Fluent::ConfigError error="'format' parameter is required"

[icalvete]

With these vertsions...

root@nodens:/etc/td-agent/config.d# td-agent-gem list fluent

*** LOCAL GEMS ***

fluent-config-regexp-type (1.0.0)
fluent-diagtool (1.0.1)
fluent-logger (0.9.0)
fluent-plugin-calyptia-monitoring (0.1.3)
fluent-plugin-elasticsearch (5.2.3, 5.2.2)
fluent-plugin-flowcounter-simple (0.1.0)
fluent-plugin-kafka (0.17.5)
fluent-plugin-metrics-cmetrics (0.1.2)
fluent-plugin-opensearch (1.0.4)
fluent-plugin-parser (0.6.1)
fluent-plugin-prometheus (2.0.2)
fluent-plugin-prometheus_pushgateway (0.1.0)
fluent-plugin-record-modifier (2.1.0)
fluent-plugin-rewrite-tag-filter (2.4.0)
fluent-plugin-s3 (1.6.1)
fluent-plugin-sd-dns (0.1.0)
fluent-plugin-systemd (1.0.5)
fluent-plugin-td (1.1.0)
fluent-plugin-utmpx (0.5.0)
fluent-plugin-webhdfs (1.5.0)
fluentd (1.14.6, 0.12.43)

When I add this config...

<filter foo.bar>
  @type parser
  key_name log
  reserve_time true
  <parse>
    @type json
  </parse>
</filter>

I get this errror

2022-07-06 18:28:25 +0000 [error]: config error file="/etc/td-agent/td-agent.conf" error_class=Fluent::ConfigError error="'format' parameter is required"

I don't see any parameter called format here https://docs.fluentd.org/filter/parser

This is my entire conf...

<match sp.local4.*>
  @type copy

  <store>
    cloud_auth 'el:XXXXX'
    cloud_id my-track:ZXUtd2VzdC0xLmF3cy5mb3VuZC5pbzodghgMkOhhhhZjjjjjjjjNDYxMGI2Y2ZhZDkxZDVlZGNhMGIkOTdlZDAhhjhjhjhDhkNDAwMDg4ZjFhNWMzNTQ4Y2VhNmE=
    logstash_format true
    logstash_prefix fluentd
    schema https
    @type elasticsearch
  </store>
  <store>
    @type stdout
    @id sp_output_stdout
  </store>
</match>
<source>
  bind 0.0.0.0
  port 5514
  tag sp
  <transport tcp>
  </transport>
  @type syslog
</source>

Any idea?