Add execution_logging config to engine schema

Document the execution_logging configuration block that was deferred
from PR #146 until the config shape stabilized (PLT-1106).

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: itsthatriver

engine/config/2.0/schema.json

@@ -320,6 +320,108 @@
       "oneOf": [{ "required": ["in_memory"] }, { "required": ["redis"] }],
       "additionalProperties": false
     },
+    "execution_logging": {
+      "type": "object",
+      "description": "Configures execution logging for tool calls.",
+      "properties": {
+        "enabled": {
+          "description": "Whether execution logging is enabled.",
+          "oneOf": [
+            { "type": "boolean", "default": false },
+            { "$ref": "#/$defs/envVarPattern" },
+            { "$ref": "#/$defs/filePattern" }
+          ]
+        },
+        "max_output_size": {
+          "description": "The maximum size in bytes of captured tool output.",
+          "oneOf": [
+            { "type": "integer", "default": 10485760 },
+            { "$ref": "#/$defs/envVarPattern" },
+            { "$ref": "#/$defs/filePattern" }
+          ]
+        },
+        "buffer_size": {
+          "description": "The number of execution log entries to buffer in memory before flushing.",
+          "oneOf": [
+            { "type": "integer", "default": 10000, "minimum": 1, "maximum": 1000000 },
+            { "$ref": "#/$defs/envVarPattern" },
+            { "$ref": "#/$defs/filePattern" }
+          ]
+        },
+        "write_batch_size": {
+          "description": "The number of execution log entries to write per batch.",
+          "oneOf": [
+            { "type": "integer", "default": 100, "minimum": 1, "maximum": 10000 },
+            { "$ref": "#/$defs/envVarPattern" },
+            { "$ref": "#/$defs/filePattern" }
+          ]
+        },
+        "write_batch_timeout": {
+          "description": "The maximum time to wait before flushing a partial batch as a duration string (e.g. '200ms'). Maximum '10s'.",
+          "oneOf": [
+            { "type": "string", "default": "200ms" },
+            { "$ref": "#/$defs/envVarPattern" },
+            { "$ref": "#/$defs/filePattern" }
+          ]
+        },
+        "drain_timeout": {
+          "description": "The maximum time to wait for buffered entries to drain on shutdown as a duration string (e.g. '30s'). Maximum '5m'.",
+          "oneOf": [
+            { "type": "string", "default": "30s" },
+            { "$ref": "#/$defs/envVarPattern" },
+            { "$ref": "#/$defs/filePattern" }
+          ]
+        },
+        "config_cache_ttl": {
+          "description": "The TTL for caching execution logging configuration as a duration string (e.g. '10s'). Maximum '1h'.",
+          "oneOf": [
+            { "type": "string", "default": "10s" },
+            { "$ref": "#/$defs/envVarPattern" },
+            { "$ref": "#/$defs/filePattern" }
+          ]
+        },
+        "coordinator_url": {
+          "description": "The URL of the execution logging coordinator service.",
+          "oneOf": [
+            { "type": "string", "format": "uri" },
+            { "$ref": "#/$defs/envVarPattern" },
+            { "$ref": "#/$defs/filePattern" }
+          ]
+        },
+        "cleanup": {
+          "type": "object",
+          "description": "Configures automatic cleanup of old execution logs.",
+          "properties": {
+            "batch_size": {
+              "description": "The number of execution log entries to process per cleanup batch.",
+              "oneOf": [
+                { "type": "integer", "default": 1000, "minimum": 1, "maximum": 100000 },
+                { "$ref": "#/$defs/envVarPattern" },
+                { "$ref": "#/$defs/filePattern" }
+              ]
+            },
+            "mark_interval": {
+              "description": "The interval between cleanup marking passes as a duration string (e.g. '30m').",
+              "oneOf": [
+                { "type": "string", "default": "30m" },
+                { "$ref": "#/$defs/envVarPattern" },
+                { "$ref": "#/$defs/filePattern" }
+              ]
+            },
+            "sweep_batch_interval": {
+              "description": "The interval between cleanup sweep batches as a duration string (e.g. '5s').",
+              "oneOf": [
+                { "type": "string", "default": "5s" },
+                { "$ref": "#/$defs/envVarPattern" },
+                { "$ref": "#/$defs/filePattern" }
+              ]
+            }
+          },
+          "additionalProperties": false
+        }
+      },
+      "additionalProperties": false
+    },
     "llm": {
       "type": "object",
       "description": "Configures the language models that can handle requests.",