name: antithesis-research description: > Analyze a codebase to figure out how it should be tested with Antithesis: map the system, identify failure-prone areas and testable properties, and produce the research artifacts needed for workload and environment planning. metadata: version: "2026-04-29 1cd5f5a"

Antithesis Research

Purpose and Goal

Research a target system and produce scratchbook artifacts that unblock the rest of the workflow. Success means:

antithesis/scratchbook/sut-analysis.md captures architecture, state, concurrency, and failure-prone areas
antithesis/scratchbook/property-catalog.md lists concrete, testable properties with priorities
antithesis/scratchbook/deployment-topology.md describes the minimal useful container topology
antithesis/scratchbook/properties/{slug}.md captures per-property evidence trails and context
antithesis/scratchbook/property-relationships.md maps suspected clusters and connections between properties
antithesis/scratchbook/evaluation/synthesis.md records categorized evaluation findings and actions taken

Prerequisites and Scoping

Start from the repo, checked-in docs, and existing scratchbook files first. Ask the user only for blockers or scoping decisions you cannot infer safely, such as:

The repo or codebase location, if it is not already clear
Which subsystem or component matters most, if the work is narrower than the whole repo
Known incidents, closed bugs, or specific failure modes worth targeting
External documentation, issue trackers, or design docs not present in the repo

If scratchbook artifacts already exist, treat them as inputs and extend them instead of rewriting them unless the user asks for a fresh pass.

Definitions and Concepts

SUT: System under test.
Workload: A synthetic workload designed to exercise the target system
Safety property (correctness): A bad thing never happens
Liveness property (progress): A good thing eventually happens
Reachability property: A code path or behavior is reachable or unreachable
Test Template: A directory of test commands located at /opt/antithesis/test/v1/{name}/. There may be more than one test template. Each timeline executes commands from a single test template. Files or subdirectories prefixed with helper_ are ignored by Antithesis.
Test Command: An executable file in a Test Template with a valid prefix. Valid prefixes: parallel_driver_, singleton_driver_, serial_driver_, first_, eventually_, finally_, anytime_
Timeline: A single linear execution of the target system and workload. Antithesis runs many timelines in parallel and branches them to search for interesting behaviors.

Documentation Grounding

Use the antithesis-documentation skill to ground Antithesis-specific terminology and implementation advice.

Properties and assertions: https://antithesis.com/docs/properties_assertions/assertions.md
Sometimes assertions: https://antithesis.com/docs/best_practices/sometimes_assertions/
Define test properties: https://antithesis.com/docs/using_antithesis/sdk/define_test_properties/
SDK runtime modes and production behavior: https://antithesis.com/docs/using_antithesis/sdk/
Optimize for testing: https://antithesis.com/docs/best_practices/optimizing.md

Reference Files

Reference	When to read
`references/scratchbook-setup.md`	Always — read first to initialize the workspace
`references/sut-discovery.md`	Discovering system characteristics through structured attention focuses
`references/sut-analysis.md`	General methodology for analyzing the codebase and understanding components
`references/property-discovery.md`	Discovering properties through structured attention focuses
`references/property-catalog.md`	Format and methodology for documenting properties
`references/faults.md`	Understanding fault types, quiet periods, and process fault availability
`references/deployment-topology.md`	Designing the container topology for Antithesis
`references/property-evaluation.md`	Evaluating the property catalog as a portfolio

Recommended Workflows

Full research pass (new project)

Read references/scratchbook-setup.md
Read references/sut-discovery.md and references/sut-analysis.md
Analyze the system using the ensemble or single-agent workflow from references/sut-discovery.md
Scan the codebase for existing Antithesis SDK assertions. Search for imports of the Antithesis SDK and calls to assertion functions (assert_always!, assert_sometimes!, assert_reachable!, assert_unreachable!, or their non-macro equivalents). For each assertion found, record the file path, line number, assertion type, and message string. Write the results to antithesis/scratchbook/existing-assertions.md. If no assertions are found, write the file with a note confirming the codebase has no existing instrumentation.
Read references/property-discovery.md and references/property-catalog.md
Discover properties using the ensemble or single-agent workflow from references/property-discovery.md
Read references/deployment-topology.md
Design the deployment topology and write it to antithesis/scratchbook/deployment-topology.md
Read references/property-evaluation.md
Evaluate the property catalog using the ensemble or single-agent workflow from references/property-evaluation.md
Address evaluation findings: apply refinements, fill gaps, escalate biases to the user
Write or update all remaining findings in the scratchbook under antithesis/scratchbook/

Targeted property research

Read references/sut-discovery.md and references/sut-analysis.md if the system model is missing or stale
Read references/property-discovery.md and references/property-catalog.md
Discover properties using the ensemble or single-agent workflow from references/property-discovery.md
Turn claimed guarantees, incidents, and bug reports into explicit properties, and choose the Antithesis assertion type that matches each one
Update antithesis/scratchbook/property-catalog.md and record assumptions or open questions
Write evidence files for new properties to antithesis/scratchbook/properties/{slug}.md
Update antithesis/scratchbook/property-relationships.md with any new clusters or connections
Read references/property-evaluation.md
Evaluate the updated property catalog using the ensemble or single-agent workflow from references/property-evaluation.md
Address evaluation findings: apply refinements, fill gaps, escalate biases to the user

