diff --git a/.kiro/specs/access-control-prover/tasks.md b/.kiro/specs/access-control-prover/tasks.md
index 376ec94..02d89e1 100644
--- a/.kiro/specs/access-control-prover/tasks.md
+++ b/.kiro/specs/access-control-prover/tasks.md
@@ -110,7 +110,7 @@ its final resolution, dominance, fact-acquisition and measurement semantics with
   - _Depends: 7.1, 7.2, 7.3_
 
 - [ ] 8. Stable symbols and conservative call resolution
-- [ ] 8.1 Capture call receiver and arity evidence in the semantic IR
+- [x] 8.1 Capture call receiver and arity evidence in the semantic IR
   - Preserve receiver expression and argument count for supported syntax while keeping existing constructors valid.
   - Done when language fixtures retain receiver and arity evidence without regressing existing IR consumers.
   - _Requirements: 3.2, 3.3_
diff --git a/src/openultrasast/semantic/cst.py b/src/openultrasast/semantic/cst.py
index e8e92e5..4e9ad34 100644
--- a/src/openultrasast/semantic/cst.py
+++ b/src/openultrasast/semantic/cst.py
@@ -206,17 +206,52 @@ def _call(node: Any, kinds: dict[str, frozenset[str]]) -> CallSite:
     # PHP wraps positional and named argument values in an `argument` node.
     arg_nodes = [arg.named_children[-1] if arg.type == "argument" and arg.named_children else arg for arg in arg_nodes]
     extra = len(arg_nodes) >= 2 and arg_nodes[1].type in _SEQUENCE
+    callee = _callee_name(node, args_node)
     return CallSite(
         order=int(node.end_byte),
-        name=_callee_name(node, args_node),
+        name=callee,
         line=_line(node),
         arg_texts=tuple(_text(arg) for arg in arg_nodes),
         arg_is_constant=tuple(_is_constant(arg, kinds) for arg in arg_nodes),
         arg_names=tuple(_identifiers(arg) for arg in arg_nodes),
         extra_arg_is_sequence=extra,
+        receiver=_receiver_text(node, args_node, callee),
+        arity=len(arg_nodes),
     )
 
 
+_RECEIVER_SEPARATORS = ("->", "::", "?.", ".")
+
+
+def _receiver_text(node: Any, args_node: Any, callee: str) -> str | None:
+    parts = [child for child in getattr(node, "named_children", ()) or () if child is not args_node]
+    final_identifier = callee
+    for separator in _RECEIVER_SEPARATORS:
+        final_identifier = final_identifier.rsplit(separator, 1)[-1]
+    final_identifier = final_identifier.strip()
+    for child in parts:
+        receiver = _receiver_before_separator(_text(child), final_identifier)
+        if receiver is not None:
+            return receiver
+    for index, child in enumerate(parts):
+        if _text(child).strip() == final_identifier:
+            before = [text for text in (_text(part).strip() for part in parts[:index]) if text]
+            if before:
+                return ".".join(before)
+            return None
+    return None
+
+
+def _receiver_before_separator(text: str, final_identifier: str) -> str | None:
+    for separator in _RECEIVER_SEPARATORS:
+        position = text.rfind(separator)
+        if position <= 0:
+            continue
+        if text[position + len(separator) :].strip() == final_identifier:
+            return text[:position].strip() or None
+    return None
+
+
 def _callee_name(node: Any, args_node: Any) -> str:
     if node.type in _KIND["php"]["call"]:
         callee = node.child_by_field_name("name") or node.child_by_field_name("function")
diff --git a/src/openultrasast/semantic/ir.py b/src/openultrasast/semantic/ir.py
index 2aacb35..4f0d097 100644
--- a/src/openultrasast/semantic/ir.py
+++ b/src/openultrasast/semantic/ir.py
@@ -27,6 +27,8 @@ class CallSite:
     arg_names: tuple[tuple[str, ...], ...]
     extra_arg_is_sequence: bool
     order: int = 0
+    receiver: str | None = None
+    arity: int | None = None
 
 
 @dataclass(frozen=True)
@@ -202,9 +204,17 @@ def _call_site(node: ast.Call) -> CallSite:
         arg_is_constant=tuple(arg_const),
         arg_names=tuple(arg_names),
         extra_arg_is_sequence=extra_sequence,
+        receiver=_receiver(node.func),
+        arity=len(node.args) + len(node.keywords),
     )
 
