OSS / core: traces and run artifacts without object storage

Enterprise / hosted deployments may use trace sink (PLASM_TRACE_SINK_URL → plasm-trace-sink) and object stores (PLASM_RUN_ARTIFACTS_URL). Core single-user OSS should rely on local disk — no S3 required.

Environment variables (implemented)

Purpose	Variable	Behavior
Local state root	PLASM_LOCAL_STATE_DIR	Parent for default trace archive + run-artifact paths and appliance bootstrap secrets.
Local trace archive	PLASM_TRACE_ARCHIVE_DIR	When set, completed traces are written under traces/{tenant_id}/{trace_id}/ (summary + NDJSON). See local_trace_archive.rs.
Run snapshots / plan archive	PLASM_RUN_ARTIFACTS_DIR	Filesystem backend for execute run JSON and plan archive. Precedence: if PLASM_RUN_ARTIFACTS_URL is set, object store wins and PLASM_RUN_ARTIFACTS_DIR is ignored for backend selection. See run_artifacts.rs.
Trace sink (optional, hosted-class)	PLASM_TRACE_SINK_URL, PLASM_TRACE_SINK_READ_URL	HTTP ingest + read base for durable tenant history beyond local archive.

Defaults: appliance vs standalone plasm-mcp

Host	Default behavior
plasm-server (appliance)	When unset, sets PLASM_LOCAL_STATE_DIR to {appliance}/local (e.g. ~/.plasm/appliance/local for the default --data-dir). Trace archive and run-artifact roots resolve under that tree. Operators may still override with explicit env vars.
Standalone plasm-mcp	Does not invent an appliance data-dir layout. Set PLASM_LOCAL_STATE_DIR (or the specific PLASM_TRACE_ARCHIVE_DIR / PLASM_RUN_ARTIFACTS_DIR paths) for durable disk; otherwise traces/artifacts stay in-memory. A common convention is $HOME/.plasm/local.

Use absolute paths in scripts and systemd/desktop entries. Ensure the process user can create those directories.

Run snapshot identity (run_id)

Execute run JSON snapshots use a single wire form: ASCII prefix pr plus 64 hexadecimal digits (lowercase in server output; parsers accept uppercase hex). This is the SHA256 of a versioned JSON bundle (pinned catalog_cgs_hash, domain_revision, entry_id, trimmed source line, serialized parsed plan, and sorted request_fingerprints) so paging and distinct HTTP batches produce distinct ids.

URI shapes (full cutover — no UUID, no /r/{n}):

• Canonical: plasm://execute/{prompt_hash}/{session_id}/run/pr{64hex}
• MCP short: plasm://session/{logical_session_ref}/run/pr{64hex}

Durable filesystem / object-store blob filenames use the full 32-byte digest (see run_artifacts.rs). Hyphenated UUID run_id segments are not accepted on GET or in resources/read.

Docs and UX alignment

• Document these vars in any core onboarding path (README / desktop installer), separate from Helm/object-store guides.
• Operator UIs that list traces expect agent /v1/traces*; durable list/detail requires local archive or sink — see http_traces.rs.