Property expansion (after triage)

Read references/property-discovery.md and references/property-catalog.md
Review triage findings from the antithesis-triage skill
Use the attention focuses from references/property-discovery.md to look for new properties inspired by triage findings
Update the relevant files in the scratchbook
Write evidence files for new properties to antithesis/scratchbook/properties/{slug}.md
Update antithesis/scratchbook/property-relationships.md with any new clusters or connections
If the expansion is substantial (a new category of properties or more than 3 new properties), read references/property-evaluation.md and evaluate the updated catalog. Small expansions of 1-3 properties in existing categories do not require a full evaluation pass.

General Guidance

Prefer specific, checkable guarantees over vague goals like "test failover"
If the system claims a guarantee in docs, comments, or issues, try to make it a property
Record not just the invariant, but why the chosen Antithesis assertion type is the right semantic fit for that property
Use Sometimes(cond) for liveness or non-trivial semantic states, not for invariants that must hold on every evaluation and not as a substitute for Reachable(...)
Identify where surgical SUT-side assertions would give materially better search guidance than workload-only checks, especially for rare, dangerous, timing-sensitive, or externally invisible states
Remember that Antithesis SDK assertions do not crash the program on failure; they are intended to be safe in production code and usually become low-overhead fallbacks or no-ops outside Antithesis
Focus on timing-sensitive, concurrency-sensitive, and partial-failure scenarios where Antithesis is strongest
Keep the deployment topology minimal; every extra container expands state space
Write down assumptions and open questions in the scratchbook instead of keeping them implicit
If only part of the research is requested, still update the relevant scratchbook files and note what remains undone

Output

antithesis/scratchbook/sut-analysis.md
antithesis/scratchbook/existing-assertions.md
antithesis/scratchbook/property-catalog.md
antithesis/scratchbook/deployment-topology.md
antithesis/scratchbook/property-relationships.md
antithesis/scratchbook/properties/{slug}.md (one per cataloged property)
antithesis/scratchbook/evaluation/synthesis.md
antithesis/scratchbook/evaluation/{lens}.md (one per evaluation lens)

These outputs should be concrete enough for the antithesis-setup skill and the antithesis-workload skill to use directly.

Self-Review

Before declaring this skill complete, review your work against the criteria below. If your agent supports spawning sub-agents, create a new agent with fresh context to perform this review — give it the path to this skill file and have it read all output artifacts. A fresh-context reviewer catches blind spots that in-context review misses. If your agent does not support sub-agents, perform the review yourself: re-read the success criteria at the top of this file, then systematically check each item below against your actual output.

Review criteria:

antithesis/scratchbook/sut-analysis.md exists and covers architecture, state management, concurrency model, and failure-prone areas
antithesis/scratchbook/existing-assertions.md exists and lists all Antithesis SDK assertions found in the codebase (or explicitly states none were found)
Evidence files correctly distinguish between instrumentation that already exists in the codebase, instrumentation that is partially present, and instrumentation that is missing — no evidence file suggests adding an assertion that is already there
antithesis/scratchbook/property-catalog.md exists, has provenance frontmatter (commit and updated), and lists concrete, testable properties — not vague goals like "test failover"
Each property has a descriptive kebab-case slug as its canonical ID
Each property has a priority and a rationale for its chosen Antithesis assertion type (Always, Sometimes, Reachable, etc.)
Properties that need internal branch guidance or replay anchors call out likely SUT-side instrumentation points, not just workload-visible checks
antithesis/scratchbook/deployment-topology.md exists and describes a minimal container topology — every container is justified
Every cataloged property has a corresponding evidence file at antithesis/scratchbook/properties/{slug}.md that captures the evidence trail, relevant code paths, and key observations
Open questions in evidence files have been investigated and resolved — no unresolved questions remain in evidence files for active properties
Properties invalidated by investigation are marked in the catalog with the reason
antithesis/scratchbook/property-relationships.md exists and groups related properties into clusters with brief notes on suspected connections and dominance
Every property slug referenced in property-relationships.md corresponds to a property in the catalog
Properties focus on timing-sensitive, concurrency-sensitive, and partial-failure scenarios where Antithesis is strongest
Claimed guarantees from docs, comments, or issues are represented as properties
Property evaluation was performed: antithesis/scratchbook/evaluation/synthesis.md exists with categorized findings
Evaluation refinements have been applied to the catalog
Evaluation gaps have been filled via targeted discovery, and the resulting properties are in the catalog with evidence files
Evaluation biases (if any) have been presented to the user with supporting evidence
The outputs are concrete enough for antithesis-setup and antithesis-workload to use directly — no ambiguous steps or missing details