Exact Rendered Decision Journaling

SKILL: Exact Rendered Decision Journaling

Domain: tool-orchestration
Trigger: Apply whenever per-message budgeting rewrites tool_result content so transcripts capture the preview string and resume logic can reapply the same decisions. Source Pattern: Distilled from reviewed tool-loop and result-shaping patterns.

Core Method

After enforceToolResultBudget persists a candidate, produce a ToolResultReplacementRecord (kind: 'tool-result', toolUseId, replacement) that stores the literal preview returned by buildLargeToolResultMessage. Pass newlyReplaced to the writeToTranscript callback so every replacement is serialized in the conversation transcript; later, reconstructContentReplacementState(messages, records, inheritedReplacements) can rebuild the same seenIds/replacements map, and provisionContentReplacementState gates the feature flag (tengu_hawthorn_steeple) so journaling stays optional.

Key Rules

• Persist the exact preview string the model consumed—the replacement record must not approximate or trim the visible content, or prompt-cache alignment breaks.
• Include toolUseId with each record so resume enforcement can quickly look up replacements without re-running persistence.
• Forward parentState.replacements into reconstructForSubagentResume when resuming forks so inherited decisions reapply exactly.
• Guard writeToTranscript; it may be undefined in ephemeral contexts, so only call it when provided.
• When the flag is disabled, provisionContentReplacementState should return undefined and journaling remains inert.

Example Application

In the query loop pass the transcript writer to applyToolResultBudget; the callback serializes newlyReplaced records, which are later replayed by provisionContentReplacementState(initialMessages, records) during resume so the budget enforces the same replacements it originally made.

Anti-Patterns (What NOT to do)

• Do not journal before persistToolResult succeeds and the preview is built—the replacement string must exist before you write it down.
• Do not drop kind: 'tool-result' or the toolUseId fields; reconstructContentReplacementState relies on them to filter and lookup.
• Avoid journaling duplicates (e.g., from re-applied replacements); only persist what is new so transcripts stay minimal.