tools-only Phase 2: FunctionNode Removal + Dead Code Cleanup
Ref: GitHub Issue #4753
Context
FunctionNode (node_type="function") breaks three core agent principles: conversation continuity, cumulative tools, and user interruptibility. Phase 1 (soft deprecation warnings) is complete. This plan covers Phase 2 (hard removal) plus cleanup of other dead code discovered during scoping.
Total estimated removal: ~5,000+ lines across production code, tests, docs, and examples.
Part 1: Remove FunctionNode class and "function" node type
1.1 Core framework
| File | What to remove/change |
|---|---|
core/framework/graph/node.py |
Delete FunctionNode class (function field from NodeSpec ( |
core/framework/graph/executor.py |
Remove FunctionNode import ("function" from VALID_NODE_TYPES (node_type == "function" branch (register_function() (node_type="function". |
core/framework/builder/workflow.py |
Remove node_type == "function" validation block (~L258-260). |
1.2 Agent Builder MCP server
| File | What to change |
|---|---|
core/framework/mcp/agent_builder_server.py |
Remove "function" from node_type description in add_node (update_node (node_type == "function" simulation branch in test_node (~L2356-2357). |
1.3 Examples & demos
| File | Action |
|---|---|
core/examples/manual_agent.py |
Rewrite to use event_loop nodes |
core/demos/github_outreach_demo.py |
Convert Sender node from function to event_loop |
core/examples/mcp_integration_example.py |
Rewrite to use event_loop nodes |
1.4 Docs & skills
| File | Action |
|---|---|
.claude/skills/hive-create/SKILL.md |
Remove "function" from node type table (~L495, L856) |
docs/developer-guide.md |
Remove "function" node type reference (~L613) |
core/MCP_SERVER_GUIDE.md |
Audit for "function" references |
docs/why-conditional-edge-priority.md |
Remove or repurpose (entire doc framed around function nodes) |
docs/environment-setup.md |
Remove "function" from node types list (~L216) |
docs/i18n/*.md |
Update BUILD diagrams in 7 i18n files (ja, ko, pt, hi, es, ru, zh-CN) removing "Function" |
core/framework/runtime/runtime_log_schemas.py |
Remove "function" from node_type comment (~L40) |
Part 2: Remove deprecated LLMNode + llm_tool_use / llm_generate
Already soft-deprecated with DeprecationWarning. No template agent uses them. Only mcp_integration_example.py references them.
| File | What to remove/change |
|---|---|
core/framework/graph/node.py |
Delete LLMNode class (~L660-1689, ~1000 lines). Largest single removal. |
core/framework/graph/executor.py |
Remove LLMNode import. Remove "llm_tool_use"/"llm_generate" from VALID_NODE_TYPES. Remove DEPRECATED_NODE_TYPES dict. Remove their branches in _get_node_implementation (~L1507-1523). Update human_input branch to use EventLoopNode instead of LLMNode. Add migration error for deprecated types. |
core/framework/mcp/agent_builder_server.py |
Remove llm_tool_use/llm_generate validation warnings and branches (~L668-683, L922-937) |
Part 3: Rewrite tests using function nodes as fixtures
These tests use node_type="function" as convenient scaffolding but actually test graph execution features (retries, fan-out, feedback edges, etc.). They all need rewriting.
| Test file | What it tests |
|---|---|
core/tests/test_on_failure_edges.py |
On-failure edge routing (~10 function nodes) |
core/tests/test_executor_feedback_edges.py |
Max node visits, feedback loops (~20+ function nodes) |
core/tests/test_executor_max_retries.py |
Retry behavior (~7 function nodes) |
core/tests/test_fanout.py |
Fan-out/fan-in parallel execution (~20+ function nodes) |
core/tests/test_execution_quality.py |
Retry + quality scoring (~8 function nodes) |
core/tests/test_conditional_edge_direct_key.py |
Conditional edge evaluation (~8 function nodes) |
core/tests/test_event_loop_integration.py |
Mixed node graph test (~2 function nodes) |
core/tests/test_runtime_logger.py |
Runtime log schema (~2 references) |
tools/tests/tools/test_runtime_logs_tool.py |
Log tool output (~2 references) |
Strategy: Create a MockNode(NodeProtocol) test helper that wraps a callable, providing the same convenience as FunctionNode but scoped to tests only. Tests swap node_type="function" for a neutral node_type="event_loop" and register a MockNode in the executor's node_registry. This minimizes rewrite effort.
