you get TypeError: Cannot read properties of undefined from a call against it, the runtime has not been injected on the current page — inject first.

Prefer build-url.py whenever you just need a URL. Drop to the in-page runtime only for steps that genuinely have to touch the DOM.

Recommended Workflows

Cascade elimination

1. Get the session ID — either by extracting it from the triage report's "Explore logs" link (python3 assets/build-url.py decode --url "$EXPLORE_LOGS_URL" | jq -r .s) or from any existing Logs Explorer URL.
2. Build a simple failure URL with the Python CLI:

   python3 assets/build-url.py failure \
     --session-id "$SESSION_ID" --property "my-failing-property" \
     --tenant "{tenant}.antithesis.com"
   

3. agent-browser open the URL, inject the runtime, run search, read the count via window.__antithesisQueryLogs.search().
4. Build a temporal URL:

   python3 assets/build-url.py not-preceded-by \
     --session-id "$SESSION_ID" --property "my-failing-property" \
     --pre-field assertion.message --pre-value "suspected-upstream-failure" \
     --tenant "{tenant}.antithesis.com"
   

5. Navigate to it, run search, note the new count.
6. If the count drops, the difference is cascade failures. If it stays the same, the failures are independent.

Failure correlation with event details

1. Search for a property failure
2. Expand the {} details on several results
3. Identify detail fields that vary across results (e.g., configuration modes, feature flags, container names, protocol versions)
4. Note whether failures cluster on a specific detail value — if all failures share a common detail that other passing events do not, that detail is likely part of the root cause

Independent cluster analysis

1. Search for a property failure
2. Switch to the Map tab
3. Count the number of distinct timeline branches with failure dots
4. Failures on the same branch are likely the same root cause
5. Pick one representative from each cluster for investigation

Output

• Event counts (total matches, matches after temporal filtering)
• Event details (timestamp, timeline, assertion details and custom key-value pairs)
• Cluster count from the multiverse map
• Log context around each failure (fault events, preceding operations)