Entity Detective

Entity Detective

Entity Detective is a server-side Fabric mod that gives admins surgical visibility into entity accumulation — find exactly where mobs, persistent creatures, and dropped items are piling up across every loaded dimension, without needing a client mod. Works in singleplayer without enabling cheats.

What it does

• Per-dimension summaries — See every entity type sorted by count, one block per dimension, across overworld, nether, and end simultaneously
• Clickable teleport links — Every chunk header and individual entity line is clickable in chat and pastes /tp @s x y z directly to the chunk centre or exact entity location
• Lazy mob detection — Pinpoint mobs stranded in chunks with no player within 128 blocks — the exact threshold Minecraft uses for despawn checks — where the server will never clean them up naturally
• Persistent mob detection — Find name-tagged mobs, item-holders, leashed animals, and vehicle riders that will never despawn even when they do tick
• MSPT profiling — Measure how many milliseconds per tick any entity type is consuming, or profile every type at once sorted by cost, over a configurable rolling window
• Live mob cap — Check current vs. maximum entities per category with colour-coded saturation so you can spot mob cap pressure at a glance

Command structure

/entitydetective ├── mob <category> │ │ category: monster | creature | ambient | axolotls | water_creature | water_ambient │ │ (bare) — Type-count summary per dimension │ │ --lazy-only — Type-count table, non-persistent mobs in lazy chunks │ │ --persistent — Type-count table, persistent mobs only │ │ --world <dim> — Scope to overworld | nether | end │ │ --range <chunks> — Scope to (2N+1)×(2N+1) chunk square (0 = single chunk) │ │ --detail — Expand to chunk-grouped entity list with clickable /tp links │ └── cap — Live mob cap (current vs max, colour-coded) │ ├── entity │ │ (bare) — Summary of all entity types by count, per dimension │ │ --lazy-only — Type-count table, non-persistent entities in lazy chunks │ │ --persistent — Type-count table, persistent entities only │ │ --world <dim> — Scope to a specific dimension │ │ --detail — Expand to chunk-grouped entity list with clickable /tp links │ ├── --range <chunks> — Instant census of every entity type within range (0 = single chunk; no tick window) │ ├── locate <type> — Locate any entity type (tab-complete from live world, substring match) │ │ --lazy-only, --world <dim>, --range <chunks>, --detail │ ├── profile <type> [ticks] │ │ Measure MSPT cost over a tick window (default 100 ticks / 5 s; max 6 000 ticks / 5 min) │ │ --range <chunks> │ └── profile all [ticks] │ Profile every entity type simultaneously, sorted by MSPT cost descending │ (bare): all dimensions | --world <dim>: one dimension | --range <chunks>: local │ └── item │ (bare) — Dropped item summary per dimension, colour-coded by severity │ --lazy-only — Type-count table, lazy chunks only │ --world <dim> — Scope to a specific dimension │ --range <chunks> — Scope to chunk square around your position │ --detail — Expand to chunk-grouped item list with clickable /tp links └── locate <item_id> Find chunks with a specific item type (tab-complete, substring match) --lazy-only, --world <dim>, --range <chunks>, --detail

--detail must always be the last flag. --range and --world are mutually exclusive.

Why lazy and persistent mobs matter

Lazy mobs are non-persistent mobs in chunks with no player within 128 blocks — the exact threshold Minecraft's despawn logic uses. Because those chunks never tick entities, the normal despawn check never runs. Mobs accumulate there indefinitely. Use --lazy-only to get a type-count table of what's building up, then add --detail for chunk-grouped clickable /tp links to teleport directly to the problem.

Persistent mobs are flagged by the game engine to never despawn, even in fully-ticking chunks. This includes name-tagged mobs, any mob that has picked up a dropped item off the ground, leashed animals, and mobs riding vehicles. Because they never despawn, they accumulate over time and increase the server's tick cost. Use --persistent to see where they are building up.

Sample output

/entitydetective mob monster --lazy-only (type-count table)

-- lazy monster [overworld]: 45 entities -- minecraft:zombie 28 minecraft:skeleton 12 minecraft:creeper 5 Total: 45 entities across 3 types

/entitydetective mob monster --lazy-only --detail (chunk-grouped, clickable)

-- monster [overworld] (lazy, --detail): 45 entities in 2 chunks -- Chunk (12, -4) × 31 → /tp @s 192 ~ -64 [196, 63, -61] — minecraft:zombie [191, 64, -68] — minecraft:skeleton "Bob" (name tagged) ...

/entitydetective entity profile all --range 10

-- Base Profile: 10-chunk range (100 ticks) -- 3.636mspt TOTAL ×102 1.779mspt avg: 0.040ms piglin ×44 1.188mspt avg: 0.043ms hoglin ×28 0.402mspt avg: 0.040ms strider ×10 3.636mspt TOTAL ×102

/entitydetective item (severity-coloured)

-- Item Types [overworld]: 2 847 items -- 2 130 items (142 entities) minecraft:cobblestone ← red 480 items ( 48 entities) minecraft:gravel ← yellow 12 items ( 4 entities) minecraft:diamond ← green

No client mod required · Works cross-dimension · Singleplayer compatible · Respects LuckPerms

Singleplayer world owner has full access without enabling cheats. On servers, requires op level 2 or the entitydetective.command LuckPerms node.
Releases · Source · License: MIT