Technical reference for Mimir’s Model Context Protocol (MCP) server — the sidecar that enables AI assistant integration.
The MCP server (mimir-mcp) runs as a Tauri sidecar process. It connects to the same SQLite database as the main app and exposes 54 tools across 8 categories.
Binary : mimir-mcp (built to crates/mimir/binaries/mimir-mcp-{target-triple})Protocol : MCP over stdioDatabase : Shared SQLite database (same file the desktop app uses; default location varies by platform — see below)Plugin : Claude Code plugin at crates/mimir-mcp/plugin/
The database path is resolved from the MIMIR_DATABASE_PATH environment variable, falling back to a platform default:
Platform Default database path
macOS ~/Library/Application Support/com.mimir.app/data/mimir.dbLinux $XDG_DATA_HOME/com.mimir.app/data/mimir.db (falls back to ~/.local/share/com.mimir.app/data/mimir.db when XDG_DATA_HOME is unset)Windows No default — MIMIR_DATABASE_PATH must be set
See Environment Variables for details.
Most tools operate on an active campaign. Until a campaign is selected with set_active_campaign, campaign-scoped tools return a NoActiveCampaign error (No active campaign. Use set_active_campaign first.). The active campaign is held in memory per server process — it is not persisted, so each new server process starts with no campaign selected.
Tool Description
list_campaignsList all available campaigns set_active_campaignSet the active campaign (required by most tools) get_campaign_detailsGet campaign info including modules and characters get_campaign_sourcesGet enabled source books for a campaign create_campaignCreate a new campaign update_campaignUpdate campaign name or description delete_campaignDelete a campaign and all its data export_campaignExport campaign as shareable archive import_campaignImport campaign from archive preview_archivePreview archive contents without importing
Tool Description
create_moduleCreate new module in active campaign list_modulesList all modules in active campaign get_module_detailsGet module info including documents, monsters, items update_moduleUpdate module name or description delete_moduleDelete module and all contents add_monster_to_moduleAdd monster from catalog or homebrew to module remove_monster_from_moduleRemove monster from module add_item_to_moduleAdd catalog item as loot to module
Tool Description
list_documentsList campaign-level or module-level documents read_documentRead full content of a document create_documentCreate document (backstory, read_aloud, dm_notes, description, custom) edit_documentEdit document using search and replace delete_documentDelete a document reorder_documentReorder documents by swapping sort positions
Tool Description
list_charactersList characters with optional filters (type, module, location, faction) get_characterGet detailed character info including classes and inventory create_characterCreate NPC or PC (auto-populates proficiencies from catalog) edit_characterUpdate ability scores, currency, race, background, traits delete_characterDelete character and all associated data level_up_characterLevel up character (handles HP, multiclass, ASI/feats, spells) add_item_to_characterAdd catalog item to character inventory remove_item_from_characterRemove item from character inventory update_character_inventoryUpdate item quantity, equipped, or attuned state get_character_inventoryGet inventory (filterable by equipped/attuned) add_character_spellAdd spell to character’s known spells remove_character_spellRemove spell from character list_character_spellsList character’s known spells (filterable by class/prepared)
Tool Description
create_mapUpload UVTT file to create new map list_mapsList maps (optionally filtered by module) get_mapGet map details including token placements update_mapUpdate map metadata (name, description, lighting) delete_mapDelete map and associated UVTT asset add_token_to_mapAdd monster or NPC token to map list_tokens_on_mapList all tokens (optionally visible only) remove_tokenRemove token placement from map
Tool Description
generate_mapGenerate Dungeondraft map from YAML config or biome preset list_map_presetsList available biome presets validate_map_configValidate YAML config without generating
A single search_catalog tool searches all catalog categories.
Tool Description
search_catalogSearch the D&D 5e catalog by category
Parameters:
Parameter Type Description
categorystring (required) One of: monster, item, spell, race, class, background, feat, condition namestring Search by name (partial match) limitinteger Maximum results (default: 20) cr_min / cr_maxnumber Challenge rating range (monsters only) monster_typestring Creature type, e.g. undead, dragon (monsters only) include_homebrewboolean Include homebrew monsters from the active campaign (monsters only, default: true) raritystring common, uncommon, rare, very rare, legendary, artifact (items only)item_typestring e.g. weapon, armor, wondrous item (items only) levelinteger Spell level, 0 for cantrips (spells only) schoolstring School of magic, e.g. evocation (spells only) class_namestring Filter by class spell list (spells only)
Results are filtered to the active campaign’s enabled sources when a campaign is set.
Homebrew items, monsters, and spells share a unified tool set. Every call takes a
content_type parameter: item, monster, or spell.
Tool Description
list_homebrewList homebrew content of one type in the active campaign get_homebrewGet a homebrew entry by ID create_homebrewCreate new homebrew, or clone from the catalog with cloned_from_name + cloned_from_source update_homebrewUpdate a homebrew entry delete_homebrewDelete a homebrew entry by ID
create_homebrew parameters:
Parameter Type Description
content_typestring (required) item, monster, or spellnamestring (required) Name of the homebrew content datastring JSON string with content data. Required when not cloning; when cloning, fields here override the catalog data item_typestring Items only: weapon, armor, potion, ring, rod, scroll, staff, wand, wondrous item, adventuring gear raritystring Items only: common, uncommon, rare, very rare, legendary, artifact crstring Monsters only, e.g. 1/4, 1, 5, 20 creature_typestring Monsters only, e.g. humanoid, dragon, undead sizestring Monsters only: T, S, M, L, H, G levelinteger Spells only: 0 for cantrip, 1–9 schoolstring Spells only, e.g. evocation, necromancy cloned_from_namestring Catalog entry to clone from; must be used with cloned_from_source cloned_from_sourcestring Source book of the cloned entry (e.g. PHB, DMG, MM)
For installation and setup, see the AI Assistant How-To .
Command Description
/mimir-campaignsList all available campaigns /create-moduleCreate a new module in the active campaign /search-monstersSearch the D&D monster catalog /search-spellsSearch the D&D spell catalog /generate-mapGenerate a procedural Dungeondraft map
Skill Description
/mimir-dmGeneral campaign management /encounter-balanceAnalyze encounter difficulty /loot-auditAudit treasure distribution /session-prepPre-session readiness review /continuity-checkFind contradictions across documents /npc-networkMap NPC relationships /pressure-testStress-test scenarios /mapgenCreative direction for map generation