 
+def _receiver(func: ast.expr) -> str | None:
+    if isinstance(func, ast.Attribute):
+        return _unparse(func.value)
+    return None
+
+
 def _end_position(node: ast.AST) -> int:
     return int(getattr(node, "end_lineno", 0) or 0) * 1_000_000 + int(getattr(node, "end_col_offset", 0) or 0)
 
diff --git a/tests/test_semantic_call_evidence.py b/tests/test_semantic_call_evidence.py
new file mode 100644
index 0000000..83df30f
--- /dev/null
+++ b/tests/test_semantic_call_evidence.py
@@ -0,0 +1,106 @@
+"""Task 8.1 -- call receiver and arity evidence in the semantic IR (Reqs 3.2, 3.3)."""
+
+from openultrasast.semantic.ir import CallSite, parse_file
+
+
+def _calls(path: str, text: str, language: str) -> list[CallSite]:
+    parsed = parse_file(path, text, language)
+    assert parsed.parse_ok, parsed.reason
+    return [call for function in parsed.functions for call in function.calls]
+
+
+PHP_SOURCE = """<?php
+final class Controller {
+    public function run(): void {
+        $this->helper('a', 'b');
+        self::staticHelper('c');
+        plain('d');
+    }
+}
+"""
+
+JAVA_SOURCE = """public final class Job {
+    void execute() {
+        getListener().onEvent(item, 1);
+    }
+}
+"""
+
+TYPESCRIPT_SOURCE = """export function handle(client: Client) {
+    client.send(payload);
+    log("done");
+}
+"""
+
+PYTHON_SOURCE = """def handle(request):
+    store.save(request.body)
+    audit(request, flag=True)
+    log("done")
+"""
+
+
+def test_php_member_call_retains_receiver_and_arity() -> None:
+    calls = {call.name: call for call in _calls("controller.php", PHP_SOURCE, "php")}
+    helper = calls["helper"]
+    assert helper.receiver == "$this"
+    assert helper.arity == 2
+
+
+def test_php_scoped_call_names_the_class_scope_as_receiver() -> None:
+    calls = {call.name: call for call in _calls("controller.php", PHP_SOURCE, "php")}
+    assert calls["staticHelper"].receiver == "self"
+    assert calls["staticHelper"].arity == 1
+
+
+def test_php_bare_function_call_has_no_receiver() -> None:
+    calls = {call.name: call for call in _calls("controller.php", PHP_SOURCE, "php")}
+    assert calls["plain"].receiver is None
+    assert calls["plain"].arity == 1
+
+
+def test_java_method_invocation_retains_receiver_expression_and_arity() -> None:
+    calls = {call.name: call for call in _calls("Job.java", JAVA_SOURCE, "java")}
+    event = calls["onEvent"]
+    assert event.receiver == "getListener()"
+    assert event.arity == 2
+
+
+def test_typescript_member_call_retains_receiver_and_arity() -> None:
+    calls = {call.name: call for call in _calls("handle.ts", TYPESCRIPT_SOURCE, "typescript")}
+    send = calls["client.send"]
+    assert send.receiver == "client"
+    assert send.arity == 1
+    assert calls["log"].receiver is None
+
+
+def test_python_attribute_call_retains_receiver_and_arity() -> None:
+    calls = {call.name: call for call in _calls("handle.py", PYTHON_SOURCE, "python")}
+    save = calls["store.save"]
+    assert save.receiver == "store"
+    assert save.arity == 1
+
+
+def test_python_keyword_argument_counts_toward_arity() -> None:
+    calls = {call.name: call for call in _calls("handle.py", PYTHON_SOURCE, "python")}
+    assert calls["audit"].receiver is None
+    assert calls["audit"].arity == 2
+
+
+def test_python_bare_call_has_no_receiver() -> None:
+    calls = {call.name: call for call in _calls("handle.py", PYTHON_SOURCE, "python")}
+    assert calls["log"].receiver is None
+    assert calls["log"].arity == 1
+
+
+def test_existing_positional_construction_stays_valid_with_default_evidence() -> None:
+    call = CallSite("perform", 7, ("x",), (False,), (("x",),), False, 3)
+    assert call.receiver is None
+    assert call.arity is None
+
+
+def test_receiver_capture_survives_whitespaced_member_syntax() -> None:
+    source = "export function go(c: Client) {\n    c . flush ( );\n}\n"
+    calls = {call.name: call for call in _calls("go.ts", source, "typescript")}
+    flush = calls["c . flush"]
+    assert flush.receiver == "c"
+    assert flush.arity == 0