Sponge

A shared session format is not maintained knowledge

Sponge can treat a portable session only as experience. A current knowledge object still needs a revision, a support path, and a decision about what remains true.

On 23 July 2026, Letta published Trajectory: A Standard Format for Agent Experience Data. The post describes a shared record for sessions from Claude Code, Codex, Letta Code, and other harnesses. hraness recorded that post as a reading note. This page is not that digest. This page states Sponge’s claim.

Maintained state is not retrieval already argued, from Jordy Zomer’s Lemmalog, that a similar snippet is not a statement of present knowledge. Retrieval is the product already treats index quality as the product problem. This page starts from a different source. Letta wanted agents to read sessions written by other harnesses without first decoding each vendor’s envelopes.

A trajectory records a run

Letta’s records are a list: harness metadata, user messages, reasoning when the harness exposes it, assistant tool calls, and tool results. The format drops per-line envelopes, duplicated payloads, UI event streams, and encrypted reasoning blobs. It can truncate long tool results. Letta reports about a fivefold token reduction on sampled coding sessions compared with native logs.

That object is useful. An agent can list sessions, normalize them, index them, search them, and consolidate lessons in a background pass Letta calls dreaming. Harbor’s ATIF format keeps a different consumer in mind: full-fidelity replay and benchmarking, with per-step metrics and untruncated payloads. Trajectory chooses the cheaper record an agent can read.

A revision fences what still holds

Searching those files still returns a past session. The hit can tell a later agent that a tool printed /workspace on 10 July 2026. It does not say whether that fact is still current, who accepted it, or which edition a reader should cite.

How Sponge knowledge works keeps citations bound to graph records. The about page calls the durable object the path: identities that survive renaming, statements that retain context, assertions that remain attributable, and editions that preserve their own history. Those objects are revision-fenced. A later private edit does not rewrite a published revision. Publication remains a later reviewed edition.

Portability and custody stay separate

People do swap harnesses. A shared session format solves a real interchange problem. It does not become the knowledge contract. An Inquiry can accumulate evidence, disagreement, and rejected proposals. People accept research. A public /k locator still requires an exact supported edition and a deliberate release.

hraness/kb keeps Markdown and Git authoritative for agent memory. Indexes and graph views are replaceable. Search finds files. It does not become the record. Sponge applies that split to a research product: experience can travel; the current record stays fenced.

Read Letta on Trajectory, or through the hraness reading note. This take is served on sponge.computer. The maintained-state take remains at Maintained state is not retrieval. The retrieval take remains at Retrieval is the product. Agent locators are collected on developer resources.