thinking-steering-and-cost changedbuild-with-claude/thinking-steering-and-cost
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37371. Set the effort level that matches your workload's default balance of quality and latency.
38382. Add prompt guidance only if Claude's triggering still doesn't match your needs at that level.
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40<Note>
41 To get less thinking on Claude Sonnet 5.5 and Claude Haiku 5.5, lower the effort level. Asking Claude Sonnet 5.5 in the system prompt to think less doesn't reliably reduce its thinking, and in Anthropic's testing, telling Claude Haiku 5.5 in the prompt to answer directly didn't stop it from thinking. See [Prompting Claude Sonnet 5.5](https://platform.claude.com/docs/en/build-with-claude/prompt-engineering/prompting-claude-sonnet-5-5#calibrate-effort) and [Prompting Claude Haiku 5.5](https://platform.claude.com/docs/en/build-with-claude/prompt-engineering/prompting-claude-haiku-5-5#use-effort-to-control-thinking).
42</Note>
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4044For broader prompting guidance with thinking, see [leverage thinking and interleaved thinking capabilities](https://platform.claude.com/docs/en/build-with-claude/prompt-engineering/claude-prompting-best-practices#leverage-thinking-and-interleaved-thinking-capabilities).
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4246### Effort levels
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8993### Per-message steering
9094
91You can also steer thinking on a per-message basis from the user turn, independently of the system prompt. Appending `"Please think hard before responding."` to a user message encourages Claude to think on that turn; `"Answer directly without deliberating."` suppresses it.
95You can also steer thinking on a per-message basis from the user turn, independently of the system prompt. Appending `"Please think hard before responding."` to a user message encourages Claude to think on that turn; `"Answer directly without deliberating."` discourages it.
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93Per-message steering is useful when only some requests in a conversation warrant extended reasoning. An agent harness, for example, can append the encouraging phrase on planning steps and the suppressing phrase on routine confirmations, without touching the system prompt or changing any request parameters between turns.
97Per-message steering is useful when only some requests in a conversation warrant extended reasoning. An agent harness, for example, can append the encouraging phrase on planning steps and the discouraging phrase on routine confirmations, without touching the system prompt or changing any request parameters between turns.
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99On Claude Haiku 5.5, the discouraging phrase doesn't reliably reduce thinking. On the Claude API and Google Cloud, run routine turns on that model with less thinking by using a [per-message effort change](https://platform.claude.com/docs/en/build-with-claude/effort#change-effort-mid-conversation-beta) (beta) instead, which also keeps the prompt cache.
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95101### Verify steering on your workload
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97103Prompt-based steering changes model behavior, so treat it like any other prompt change: measure before you ship. Run a representative sample of your traffic with and without the guidance, and compare how often thinking triggers (the presence of thinking blocks in responses), output token usage, latency, and answer quality on the cases that matter to you.
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121127Consecutive requests that keep the same thinking configuration and effort level preserve prompt caching; see [Thinking and prompt caching](https://platform.claude.com/docs/en/build-with-claude/thinking#thinking-and-prompt-caching) for the full rules. The resolved effort value is rendered into the prompt, so changing it between requests invalidates cache breakpoints, just as changing the legacy [`budget_tokens`](https://platform.claude.com/docs/en/build-with-claude/extended-thinking#extended-thinking-with-prompt-caching) parameter does on models that use it. Setting `effort` explicitly to the model's default is equivalent to omitting it and does not break the cache.
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123The practical consequence: pick a thinking configuration and an effort level per conversation and keep them. If some turns need more or less thinking, steer with [per-message prompting](https://platform.claude.com/docs/en/build-with-claude/thinking-steering-and-cost#tuning-thinking-behavior): guidance appended to the newest user message leaves earlier cache breakpoints intact, where a configuration or effort change does not.
129The practical consequence: pick a thinking configuration and a top-level effort level per conversation and keep them. If some turns need more or less thinking, use a [per-message effort change](https://platform.claude.com/docs/en/build-with-claude/effort#change-effort-mid-conversation-beta) (beta) on models that support it, or steer with [per-message prompting](https://platform.claude.com/docs/en/build-with-claude/thinking-steering-and-cost#tuning-thinking-behavior). Both leave earlier cache breakpoints intact, where a change to the thinking configuration or the top-level effort level does not.
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125131The following example demonstrates the invalidation with a multi-turn script you can run yourself:
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No line in this hunk matches that.