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The spec is the test

Write down what “good” means, and have an agent taste it — Agent Driven Evaluation. The plan’s deterministic check: steps verify the measurable; for the subtle “is it actually right?” an agent-check: step has an agent taste the live batch with the full probe kit and judge.

— tenet 6

The idea

Section titled “The idea”

A specification that is only prose decays quietly. Nothing executes it, so nothing tells you the day it stops being true.

Every candy here writes its specification as a runnable plan instead — an ordered list of steps, each carrying exactly one intent:

Intent Meaning
run: changes state (the install timeline)
check: an idempotent probe — deterministic, and the mandatory minimum
agent-run: an agent-performed action that may mutate
agent-check: an agent grades the live deployment; an unparseable or timed-out grader fails the step
include: compose another entity’s plan

Two properties make this more than a test suite. First, it is mandatory: every candy must ship a non-empty description: and at least one deterministic check: step, or charly box validate refuses the project. There is no such thing here as a candy nobody can verify.

Second, the plan is baked into the image as an OCI label, so it travels with the artifact. A pulled image can be checked without its source repository — the thing that claims a behaviour also carries the means to test that claim.

The agent-check: steps cover what deterministic probes cannot express — “does the desktop actually render correctly”, “can a client really open a session”. An agent probes the live deployment and judges. That half stays opt-in; the deterministic half never is.

In practice

Section titled “In practice”

The ripgrep candy’s plan is a real one. Note that it does not merely assert the binary exists — it asserts the tool behaves, including the negative case: the binary lands at a fixed path, rg --version reports a parseable version, a present pattern prints the matching line, and an absent pattern exits non-zero.

Run the plan against the built image, in a disposable throwaway container:

Terminal window
charly --repo opencharly/distro-fedora check box tutorial-shell
  PASS  check the rg binary is installed at /usr/bin/rg
  PASS  check rg reports a parseable ripgrep version on stdout  exit=0
  PASS  check rg prints the matching line for a pattern present in piped input  exit=0
  PASS  check rg exits 1 (no match) when the pattern is absent, never matching spuriously  exit=0
  ...
  SKIP  check service=sshd  context [runtime] not active in box mode


24 steps: 19 passed, 0 failed, 5 skipped

Steps marked context: [runtime] skip here by design — a service cannot be running in an image. Run the same plan against a live deployment and they execute, with deploy-time variables (${HOST_PORT:N}, ${VOLUME_PATH:name}) resolved at execution time so one check survives port remaps:

Terminal window
charly check live <deployment>

See also

Section titled “See also”