Kimi K2 family ↗
noOriginal Documentation
Documentation Index#
Fetch the complete documentation index at: https://docs.fireworks.ai/llms.txt Use this file to discover all available pages before exploring further.
Using Kimi K2 family models in agentic and tool-calling workflows on Fireworks.
Using the Kimi K2 family in agentic workflows#
Always set max_tokens#
Models in the Kimi K2 family can produce very long reasoning traces before arriving at a final answer. In agentic workflows where output is parsed and passed to downstream steps, always set max_tokens explicitly:
response = client.chat.completions.create(
model="accounts/fireworks/models/kimi-k2-instruct",
messages=messages,
max_tokens=512,
tools=tools,
)Starting points by output type:
| Output type | Suggested max_tokens |
|---|---|
| Tool call responses | 256–512 |
| Short text | 512–1024 |
| Structured JSON | 1024–2048 |
| Long-form reasoning | 4096+ |
Tool schema design#
Kimi K2 family models perform best when tools have clearly distinct names, descriptions, and parameter schemas. When tools have overlapping surface areas the model may select the wrong one.
# Less clear — overlapping descriptions
tools = [
{"type": "function", "function": {"name": "read", "description": "Read data from a source", "parameters": {"type": "object", "properties": {}}}},
{"type": "function", "function": {"name": "exec", "description": "Execute an operation on a source", "parameters": {"type": "object", "properties": {}}}},
]
# More clear — distinct names and explicit scope
tools = [
{
"type": "function",
"function": {
"name": "read_file",
"description": "Read the contents of a file at a given path. Use this to inspect existing content before making changes. Do not use this to run code.",
"parameters": {"type": "object", "properties": {}},
},
},
{
"type": "function",
"function": {
"name": "execute_command",
"description": "Run a shell command and return its output. Use this to run scripts, tests, or system operations. Do not use this to read file contents.",
"parameters": {"type": "object", "properties": {}},
},
},
]Best practices:
- Name tools by their primary action, not their domain (
read_filenotfile_tool). - Write descriptions that distinguish tools from each other, including what each tool is not for.
- Avoid optional parameters that make two tools look identical with only a flag difference.
Timeouts for agentic loops#
Inference for Kimi K2 family models can be slow on large inputs. For multi-step agents, set your client read timeout to at least 10–30 minutes per call. See Reliability and error handling.