openrouter-context-optimization

Openrouter Context Optimization

Overview

This skill covers techniques for managing token budgets, optimizing prompt length, and making the most of each model's context window.

Prerequisites

• OpenRouter integration
• Tokenizer library (tiktoken for OpenAI models, or approximate counting)

Instructions

1. Count tokens before sending: Use tiktoken (Python) or js-tiktoken (JS) to estimate token counts before making API calls; abort if the prompt exceeds the model's context limit
2. Implement conversation pruning: For multi-turn chats, drop or summarize older messages when total tokens approach the context limit, keeping system prompts and recent messages
3. Optimize system prompts: Move static instructions to the system message and keep them concise; every token in the system prompt is repeated on every request
4. Use response length controls: Set max_tokens to the minimum needed for your use case; shorter completions cost less and return faster
5. Select models by context need: Route short-context tasks to cheaper models and reserve large-context models (128K+) for tasks that genuinely need them

Output

• Token budget calculator that warns before exceeding context limits
• Conversation pruning middleware that keeps chats within context bounds
• Cost reduction from optimized prompt engineering (typically 20-40% savings)

Error Handling

Error	Cause	Fix
400 context_length_exceeded	Prompt + max_tokens exceeds model limit	Prune messages or switch to a model with a larger context window
Truncated responses	max_tokens set too low	Increase max_tokens or split the task into smaller requests
Token count mismatch	Wrong tokenizer for the model	Use the correct tokenizer per model family; fall back to rough estimation (1 token ~ 4 chars)

See ${CLAUDE_SKILL_DIR}/references/errors.md for full error reference.

Examples

See ${CLAUDE_SKILL_DIR}/references/examples.md for runnable code samples.

Resources

• OpenRouter Documentation
• OpenRouter Models
• OpenRouter API Reference
• OpenRouter Status