mcpbeat

E2e Audit

datadog/e2e-audit

Judge whether Agent behavior belongs in a new-e2e, integration, or unit test

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on the repository, not the skill itself

Install

one command, takes just this skill from the repository
npx skills add https://github.com/DataDog/datadog-agent --skill e2e-audit

The instruction itself

10 sections, as written by the author

Decide whether assertions about proposed or existing Agent behavior belong in

a full new-e2e test, an integration test, or a unit test. Produce only a

verdict and rationale. Never edit, move, or delete tests.

Principle

Analyze observable claims and failure modes, not entire test files or individual

assert or require calls. Group checks that validate the same contract as one

assertion, including implicit claims such as successful installation, startup,

or command execution.

Choose the cheapest test that preserves the boundary and failure mode that

matter. Do not ask only whether an assertion *can* be made with mocks; ask what

the assertion would stop validating if its dependencies were replaced.

E2E justified

Use new-e2e when the deployed Agent or its real environment is part of the

behavior being validated. This includes boundaries such as:

  • installation, packaging, permissions, or merged deployed configuration;
  • process or service lifecycle, cross-process communication, or CLI behavior

that depends on the running Agent;

  • kernel, operating-system, cloud, container-orchestrator, or network behavior

that cannot be represented faithfully by a local dependency;

  • user-visible data reaching fakeintake when the Agent's real assembly,

configuration, encoding, or forwarding path is material to the test.

A behavior is not E2E-worthy merely because the current test reaches it through

SSH, a CLI, or remote infrastructure. If those layers add no relevant coverage,

use a lower-level test.

Should be an integration test

Use an integration test when the important boundary can be preserved locally,

for example by wiring components with fx.Test, using a local fakeintake, or

using a real local daemon, driver, or hardware dependency. A real local

dependency does not by itself require new-e2e.

Should be a unit test

Use a unit test when the behavior is isolated logic and does not require a real

component graph, process, or external dependency.

Layered coverage and residual E2E value

Duplicating an E2E assertion in a unit or integration test is useful when the

lower-level test preserves its failure mode: it provides faster PR feedback,

more deterministic failures, and easier debugging. Do not treat this useful

duplication as waste by itself.

After identifying lower-level coverage, reevaluate what the E2E test uniquely

validates. Repeating the same assertion through the deployed Agent can still be

valuable when it catches assembly, configuration, packaging, lifecycle, or

forwarding failures that the lower-level test cannot. If nearly all material

assertions have equivalent lower-level coverage and the E2E test preserves no

meaningful additional boundary, its feedback no longer justifies its

provisioning, runtime, and maintenance cost; recommend removing it. Base this

decision on residual failure coverage, not only the number of duplicated

assertions.

Procedure

Proposed behavior

  • List the observable claims that the proposed test would assert.
  • For each assertion, state the failure it is intended to catch.
  • Identify the smallest environment that preserves each failure mode.
  • Classify each assertion. If E2E is justified, name the real boundary that

would be lost in a lower-level test.

  • Give an overall verdict based on the assertion requiring the broadest real

boundary.

If the description does not establish the relevant assertions or boundaries,

ask for the missing information or return an explicitly uncertain verdict.

Existing tests

  • Resolve every concrete suite. For directories, find all *_test.go files.

Follow shared suites, setup code, helpers, and provisioners rather than

judging files in isolation.

  • Read each test and subtest, including setup, gating, environment updates,

and cleanup. Inspect the production code it exercises before deciding that

an assertion can be tested at a lower level.

  • Inventory the observable claims in each test. Include implicit claims from

setup and lifecycle operations, and group checks that cover the same

contract.

  • For each assertion, state the failure it catches, identify the smallest

environment that preserves that failure, note equivalent lower-level

coverage, and classify it using the principle above.

  • Give the suite-level verdict:
  • If any assertion needs the deployed Agent boundary, the suite remains E2E;

name the assertion and boundary that determine this verdict.

  • If none does, recommend an integration or unit test as appropriate.
  • Recommend duplicating suitable assertions at a lower level when that would

provide faster PR feedback, more deterministic failures, or easier

debugging, even if the suite initially remains E2E.

  • After accounting for that lower-level coverage, identify the failure modes

and real boundaries that only the E2E test preserves. If nearly all material

assertions are duplicated and no meaningful E2E-only boundary remains,

recommend removing the E2E test. Weigh its residual value against runtime,

provisioning, flakiness, and maintenance cost; do not assume all cost is

paid only once at suite setup.

  • When reviewing several suites, briefly note redundant provisioners or

equivalent coverage that could be consolidated.

For large reviews, inspect files in parallel if possible, then verify and

synthesize the results.

Output

Use one of these verdicts:

  • E2E justified
  • Should be an integration test
  • Should be a unit test

For proposed behavior, classify each expected assertion and return an overall

verdict with a short reason. For existing tests, classify each material

assertion and return one verdict per concrete suite, naming the assertion and

boundary that determine it. State what the E2E test uniquely validates after

accounting for lower-level coverage, or say that no material E2E-only boundary

remains. When several assertions differ, use a concise table with these

columns: assertion, failure caught, smallest environment, and classification.

Add only material uncertainty, lower-level candidates, or consolidation

opportunities.

Examples

Input: Verify that installing the Agent package creates a running service

with the expected permissions and that data reaches fakeintake after a reboot.

Output: E2E justified — The package installation, service lifecycle,

permissions, reboot, and forwarding path are the behavior under test; a

lower-level test would not preserve those deployed-system boundaries.

Input: Verify that the assembled Agent components transform a payload and

send it to a local fakeintake.

Output: Should be an integration test — A locally assembled component

graph and fakeintake preserve the component wiring and payload boundary without

provisioning remote infrastructure.

Input: Verify that the configuration parser rejects a negative timeout and

applies the default when the field is absent.

Output: Should be a unit test — This is isolated parsing and validation

logic that does not require a real component graph, process, or external

dependency.

Do not propose implementation changes unless the user asks for them.

How to use it

Copy the folder

Take datadog/e2e-audit from the repository into ~/.claude/skills for personal use, or into .claude/skills inside a project.

Check the name does not clash

The agent identifies a skill by the name field in its header. Two skills with the same name cannot sit side by side — one of them will be ignored.