Rubber Duck

Rubber Duck Review

Overview

The classic debugging trope, aimed at hallucination. The main session is the Presenter — it did the work and holds the real reasoning (including the hedges it never wrote down). It reconstructs the topic out loud, in its own words, to a Listener: a spawned subagent pinned to a different-vendor model that has NOT seen the reasoning and interrogates it adversarially. Two forces do the work:

1. The Feynman effect — reconstructing the argument from scratch surfaces the Presenter's own hand-waving before the Listener even replies.
2. An unstaked skeptic — the Listener has no investment in the conclusion, so it catches what the artifact's own self-review rationalized past.

This is a dialogue, not a static-artifact review: the Presenter reconstructs the argument live, and the divergence between the reconstruction and the written artifact is itself a finding.

When to use / when NOT

Use before shipping a findings doc, design, RCA, or investigation you want to be honest — anything where a "confirmed" might be hiding an unproven leap, or a magnitude might be hand-waved. Do NOT use for simple lookups or routine turns: it costs one+ extra model run per round and real Presenter effort. A deliberate, occasional move.

Roles

• Presenter — you, the main session. Reconstructs the topic from understanding (NOT copy-paste), answers the Listener's probes honestly, builds the reconciliation ledger. Ideal: reconstruct before re-reading the artifact, so the divergence between what you believe and what you wrote is genuine; at minimum, articulate in your own words rather than pasting the doc.
• Listener — a spawned subagent. Cross-vendor, large-window, lean. Sees the Presenter's explanation plus the original user request (the ask, for grounding — not the artifact or the reasoning), so it attacks the claims as articulated, which is what exposes explanation-vs-artifact drift. Residual gap: a self-consistent fabrication the Presenter also grounds falsely can survive — the blind Listener bounds overclaim and inconsistency, not a mutually-consistent hallucination.

Procedure (you are the Presenter)

1. Reconstruct — explain the topic in your own words: objective, key observations, the mechanism/claim, the eliminations you ran, and the honest status. Compress to the load-bearing claims (see constraints).
2. Spawn the Listener — ONE spawn_run, model= a large-window model from a different vendor than your own family. task = the Listener charter (below) with your explanation and the original user request (the ask, for grounding) filled in. State the topic neutrally — do NOT signal which claims you think are weak or what you expect it to find; a led listener just mirrors you.
3. Wait for the [Subagent completion event]. Do not answer for it.
4. Answer with evidence, not prose — for each probe, answer by CHECKING a real signal (data, code, source) rather than re-justifying the original wording (re-justifying re-anchors you to the error — CoVe). Concede ONLY when the probe shows a concrete gap or you can't ground the claim; do NOT cave to pushback alone (models frequently reverse a correct answer under mere challenge, absent new evidence). Mark each HELD (survived and grounded) or CONCEDE; a probe you can't ground is itself a finding. In the reconciliation ledger a CONCEDE maps to DOWNGRADED (a weaker-but-true wording exists) or GAP-FLAGGED (the hole needs new evidence).
5. Iterate to convergence — keep running rounds while each surfaces a NEW ungrounded claim, gap, or contradiction. Each round re-spawns the same-model Listener with a distilled transcript (open findings + live probes, not the verbatim dialogue — a raw transcript blows the 5000-char task cap by round 2-3). STOP when a full round yields nothing new and every prior finding is resolved (HELD-grounded, DOWNGRADED, fixed, or logged as an honest OPEN gap). Convergence is the Listener running dry — not you declaring "done" (a Presenter's self-satisfaction is the very blind spot this skill defeats). Safety cap 8 rounds; hitting it unconverged IS a finding — report the unresolved OPEN items. Agreement is never a stop signal; only no new grounded objection is.
6. Reconcile — build the ledger (below) against the ACTUAL artifact and propose edits.

