[BUG] Runtime: go | Agent fails to call sub-agents | Missing "request" field

[sidritic]

📋 Prerequisites

• I have searched the existing issues to avoid creating a duplicate
• By submitting this issue, you agree to follow our Code of Conduct
• I am using the latest version of the software
• I have tried to clear cache/cookies or used incognito mode (if ui-related)
• I can consistently reproduce this issue

🎯 Affected Service(s)

Controller Service

🚦 Impact/Severity

Minor inconvenience

🐛 Bug Description

I have a multi-agent architecture: 1 orchestrator delegating tasks to the sub-agents.
Given the better performance of runtime: go, I switched all of the Agents to it. The single agents seem to work as before, while the main agent (the orchestrator) can not delegate tasks. E.g. error

required: missing properties: [\"request\"]"}

Direct tools seem to be working properly, e.g. datetime_get_current_time

Workaround: reverted the orchestrator agent to the default runtime (python) and kept all sub-agents with runtime: go

🔄 Steps To Reproduce

1. create 2 agents, using runtime: go
2. config one of them to use the other as a sub-agent
3. ask smth to the "main" agent that would delegate to the sub-agent

🤔 Expected Behavior

Agents with runtime: go should be able to delegate task to sub-agents.
The proper field "request" is filled during the delegation.

📱 Actual Behavior

Agent with runtime: go can't deletate tasks to sub-agents.
Intput during delegate has empty request field

💻 Environment

AWS EKS - eks.29
Kubernetes - 1.33
Kagent: 0.8.6
Model: Bedrock - Anthropic Claude Sonnet 4.5

🔧 CLI Bug Report

No response

🔍 Additional Context

No response

📋 Logs

📷 Screenshots

It send an empty request field to the sub-agents:

🙋 Are you willing to contribute?

• I am willing to submit a PR to fix this issue

[supreme-gg-gg]

Hi @sidritic thanks for reporting the issue, would you mind providing the pod's logs when this issue happened? I wasn't able to reproduce this with Gemini / OpenAI, it could be something with our Bedrock support when used with Go runtime.

[sidritic]

It looks like the main agent is using the field task when delegating to the sub-agents, instead of the expected request.

