experiment — pre-registration (proposal) type skill

The LIVE type skill for dispatch_type: experiment. When/whether to dispatch and all universal law — triggers, the human gate, lifecycle, final_approver, exit_reason, the invariants — live in the router (.claude/skills/domainspec-subagents-strategy/SKILL.md); nothing here overrides it. Record/sheet mechanics — the two appends, the appender, validation — and the inline field definitions you actually read live in register-dispatch (.claude/skills/register-dispatch/SKILL.md). Constitution §5 (internal_tools/subagents-dispatch-hooks/constitution/subagents-strategy-constitution-proposal.md) is the upstream authority for those fields only — not a routine read. This skill defines no field; it says what a good experiment dispatch contains.

What this dispatch is — propose, don't run. An experiment dispatch pre-registers a falsifiable experiment: the designer authors a success/failure criterion and the skeptic attacks its internal validity, producing a frozen, validity-checked criterion.md — the experiment proposal. Running the probe and adjudicating survived-vs-falsified is a separate downstream step, not part of this dispatch (the run phase, below). The deliverable here is a proposal good enough to run later and re-adjudicate deterministically — not a result.

The grader is the differentiator (peer, not re-skin)

Experiment is a peer of its siblings because its grader differs, not because its roles are renamed:

Type	Grader
research	coverage / claim ≤ proof
review	severity × flaw-verification over an existing artifact
experiment	falsification against a pre-registered criterion + internal validity + reproducibility

The load-bearing property is pre-registration: the criterion is frozen before the result exists (research is judged after, by coverage). This dispatch owns the pre-registration and the internal-validity + reproducibility-by-design half of the grader; falsification is rendered later, by the run (below). Justify experiment by its grader, never its roles — renamed roles over the same grader is a re-skin, not a type (the vacuity trap).

Roles — experiment semantics over the existing enums (NO new enum values)

This dispatch (propose) uses the first two; the run phase (separate, downstream) uses the last two:

Conceptual role	agents[].role	phase	function / guards against
designer	writer	propose (here)	authors the pre-registered criterion (an artifact) — guards against post-hoc criteria
skeptic	skeptic	propose (here)	attacks internal validity at design time — guards against a criterion that does not test the hypothesis
runner	explorer	run (later)	runs the probe = reasoning/investigation, NOT code execution — produces the raw result
adjudicator	auditor	run (later)	renders the verdict against the frozen criterion — guards against moving the goalposts

A group's function is read off its agents' roles, its workflow position off its connections. A propose dispatch may be as small as one designer (n = 1); a skeptic is added whenever the criterion's validity is worth attacking before freeze (almost always).

Criterion freeze — topology + immutability, never a column

Pre-registration is enforced by topology + the human-gate freeze + immutability, never a schema field:

• The designer authors the criterion and the skeptic attacks it; the criterion lands in working_folder as a durable artifact and is frozen at the P2 human gate — before any run exists. That is what "pre-registered" means here.
• The frozen criterion is read-only downstream: any edit after freeze is a new criterion (re-enters the P2 gate as a fresh proposal), never an in-place mutation. That immutability is what makes "pre-registered" verifiable against an artifact: the criterion file exists and predates any result.
• The criterion lives as the designer's output artifact in working_folder — never a ledger column. The appender rejects success_metric as an unknown key; a criterion column would repeat the vacuity error v0.5.2 killed.
• experiment is a LIVE type, so working_folder is REQUIRED (appender).

The criterion artifact — what criterion.md must contain

The criterion is the designer's frozen output; this is artifact content, not a ledger field (the column boundary above stands). Saying what makes a criterion adjudicable and re-derivable is the skill's job — it defines no field. A good criterion artifact pins, before any run:

• One falsifiable hypothesis — a single claim whose falsifying observation you can name; not two claims joined by "and".
• Non-goals — what the probe explicitly does not test. This is what keeps the hypothesis a single claim, not scope decoration.
• The falsification condition + a mechanical verdict rule — the observable(s) that will decide the outcome and a rule mapping them to a verdict deterministically. The rule resolves only into SURVIVED / FALSIFIED / INVALID — never an execution-status tier (pass/flag/block); that mapping is deferred (Reserved boundary). Structure (a metric, a threshold, a counted shape) is encouraged where it sharpens determinism, but it lives in the artifact — never promoted to a registry column.
• The discrimination check — both outcomes must be informative: state what a SURVIVED and a FALSIFIED each would teach. A criterion only one outcome could ever produce fails the skeptic's non-discrimination axis (below) — fix it at design time, before freeze, not after.
• Pre-registered names/categories — any label, bucket, or category the probe will use, fixed before it sees data; guards against post-hoc naming.

