Opus 5 spawns 17 subagents and burns 1.5M cached tokens on a simple lookup, Reddit user warns

tr14l · reddit · 2026-09-22

A Reddit user reports that Opus 5 pointlessly shotgun-blasts subagents on simple tasks: a basic lookup of the latest Qwen models and benchmarks spawned 17 agents and triggered 1.5M cache reads, torching the token budget for a three-paragraph answer.

The author says switching to Fable eliminated the problem entirely — it's slightly more expensive per token but usage stays predictable with almost no refresh waits. They also suspect Opus's behavior has degraded since 4.6 ("4.8 was usable, 5 is not trustworthy"), and wonder if runaway background subagents explain the wave of "something is up with Anthropic usage" posts.

TL;DR: use Fable; Opus will blow through your usage for no reason.

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