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Official agent skill

Extending Personhog Test Harness

by PostHog in PostHog/posthog

When and how to add scenarios, chaos events, and invariants to the personhog e2e test harness (rust/personhog-test-harness).

OfficialCustom licenceAuto-check passedTesting & QA

Install Extending Personhog Test Harness

skills CLI
$ npx skills add PostHog/posthog --skill extending-personhog-test-harness -a claude-code

Project install by default; add -g for ~/.claude/skills/.

GitHub CLI
$ gh skill install PostHog/posthog extending-personhog-test-harness --agent claude-code

Project scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).

Manual copy
$ git clone --depth 1 https://github.com/PostHog/posthog.git skills-src && mkdir -p .claude/skills && cp -r skills-src/.agents/skills/extending-personhog-test-harness .claude/skills/extending-personhog-test-harness && rm -rf skills-src

Use ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.

Claude Code skills documentation · loads skills from .claude/skills/

Facts

Skill name
extending-personhog-test-harness
GitHub stars
40k
Token cost
~1.2k tokens
SKILL.md length
584 words
Files
1
Skills in repo
254
Repo updated
First seen
Licence
Custom licence

At a glance

When and how to add scenarios, chaos events, and invariants to the personhog e2e test harness (rust/personhog-test-harness).

  • Works in 6 steps: Add the stack primitive if the… → Add the GateArgs flag, the ChaosEvent… → Guard invalid combinations in gate.rs… → …
  • Terms: personhog gate
  • SKILL.md covers When to add a scenario, Where things live, Adding a chaos scenario and Validating a fix with the…
  • Calls cargo

What it does

Extending Personhog Test Harness is an agent skill from PostHog/posthog, published by the product's own GitHub organization. When and how to add scenarios, chaos events, and invariants to the personhog e2e test harness (rust/personhog-test-harness). Use after fixing a bug or regression in the personhog leader path (leader, router, writer, replica, coordination protocol) so the fix gets a permanent regression scenario; when adding a new failure mode to test (crashes, drains, zombies, lag, failover); or when a new correctness property needs asserting during runs. Trigger terms: personhog gate, chaos scenario, test harness, leader path…

Its SKILL.md is about 1.2k tokens, which your agent loads only when the skill is triggered. It is a single SKILL.md file with no bundled scripts.

It sits in Testing & QA, covering Backup and disaster recovery and End-to-end testing. It works with Rust. The repository describes itself as: :hedgehog: PostHog is the leading platform for building self-driving products. Our developer tools – AI observability, analytics, session replay, flags, experiments, error…

When your agent uses it

  • Terms: personhog gate
  • Leader path regression

Example prompts

  • “/extending-personhog-test-harness”

Requirements

  • Docker

Workflow steps

6 steps, taken from the first numbered list in SKILL.md.

  1. Add the stack primitive if the disruption is new (prefer process signals
  2. Add the GateArgs flag, the ChaosEvent variant, and its
  3. Guard invalid combinations in gate.rs with an early bail! (for example,
  4. Rehearse locally until deterministic — three consecutive green runs is the
  5. Only failed-but-unacked requests are tolerable during chaos; the invariant
  6. Add the scenario to the personhog-gate CI job in

What it can do on your machine

Read from SKILL.md and the folder at commit c012c8d. It shows what the files ask for, not the result of running them.

  • Tool permissions

    Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.

    From allowed-tools in the SKILL.md frontmatter.

  • Runs code

    Shell commands in SKILL.md call:

    • cargo

    From the folder's file list and the shell code blocks in SKILL.md.

  • Network

    No URLs in SKILL.md.

    From URLs in SKILL.md, links to its own repository left out.

  • Credentials

    Names no API keys, tokens, secrets or passwords.

    From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

Context cost

Extending Personhog Test Harness loads about 1.2k tokens when it runs. Until then it costs about 152 tokens; SKILL.md has 584 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it
~152
When it runs · the whole SKILL.md, loaded when a task matches
~1.2k

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

Auto-check passed

The automated check found no risky patterns in SKILL.md.

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.

SKILL.md

Its licence (Custom licence) doesn't allow us to republish the file, so here is its outline and opening line. It has 584 words (~1,249 tokens).