This content is what lets a later adjudicator re-derive the same verdict from the same frozen criterion + result (the reproducibility property below). It is guidance on the artifact, owned here; it adds no field to the sheet or the ledger.

Validity gates — the skeptic's axes (checked at design time, before freeze)

The skeptic attacks the criterion's internal validity before it is frozen — these are design properties, checkable without running anything:

• confounds — a result would be explained by something other than the hypothesis.
• non-discrimination — the criterion would pass/fail regardless of the hypothesis (it does not test the hypothesis).
• reproducibility absent — the verdict would not be deterministically re-derivable from the frozen criterion + a result.

A criterion that nothing could falsify is INVALID by design — it never reaches freeze; it goes back to the designer. Catching this here, before any run, is the whole point of proposing separately from running.

Verdict vocabulary (defined here; SURVIVED/FALSIFIED rendered at run)

verdict	rendered	meaning
INVALID	propose (here)	the skeptic knocked down internal validity — the criterion does not test the hypothesis; redesign before freeze
SURVIVED	run (later)	adjudicated against the frozen criterion — the probe did not falsify the hypothesis
FALSIFIED	run (later)	adjudicated against the frozen criterion — the probe falsified it

This dispatch closes resolved when the final_approver accepts a frozen, validity-checked criterion.md (the proposal is ready to run later). If the skeptic finds the design unfalsifiable, that INVALID outcome is a successful detection — the criterion goes back to the designer, and a re-designed criterion is a new dispatch, not a non-close. SURVIVED/FALSIFIED belong to the later run and never close this dispatch. Contrast: research = GO/…/KILL; review = UPHELD/REFUTED/DOWNGRADED. The verdict vocabulary does not map onto execution-status (pass/flag/block) — that cross-project unification is deferred (Arcanum F1).

Canonical shape (v0.6.0 chassis)

This dispatch (propose) — designer authors, skeptic attacks, criterion frozen at the P2 gate:

designer ◀──zig-zag──▶ skeptic   ⇒  frozen criterion.md

The skeptic checks validity in zig-zag (or parallel) with the designer; zig-zag/feedback carry loop_cap. A feedback back-edge is conditional (P6) — here, when the skeptic's validity attack means the criterion must be re-designed before freeze. A bare n = 1 designer (no skeptic) is allowed for a trivial pre-registration but forgoes the design-time validity check.

The run is a separate downstream dispatch (not authored here): it consumes the frozen criterion.md read-only and renders SURVIVED/FALSIFIED.

(later, separate)  runner ──sequential──▶ adjudicator   ⇒  experiment.md + findings.md

Reserved boundary (state it; do not block on it)

• The run phase is downstream — this skill stops at the frozen proposal. How the run is dispatched (a follow-up run step, manual, or a future runner) is out of scope here.
• The code-execution runner is RESERVED — gated on the code type landing with an execution substrate. A run needing to execute code waits for code LIVE; the narrow run is reasoning/investigation over artifacts, not code execution.
• Reproducibility = deterministic RE-ADJUDICATION — another agent, same frozen criterion + result, reaches the same verdict — NOT re-execution. The criterion artifact is authored here to make that possible later.

Inherited rule (cited, not invented)

final_approver may never sit in a working group (constitution P12 / §5). In the propose dispatch the designer and skeptic are working-group members, so neither may double as final_approver — use parent or a dedicated approver group (its single agent's role is auditor). The same rule binds the run's adjudicator later.

Outputs (P9 pattern, experiment flavor)

This dispatch (propose) produces one artifact in working_folder:

• criterion.md — the frozen, validity-checked pre-registration (the content above). This is the dispatch's deliverable. With a skeptic in the loop, criterion.md records that it passed the design-time validity gates (or carries the INVALID finding that sent it back for redesign).

The later run (separate dispatch) produces the other two, against the frozen criterion.md:

• experiment.md — the runner's probe + raw result, persisted verbatim.
• findings.md — the adjudication: every load-bearing verdict citing the criterion + result it rests on, ending in SURVIVED/FALSIFIED.

The requirement is the FILES, not who writes them. Append/close mechanics are register-dispatch's — do not restate them here.

Names

Draw agent_name from telemetry/agents/agent-pool.yaml (ordered role_fit). Falsification fits the philosophy-of-science figures: Popper, Lakatos, Hume, Feyerabend, Kuhn (role_fit: [skeptic, writer]) for this dispatch's skeptic/designer; primary-role_fit explorers for the run's runner; an auditor fit (Vlachopulos, Loregian, Brandenburg) for the run's adjudicator. Never reuse a name within one dispatch; never invent one — and the skeptic that attacks validity is never the designer whose criterion it attacks (P12's spirit at agent scale).