i recently added this command to the claude-api skill. run it in Claude Code to fix common prompting "anti-patterns" that can hobble frontier models: /claude-api prompt-audit patterns include: 1/Verification rituals. Instructions like "double-check your work” or "verify twice before responding” are often taken literally by frontier models and can waste tokens. 2/ Thoroughness and emphasis boosters. "Be maximally thorough," "CRITICAL: YOU MUST ALWAYS…" can lead to verbosity and extra tool calls when working with frontier models. 3/ Mandatory procedures and scratchpad scaffolds. Fixed step processes (e.g., "think step by step in a scratchpad") or reasoning templates are rituals that frontier models don't need. This scaffolding can stack on top of native reasoning and use unnecessary tokens. 4/ Stale examples. Few-shot examples tuned to an older model's failure modes can teach a frontier model to imitate long reasoning chains on requests that don't need them. 5/ Contradictory rules. Frontier models are better at instruction following. Contradictory instructions ("always refund within policy" vs. "never issue refunds without escalation") can be followed more literally by frontier models, resulting in degraded performance. 6/ Dated configuration. Settings written for an older Claude generation (e.g., manual thinking budgets) can be rejected by the Claude Platform with newer models. these patterns accumulate in prompts over time, and can quietly degrade performance when upgrading to newer models. a common reason is the frontier models are better at instruction following, so these anti-patterns steer them to spend unnecessary tokens. example: i tested a migration from Opus 4.8 to Opus 5 on an internal customer support benchmark. with Opus 5 (and other frontier models like Fable 5.1), verification rituals ("verify twice") use unnecessary tokens by duplicating work. emphasis boosters ("be maximally thorough") become dozens of unneeded searches. applying prompt audits can improve performance and reduce cost (as shown in example attached and will be sharing a full write-up soon). also, the skill is also open source and some of this guidance likely applies generally across frontier models

Lastly, you can now give a Claude Managed Agent an advisor: a stronger model it can call mid-session for a second opinion. Add one line to the roster and the working agent gets an advisor.

We've updated our "zoom tool" cookbook. When large images get downscaled, important detail can be lost. A zoom tool lets Claude request a region and get that crop back from the full-res original.

We've raised Claude Platform API rate limits for all users and simplified the tiers, which are no longer based on API spend. The latest Sonnet and Haiku models now provide 5x higher rate limits at the highest tier.