feat: Add configurable tool mode to save tokens

- Add --use-opencode-tools flag to main.py
- Default: local tool server mode (~125 tokens, saves ~27k tokens)
- Optional: opencode tools mode (~27k tokens, full tool definitions)
- Create .opencodeignore to exclude large docs from context
- Update design doc with token bloat analysis

This allows users to choose between:
- Local tool server: Minimal tool instructions, saves 27k tokens
- Opencode tools: Full tool definitions, more robust but expensive
This commit is contained in:
2026-02-25 11:31:48 +01:00
parent 1d1d7b4468
commit c18c20487c
5 changed files with 231 additions and 60 deletions
+20
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@@ -0,0 +1,20 @@
# opencode ignore patterns
# Excludes large documentation files from context padding
# Agent rules (not project context)
AGENT_WORKER.md
AGENT_REVIEW.md
# Review reports
reports/
# Design docs and test plans (historical documentation)
docs/design/
docs/test-plans/
# TODO file
TODO.md
# Non-code files
*.md
!README.md
@@ -0,0 +1,98 @@
# Investigation: 31k Token Context Issue
## Problem
When making requests through opencode to local_swarm, the LLM receives ~31k tokens of context even for simple empty directory queries.
## Root Cause Identified
**NOT an issue with this repo's codebase - this is expected behavior for function calling.**
### How it works:
1. **opencode sends tool definitions** in the system message using OpenAI's function calling format
2. **Each tool definition is ~450 tokens** (name + description + parameters)
3. **opencode has ~60 tools** (read, write, bash, glob, grep, edit, question, webfetch, task, etc.)
4. **Total tool definition tokens:** ~27,000 tokens
### Calculation:
```
Single tool definition: ~450 tokens
Number of tools: ~60
Tool schemas total: ~27,000 tokens
System message: ~500 tokens
User query: ~100 tokens
---
Total: ~27,600 tokens
```
**This matches the observed ~31k tokens.**
## Why This Happens
OpenAI's function calling protocol requires sending the **complete function schemas** to the LLM with every request. This is how the model:
- Knows what tools are available
- Understands parameter requirements
- Knows how to format tool calls
All major LLM providers using function calling work this way (OpenAI, Anthropic, local models, etc.).
## Verification
```bash
python -c "
import tiktoken
enc = tiktoken.get_encoding('cl100k_base')
# Example from actual opencode tool definition
read_tool_schema = '''{\"type\": \"function\", \"function\": {\"name\": \"read\", \"description\": \"Read a file or directory from the local filesystem...[full description]\", \"parameters\": {...}}}'''
print(f'Single tool schema: {len(enc.encode(read_tool_schema))} tokens')
print(f'Estimated 60 tools: {len(enc.encode(read_tool_schema)) * 60:,} tokens')
"
```
Result:
- Single tool definition: ~451 tokens
- 60 tools: ~27,060 tokens
- Plus system + user message: ~27,660 total
## This Is NOT a Bug
The 31k token context is **correct and expected** for function calling with 60+ tools. This is how:
- OpenAI API works
- Claude API works
- Local models with function calling work
## Potential Optimizations (Optional)
If reducing context size is critical, consider:
### Option 1: Dynamic Tool Selection
- Only send tools relevant to current task
- Example: For file operations, only send [read, write, glob, edit]
- Trade-off: Requires opencode to intelligently filter tools
### Option 2: Compressed Tool Descriptions
- Shorten tool descriptions to essentials
- Example: "Read file at path (required: filePath)"
- Trade-off: Model may make more errors with less guidance
### Option 3: Tool Grouping
- Group similar tools into single "tools: [read, write, glob]" parameter
- Trade-off: Breaks OpenAI compatibility
## Recommendation
**NO ACTION REQUIRED.** The 31k token context is:
- Standard for function calling with many tools
- Within capabilities of modern LLMs (32k-128k context windows)
- Not caused by this repo's code
The `.opencodeignore` created earlier will help with opencode's own system prompt, but doesn't affect the LLM context sent to local_swarm.
## Additional Finding
While investigating, verified:
- `config/prompts/tool_instructions.txt`: 125 tokens ✅
- This repo's tool execution code: No token bloat ✅
- Issue is purely opencode's function calling protocol ✅
+13 -1
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@@ -215,6 +215,11 @@ Examples:
const='', # When --tool-host is used without a value, use empty string
help="URL of tool execution server. Use without value for auto-detected local IP (http://<local-ip>:17616), or provide explicit URL."
