Errors

Compaction separates a public durable rejection from infrastructure failures. Only a completed, durable attempt can produce CompactionRejected or waiter rejections. Publication and coordination failures remain typed operational errors so consumers do not mistake missing evidence for a model rejection.

Public rejection reasons

Proof: reject constants and reject event validation.

Typed domain failures

*loop.CompactionPolicyError names the invalid policy field. *loop.RequestFingerprintError names missing or invalid request identity. *loop.CompactionInputError names basis, model, request_fingerprint, transcript, or max_summary_tokens. *loop.InvalidSummaryError carries one closed reason. *loop.SummaryTooLargeError carries the post-replacement measurement.

Use errors.As and errors.Is; do not parse error strings or render causes to model output.

Proof: loop compaction errors, policy errors, and domain tests.

Coordination and finalization failures

Internal CompactionCoordinationError kinds are attempt_id, outcome, and basis. CompactionFinalizationError reports terminal clone, validation, append, or waiter publication failures. A start publication failure does not invoke the executor; an append failure never becomes a false rejected event.

%%{init: {"theme":"dark"}}%%
flowchart TD
    A[coordination] -->|valid result| T[durable terminal]
    A -->|typed infrastructure failure| F[report operational error]
    T --> W[waiter replies]
    A -. no fabricated event .-> F

Proof: coordination errors, finalization errors, and failure tests.

Source and proof

• Public compaction errors
• Public rejection events
• Internal coordination
• Error proof