# Build or refactor a SillyTavern Game Master / Storyteller / Dungeon Master character card for a tabletop RPG system. > Source: > Published: 2026-07-10 18:25:07+00:00 The named failure modes to diagnose against. When reviewing a card, quote the offending field text, name the pattern, and say why it bites. Lead with the biggest structural issue — usually the chimera or tone-in-foundation — not a pile of nitpicks. **Symptom:** description/personality are mostly atmosphere — "velvet over gravel," "the smell of rain on asphalt," "ozone-scent of a discharging lasgun," "the terrifying indifference of the void." Sensory mood-piece prose where behavior should be. **Why it bites:** the persona fields define what the model *is*, so a mood persona pulls every response toward florid narration and fights "run a game, keep it short." Tone is also un-swappable when it's baked into the always-on foundation. **Fix:** move tone to the override; put GM behavior and NPC principles in personality; identity (with a thin setting floor) in description. **Symptom:** the card defines one narrator voice (often with a signature like "a knowing smirk"); nothing tells it to voice distinct NPCs with separate agendas. Often paired with "NPCs feel flat / lack their own goals." **Why it bites:** told to *be* one narrator, the model filters every NPC through that single voice and orients them all around the player. This is the usual root cause of "flat NPCs." **Fix:** the NPC-agency principle (each NPC wants something and pursues it; withholds; compartmented knowledge; distinct register) plus behavioral examples showing two NPCs sounding different. **Symptom:** instructions like "if the narrative stalls, introduce a sudden vox-transmission, a cultist ambush, or a localized warp-phenomenon to force a choice." **Why it bites:** it tells the GM to spawn new threats when *it* feels pacing lag, producing random, unearned complications disconnected from the fiction. **Fix:** replace with "press with what's already true" — an existing NPC acts on its goal, a consequence in motion arrives, a clock advances. Momentum becomes a consequence of NPC agency, not a spawn mechanic. **Symptom:** an NPC's line is followed by a sentence narrating what they *didn't* do or what their reply *meant*: "She doesn't ask why you want it. She's a Brujah who knows what pre-assault recon looks like, and she just confirmed she's moving tonight." **Why it bites:** the model grades its own NPC instead of playing her, and restates in prose what the dialogue already showed. Pure novelist reflex, redundant and un-GM-like. **Fix:** "play NPCs, don't grade them — the line stands on its own. Never append a sentence explaining what an NPC didn't do, didn't ask, or what its reply signified." End the turn on what they actually say or do. **Symptom:** the card narrates the player's thoughts, expectations, or actions — "shorter than your message, which is exactly what you expected." **Why it bites:** it reaches into the player's head and takes their agency. Adjacent to acting *for* the player. **Fix:** state only what the character perceives and how the world responds; never narrate the player's interior or choices. **Symptom:** the card stitches incompatible sources. E.g. Wrath & Glory *rules* + a video-game's *cast and setting* + Dark Heresy *example scenes* + generic grimdark *persona* — four sources, none reconciled. Or "V20 lore with V5 rules" where the lorebook lists V20 disciplines that contradict the actual V5 character. **Why it bites:** the layers fight; examples teach the wrong game; the model gets contradictory mechanics. This is usually the single biggest issue when present — diagnose it first. **Fix:** pick one rules system, one setting, one register; make the examples teach *that* game; push campaign specifics to overrides/lorebooks. **Symptom:** mandatory rigid output structure stamped on every turn — emoji headers, "✓ No Roll Needed" footers appended to pure narration, form-like checkpoint blocks. **Why it bites:** it's un-GM-like and reads like assistant UI bleeding into the game. The *intent* (call-and-stop, handle the dice) is usually right; the *implementation* (stamp every response) is heavy-handed. **Fix:** keep the behavior, drop the per-turn stamp. Use a light structured roll-call only when a roll is live (crunch-heavy systems) or fold it into prose (RP-heavy); no footer when no roll is needed. **Symptom:** ranges from harmful to load-bearing. Bad: edition-wrong or video-game-scraped entries (e.g. "Thaumaturgy" with Bloodlines spell names) that fire on keyword mid-scene and inject wrong mechanics. Good: an accurate rules-reference for a crunchy system the model is fuzzy on. **Why it bites (bad case):** keyed entries fire near live context and can mislead mechanics or burn context with noise the experienced table doesn't need. **Fix:** disable/prune edition-wrong and redundant entries; *keep* accurate rules references for crunch-heavy systems; move campaign-specific lore to the override layer. Don't reflexively nuke a lorebook — judge entry by entry. **Symptom:** the card's `system_prompt` is a thin stub while a strong ruleset lives in the global preset (or vice versa). **Why it bites:** if "Prefer Char. Instructions" is on, the card's `system_prompt` /`post_history` *replace* the global ones; if off, the card's never load. Either way one silently wins, and it may be the weaker copy. **Fix:** flag the setting to the user; make sure the version that wins is the strong one; don't keep two different-strength copies of the rules competing. **Symptom:** "if a rule is in the way of fun, change or ignore it" sitting next to "treat tracker data as absolute canonical truth" and a mandatory dice system. **Why it bites:** licenses the model to fudge exactly the math the rest of the card calls sacred — especially damaging in crunch-heavy systems. **Fix:** resolve the contradiction explicitly; in crunchy systems, run rules-as-written and stop softening outcomes in the player's favor (the system already accounts for it).