Session Storage And Retention

Start With The Local Truth

The default Agent SDK behavior writes session transcripts to local JSONL files. That is convenient for single-user development and local review. It is not enough for multi-host systems, ephemeral containers, CI runners, or teams that need governed retention.

Before building a central archive, decide whether local transcripts are the system of record, a cache, or a staging copy. That decision affects deletion, access review, encryption, and incident response.

When To Use SessionStore

Anthropic documents a SessionStore adapter that can mirror transcripts to S3, Redis, a database, or another backend. The required methods are conceptually simple: append new transcript entries and load them back when a session resumes. Operationally, the hard part is governance.

Use external storage when sessions need to resume across hosts, survive container restarts, meet compliance retention, or support centralized audit. If none of those are true, a local transcript plus project-level review notes may be enough.

Practical Retention Classes

Not every transcript deserves the same lifetime. A one-off exploratory prompt can expire quickly. A transcript that produced a production PR, security decision, migration, incident response action, or customer-facing output may need to live beside the business record it supports.

NIST log-management guidance emphasizes planned infrastructure and processes. Applied to agent transcripts, that means retention windows, access rules, integrity checks, export processes, and disposal workflows should be written before the archive becomes large.

• Ephemeral: personal experiments and abandoned sessions.
• Project evidence: sessions tied to a PR, issue, release, or design decision.
• Audit evidence: sessions tied to security, compliance, customer data, production incidents, or high-risk automation.

Deletion Needs A Ledger Too

Deleting transcripts is sometimes correct. The archive may contain secrets, personal data, customer information, or obsolete local work. But deletion should leave a minimal record: which session ID, which storage key, who approved, when, and under what retention policy.

If a transcript has already been summarized into a PR or incident note, make sure the summary does not preserve sensitive material that deletion was supposed to remove.