{
  "level": "error",
  "timestamp": "2026-04-10T08:06:43.740Z",
  "caller": "agent/agent.go:323",
  "msg": "Tool execution completed with error",
  "tool": "kagent__NS__AAA_specialist",
  "functionCallID": "toolu_bdrk_01G4wNCcpP19u2szczBUjLAn",
  "sessionID": "aaa-bbbbbbbb-cccc-dddd-eeee-ffffffffffff",
  "invocationID": "e-4df1455b-b22a-4309-8caf-da9782f72073",
  "error": "validating root: required: missing properties: [\"request\"]",
  "stacktrace": "github.com/kagent-dev/kagent/go/adk/pkg/agent.CreateGoogleADKAgentWithSubagentSessionIDs.makeAfterToolCallback.func3\n\t/workspace/adk/pkg/agent/agent.go:323\ngoogle.golang.org/adk/internal/llminternal.(*Flow).invokeAfterToolCallbacks\n\t/root/go/pkg/mod/google.golang.org/adk@v1.0.0/internal/llminternal/base_flow.go:741\ngoogle.golang.org/adk/internal/llminternal.(*Flow).callTool\n\t/root/go/pkg/mod/google.golang.org/adk@v1.0.0/internal/llminternal/base_flow.go:711\ngoogle.golang.org/adk/internal/llminternal.(*Flow).handleFunctionCalls.func2\n\t/root/go/pkg/mod/google.golang.org/adk@v1.0.0/internal/llminternal/base_flow.go:613"
}
{
  "level": "error",
  "timestamp": "2026-04-10T08:06:43.740Z",
  "caller": "agent/agent.go:345",
  "msg": "Tool execution failed",
  "tool": "kagent__NS__AAA_specialist",
  "functionCallID": "toolu_bdrk_01G4wNCcpP19u2szczBUjLAn",
  "sessionID": "aaa-bbbbbbbb-cccc-dddd-eeee-ffffffffffff",
  "invocationID": "e-4df1455b-b22a-4309-8caf-da9782f72073",
  "args": "{}",
  "error": "validating root: required: missing properties: [\"request\"]",
  "stacktrace": "github.com/kagent-dev/kagent/go/adk/pkg/agent.CreateGoogleADKAgentWithSubagentSessionIDs.makeOnToolErrorCallback.func4\n\t/workspace/adk/pkg/agent/agent.go:345\ngoogle.golang.org/adk/internal/llminternal.(*Flow).invokeOnToolErrorCallbacks\n\t/root/go/pkg/mod/google.golang.org/adk@v1.0.0/internal/llminternal/base_flow.go:757\ngoogle.golang.org/adk/internal/llminternal.(*Flow).callTool\n\t/root/go/pkg/mod/google.golang.org/adk@v1.0.0/internal/llminternal/base_flow.go:698\ngoogle.golang.org/adk/internal/llminternal.(*Flow).handleFunctionCalls.func2\n\t/root/go/pkg/mod/google.golang.org/adk@v1.0.0/internal/llminternal/base_flow.go:613"
}
{
  "level": "info",
  "timestamp": "2026-04-10T08:06:43.740Z",
  "caller": "agent/agent.go:308",
  "msg": "Tool execution started",
  "tool": "kagent__NS__AAA_specialist",
  "functionCallID": "toolu_bdrk_01G4wNCcpP19u2szczBUjLAn",
  "sessionID": "aaa-bbbbbbbb-cccc-dddd-eeee-ffffffffffff",
  "invocationID": "e-4df1455b-b22a-4309-8caf-da9782f72073",
  "args": "{}"
}
{
  "level": "error",
  "timestamp": "2026-04-10T08:06:40.934Z",
  "caller": "agent/agent.go:323",
  "msg": "Tool execution completed with error",
  "tool": "kagent__NS__AAA_specialist",
  "functionCallID": "toolu_bdrk_01QWgvKqusiXFC5AwaqjHNjm",
  "sessionID": "aaa-bbbbbbbb-cccc-dddd-eeee-ffffffffffff",
  "invocationID": "e-4df1455b-b22a-4309-8caf-da9782f72073",
  "error": "validating root: required: missing properties: [\"request\"]",
  "stacktrace": "github.com/kagent-dev/kagent/go/adk/pkg/agent.CreateGoogleADKAgentWithSubagentSessionIDs.makeAfterToolCallback.func3\n\t/workspace/adk/pkg/agent/agent.go:323\ngoogle.golang.org/adk/internal/llminternal.(*Flow).invokeAfterToolCallbacks\n\t/root/go/pkg/mod/google.golang.org/adk@v1.0.0/internal/llminternal/base_flow.go:741\ngoogle.golang.org/adk/internal/llminternal.(*Flow).callTool\n\t/root/go/pkg/mod/google.golang.org/adk@v1.0.0/internal/llminternal/base_flow.go:711\ngoogle.golang.org/adk/internal/llminternal.(*Flow).handleFunctionCalls.func2\n\t/root/go/pkg/mod/google.golang.org/adk@v1.0.0/internal/llminternal/base_flow.go:613"
}
{
  "level": "error",
  "timestamp": "2026-04-10T08:06:40.934Z",
  "caller": "agent/agent.go:345",
  "msg": "Tool execution failed",
  "tool": "kagent__NS__AAA_specialist",
  "functionCallID": "toolu_bdrk_01QWgvKqusiXFC5AwaqjHNjm",
  "sessionID": "aaa-bbbbbbbb-cccc-dddd-eeee-ffffffffffff",
  "invocationID": "e-4df1455b-b22a-4309-8caf-da9782f72073",
  "args": "{}",
  "error": "validating root: required: missing properties: [\"request\"]",
