Module context 

Context management — output truncation and history window management.

Structs

ContextManager

Manages the context window, truncating history when approaching token limits.

TruncationResult

Result of context truncation, used for async compression.

Enums

TruncationAction

Type of truncation action, determines how the caller should handle the result.

Functions

estimate_messages_tokens

Estimate tokens for a list of messages.

estimate_messages_tokens_with_margin

Estimate tokens for messages, applying the configured safety margin.

estimate_tokens

Estimate token count for a string.

format_removed_messages_as_transcript

Format removed messages into a compact transcript for summary generation. Extracts user messages, assistant text, and tool call names only. Truncates each message to keep the transcript concise.

get_merge_level

Get the merge level (number of times this segment has been merged). 0 = fresh segment, 1 = merged once, etc.

is_summary_segment

Check whether a message is a summary segment (any merge level, including legacy notice).

truncate_output

Truncate tool output based on line count and byte limits.