Struct EventLoopLogger 

pub struct EventLoopLogger { /* private fields */ }

Logger for recording event loop execution.

This logger writes a human-readable log of the event loop’s progression:

• which effects ran
• what events were emitted
• how long each effect took
• what phase/iteration/retry context was active

The log is always-on (not just for crashes) and is written to .agent/logs-<run_id>/event_loop.log for easy diagnosis.

Redaction: This logger must never include sensitive content like prompts, agent outputs, secrets, or credentials.

Implementations

impl EventLoopLogger

pub fn new() -> Self

Create a new EventLoopLogger.

The sequence counter starts at 1 for the first logged effect.

pub fn from_existing_log( workspace: &dyn Workspace, log_path: &Path, ) -> Result<Self, Error>

Create a new EventLoopLogger that continues from an existing log file.

This reads the last sequence number from the existing log file and starts the counter from last_seq + 1. This is important for resume scenarios to maintain monotonically increasing sequence numbers within a run.

Arguments

• workspace - Workspace implementation for reading the log file
• log_path - Path to the existing event loop log file

Returns

• Ok(EventLoopLogger) - Logger initialized with next sequence number
• Err(std::io::Error) - If reading the log file fails

Behavior

• If the log file doesn’t exist or is empty, starts at seq=1
• If the log file exists, reads the last line to extract the sequence number
• If the last line doesn’t match the expected format, starts at seq=1
• The sequence counter is set to last_seq + 1 to continue the sequence

pub fn log_effect(&mut self, params: LogEffectParams<'_>) -> Result<(), Error>

Log an effect execution.

This writes a single line to the event loop log with the following format:

<seq> ts=<rfc3339> phase=<Phase> effect=<Effect> event=<Event> [extra=[E1,E2]] [ctx=k1=v1,k2=v2] ms=<N>

Example:

1 ts=2026-02-06T14:03:27.123Z phase=Development effect=InvokePrompt event=PromptCompleted ms=1234
2 ts=2026-02-06T14:03:28.456Z phase=Development effect=WriteFile event=FileWritten ctx=file=PLAN.md ms=12

Best-Effort Logging

Write failures are returned but do not affect pipeline correctness. This is intentional: event loop logging is observability-only and must not affect pipeline correctness. If logging fails (e.g., disk full, permissions), the pipeline continues execution.

Callers who want visibility into logging failures should check the return value and log to the pipeline logger if desired.

Trait Implementations

impl Default for EventLoopLogger

fn default() -> Self

Returns the “default value” for a type.