dsh-rlm-mode

dsh-rlm-mode

The DASHR plugin for the DeepSeek Harness — the RLM mode: a stateful ctx.rlmRuntime provider (one persistent IPython kernel subprocess per session, the run's principal, held in a map inside the one service instance per mount — the upstream "plugins key their state by Session/Agent" model, which a per-mount realm cannot provide on its own. Each run() is one cell on the calling session's kernel; variables, imports, and definitions assigned in run N survive into run N+1 — state codification (blueprint §1.1 channel ②), deliberately NOT the per-run isolation a one-shot execution backend provides — and two sessions sharing one service instance never see each other's variables.

Naming (v0.1.5 layer model): the runtime class is DashrRuntime — the standing-mount-layer component (one instance per mount holding the cross-session kernel map), and therefore the de facto daemon while the profile-level DashrDaemon concept stays an empty shell; the session layer is the ipykernel subprocess itself, a pure interpreter with no harness awareness.

This is M1 of DASHR: the kernel provider. The consumer half — the ipython transport tool, the Python SDK renderer, and the presentation plugin that binds them to the dsh tool registry — lives in the sibling package dsh-rlm-mode (../dashr-presentation). The provider registers the service key rlmRuntime through its own vendored Service Definition (see src/vendored/rlm-runtime.ts), so it carries zero dsh runtime package dependencies: only @deepseek-ai/cordis (peer), schemastery, and zeromq.

Package positioning

• npm name: dsh-rlm-mode (local --patch development; publish scope still open — blueprint §11 #4).
• A standard Cordis plugin (Context + schemastery Config, every tunable configurable from cordis.yml, no hardcoded tunables).
• "Registrations are effects": the kernel lifecycle (lazy spawn on a key's first run(), teardown on that session's agent/disposed, optional snapshot at either teardown) is effect-owned, so plugin disposal tears every subprocess down.
• Published surface: lib/ only (files: ["lib"], main/types/exports pointing at lib/index.js / lib/index.d.ts) — the build emits beside the manifest (outDir: 'lib'; the tsdown default dist/ left the exports map dangling, fixed in M2B). The root also re-exports the vendored Service Definition's public contract (RLMRuntime plus the CodeRun* / CodeBinding* / CodeJsonValue types) so consumers depend on the published shape instead of reaching into sources. The declaration keeps dependency imports external (dts: { resolve: false }): bundled copies would create duplicate type identities in a consumer's program.

Install

npm install dsh-rlm-mode

The provider needs a Python interpreter with ipykernel (and dill for snapshots). For development and tests, create a dedicated kernel venv:

npm run kernel:venv        # uv venv .venv-kernel + ipykernel + dill

Tests pick the kernel interpreter from DASHR_TEST_PYTHON, falling back to ./.venv-kernel/bin/python, then python3 — see test/helpers.ts.

Configuration

Every field of the plugin Config (schemastery defaults shown):

Field	Default	Meaning
python	python3	Interpreter with ipykernel installed; spawned with -m ipykernel_launcher.
startupTimeoutMs	30000	Budget for kernel spawn → ready, in milliseconds.
runTimeoutMs	120000	Wall budget per run; expiry interrupts the kernel then force-settles.
interruptGraceMs	2000	Grace between a timeout/abort interrupt and the force-settle.
interruptConfirmMs	250	Confirm window between the control-channel interrupt and the SIGALRM escalation (must be < interruptGraceMs); see "Interrupts" below.
disposeTimeoutMs	5000	Budget for graceful kernel teardown (shutdown_request → SIGKILL).
snapshotTimeoutMs	30000	Budget for internal snapshot/restore cells (dill dump/load).
maxOutputBytes	67108864	Hard cap for serialized log-array, completion-value, and failure-message payloads.
snapshotDir	(unset)	Base directory for per-session namespace snapshots (<dir>/<principal>/state.dill + manifest.json); none when absent.
snapshotSizeCapBytes	268435456	Serialized-size cap for a turn-end snapshot; over-cap snapshots are skipped (one-time model warning).
username	dashr	Jupyter username stamped on wire messages.