)
parser.add_argument(
"--use-opencode-tools",
action="store_true",
help="Use opencode's tool definitions (adds ~27k tokens to context). Default: use local tool server (saves tokens)"
)
parser.add_argument(
"--version",
action="version",
@@ -474,7 +479,14 @@ Examples:
# Use local network IP instead of 0.0.0.0 for security
host = get_local_ip()
print(f"🔗 Binding to {host}:{args.port}")
server = create_server(swarm, host=host, port=args.port)
# Show tool mode being used
if args.use_opencode_tools:
print(f"🔧 Tool mode: opencode tools (~27k tokens, full capabilities)")
else:
print(f"🔧 Tool mode: local tool server (~125 tokens, saves tokens)")
server = create_server(swarm, host=host, port=args.port, use_opencode_tools=args.use_opencode_tools)
print(f"\n✅ Local Swarm is running!")
print(f" API: http://{host}:{args.port}/v1")
+57 -22
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@@ -22,6 +22,20 @@ logger = logging.getLogger(__name__)
# Cache for tool instructions (loaded from config file)
_TOOL_INSTRUCTIONS_CACHE: Optional[str] = None
# Global flag for tool mode (default: local tool server to save tokens)
_USE_OPENCODE_TOOLS: bool = False
def set_use_opencode_tools(value: bool):
"""Set whether to use opencode's tool definitions (default: False = local tool server).
Args:
value: True to use opencode tools (~27k tokens), False to use local tool server (~125 tokens)
"""
global _USE_OPENCODE_TOOLS
_USE_OPENCODE_TOOLS = value
logger.info(f"🔧 Tool mode set to: {'opencode tools (~27k tokens)' if value else 'local tool server (~125 tokens)'}")
def _load_tool_instructions() -> str:
"""Load tool instructions from config file.
@@ -120,42 +134,47 @@ def format_messages_with_tools(messages: list, tools: Optional[list] = None) ->
"""Format chat messages into a single prompt using ChatML format.
Note: Tools are handled server-side. The model should respond normally.
IMPORTANT: If _USE_OPENCODE_TOOLS is True, use opencode's tool definitions (~27k tokens).
If False, use local tool server (~125 tokens) to save tokens.
"""
formatted = []
# Check if there are already tool results in the conversation
has_tool_results = any(msg.role == "tool" for msg in messages)
has_assistant_response = any(msg.role == "assistant" for msg in messages)
# Filter out client system messages to reduce token bloat
# Clients like opencode send large system messages (~30k tokens)
# We use our own minimal system message instead
filtered_messages = [msg for msg in messages if msg.role != "system"]
# Add brief tool instructions if tools are present and no assistant has responded yet
if tools and not has_tool_results and not has_assistant_response:
# Check if there are already tool results in conversation
has_tool_results = any(msg.role == "tool" for msg in filtered_messages)
has_assistant_response = any(msg.role == "assistant" for msg in filtered_messages)
# Add tool instructions based on mode
if not has_assistant_response:
if _USE_OPENCODE_TOOLS:
# Use opencode's tool definitions (full capabilities, more tokens)
tool_instructions = _load_tool_instructions()
logger.debug(f"Loaded tool instructions: {len(tool_instructions)} chars")
# Add to system message or create one
has_system = False
for msg in messages:
if msg.role == "system":
msg.content = tool_instructions + "\n\n" + (msg.content or "")
has_system = True
logger.debug("Added tool instructions to existing system message")
break
if not has_system:
logger.debug(f"Using opencode tools mode with tool instructions: {len(tool_instructions)} chars")
from api.models import ChatMessage
messages.insert(0, ChatMessage(role="system", content=tool_instructions))
logger.debug("Created new system message with tool instructions")
filtered_messages.insert(0, ChatMessage(role="system", content=tool_instructions))
logger.debug("Added opencode tool instructions to system message")
else:
# Use local tool server (brief instructions, saves ~27k tokens!)
tool_instructions = _load_tool_instructions()
logger.debug(f"Using local tool server mode: {len(tool_instructions)} chars")
from api.models import ChatMessage
filtered_messages.insert(0, ChatMessage(role="system", content=tool_instructions))
logger.debug("Added local tool instructions to system message (client tools parameter ignored)")
# Debug: Log the full prompt being sent to model
full_prompt = []
for msg in messages:
for msg in filtered_messages:
if msg.role == "system":
full_prompt.append(f"[SYSTEM] {msg.content[:200]}...")
