Steering Claude's rhyme-plan feature swaps the target rhyme word under ablation, or abandons rhyme entirely under concept injection

claim-biology-llm-poetry-planning-preactivates-rhyme-words establishes that entity-claude-3-5-haiku pre-activates a candidate end-of-line rhyme word (in the worked example, "rabbit," rhyming with "grab it") before composing the line, and records the report's quantified 70%-of-cases steering-success figure. Anthropic's companion piece to entity-on-the-biology-of-a-large-language-model describes the same intervention qualitatively, and the two outcomes differ by what is steered into the planning feature, not just whether the line changes:

• Ablating the planned "rabbit" feature — removing it without replacing it — yields a different rhyme: "it writes a new one ending in 'habit', another sensible completion." The model still hunts for a rhyme; it just picks a different one.
• Injecting an unrelated concept feature, "green," in the same planning slot produces a different shape of change — "causing Claude to write a sensible (but no-longer rhyming) line which ends in 'green'": the model abandons the rhyme scheme and restructures the line to end sensibly on the new concept instead.

Anthropic frames this pair as demonstrating "both planning ability and adaptive flexibility—Claude can modify its approach when the intended outcome changes": the causal role of the pre-activated feature (change the input to the plan, change the output) plus the model's capacity to re-plan a coherent line around whatever the plan now contains, rather than producing a broken or nonsensical completion either way. Both interventions are entity-feature-steering variants on the same entity-attribution-graphs case study; see claim-biology-llm-poetry-planning-preactivates-rhyme-words for the paper's own quantification of the ablation/injection pool at 70% success across 25 poems, and cot-faithfulness-anthropic-biology for the paper's broader findings on this architecture.