| name | coc-mythos-reference |
| description | Provide spoiler-aware Mythos references for COC mode. Use for monsters, deities, spells, tomes, artifacts, combat stats, source pages, and Keeper-only lookup during scenario preparation or play. |
COC Mythos Reference
Use
Use this skill for Keeper-side lookup of Mythos entities, tomes, spells, artifacts, and monster stats.
Spoiler Safety
Do not reveal true monster identities, secret spell effects, hidden tome contents, or scenario answers to the player without [spoiler_warning] and confirmation.
Sources
Prefer structured scenario JSON and source maps first. Use PDFs for detailed lookup only when needed, then summarize rather than quoting long passages.
Monster Presentation Contract
Every entry in references/rules-json/monsters.json carries a structured
presentation block (Keeper Rulebook Ch14 p.280-282). Honor it whenever that
monster is in play:
never_name_until — do not speak the creature's true name until pacing
horror_stage reaches this stage (default revelation). Climb the Ch10
presentation ladder first.sensory_signature — sample early-stage scenes from these sensory
strings (smell, sound, residue, wrong geometry). Prefer the director's
mythos_presentation.sensory_signature_sample when present.death_residue — when a body or remains are found, describe this
residue rather than inventing a clean corpse. Deities and Great Old Ones
at 0 HP are dispersed or banished, not killed — their residue reflects
absence, collapse, or unmaking, never a mundane corpse.combat_goal — run the fight toward kill, capture, flee, or
ritual. Intelligent species do not fight to the death (p.281).retreat_below_hp_fraction — when current HP falls below this fraction
of maximum, the creature attempts retreat or disengagement. Mindless
threats may leave this null.
Lookup is by structured monster id only (monster_ids / monster_id on the
active scene or threat fronts). Never infer a creature's identity by scanning
player-facing prose.
Tome Reading
When an investigator studies a Mythos tome (Keeper Rulebook Ch11 p.217-226),
drive the mechanical phases through coc_tomes.TomeSession (skim →
initial → full → research). Route returned san_loss_expr through
SanitySession; merge returned CM gains into the character sheet. Do not invent
study weeks, CMI/CMF, or Mythos Rating — read them from tomes.json.
Sensory description (p.224-226). Present the physical book before its
contents: binding, smell, weight, ink that seems wrong, pages that resist or
invite the eye. Early contact is atmosphere and table-of-contents level
(skim); deeper phases unlock structured Mythos insight, not a lore dump.
Book as personality. Treat a major tome as a presence with temperament —
jealous, seductive, pedantic, hostile — that colors how knowledge arrives.
The book's "voice" is Keeper framing; mechanical outcomes still come from the
engine (CM, SAN expression, weeks, research roll contract).
Plot-critical tomes must not dead-end (p.211-212). Language and other
failure gates may block ordinary study, but when the scenario requires the
tome (plot_critical=True), skip the hard stop and continue with
keeper_note: skip_failure_gate. Never strand the investigation on a failed
Own Language / Other Language check for a book the plot needs open.
