SRD Skills as World Operators

Gameplay as Graph Mutation describes the design lens: every meaningful action resolves to a defined effect on the world. This page applies that lens to the SRD skill catalog — what shape of effect each skill produces, and which target types it operates on.

The four shapes are the same as in the operator-lens page: reads project a typed slice of the world back to the player, soft writes apply session-bounded overlays, hard writes commit durable changes, and concealments temporarily hide otherwise-visible facts.

The same skill against different target types is a different operator — Arcana on an NPC reveals different information than Arcana on a location. The parser dispatches on the (skill, target) pair.

Reads

Reads are the bulk of the skill catalog. They constrain what the LLM is allowed to surface to one shape: a typed projection of what's actually true.

Skill	What it reveals
Insight	NPC attitudes — toward the party, toward other NPCs, toward factions in scope. Against a hostile NPC, also surfaces faction allegiances the NPC would otherwise conceal.
Investigation	Physical evidence at a location — what happened here, and what the residue says about who was involved.
Perception	Hidden things at a location: items that aren't on display, exits that aren't obvious.
Survival	The shape of the area — paths, hidden routes, who or what might be passing through.
Medicine	An NPC's physical state — wounds, conditions, hidden afflictions.
Arcana (NPC)	Active magic effects on a creature.
Arcana (item)	Magical properties of an item.
Arcana (location)	Active magic effects on an area.
Nature (beast)	The creature's full statistics.
Nature (location)	The terrain — what's traversable, what's resource, what's hazard.
History	What the recorded lore says about a person, place, event, or item — if a record exists.
Religion	Doctrinal context — what a faith would say about this entity.

Soft writes

Soft writes apply session-bounded shifts that decay at session end. They're how the player nudges the social fabric without making a permanent commitment.

Skill	Effect
Persuasion	Tilts an NPC's disposition toward the party by a bounded amount.
Animal Handling	The same effect, but on a beast NPC.
Performance	A broadcast tilt — affects the audience at a venue, not a single target.

Hard writes

Hard writes commit durable mutations. They cost more than soft writes do — either resource cost or risk — because they outlast the session.

Skill	Effect
Sleight of Hand	Transfers ownership of an item from an NPC to the player party. The transfer is real and persists. Whether anyone notices is a separate matter — Stealth covers concealment.
Deception	Shifts the cover story an NPC holds about a topic. The NPC carries the false version forward into future conversations until something contradicts it.

Concealments

Concealments temporarily hide facts from the perception layer. They don't change what's true; they change what other characters get to see or remember.

Skill	Effect
Stealth	Conceals the player's actions from the NPCs who'd otherwise witness them. Actions covered by Stealth don't accumulate into the witnesses' knowledge.

Special: the truth-gate

Skill	Effect
Intimidation	Against a hostile NPC, lifts the cover story for the turn — the truth surfaces despite the NPC's preference to lie. Against a non-hostile NPC, no effect: there is no truth to compel out.

Special: traversal

Skill	Effect
Athletics	Bypass a physical barrier on a path between locations — a locked door, a wall to climb, a river to swim. The connection between locations stays; what changes is whether you've cleared this particular gate.
Acrobatics	Bypass a traversal hazard on a path — a narrow ledge, an unstable surface, a gap to leap. Like Athletics, the connection stays; what changes is whether you've cleared this particular passage.

How class identity expresses itself

In a system where every skill is an operator and every operator has the same shape regardless of who's wielding it, class identity comes from proficiency and expertise distribution — which operators a character is reliably effective with — not from class-exclusive abilities.

A Bard is a Bard because Persuasion and Insight are tools they sharpen further than other classes do. A Rogue is a Rogue because Stealth, Sleight of Hand, and Investigation are theirs to specialize in. The mechanical engine is the same for everyone; the margins on the operators are what separates the callings.

Read on

• Gameplay as Graph Mutation — the design lens this page applies. World as substrate, gameplay as mutation, the four operator shapes.
• The LLM Pipeline — how skill checks flow through the pipeline: the parser identifies which skill applies, the deterministic engine resolves the roll, the narrator authors the prose around the result.