fvtt-mcp-molten5e: Skill for Claude Code

.claude/skills/bestiary-builder/SKILL.md

bestiary-builder is a skill for Claude Code from Txpple/fvtt-mcp-molten5e. It costs 194 tokens per session (1,658 once invoked), scanned A, original, MIT.

A workflow for adding creatures the party has encountered to a player-facing Bestiary journal in Foundry Virtual Tabletop, a platform for running tabletop role-playing games online. It adds the creature's artwork and story description, not its game statistics.

In plain words
What is it for?
Use it after the party fights or encounters a creature to create an alphabetical, player-visible journal entry, or prepare one for the game master only.
Why use it?
It keeps the shared bestiary organised and prevents entries from being revealed before the party has earned that knowledge.

Skill for Claude Code

Written for Claude Code: installed under .claude/. Also seen: reads .claude/ paths.

This is Txpple/fvtt-mcp-molten5e's own configuration. It tells Claude Code how to work on fvtt-mcp-molten5e itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything fvtt-mcp-molten5e configures →

Reuse

Borrowing it

Nothing to install: this file belongs to Txpple/fvtt-mcp-molten5e. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file
curl -O https://raw.githubusercontent.com/Txpple/fvtt-mcp-molten5e/main/.claude/skills/bestiary-builder/SKILL.md
Clone the repo
git clone --depth 1 https://github.com/Txpple/fvtt-mcp-molten5e

Made for: Claude Code.

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README.md
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Per session 194 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,658 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00194 $0.01658
Opus 5 $0.00097 $0.00829
Sonnet 5 $0.00039 $0.00332
Haiku 4.5 $0.00019 $0.00166

Measured 10d ago against content hash 7fca2f393024, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-10, from the pricing page.

Security

Grade A, and why

bestiary-builder scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 10d ago.

The scan reads SKILL.md. This mod also ships 1 executable file (bestiary-entry.mjs), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

.claude/skills/bestiary-builder/SKILL.md · 113 lines

How it starts

The opening of the file, as written. The whole thing — 113 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Bestiary builder

The Bestiary is one journal — Bestiary, in the Adventure Log folder — with one page per creature, alphabetical. Players can open it; it is how they learn what they just fought.

The deterministic half is the bundled script bestiary-entry.mjs (next to this file). There is no MCP tool for this: reading a compendium journal page and setting entry-level journal ownership both sit outside the tool surface, so the script drives the live session directly through dist/foundry.js. Everything else — upload-asset, list-journals, set-journal-page-visibility — is normal tooling.

Step 0 — Has it been earned?

The house rule: a page goes in after the party has fought the thing, not when the DM statted it. The bestiary is the players' trophy shelf and their reference; it must never front-run an encounter.

  • Killed it → add it, player-visible.
  • Fought it and it got away (the will-o'-wisp) → still add it; they met it and paid for the knowledge.
  • Only glimpsed / heard rumored → ask the DM before adding.
  • Prepped for a future session (the displacer beasts) → add it with --gm-only if the DM wants it staged, and reveal it later with set-journal-page-visibility.

If a session recap is the source, work from the campaign repo's sessions/<date>/recap.md — it names every creature that took a turn.

Step 1 — Resolve the real creature

Compendium-first, premium books only (design.md §2.3 — never the SRD). Name it as the Monster Manual names it:

  • Shared lore is normal. The MM writes one narrative for a family: Hobgoblin Warrior, Captain and Warlord all point at Hobgoblins; Twig/Vine/Needle/Tree Blight all point at Blights. Pass any variant and the script lands on the shared page — so a party that fought both twig and vine blights gets one "Blights" page, not two. Re-running for the second variant just refreshes it.
  • Use --page when the family name should win. --monster "Hobgoblin Warrior" --page "Hobgoblins" titles the page for the family rather than the one variant they killed.
  • Reskins and masked identities. A world NPC may be a reskin of an MM creature (or wear a trueName mask). Resolve to the true MM creature for the lore, but do not title the page with a name the players haven't earned — if they only know it as "the thing in the webs", ask the DM what to call it.
  • Not in the Monster Manual (homebrew, a Ravenloft/adventure-pack creature, a custom NPC): the script exits with not in the Monster Manual or no lore embed in its biography. Stop and ask the DM for the narrative — never invent monster lore, and never paste a stat block. Then build the page by hand with create-journal/update-journal in the same house shape, or run with --no-art and edit the text in after.

Read the full file on GitHub · 113 lines

Files

What ships with it

1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 10d ago First seen · 113 lines · 194 tokens per session scan A 7fca2f393024

Subscribe to this mod's changes

bestiary-builder is a skill published in the GitHub repository Txpple/fvtt-mcp-molten5e (0 stars, last pushed today), licensed MIT. It adds 194 tokens to every session and 1,658 once invoked, about $0.0010 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

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