diff --git a/README.md b/README.md
index 568b004..b8b1cfe 100644
--- a/README.md
+++ b/README.md
@@ -86,6 +86,28 @@ Defaults live in `config.lua`.
   `j('j_key', {gives...}, {wants...})`, or add a famous pair to the `PAIRS`
   table at the bottom. Modded jokers can be added the same way using their
   full key (e.g. `j_mymod_cooljoker`) — unknown jokers simply score 0.
+- **From another mod:** if your mod adds jokers, teach the advisor about
+  them at load time (any point after Combo Advisor has loaded):
+
+  ```lua
+  if JCA then
+      -- gives/wants use the tag names from synergies.lua
+      JCA.register('j_mymod_cooljoker', {'xmult'}, {'faces'})
+      -- optional: opts {no_generic = true} if the generic
+      -- "+Mult feeds the multiplier" logic misreads your joker
+      JCA.register('j_mymod_slotless', {'xmult'}, nil, {no_generic = true})
+      -- famous pair (+4, discoverable, shown in the Combos tab);
+      -- keep the blurb under ~34 characters
+      JCA.register_pair('j_mymod_cooljoker', 'j_pareidolia',
+          'every card becomes a face for it')
+      -- known trap: warning-only red tooltip line
+      JCA.register_clash('j_mymod_cooljoker', 'j_vampire',
+          'drains the enhancements it needs')
+  end
+  ```
+
+  Unknown tags are dropped with a `JCA:` log line instead of erroring, so
+  a typo in your registration can never break a load.
 - **Tune sensitivity:** use the in-game Config tab, or change the defaults
   in `config.lua`.
 
diff --git a/main.lua b/main.lua
index cc57e15..c6aa108 100644
--- a/main.lua
+++ b/main.lua
@@ -174,6 +174,63 @@ function JCA.weakest_link()
     if worst and worst_total < best_total then return worst end
 end
 
+-- Public API for other mods ----------------------------------------------------
+-- Lets a mod teach the advisor its own jokers (which otherwise score 0).
+-- Call any time after this mod has loaded. Tags must come from the sets in
+-- synergies.lua; unknown tags are dropped with a log line rather than
+-- crashing someone else's load.
+
+local KNOWN_TAGS = { mult = true, chips = true, xmult = true }
+for t in pairs(data.tag_text) do KNOWN_TAGS[t] = true end
+
+local function checked_tag_set(key, list)
+    local set = {}
+    for _, t in ipairs(list or {}) do
+        if KNOWN_TAGS[t] then
+            set[t] = true
+        else
+            print(('JCA: %s: dropping unknown tag %q'):format(key, tostring(t)))
+        end
+    end
+    return set
+end
+
+-- gives/wants are arrays of tag names. opts: {no_generic = true} excludes
+-- the joker from the generic mult/xmult complement (see Joker Stencil).
+-- Re-registering a key overwrites its entry.
+function JCA.register(key, gives, wants, opts)
+    assert(type(key) == 'string' and key ~= '', 'JCA.register: key required')
+    JCA.db[key] = {
+        gives = checked_tag_set(key, gives),
+        wants = checked_tag_set(key, wants),
+        no_generic = opts and opts.no_generic or nil,
+    }
+end
+
+-- Famous pair: flat +4, shown in the Combos tab, discoverable in play.
+-- Keep the blurb under ~34 chars so it fits one tooltip row.
+function JCA.register_pair(a, b, blurb)
+    assert(type(a) == 'string' and type(b) == 'string',
+        'JCA.register_pair: two joker keys required')
+    if blurb and #blurb > 34 then
+        print(('JCA: pair %s|%s blurb exceeds 34 chars, may clip'):format(a, b))
+    end
+    local pk = pair_key(a, b)
+    if not JCA.pair_bonus[pk] then
+        JCA.pair_list[#JCA.pair_list + 1] = {a, b, blurb}
+    end
+    JCA.pair_bonus[pk] = true
+    JCA.pair_blurb[pk] = blurb
+    JCA._pairs_dirty = true -- combos tab re-sorts on next open
+end
+
+-- Known trap: warning-only red tooltip line, never affects the score.
+function JCA.register_clash(a, b, warning)
+    assert(type(a) == 'string' and type(b) == 'string',
+        'JCA.register_clash: two joker keys required')
+    JCA.clash_blurb[pair_key(a, b)] = warning
+end
+
 local function in_buy_area(card)
     return card.area and (card.area == G.shop_jokers or card.area == G.pack_cards)
 end
@@ -829,7 +886,8 @@ end
 local PAIRS_PER_PAGE = 6
 local sorted_pairs
 local function combos_tab_def(page_no)
-    if not sorted_pairs then
+    if not sorted_pairs or JCA._pairs_dirty then
+        JCA._pairs_dirty = false
         sorted_pairs = {}
         for _, p in ipairs(JCA.pair_list) do
             sorted_pairs[#sorted_pairs + 1] = {p[1], p[2], score = JCA.score(p[1], p[2])}