fix(meta): pick an optimisation goal the campaign objective allows

Third failure in the same chain, one object further each time: "Performance
goal isn't available: You can't use the selected performance goal with your
campaign objective" (code 100, subcode 2490408).

DEFAULT_OPTIMIZATION_GOAL was a single global constant, LEAD_GENERATION,
applied whatever the objective was. That is correct for OUTCOME_LEADS and
wrong for every other objective Meta offers — including OUTCOME_TRAFFIC,
which is what the connection test builds.

Defaults now come from a per-objective table, and an unknown objective
falls back to LINK_CLICKS: valid for the widest range of objectives, where
a lead goal is valid for exactly one. An explicit advanced.optimization_goal
still wins, and is still checked against the allowlist.

Deliberately not validating goal-against-objective beyond the defaults.
Meta's full compatibility matrix is not something this code can assert
confidently, and a wrong matrix would reject setups that actually work —
worse than the failure it would prevent, which sync already surfaces
legibly now.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

src/adclaw/meta/objects.py

@@ -49,7 +49,30 @@ from typing import Any
 
 from ..campaigns.models import CampaignSpec
 
-DEFAULT_OPTIMIZATION_GOAL = "LEAD_GENERATION"
+# Meta pairs an ad set's optimisation goal with its campaign's objective and
+# rejects a mismatch with code 100 / subcode 2490408 — at ad-set creation,
+# which is *after* the campaign object exists. A single global default is
+# therefore wrong for every objective but one: LEAD_GENERATION on an
+# OUTCOME_TRAFFIC campaign is what the live connection test hit.
+#
+# These are the conservative choice per objective — the goal Meta treats as
+# that objective's natural optimisation — not the only valid one. A caller
+# who wants something else sets advanced.optimization_goal, and owns
+# checking Meta accepts it for their objective.
+DEFAULT_OPTIMIZATION_GOAL_BY_OBJECTIVE = {
+    "OUTCOME_TRAFFIC": "LINK_CLICKS",
+    "OUTCOME_LEADS": "LEAD_GENERATION",
+    "OUTCOME_ENGAGEMENT": "POST_ENGAGEMENT",
+    "OUTCOME_AWARENESS": "REACH",
+    "OUTCOME_SALES": "OFFSITE_CONVERSIONS",
+    "OUTCOME_APP_PROMOTION": "LINK_CLICKS",
+}
+
+# Fallback for an objective not in the table above. LINK_CLICKS is valid for
+# the widest range of objectives, so an unknown objective degrades to
+# something Meta is most likely to accept rather than to a lead goal that
+# only OUTCOME_LEADS takes.
+DEFAULT_OPTIMIZATION_GOAL = "LINK_CLICKS"
 DEFAULT_BILLING_EVENT = "IMPRESSIONS"
 
 # Graph requires a bid strategy on every ad set that carries its own budget,
@@ -145,8 +168,10 @@ def build_ad_set_payload(spec: CampaignSpec, campaign_id: str) -> dict[str, Any]
             "Set at least one of countries, age_min, age_max or genders.",
         )
 
-    optimization_goal = spec.advanced.get(
+    optimization_goal = spec.advanced.get("optimization_goal") or (
-        "optimization_goal", DEFAULT_OPTIMIZATION_GOAL,
+        DEFAULT_OPTIMIZATION_GOAL_BY_OBJECTIVE.get(
+            spec.objective or "", DEFAULT_OPTIMIZATION_GOAL,
+        )
     )
     if optimization_goal not in ALLOWED_OPTIMIZATION_GOALS:
         raise ValueError(

tests/test_meta_writes.py

@@ -18,6 +18,9 @@ import pytest
 
 from adclaw.meta.client import MetaClient, MetaError
 from adclaw.meta.objects import (
+    ALLOWED_OPTIMIZATION_GOALS,
+    DEFAULT_OPTIMIZATION_GOAL,
+    DEFAULT_OPTIMIZATION_GOAL_BY_OBJECTIVE,
     build_ad_set_payload,
     build_campaign_payload,
     build_creative_payload,
@@ -651,3 +654,63 @@ async def test_create_ad_set_sends_the_bid_strategy():
 
     sent = transport.calls[0]["params"]["bid_strategy"]
     assert sent == "LOWEST_COST_WITHOUT_CAP"
+
+
+# ---------------------------------------------------------------------------
+# optimisation goal: Meta pairs it with the campaign objective
+# ---------------------------------------------------------------------------
+
+
+def test_the_default_optimisation_goal_follows_the_objective():
+    """A traffic campaign cannot optimise for leads.
+
+    Meta rejects the pair with code 100 / subcode 2490408, at ad-set
+    creation — after the campaign object exists. The default used to be
+    LEAD_GENERATION for every objective, which is correct for exactly one
+    of them and is what the live connection test hit.
+    """
+    assert (
+        build_ad_set_payload(_spec(objective="OUTCOME_TRAFFIC"), campaign_id="c1")[
+            "optimization_goal"
+        ]
+        == "LINK_CLICKS"
+    )
+    assert (
+        build_ad_set_payload(_spec(objective="OUTCOME_LEADS"), campaign_id="c1")[
+            "optimization_goal"
+        ]
+        == "LEAD_GENERATION"
+    )
+    assert (
+        build_ad_set_payload(_spec(objective="OUTCOME_AWARENESS"), campaign_id="c1")[
+            "optimization_goal"
+        ]
+        == "REACH"
+    )
+
+
+def test_every_mapped_default_is_one_we_allow():
+    """The table and the allowlist have to agree, or a perfectly ordinary
+    objective raises ValueError on its own default."""
+    for objective, goal in DEFAULT_OPTIMIZATION_GOAL_BY_OBJECTIVE.items():
+        assert goal in ALLOWED_OPTIMIZATION_GOALS, objective
+    assert DEFAULT_OPTIMIZATION_GOAL in ALLOWED_OPTIMIZATION_GOALS
+
+
+def test_an_unknown_objective_falls_back_to_the_widest_goal():
+    """Better a goal most objectives accept than a lead goal only one does."""
+    payload = build_ad_set_payload(_spec(objective="OUTCOME_SOMETHING_NEW"),
+                                   campaign_id="c1")
+
+    assert payload["optimization_goal"] == "LINK_CLICKS"
+
+
+def test_an_explicit_optimisation_goal_still_wins():
+    spec = _spec(
+        objective="OUTCOME_TRAFFIC",
+        advanced={"optimization_goal": "LANDING_PAGE_VIEWS"},
+    )
+
+    payload = build_ad_set_payload(spec, campaign_id="c1")
+
+    assert payload["optimization_goal"] == "LANDING_PAGE_VIEWS"