  "stacktrace": "github.com/kagent-dev/kagent/go/adk/pkg/agent.CreateGoogleADKAgentWithSubagentSessionIDs.makeOnToolErrorCallback.func4\n\t/workspace/adk/pkg/agent/agent.go:345\ngoogle.golang.org/adk/internal/llminternal.(*Flow).invokeOnToolErrorCallbacks\n\t/root/go/pkg/mod/google.golang.org/adk@v1.0.0/internal/llminternal/base_flow.go:757\ngoogle.golang.org/adk/internal/llminternal.(*Flow).callTool\n\t/root/go/pkg/mod/google.golang.org/adk@v1.0.0/internal/llminternal/base_flow.go:698\ngoogle.golang.org/adk/internal/llminternal.(*Flow).handleFunctionCalls.func2\n\t/root/go/pkg/mod/google.golang.org/adk@v1.0.0/internal/llminternal/base_flow.go:613"
}
{
  "level": "info",
  "timestamp": "2026-04-10T08:06:40.934Z",
  "caller": "agent/agent.go:308",
  "msg": "Tool execution started",
  "tool": "kagent__NS__AAA_specialist",
  "functionCallID": "toolu_bdrk_01QWgvKqusiXFC5AwaqjHNjm",
  "sessionID": "aaa-bbbbbbbb-cccc-dddd-eeee-ffffffffffff",
  "invocationID": "e-4df1455b-b22a-4309-8caf-da9782f72073",
  "args": "{}"
}
{
  "level": "error",
  "timestamp": "2026-04-10T08:06:37.043Z",
  "caller": "agent/agent.go:323",
  "msg": "Tool execution completed with error",
  "tool": "kagent__NS__AAA_specialist",
  "functionCallID": "toolu_bdrk_01LebmY6zBwnNPfxkF1xZJQZ",
  "sessionID": "aaa-bbbbbbbb-cccc-dddd-eeee-ffffffffffff",
  "invocationID": "e-4df1455b-b22a-4309-8caf-da9782f72073",
  "error": "validating root: unexpected additional properties [\"$task\"]",
  "stacktrace": "github.com/kagent-dev/kagent/go/adk/pkg/agent.CreateGoogleADKAgentWithSubagentSessionIDs.makeAfterToolCallback.func3\n\t/workspace/adk/pkg/agent/agent.go:323\ngoogle.golang.org/adk/internal/llminternal.(*Flow).invokeAfterToolCallbacks\n\t/root/go/pkg/mod/google.golang.org/adk@v1.0.0/internal/llminternal/base_flow.go:741\ngoogle.golang.org/adk/internal/llminternal.(*Flow).callTool\n\t/root/go/pkg/mod/google.golang.org/adk@v1.0.0/internal/llminternal/base_flow.go:711\ngoogle.golang.org/adk/internal/llminternal.(*Flow).handleFunctionCalls.func2\n\t/root/go/pkg/mod/google.golang.org/adk@v1.0.0/internal/llminternal/base_flow.go:613"
}
{
  "level": "error",
  "timestamp": "2026-04-10T08:06:37.043Z",
  "caller": "agent/agent.go:345",
  "msg": "Tool execution failed",
  "tool": "kagent__NS__AAA_specialist",
  "functionCallID": "toolu_bdrk_01LebmY6zBwnNPfxkF1xZJQZ",
  "sessionID": "aaa-bbbbbbbb-cccc-dddd-eeee-ffffffffffff",
  "invocationID": "e-4df1455b-b22a-4309-8caf-da9782f72073",
  "args": "{\"$task\":\"List all available datasources in Loki\"}",
  "error": "validating root: unexpected additional properties [\"$task\"]",
  "stacktrace": "github.com/kagent-dev/kagent/go/adk/pkg/agent.CreateGoogleADKAgentWithSubagentSessionIDs.makeOnToolErrorCallback.func4\n\t/workspace/adk/pkg/agent/agent.go:345\ngoogle.golang.org/adk/internal/llminternal.(*Flow).invokeOnToolErrorCallbacks\n\t/root/go/pkg/mod/google.golang.org/adk@v1.0.0/internal/llminternal/base_flow.go:757\ngoogle.golang.org/adk/internal/llminternal.(*Flow).callTool\n\t/root/go/pkg/mod/google.golang.org/adk@v1.0.0/internal/llminternal/base_flow.go:698\ngoogle.golang.org/adk/internal/llminternal.(*Flow).handleFunctionCalls.func2\n\t/root/go/pkg/mod/google.golang.org/adk@v1.0.0/internal/llminternal/base_flow.go:613"
}
{
  "level": "info",
  "timestamp": "2026-04-10T08:06:37.043Z",
  "caller": "agent/agent.go:308",
  "msg": "Tool execution started",
  "tool": "kagent__NS__AAA_specialist",
  "functionCallID": "toolu_bdrk_01LebmY6zBwnNPfxkF1xZJQZ",
  "sessionID": "aaa-bbbbbbbb-cccc-dddd-eeee-ffffffffffff",
  "invocationID": "e-4df1455b-b22a-4309-8caf-da9782f72073",
  "args": "{\"$task\":\"List all available datasources in Loki\"}"
}
{
  "level": "info",
  "timestamp": "2026-04-10T08:06:33.566Z",
  "logger": "kagent-executor",
  "caller": "a2a/executor.go:117",
  "msg": "Execute",
  "taskID": "019d766d-b15d-70b5-979c-0c5e4daf79fb",
  "contextID": "aaa-bbbbbbbb-cccc-dddd-eeee-ffffffffffff",
  "appName": "kagent__NS__orchestrator_agent",
  "userID": "admin@kagent.dev"
}
{
  "level": "info",
  "timestamp": "2026-04-10T08:04:39.391Z",