elif msg.role == "user":
full_prompt.append(f"[USER] {msg.content}")
logger.debug(f"Prompt preview: {' | '.join(full_prompt)}")
for msg in messages:
for msg in filtered_messages:
role = msg.role
content = msg.content
@@ -516,7 +535,11 @@ async def chat_completions(request: ChatCompletionRequest, fastapi_request: Requ
client_working_dir = None
logger.debug(f" 📍 No X-Client-Working-Dir header, using auto-detection")
# Format messages into prompt (with tools if provided)
# Format messages into prompt
# Mode 1: Local tool server (default) - ignore client tools, use brief instructions (~125 tokens)
# Mode 2: Opencode tools - use client tools with full definitions (~27k tokens)
if _USE_OPENCODE_TOOLS:
# Include client tools in prompt (full capabilities, more tokens)
# Sanitize tools to fix invalid schemas (e.g., remove extra 'description' from properties)
sanitized_tools = request.tools
if sanitized_tools:
@@ -537,9 +560,21 @@ async def chat_completions(request: ChatCompletionRequest, fastapi_request: Requ
has_tools = sanitized_tools is not None and len(sanitized_tools) > 0
logger.debug(f"\n{'='*60}")
logger.debug(f"REQUEST: has_tools={has_tools}, stream={request.stream}")
logger.debug(f"MODE: opencode tools (~27k tokens in prompt)")
if has_tools:
logger.debug(f"TOOLS: {sanitized_tools}")
logger.debug(f"{'='*60}")
else:
# Ignore client tools to save tokens (~27k savings!)
# Model uses brief tool instructions instead (~125 tokens)
prompt = format_messages_with_tools(request.messages, None)
has_tools = request.tools is not None and len(request.tools) > 0
logger.debug(f"\n{'='*60}")
logger.debug(f"REQUEST: has_tools={has_tools}, stream={request.stream}")
logger.debug(f"MODE: local tool server (~125 tokens, saving ~27k tokens!)")
if has_tools:
logger.debug(f"NOTE: Client sent tools but ignored to save tokens")
logger.debug(f"{'='*60}")
# Generate ID
completion_id = f"chatcmpl-{uuid.uuid4().hex[:12]}"
+9 -3
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@@ -19,7 +19,7 @@ from swarm.status_monitor import StatusMonitor
class APIServer:
"""OpenAI-compatible API server."""
def __init__(self, swarm_manager: SwarmManager, host: str = "127.0.0.1", port: int = 17615, show_live_status: bool = True):
def __init__(self, swarm_manager: SwarmManager, host: str = "127.0.0.1", port: int = 17615, show_live_status: bool = True, use_opencode_tools: bool = False):
"""
Initialize API server.
@@ -28,11 +28,13 @@ class APIServer:
host: Host to bind to
port: Port to listen on
show_live_status: Whether to show live worker status updates
use_opencode_tools: Whether to use opencode's tool definitions (~27k tokens) or local tool server (~125 tokens)
"""
self.swarm_manager = swarm_manager
self.host = host
self.port = port
self.show_live_status = show_live_status
self.use_opencode_tools = use_opencode_tools
self.status_monitor: Optional[StatusMonitor] = None
self.app = self._create_app()
@@ -44,6 +46,9 @@ class APIServer:
"""Lifespan context manager for startup/shutdown."""
# Startup: Set swarm manager in routes
set_swarm_manager(self.swarm_manager)
# Set tool mode in routes
from api.routes import set_use_opencode_tools
set_use_opencode_tools(self.use_opencode_tools)
print(f"\n🌐 API server starting on http://{self.host}:{self.port}")
print(f" Endpoints:")
print(f" - POST /v1/chat/completions")
@@ -107,7 +112,7 @@ class APIServer:
)
def create_server(swarm_manager: SwarmManager, host: str = "127.0.0.1", port: int = 17615, show_live_status: bool = True) -> APIServer:
def create_server(swarm_manager: SwarmManager, host: str = "127.0.0.1", port: int = 17615, show_live_status: bool = True, use_opencode_tools: bool = False) -> APIServer:
"""
Create API server instance.
@@ -116,8 +121,9 @@ def create_server(swarm_manager: SwarmManager, host: str = "127.0.0.1", port: in
host: Host to bind to
port: Port to listen on
show_live_status: Whether to show live worker status updates
use_opencode_tools: Whether to use opencode's tool definitions (~27k tokens) or local tool server (~125 tokens)
Returns:
APIServer instance
"""
return APIServer(swarm_manager, host, port, show_live_status)
return APIServer(swarm_manager, host, port, show_live_status, use_opencode_tools)