The September Price Increase for Sonnet 5 Isn't Happening. Rebuilding a Forecast I Got Wrong in July
Sonnet 5's introductory $2/$10 pricing was supposed to rise to $3/$15 on September 1. It won't. Here's how to recompute your own effective cost from the usage numbers you already have, with working code.
Claude Sonnet 4.6 vs Opus 4.6 — A Task-by-Task Selection Guide From Daily Use
Choosing between Sonnet 4.6 and Opus 4.6 comes up more often than you'd expect. From someone who uses both daily, here's a task-by-task breakdown — plus how the same yardsticks carry over to Sonnet 5 and Opus 4.8, and where a narrower price gap moves the break-even.
Fable 5 Is Back Worldwide and Sonnet 5 Is the Default — Where Each of the Three Models Belongs in a Solo Automation Stack
With Fable 5 redeployed worldwide and Sonnet 5 now the default, solo automation suddenly has three capable top-tier models to reach for. Instead of ranking them, this piece assigns each a role and captures that in a policy object with a fallback ladder and run-level logging.
When to Use Claude Code's Native 1M Context — and When Not To: A Cost-Based Rule
With Sonnet 5 as the default, Claude Code now handles a native 1M-token context. A big window is convenient, but every token you park in it is billed again each turn. Should you load the whole repo, or feed slices? Here is an estimable token model and a decision rule that gives a concrete answer per situation, with working code and the traps to avoid.
A 1M Context Window Is the New Default — So I Built an Admission Policy Instead of Filling It
Sonnet 5 is now the Claude Code default and native 1M context is standard. The hard errors disappeared, but a quieter kind of degradation took their place. Here is how I made it visible with a probe, plus an admission policy and an effective-token-cost view — with working code and my own measurements.
A 40% Lower Price Doesn't Mean a 40% Lower Bill — Measuring the Opus 4.8 to Sonnet 5 Migration by Cost per Completed Task
Sonnet 5's intro pricing looks ~40% cheaper than Opus 4.8, yet extra tool turns can flip the math. Working TypeScript for consumption vectors, a paired-run harness, and break-even turn counts.
Which Model Ran Last Night's Unattended Session? Building Model Attribution and Default-Drift Detection After the Sonnet 5 Switch
Claude Code's default model switched to Sonnet 5, and unpinned headless runs changed models silently. Here is a working design for extracting the actual model from run output, appending an atomic run record, and deciding per task lineage whether to pin or follow the default.
Introductory Pricing Has an End Date — Effective-Dated Cost Forecasts for the Sonnet 5 Price Step
Claude Sonnet 5's introductory $2/$10 pricing ends on 2026-08-31 and reverts to $3/$15. A static price map will quietly understate your September forecast by a third. Here is an effective-dated price table and forecast design that absorbs the step.