Kimi hit the context limit:

Error: This model's context length is 8192 tokens

Here is how to fix it.

Fix 1: Use larger context model

Kimi offers different context sizes:

# 8K context (default)
model = "moonshot-v1-8k"

# 32K context
model = "moonshot-v1-32k"

# 128K context
model = "moonshot-v1-128k"

Fix 2: Truncate input

def truncate_to_fit(prompt, max_tokens=7000):
    # Rough estimate: 1 token ≈ 2 Chinese characters
    max_chars = max_tokens * 2
    if len(prompt) > max_chars:
        return prompt[:max_chars] + "\n... (truncated)"
    return prompt

Fix 3: Summarize long documents

# Step 1: Summarize
summary = client.chat.completions.create(
    model="moonshot-v1-8k",
    messages=[{
        "role": "user",
        "content": f"Summarize in 500 words:\n{long_document}"
    }]
)

# Step 2: Use summary
response = client.chat.completions.create(
    model="moonshot-v1-8k",
    messages=[{
        "role": "user",
        "content": f"Based on: {summary.choices[0].message.content}\n\nDo X"
    }]
)

Fix 4: Use RAG

For large knowledge bases:

# Instead of sending entire document
# Use embeddings to find relevant chunks
relevant = search_embeddings(query, document_embeddings)
context = "\n".join(relevant[:5])

Fix 5: Split into chunks

def process_in_chunks(document, chunk_size=7000):
    chunks = [document[i:i+chunk_size] for i in range(0, len(document), chunk_size)]
    results = []
    for chunk in chunks:
        response = call_api(f"Process: {chunk}")
        results.append(response)
    return "\n".join(results)

Still not working?

1. Use 128K model — Larger context window
2. Summarize first — Reduce before sending
3. Use RAG — Retrieve only relevant content
4. Split tasks — Break into smaller requests

FAQ

What is the context limit for Kimi?

Kimi offers three context sizes: 8K, 32K, and 128K tokens. The default is 8K. Use the 128K model for long documents, but be aware it is slower.

How do I count tokens?

Use a tokenizer library like tiktoken. As a rough estimate, 1 token is about 4 characters for English text or 2 Chinese characters. Kimi’s API will reject requests that exceed the context limit.

Can I increase the context limit?

Not directly. The limit is set by the model. Use the 128K model for larger context, or summarize/summarize your input to fit within the limit.

Related: Kimi K3 Complete Guide · Kimi API Timeout Fix · Context Window Explained · Best Chinese AI Models 2026