Escalate hard decisions with the advisor tool changedadvisor
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8383
8484The advisor must be at least as capable as the main model. The accepted advisors for each main model are:
8585
86| Main model | Accepted advisors | Notes |
87| ---------------------- | ------------------------------------------- | ---------------------------------------------------------------------------------------------- |
88| Haiku 4.5 | Fable, Opus, Sonnet | Haiku can call the advisor but cannot act as one |
89| Sonnet 4.6 | Fable, Opus, Sonnet | |
90| Sonnet 5.5 or Sonnet 5 | Fable, Opus 4.7 or later, Sonnet 5 or later | A Sonnet 4.6 advisor is rejected, and the API refuses an Opus 4.6 advisor |
91| Opus 4.6 | Fable, Opus, Sonnet 5 or later | A Sonnet 4.6 advisor is rejected |
92| Opus 4.7 or Opus 4.8 | Fable, and Opus 4.7 or later | An Opus 4.6 or Sonnet advisor is rejected |
93| Opus 5.5 or Opus 5 | Fable, and Opus 5 or later | An Opus 4.6 or Sonnet advisor is rejected, and the API refuses an Opus 4.7 or Opus 4.8 advisor |
94| Fable 5 | Fable 5.1 or Fable 5 | An Opus or Sonnet advisor is rejected |
95| Fable 5.1 | Fable 5.1 | An Opus or Sonnet advisor is rejected, and the API refuses a Fable 5 advisor |
86| Main model | Accepted advisors | Notes |
87| - | - | - |
88| Haiku 4.5 | Fable, Opus, Sonnet | Haiku can call the advisor but cannot act as one |
89| Sonnet 4.6 | Fable, Opus, Sonnet | |
90| Sonnet 5.5 or Sonnet 5 | Fable, Opus 4.7 or later, Sonnet 5 or later | A Sonnet 4.6 advisor is rejected, and the API refuses an Opus 4.6 advisor |
91| Opus 4.6 | Fable, Opus, Sonnet 5 or later | A Sonnet 4.6 advisor is rejected |
92| Opus 4.7 or Opus 4.8 | Fable, and Opus 4.7 or later | An Opus 4.6 or Sonnet advisor is rejected |
93| Opus 5.5 or Opus 5 | Fable, and Opus 5 or later | An Opus 4.6 or Sonnet advisor is rejected, and the API refuses an Opus 4.7 or Opus 4.8 advisor |
94| Fable 5 | Fable 5.1 or Fable 5 | An Opus or Sonnet advisor is rejected |
95| Fable 5.1 | Fable 5.1 | An Opus or Sonnet advisor is rejected, and the API refuses a Fable 5 advisor |
9696
9797Fable 5.1 requires Claude Code v2.1.257 or later. Both Fable models require [Fable access](/docs/en/model-config#work-with-fable).
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119119Any accepted pairing works. These combinations balance cost against capability in different ways:
120120
121| Pairing | When to use |
122| ---------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------ |
123| Sonnet main + Opus advisor | Sonnet handles routine work and escalates planning, ambiguous failures, and completion checks to Opus |
124| Sonnet main + Fable advisor | Fable guidance at decision points without running Fable throughout. Requires Fable access |
125| Haiku main + Opus advisor | Lowest-cost main model with strong planning. Expect higher cost than Haiku alone but lower than switching the main model to Sonnet or Opus |
126| Opus main + Opus advisor | A second Opus reviews the first. Useful for high-stakes tasks where an independent check matters more than cost |
127| Fable main + Fable advisor | Highest-capability pairing when Fable is available. Claude Code doesn't apply an Opus or Sonnet advisor to a Fable main model |
128| Sonnet main + Sonnet advisor | A lower-cost second opinion for catching routine oversights |
121| Pairing | When to use |
122| - | - |
123| Sonnet main + Opus advisor | Sonnet handles routine work and escalates planning, ambiguous failures, and completion checks to Opus |
124| Sonnet main + Fable advisor | Fable guidance at decision points without running Fable throughout. Requires Fable access |
125| Haiku main + Opus advisor | Lowest-cost main model with strong planning. Expect higher cost than Haiku alone but lower than switching the main model to Sonnet or Opus |
126| Opus main + Opus advisor | A second Opus reviews the first. Useful for high-stakes tasks where an independent check matters more than cost |
127| Fable main + Fable advisor | Highest-capability pairing when Fable is available. Claude Code doesn't apply an Opus or Sonnet advisor to a Fable main model |
128| Sonnet main + Sonnet advisor | A lower-cost second opinion for catching routine oversights |
129129
130130## When Claude consults the advisor
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186186
187187The advisor is one of several ways to combine model strengths. Pick based on when you want a second model involved.
188188
189| Approach | When the stronger model runs | How it starts |
190| ----------------------------------------------------------- | -------------------------------------------------------------------------------------------------------------------------------------- | -------------------------------------------- |
191| Advisor tool | At decision points mid-task | Claude calls it when it needs guidance |
192| [`opusplan`](/docs/en/model-config#opusplan-model-setting) | During plan mode when [allowed by `availableModels`](/docs/en/model-config#restrict-model-selection), then switches to Sonnet for execution | You enter plan mode |
193| [Subagents](/docs/en/sub-agents#choose-a-model) with `model` set | For the entire delegated subtask | Claude delegates, or you invoke the subagent |
194| [`/model`](/docs/en/model-config#setting-your-model) | From the next request onward | You switch models |
189| Approach | When the stronger model runs | How it starts |
190| - | - | - |
191| Advisor tool | At decision points mid-task | Claude calls it when it needs guidance |
192| [`opusplan`](/docs/en/model-config#opusplan-model-setting) | During plan mode when [allowed by `availableModels`](/docs/en/model-config#restrict-model-selection), then switches to Sonnet for execution | You enter plan mode |
193| [Subagents](/docs/en/sub-agents#choose-a-model) with `model` set | For the entire delegated subtask | Claude delegates, or you invoke the subagent |
194| [`/model`](/docs/en/model-config#setting-your-model) | From the next request onward | You switch models |
195195
196196## See also
197197
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