  "caller": "server/server.go:77",
  "msg": "Starting Go ADK server!",
  "addr": "0.0.0.0:8080"
}
{
  "level": "info",
  "timestamp": "2026-04-10T08:04:39.390Z",
  "caller": "app/app.go:118",
  "msg": "Using KAgent task store",
  "url": "http://kagent-controller.kagent:8083"
}
{
  "level": "info",
  "timestamp": "2026-04-10T08:04:39.390Z",
  "caller": "app/app.go:114",
  "msg": "Using KAgent session service",
  "url": "http://kagent-controller.kagent:8083"
}
{
  "level": "info",
  "timestamp": "2026-04-10T08:04:39.390Z",
  "caller": "agent/agent.go:152",
  "msg": "Successfully created Google ADK LLM agent",
  "toolsCount": 5,
  "toolsetsCount": 1
}
{
  "level": "info",
  "timestamp": "2026-04-10T08:04:39.390Z",
  "caller": "agent/agent.go:140",
  "msg": "Creating Google ADK LLM agent",
  "name": "orchestrator_agent",
  "hasDescription": true,
  "hasInstruction": true,
  "toolsCount": 5,
  "toolsetsCount": 1
}
{
  "level": "info",
  "timestamp": "2026-04-10T08:04:39.390Z",
  "caller": "models/anthropic.go:135",
  "msg": "Initialized Anthropic Bedrock model",
  "model": "arn:aws:bedrock:eu-west-1:111111111111:inference-profile/eu.anthropic.claude-sonnet-4-5-20250929-v1:0",
  "region": "eu-west-1"
}
{
  "level": "info",
  "timestamp": "2026-04-10T08:04:39.390Z",
  "caller": "agent/agent.go:68",
  "msg": "Wired remote A2A agent tool",
  "name": "kagent__NS__kube_specialist",
  "url": "http://kube-specialist.kagent:8080"
}
{
  "level": "info",
  "timestamp": "2026-04-10T08:04:39.390Z",
  "caller": "agent/agent.go:68",
  "msg": "Wired remote A2A agent tool",
  "name": "kagent__NS__BBB_specialist",
  "url": "http://BBB-specialist.kagent:8080"
}
{
  "level": "info",
  "timestamp": "2026-04-10T08:04:39.390Z",
  "caller": "agent/agent.go:68",
  "msg": "Wired remote A2A agent tool",
  "name": "kagent__NS__CCC_specialist",
  "url": "http://CCC-specialist.kagent:8080"
}
{
  "level": "info",
  "timestamp": "2026-04-10T08:04:39.390Z",
  "caller": "agent/agent.go:68",
  "msg": "Wired remote A2A agent tool",
  "name": "kagent__NS__AAA_specialist",
  "url": "http://AAA-specialist.kagent:8080"
}
{
  "level": "info",
  "timestamp": "2026-04-10T08:04:39.390Z",
  "caller": "mcp/registry.go:63",
  "msg": "Processing SSE MCP tools",
  "sseToolsCount": 0
}
{
  "level": "info",
  "timestamp": "2026-04-10T08:04:39.390Z",
  "caller": "mcp/registry.go:107",
  "msg": "Successfully added HTTP MCP toolset",
  "url": "http://kagent-tools.kagent:8084/mcp"
}
{
  "level": "info",
  "timestamp": "2026-04-10T08:04:39.390Z",
  "caller": "mcp/registry.go:97",
  "msg": "Adding HTTP MCP tool",
  "index": 1,
  "url": "http://kagent-tools.kagent:8084/mcp",
  "toolFilterCount": 1,
  "tools": [
    "datetime_get_current_time"
  ]
}
{
  "level": "info",
  "timestamp": "2026-04-10T08:04:39.390Z",
  "caller": "mcp/registry.go:44",
  "msg": "Processing HTTP MCP tools",
  "httpToolsCount": 1
}
{
  "level": "info",
  "timestamp": "2026-04-10T08:04:39.390Z",
  "caller": "cmd/main.go:151",
  "msg": "Using KAgent session service",
  "url": "http://kagent-controller.kagent:8083"
}
{
  "level": "info",
  "timestamp": "2026-04-10T08:04:39.390Z",
  "caller": "cmd/main.go:140",
  "msg": "Token service started"
}
{
  "level": "info",
  "timestamp": "2026-04-10T08:04:39.390Z",
  "caller": "cmd/main.go:125",
  "msg": "ADK telemetry initialized"
}
{
  "level": "info",
  "timestamp": "2026-04-10T08:04:39.390Z",
  "caller": "cmd/main.go:234",
  "msg": "Built app_name from environment variables",
  "KAGENT_NAMESPACE": "kagent",
  "KAGENT_NAME": "orchestrator-agent",
  "app_name": "kagent__NS__orchestrator_agent"
}
{
  "level": "info",
  "timestamp": "2026-04-10T08:04:39.390Z",
  "caller": "cmd/main.go:90",
  "msg": "Agent configuration",
  "model": "bedrock",
  "stream": false,
  "httpTools": 1,
  "sseTools": 0,
  "remoteAgents": 4
}
{
  "level": "info",
  "timestamp": "2026-04-10T08:04:39.390Z",
  "caller": "cmd/main.go:89",
  "msg": "Loaded agent config",
  "configDir": "/config"
}
{
  "level": "info",
  "timestamp": "2026-04-10T08:04:39.389Z",
  "caller": "cmd/main.go:53",
  "msg": "Logger initialized"
}