“The harness (rust/personhog-test-harness/, see its README for usage) spawns a real personhog stack and asserts one invariant three ways: every acked write is visible afterwards — live via read-your-write probers, at end-of-run via strong reads, and durably via Postgres at…”

— opening of SKILL.md by PostHog, Custom licence
name
extending-personhog-test-harness

Read the full SKILL.md on GitHub

Files

Just SKILL.md in .agents/skills/extending-personhog-test-harness of PostHog/posthog.

Open the folder on GitHubat commit c012c8d

Used in 1 other repository

We found 1 copy of this SKILL.md (exact, near-identical or edited) in other folders. This page covers the copy in PostHog/posthog, which our catalogue first saw on October 7, 2026.

Compare with similar skills

Extending Personhog Test Harness next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.

Extending Personhog Test Harness compared with similar skills
SkillStarsUsed inTokensAuto-checkLicenceRepo updated
Extending Personhog Test Harness this skillPostHog/posthog40k—~1.2kAutomated safety check: PassCustom licence
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Warp Integration Test Videowarpdotdev/warp65k1 repos~2.6kAutomated safety check: PassAGPL-3.0
Hydra Devstreamband/hydra-srt147—~995Automated safety check: PassApache-2.0
Desktop App Driving with Reticlereticlehq/reticle1.2k—~1.3kAutomated safety check: PassApache-2.0
Test Specialisttravisjneuman/.claude100—~3.7kAutomated safety check: PassMIT

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Works with

Categories

Questions about Extending Personhog Test Harness

What does Extending Personhog Test Harness do?

When and how to add scenarios, chaos events, and invariants to the personhog e2e test harness (rust/personhog-test-harness). Extending Personhog Test Harness is an agent skill from PostHog/posthog, published by the product's own GitHub organization. When and how to add scenarios, chaos events, and invariants to the personhog e2e test harness (rust/personhog-test-harness).

When should I use Extending Personhog Test Harness?

Extending Personhog Test Harness fits situations like: terms: personhog gate; leader path regression.

How do I install Extending Personhog Test Harness in Claude Code?

Run `npx skills add PostHog/posthog --skill extending-personhog-test-harness -a claude-code`. Or copy the skill folder (.agents/skills/extending-personhog-test-harness in PostHog/posthog) into .claude/skills/extending-personhog-test-harness in your project. Claude Code loads it when a task matches its description.

How do I install Extending Personhog Test Harness in Codex?

Run `npx skills add PostHog/posthog --skill extending-personhog-test-harness -a codex`. Or copy the skill folder (.agents/skills/extending-personhog-test-harness in PostHog/posthog) into .agents/skills/extending-personhog-test-harness in your project. Codex loads it when a task matches its description.

Can I use Extending Personhog Test Harness in Cursor, Gemini CLI or GitHub Copilot?

Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add PostHog/posthog --skill extending-personhog-test-harness -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/extending-personhog-test-harness, .gemini/skills/extending-personhog-test-harness, .github/skills/extending-personhog-test-harness and .opencode/skills/extending-personhog-test-harness in your project.

What does Extending Personhog Test Harness need to run?

Going by SKILL.md and its folder, Extending Personhog Test Harness needs the command-line tools its instructions call (cargo). Our summary lists: Docker.

Does Extending Personhog Test Harness access the network?

SKILL.md contains no URLs. Any network use would come from the scripts or tools the agent runs. This is read from the text; nothing was executed.

Is Extending Personhog Test Harness safe to install?

Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. Review the folder before installing.

What licence does Extending Personhog Test Harness use?

Extending Personhog Test Harness has a licence file (the repository's licence) that doesn't match a standard licence. Read it on GitHub before reusing the skill.

How many tokens does Extending Personhog Test Harness use?

About 1.2k tokens (SKILL.md is roughly 5k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full.

What are the alternatives to Extending Personhog Test Harness?

Skills that share tags, products or a category with Extending Personhog Test Harness: Kaniop Development (pando85/kaniop, 132 stars), Warp Integration Test Video (warpdotdev/warp, 65k stars), Hydra Dev (streamband/hydra-srt, 147 stars) and Desktop App Driving with Reticle (reticlehq/reticle, 1.2k stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.

Who maintains Extending Personhog Test Harness?

PostHog (a GitHub organization, an official publisher) maintains it in PostHog/posthog, which has 40,209 GitHub stars. The repository holds 254 skills in this directory. The repository was last updated on October 10, 2026.

Source: PostHog/posthog on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.