Model Routing Guide¶

This guide provides source-backed decision logic for selecting the optimal model and configuration for specific task types, balancing latency, cost, and reasoning depth.

Anthropic (Claude)¶

Anthropic models are categorized into three "tiers" of capability. Choosing the right tier depends on the complexity of the reasoning required.

Tier	Model	Best For	Decision Logic
Haiku	Claude 3.5 Haiku	Low-latency, high-volume tasks	Use for basic extraction, classification, and simple summarization where speed is critical.
Sonnet	Claude 3.5 Sonnet	General knowledge work, coding, and tool use	The default choice for most agentic workflows. High intelligence with manageable latency.
Opus	Claude 3 Opus	Complex reasoning, large-scale strategy, and high-fidelity creative work	Use when Sonnet fails on extreme logic puzzles or when maximum creative "nuance" is required.

OpenAI¶

OpenAI's latest frontier models (starting with GPT-5.4) introduce explicit Reasoning Effort levels, allowing developers to trade time/compute for accuracy.

GPT-5.4 Effort Levels¶

Level	Latency	Reasoning Depth	Recommended Use Case
None	Ultra-low	Surface-level	Rapid document parsing, simple chat responses.
Medium	Moderate	Balanced	Standard coding tasks, multi-step tool orchestration.
High	High	Deep	Complex bug fixes, architecture reviews.
X-High	Very High	Maximum	Frontier scientific reasoning, high-stakes logic verification.

GPT-5.3 Codex Transition¶

GPT-5.4 incorporates the specialized coding strengths of GPT-5.3-Codex. - Legacy Decision: If a workflow specifically requires the legacy Codex behavior (deterministic code completion), continue using GPT-5.3-Codex. - Modern Decision: For agentic coding where the model must use tools and iterate, GPT-5.4 (at Medium/High effort) is the recommended successor.

Task-Based Routing Summary¶

Task Type	Recommended Model	Effort/Tier
Simple Extraction	Claude 3.5 Haiku	N/A
Standard Coding	Claude 3.5 Sonnet	N/A
Complex Debugging	GPT-5.4	High / X-High
Creative Writing	Claude 3 Opus	N/A
Agentic Tool Use	Claude 3.5 Sonnet	N/A
Document Summarization	Claude 3.5 Haiku	N/A
Rapid Code Completion	GPT-5.3 Codex	N/A

Sources / References¶

Contribution Metadata¶

Last reviewed: 2026-04-20
Confidence: high