Guides, model notes and product updates

Responses API vs Chat Completions comes down to who owns conversation state, and this guide pairs a decision table with matching requests, tool and streaming differences, per-model format checks, and a migration checklist.

A coding agent should not break because a model name changed. Here is how an MCP model catalog makes model choice a runtime lookup, with request examples, routing rules, and verification habits.

A dated four-model streaming sample from TokenLab shows why first visible token, total time and tokens per second must be measured separately, with a harness, headers to log and rate-limit math.

A practical guide to AI model deprecation and versioning on TokenLab: which lifecycle fields exist, a CI check script, what a missing model returns, and a fallback pattern.