Dune/docs/PLANETOLOGIST_RULES.md

Planetologist rule contract

Updated 13 September 2026. This note audits the movement and battle effects of the Planetologist Leader Skill against its physical card, the common Leader Skills rules, the GF9 base battle rules and designer Jack Reda's walkthrough. The connected prototype is described below; other Leader Skill effects remain separate work.

Printed effect and legal card role

The physical Planetologist card instructs its owner to reveal one green Special card, other than a Cheap Hero, as part of the Battle Plan “in place of a weapon.” It adds 2 to that skilled leader disc and says to discard the Special after the battle. The card therefore creates a distinct legal role for the physical Special card:

• it occupies the Battle Plan's weapon slot;
• it is revealed as a Special used in place of a weapon, rather than converted into a Weapon Treachery Card;
• it supplies no projectile, poison, lasgun or other attack and does not satisfy a skill or rule that requires an actual named Weapon type;
• its printed utility effect is not activated; and
• the exact physical card is committed to that plan and cannot also be spent for its ordinary effect, Karama, Truthtrance or another pending use.

The designer gives Hajr and Thumper as examples, then specifically describes using Family Atomics for +2 without blowing the Shield Wall. This confirms that Planetologist grants an alternate battle use despite the Special card's ordinary phase or trigger. Jack Reda walkthrough, 10:36–11:05

The substitution is available only when the assigned Planetologist leader is the leader actually used in the Battle Plan. Moving the skilled leader and skill card behind the shield as a bluff, then selecting another leader, turns off both skill bands. The other leader cannot place a green Special in the weapon slot through Planetologist. GF9 CHOAM & Richese rulebook, p. 9

Current base-deck inventory

The current 33-card base deck contains these eligible printed green Special cards:

Printed card	Physical copies	Current identities
Family Atomics	1	effect: atomics
Weather Control	1	effect: weather
Hajr	1	effect: hajr
Tleilaxu Ghola	1	effect: ghola
Harvester	1	effect: harvester
Karama	2	effect: karama
Truthtrance	2	effect: truthtrance

All nine physical copies may take the Planetologist weapon-slot role. Their ordinary timing does not need to be legal because that printed effect is not being played. A pending or already committed physical card remains unavailable because Planetologist does not create a second copy.

Cheap Hero and Cheap Heroine are printed green Special components but are excluded. “Cheap Hero” is the rules' generic component class for both named copies; each instead occupies the leader position with strength zero. The base FAQ also says a Cheap Hero cannot substitute for a weapon or defense. GF9 base rulebook and Q&A, pp. 10, 23

For today's baseDeck(), kind === 'special' happens to select the nine eligible non-Hero copies. That coincidence is not the printed rule. Eligibility should be bound to a canonical printed-green-Special classification or explicit physical identities, because the code's generic special kind is also used by later expansion modules. The designer's Thumper example proves that expansion cards can qualify, but it does not make every future card encoded as special green or eligible.

Survival and scoring

The common Leader Skills rule says a skill applies in the current battle unless its assigned leader is killed in that battle. Planetologist adds 2 to the leader disc, so the receipt is conditional on that exact leader surviving weapon, traitor and explosion resolution. If the leader dies, neither its printed strength nor the Planetologist +2 contributes to the battle total. GF9 CHOAM & Richese rulebook, p. 9

A captured skilled leader follows the expansion's general Harkonnen Q&A: the captor has only the lower battle band and only while actually using that captured leader. A surviving captured Planetologist may therefore use the same green-Special substitution and +2; the original faction has no normal movement band while the leader and skill are captured.

Mandatory discard

The Special card's own final instruction is unconditional once it is revealed through this substitution: discard it after the battle. This is more specific than the base rule allowing an ordinary winner to keep cards played in its plan. The physical outcome is:

Battle outcome	Planetologist Special disposition
Ordinary win	Discard; the winner has no retention choice for this card.
Ordinary loss	Discard under both the base loser rule and the skill card.
Opponent reveals the Planetologist leader as a traitor	Discard with the traitored player's played cards; the leader dies and supplies no +2.
Both leaders are traitors	Discard with the played cards; the Planetologist leader dies and supplies no +2.
Lasgun–shield explosion	Discard after the battle; a killed Planetologist supplies no +2.
Planetologist owner reveals the opposing leader as a traitor	Discard under Planetologist's later, card-specific instruction even though the base traitor winner ordinarily loses nothing.

The last row is a rules-specificity inference. No located publisher Q&A asks about Planetologist versus a successful traitor call. The physical Leader Skill plainly says to discard after the battle and prints no winner or traitor exception, so retaining it would require adding an exception absent from the later card. The GF9 November 2020 FAQ confirms the general winner-retention rule, while the Planetologist card supplies the narrower override.

