diff --git a/src/php/ext/grpc/call.c b/src/php/ext/grpc/call.c
index 66b26716b13..03f4d56901f 100644
--- a/src/php/ext/grpc/call.c
+++ b/src/php/ext/grpc/call.c
@@ -16,6 +16,11 @@
  *
  */
 
+/**
+ * class Call
+ * @see https://github.com/grpc/grpc/tree/master/src/php/ext/grpc/call.c
+ */
+
 #include "call.h"
 
 #include <ext/spl/spl_exceptions.h>
@@ -193,7 +198,7 @@ zval *grpc_php_wrap_call(grpc_call *wrapped, bool owned TSRMLS_DC) {
  *                             Must not be closed.
  * @param string $method The method to call
  * @param Timeval $deadline_obj The deadline for completing the call
- * @param string $host_override The host is set by user (optional)
+ * @param string $host_override = "" The host is set by user (optional)
  */
 PHP_METHOD(Call, __construct) {
   zval *channel_obj;
diff --git a/src/php/ext/grpc/call_credentials.c b/src/php/ext/grpc/call_credentials.c
index 484b9b54bf4..a57a8410366 100644
--- a/src/php/ext/grpc/call_credentials.c
+++ b/src/php/ext/grpc/call_credentials.c
@@ -16,6 +16,11 @@
  *
  */
 
+/**
+ * class CallCredentials
+ * @see https://github.com/grpc/grpc/tree/master/src/php/ext/grpc/call_credentials.c
+ */
+
 #include "call_credentials.h"
 
 #include <ext/spl/spl_exceptions.h>
diff --git a/src/php/ext/grpc/channel.c b/src/php/ext/grpc/channel.c
index 059e8333db1..47483812b25 100644
--- a/src/php/ext/grpc/channel.c
+++ b/src/php/ext/grpc/channel.c
@@ -16,6 +16,11 @@
  *
  */
 
+/**
+ * class Channel
+ * @see https://github.com/grpc/grpc/tree/master/src/php/ext/grpc/channel.c
+ */
+
 #include "channel.h"
 
 #include <ext/standard/php_var.h>
diff --git a/src/php/ext/grpc/channel_credentials.c b/src/php/ext/grpc/channel_credentials.c
index 4fa99b1012d..a1611d13518 100644
--- a/src/php/ext/grpc/channel_credentials.c
+++ b/src/php/ext/grpc/channel_credentials.c
@@ -16,6 +16,11 @@
  *
  */
 
+/**
+ * class ChannelCredentials
+ * @see https://github.com/grpc/grpc/tree/master/src/php/ext/grpc/channel_credentials.c
+ */
+
 #include "channel_credentials.h"
 
 #include <ext/standard/sha1.h>
@@ -134,10 +139,10 @@ PHP_METHOD(ChannelCredentials, createDefault) {
 
 /**
  * Create SSL credentials.
- * @param string $pem_root_certs PEM encoding of the server root certificates
- * @param string $pem_key_cert_pair.private_key PEM encoding of the client's
+ * @param string $pem_root_certs = "" PEM encoding of the server root certificates (optional)
+ * @param string $private_key = "" PEM encoding of the client's
  *                                              private key (optional)
- * @param string $pem_key_cert_pair.cert_chain PEM encoding of the client's
+ * @param string $cert_chain = "" PEM encoding of the client's
  *                                             certificate chain (optional)
  * @return ChannelCredentials The new SSL credentials object
  */
diff --git a/src/php/ext/grpc/server.c b/src/php/ext/grpc/server.c
index 8c7eaee203f..7f3c3b8e3bb 100644
--- a/src/php/ext/grpc/server.c
+++ b/src/php/ext/grpc/server.c
@@ -16,6 +16,11 @@
  *
  */
 
+/**
+ * class Server
+ * @see https://github.com/grpc/grpc/tree/master/src/php/ext/grpc/server.c
+ */
+
 #include "server.h"
 
 #include <ext/spl/spl_exceptions.h>
diff --git a/src/php/ext/grpc/server_credentials.c b/src/php/ext/grpc/server_credentials.c
index 72ce50fff72..2c2f9c185f3 100644
--- a/src/php/ext/grpc/server_credentials.c
+++ b/src/php/ext/grpc/server_credentials.c
@@ -16,6 +16,11 @@
  *
  */
 
+/**
+ * class ServerCredentials
+ * @see https://github.com/grpc/grpc/tree/master/src/php/ext/grpc/server_credentials.c
+ */
+
 #include "server_credentials.h"
 
 #include <ext/spl/spl_exceptions.h>
@@ -56,9 +61,9 @@ zval *grpc_php_wrap_server_credentials(grpc_server_credentials
 
 /**
  * Create SSL credentials.
- * @param string pem_root_certs PEM encoding of the server root certificates
- * @param string pem_private_key PEM encoding of the client's private key
- * @param string pem_cert_chain PEM encoding of the client's certificate chain
+ * @param string $pem_root_certs PEM encoding of the server root certificates
+ * @param string $pem_private_key PEM encoding of the client's private key
+ * @param string $pem_cert_chain PEM encoding of the client's certificate chain
  * @return Credentials The new SSL credentials object
  */
 PHP_METHOD(ServerCredentials, createSsl) {
diff --git a/src/php/ext/grpc/timeval.c b/src/php/ext/grpc/timeval.c
index 8f0048def6e..3cfab86849c 100644
--- a/src/php/ext/grpc/timeval.c
+++ b/src/php/ext/grpc/timeval.c
@@ -16,6 +16,11 @@
  *
  */
 
+/**
+ * class Timeval
+ * @see https://github.com/grpc/grpc/tree/master/src/php/ext/grpc/timeval.c
+ */
+
 #include "timeval.h"
 
 #include <ext/spl/spl_exceptions.h>