Constraints the live prototype exposed — READ THESE

• Listener must be LEAN + LARGE-WINDOW. Subagents inherit the full injected KiroCrew context (skill descriptions, memory, lessons — not full skill bodies, but still large). A small-window model overflows its context window before it can read your task (a real prototype failure), so pin the Listener to a large-window model from a different vendor than your Presenter's family. Trim the inheritance with spawn_run's three flags: spawn the Listener with include_memory=false and include_lessons=false, because the Presenter's memory and saved lessons are exactly the reasoning the Listener must not have seen. Keep include_project=true when the topic is code in the active project. The Listener is told which groups were withheld, so it flags a gap rather than inventing context.
• Keep the charter + explanation compact. If the topic is large, compress the explanation to its essential claims — do NOT paste the whole artifact, and for a genuinely large topic write it to a file and hand the Listener the path. Compression is a feature: stating the argument in a few hundred words is the rubber-duck effect.
• Cross-vendor is the point. A same-family Listener tends to rationalize the way the Presenter does (same-family models often diverge too, but cross-vendor maximizes failure-mode diversity). Discover the live menu with kiro-cli chat --list-models --format json; prefer large context_window_tokens, pick a different vendor than yours.

Listener charter (the task, {TOPIC_EXPLANATION} filled in)

You are the LISTENER in a "rubber duck review" — an adversarial skeptic. A presenter
explained a topic to you. You have NOT seen their doc or data — only the explanation
and the original ask below. Force honesty by LOCATING defects — name the specific claim, number, or step
that is suspect and say why; do NOT fix or rewrite anything (error-finding, not fixing,
is your job). Judge only factual support and logical validity — ignore length,
formatting, fluency, and confident tone. Separate OBSERVED from INFERRED and challenge
every inference; demand the counterfactual for any causal claim; flag n=1 / single-
sample bases; refuse "confirmed" for anything whose stated objective has not actually
moved in an experiment; attack estimated or hand-waved magnitudes; hunt internal
contradictions (a number in one place that undercuts another). Don't be agreeable. If
something is genuinely solid, say so in one line and move on — spend your effort on the
soft joints.

TOPIC EXPLANATION:
"""
{TOPIC_EXPLANATION}
"""

ORIGINAL USER REQUEST (the ask — for grounding only; NOT the artifact or reasoning):
"""
{ORIGINAL_ASK}
"""

Produce your interrogation, structured EXACTLY as:
1. HARDEST QUESTIONS — ranked numbered list. Each targets a specific claim and states
   what a satisfying answer must contain.
2. SUSPECTED WEAKNESSES — bullets, each tagged with ONE of: [OVERCLAIM] / [GAP] /
   [INCONSISTENCY] / [UNSUPPORTED-MAGNITUDE] / [MISSING-COUNTERFACTUAL] / [SAMPLE-SIZE].
   State the claim and why it's soft.
3. VERDICT — one paragraph: is the presenter's honesty label accurate, or does it still
   overclaim somewhere? Name the single weakest joint that, if it broke, would collapse
   the most of the thesis.
Be concise and surgical. No preamble.

Reconciliation ledger — the Presenter's deliverable

Compare the Listener's findings against the ACTUAL artifact and classify every challenged claim, one row each, with a proposed edit:

• HELD — survives the probe and is grounded; note why the objection fails. A coherent-but-ungrounded claim is NOT held — downgrade or gap-flag it (a fluent explanation must not launder an unsupported claim into HELD).
• DOWNGRADED — overstated; give the corrected, weaker-but-true wording (e.g. "confirmed" → "leading hypothesis"; a p99.9-vs-p99.9 ratio → a paired ratio).
• GAP-FLAGGED — a real hole; say what's missing and whether it's answerable from data on hand vs needs a new experiment.
• CONTRADICTED — internally inconsistent; name both sides.

Edit mode

Propose-only by default. Present the ledger + proposed edits; apply to the artifact only on explicit user confirmation — findings docs are high-stakes, keep the human in the loop. "Apply" mode edits via artifact_update / file write after sign-off.