“Unused bluff” needs a physical distinction. A green Special actually revealed in the weapon slot through Planetologist has been used in that alternate role and is discarded even when +2 cannot affect the result or the winner is decided by a traitor. A Special merely carried behind the shield but omitted from the Battle Plan remains in hand; no rule reveals or discards it. A plan using a different leader cannot legally commit the Special in Planetologist's role.

Persistent evidence

The source archive at /home/quintine/.local/share/dune/sources contains:

• leader-skills-tabletopfinder-all-upscaled.png, on which the complete Planetologist face is readable;
• leader-skills-designer-video-auto-transcript.txt, with the Planetologist explanation at transcript seconds 594–666;
• choam-richese-rulebook-en.pdf and its layout-preserving text extraction; and
• dune-rulebook-gf9-mirror.pdf and its extraction, preserving the common battle disposition and traitor rules.

The designer's official expansion page links the GF9 rulebook. The full local source hashes and retrieval URLs are recorded in leader-skills-source-provenance.txt.

Implementation boundary

A focused implementation can expose the nine base physical copies as weapon slot choices only for the selected, concealed Planetologist leader. It should record the selected physical identity and alternate role in the sealed plan, apply +2 only after confirming that leader survives, suppress the card's native effect, and force exactly one discard after every revealed outcome. Rejected or canceled plan changes must release the reservation without discarding the card.

Expansion eligibility should be added from each component's printed category, not inferred from the shared TypeScript special bucket. The traitor-winner discard row should remain documented as the explicit later-card reading because the sources contain no direct Q&A for that collision.

Normal movement and supported prototype

The first band gives a choice for one movement: add one to normal range with a maximum of three, or gather physical forces from exactly two different territories to one shared destination using each group's ordinary range. These alternatives do not stack. Moving multiple selected sectors of the same territory remains one origin. Both groups retain normal storm, path, occupancy and force-selection rules; the combined move spends one movement. Hajr can provide another normal movement. See the physical-card contract and the designer's example.

Fremen's native range and Planetologist are independent. With the range alternative, a distance-two move needs only ordinary range one plus Planetologist. Distance three without city ornithopters uses the Fremen advantage and opens its real Karama response. Cancellation leaves forces and the movement opportunity in place; the replacement may still use Planetologist. A gather using Fremen range two also retains that response, with both origins saved and revalidated before continuation. This applies the existing cancellation contract, not a new phase-wide restriction or an automatic shortened destination.

The November 2020 FAQ, p. 4 and base rules, p. 18 determine a common Bene Gesserit arrival stance when no other faction is present, or when existing BG forces determine the stance. The prototype supports mixed advisor/fighter origins in those cases, and uniform origins generally. Source advisor locks carry forward. Mixed origins entering an enemy-only territory need a combined advisor-flip/cancellation continuation and remain explicitly guarded; this is an implementation gap, not a rule that forbids every mixed move. No source was found granting a chosen group order that makes fighters arrive as advisors.

The current runtime supports only the six base factions and the nine base green Special copies above. Expansion rosters, other optional modules, No-Field and Discovery/Richese flight combinations remain gated. Before enabling Ix, calculate range for each selected origin's own cyborgs and extend its cancellation trigger for Planetologist's added range. Aggregate elite counts must not lend one group's cyborg speed to a separate suboid-only origin. The expansion green-Special inventory must also be audited before admitting those physical cards.

The movement control builds ordinary authoritative actions with an explicit range or gather choice. Bots use the same range helper and submit physical source/elite counts. Saved Fremen continuations bind the selected skill leader, choice and exact two-origin list; stale custody or receipts reject before spending a response card. The weapon selector exposes eligible Specials only for the selected skilled leader and explains +2 and mandatory discard. Bot candidates use that same eligibility and pair validation. This is a connected prototype with partial combination coverage, not complete Leader Skills compliance or a publication gate.

Verification evidence, 13 September 2026

The final focused union passes 84 cases, including the 24-case Planetologist union and existing skills, Fremen cancellation and battle quote regressions. Independent movement and battle review closed after the stale already-dead disc reproducer was fixed. First-choice tests prove all four bot profiles actually use both alternatives in suitable fixtures. Two source-bound full-game samples finish with zero rejected actions and six saved restorations each; Basic executes both movement choices, Advanced executes boosted range. These do not establish full combination acceptance or calibrated difficulty ordering.

The browser journey verifies genuine setup, range availability, physical gather, private refresh and the weapon selector's Special role. A separately staged battle in that new QA room verifies traitor-loss cleanup, one Special discard, skill death return and the unchanged Shield Wall. The checkpoint record separates those fixtures from the complete-game samples. Required broad check results, source fingerprints and saved-game comparisons are retained privately outside the checkout and reported in the verified commit.