Part 4: Items NOT recommended for removal
| Item | Reason to keep |
|---|---|
RouterNode |
Architecturally sound (deterministic routing), just lacks template examples |
human_input node type |
Valid HITL pattern, but switch implementation from LLMNode to EventLoopNode |
register_function in tool_registry.py |
For tool registration — completely different concept from function nodes |
Part 5: Remove the Planner-Worker subsystem (~3,900 lines dead code)
The entire Planner-Worker-Judge pattern has zero external consumers. No template agent, example, demo, or runner references it. It is only consumed by:
- Its own internal files (self-referential imports)
- The agent-builder MCP server (exposes tools for it)
- Its own dedicated tests
5.1 Delete these files entirely
| File | Lines | What |
|---|---|---|
core/framework/graph/flexible_executor.py |
552 | FlexibleGraphExecutor — Worker-Judge orchestrator |
core/framework/graph/worker_node.py |
620 | WorkerNode — plan step dispatcher |
core/framework/graph/plan.py |
513 | Plan, PlanStep, ActionType, ActionSpec data structures |
core/framework/graph/judge.py |
406 | HybridJudge — step result evaluator |
core/framework/graph/code_sandbox.py |
413 | CodeSandbox — sandboxed code execution |
core/tests/test_flexible_executor.py |
442 | FlexibleGraphExecutor tests |
core/tests/test_plan.py |
592 | Plan data structure tests |
core/tests/test_plan_dependency_resolution.py |
384 | Plan dependency resolution tests |
5.2 Clean up exports
core/framework/graph/__init__.py — Remove all planner-worker exports: FlexibleGraphExecutor, ExecutorConfig, WorkerNode, StepExecutionResult, HybridJudge, create_default_judge, CodeSandbox, safe_eval, safe_exec, Plan, PlanStep, ActionType, ActionSpec, and all related symbols.
5.3 Remove MCP tools from agent-builder server
core/framework/mcp/agent_builder_server.py — Remove these 7 MCP tools:
| MCP tool | Description |
|---|---|
create_plan |
Creates a plan with steps |
validate_plan |
Validates plan structure |
simulate_plan_execution |
Dry-run simulation |
load_exported_plan |
Loads plan from JSON |
add_evaluation_rule |
Adds HybridJudge rule |
list_evaluation_rules |
Lists evaluation rules |
remove_evaluation_rule |
Removes evaluation rule |
Also remove:
from framework.graph.plan import Planimport (~L39, L3731)_evaluation_rulesglobal list (~L2528)"evaluation_rules"from export/session data (~L1859)load_plan_from_json()helper function (~L3721-3733)
Execution order
- Create
MockNodetest helper — unblocks all test rewrites - Rewrite tests using function nodes as fixtures (Part 3)
- Remove
FunctionNodeclass + all references (Part 1) - Remove
LLMNodeclass + deprecated types (Part 2) - Delete Planner-Worker subsystem files (Part 5.1)
- Clean up
__init__.pyexports (Part 5.2) - Remove MCP tools for plans/evaluation from agent-builder server (Part 5.3)
- Update examples/demos/docs/skills (Parts 1.3, 1.4)
- Run full test suite to verify
Verification
pytest core/tests/— all tests passpytest tools/tests/— runtime log tests pass- Load any template agent JSON — no errors
- Attempt to load a graph with
node_type="function"— clearRuntimeErrorwith migration guidance - Attempt to load a graph with
node_type="llm_tool_use"— clearRuntimeErrorwith migration guidance - Agent builder MCP:
add_nodewithnode_type="function"— rejected with helpful message - Plan/evaluation MCP tools no longer appear in tool list