Persistent-state semantics

• Cell semantics: each run({ program }) is one cell on the calling session's kernel namespace (user_ns) — a pure IPython REPL. Top-level await works; a top-level return is a SyntaxError, exactly as in a native IPython cell. The completion value is the LAST expression's value (REPL displayhook-style): a statement-ending cell or a None final expression yields no value field, and a non-JSON value comes back as its repr text.
• Session keying (M3-A): one kernel per distinct request.principal (the presentation bridge passes the calling agent's session id); runs without a principal share one default key, preserving M1 semantics. The service instance count is unchanged — one per mount — the keying is a Map<principal, kernel> inside the provider.
• Kernel lifetime: lazy start on a key's first run(); teardown when that session's agent is disposed (the dsh agent/disposed event, payload { agent: { id } }, listened through the untyped cordis event service to keep this package's zero-dsh-dependency rule) and on plugin disposal (shutdown_request, then SIGKILL after disposeTimeoutMs). A kernel that dies unexpectedly is never reused in-process: it respawns onto its nearest replayable snapshot (or a fresh empty kernel when none exists) and the run that observed the death gets an explicit worker-exit naming what was lost.
• Turn-end snapshots (M3-B): with snapshotDir configured, every successful run is followed by a size-capped snapshot cell that dumps the user namespace to <snapshotDir>/<principal>/state.dill + manifest.json (turn, pythonVersion, venvPath = the kernel's own sys.executable, skills, names, sizeBytes). A namespace whose serialized size exceeds snapshotSizeCapBytes is skipped — estimated BEFORE any dill IO by a bounded walk that reads numpy/pandas in-memory footprints, then confirmed against the actual .part dump — and the model is warned once through the run's own logs. Skipped snapshots never replace the previous good one.
• Restore-on-first-boot (M3-B): a key's first kernel boot restores its on-disk snapshot before running user code. The kernel validates the manifest itself (python version, interpreter identity, skills); a non-replayable snapshot degrades to an EMPTY namespace and the first run tells the model so. Variable state and the append-only transcript are NOT transactionally consistent (blueprint §8.3): the snapshot is a point-in-time namespace capture that can lag the transcript, and a degraded restore never fabricates variables the transcript once saw.
• Interrupts (M3-A hardened): aborts/timeouts escalate in two phases — the zmq control interrupt_request first, then SIGALRM only after interruptConfirmMs if the cell has still not settled. The kernel-side bootstrap installs a busy guard that only raises KeyboardInterrupt while a dashr cell is actually executing, so a signal landing on an idle or booting kernel is swallowed instead of terminating the process (the M1 same-tick dual send killed idle kernels deterministically — 10/10 same-tick, 8/10 at +1-2ms, 40/40 during cold boot; see test/interrupt-race.spec.ts). The hard-abort contract is intact: a busy while True: pass still breaks inside the grace (blueprint §10.4).
• Concurrency: the bridge serializes cells per kernel (executeCell awaits the previous cell), so concurrent run() calls on one session queue rather than interleave; see test/parallel.spec.ts. Runs on DIFFERENT principals execute on their own kernels concurrently.
• What snapshots do NOT carry (M4-B): the Continual Harness — the presentation-side durable prompt store behind the dashr:harness section and the refine() binding — lives OUTSIDE the kernel namespace and snapshotDir, persisted under its own harnessDir by the presentation package. A snapshot/restore cycle therefore never rolls harness entries back (and a harness edit never invalidates a snapshot): the two persistence channels are keyed by the same agent id but are otherwise independent (blueprint §8.4). Anything a cell stores in ordinary variables follows the snapshot rules above as before.

Testing

npm install
npm run kernel:venv     # once; or export DASHR_TEST_PYTHON=/path/to/python
npm run typecheck       # tsc --noEmit
npm test                # vitest --run (fileParallelism: false)

Teardown discipline: every test context is disposed through onTestFinished, and CI must assert no orphan kernels remain:

pgrep -cf -- '-[m] ipykernel_launcher' || echo no-orphans

(The -[m] trick prevents pgrep from matching itself; 208 orphaned kernels once exhausted machine memory while every unit test stayed green — blueprint §10.8/§10.9.)

Presentation half (ipython transport, SDK, bindings, harness)

dsh-rlm-mode

The DASHR agent-plane presentation row (blueprint §7.4): the plugin an agent preset carries to present the RLM runtime's tools to the model as cells on a persistent IPython kernel.

Mounted in a preset's standing scope, it contributes:

• ipython — the only tool the model may call directly. One call = one cell on the persistent kernel (ctx.rlmRuntime, provided by the sibling package dsh-rlm-mode). Variables, imports, and definitions survive across calls. Nested tool calls ride the host registry's native scheduling pipeline as FLAT top-level callables — await name({...}) inside the cell, one positional arguments object per callable, keyword arguments rejected. Every binding — registry tool or bridge callable — uses this same one-object form; the bridge callables rlm, agent_message, agent_list, rlm_workflow, rlm_ralph, refine, and compact are declared in the same catalog block as the registry tools (see "Delegation and messaging" and "Continual Harness + refine()").
• dashr:tool-catalog — a generated Python SDK prompt section: one named TypedDict per tool argument/output object and one top-level async def name(args) -> Output per visible tool (the flat v0.1.5 shape — no Tools protocol, no tools singleton), plus the cell contract (persistent namespace, completion-value rules, ToolCallError, sub-call concurrency). The bridge callables render in the SAME block — no separate "callables" annotation.
• The model-direct collapse — an assembly filter leaves ipython the only contributed tool schema, and a monotonic guard denies a model-direct call naming anything else with the route back into a cell. Both are scoped to the mounting composition, so a PTC (native Code Mode) preset in the same process keeps its own presentation.

Install

dsh plugin add dsh-rlm-mode

That installs this package — and, through its peer chain, the dsh-rlm-mode kernel provider — into the dsh profile. --patch variants (dsh plugin --patch ... / a profile overlay) work the same way; the package is a plain npm install from the profile's perspective.

Two more setup facts:

• Kernel interpreter. The provider spawns a Python interpreter with ipykernel installed (plus dill if you want dispose-time state snapshots). The shipped preset resolves it from DASHR_KERNEL_PYTHON, falling back to python3. A dedicated venv keeps it clean:

  python3 -m venv ~/.dashr-kernel && ~/.dashr-kernel/bin/pip install ipykernel dill
  # then: export DASHR_KERNEL_PYTHON=~/.dashr-kernel/bin/python
  

• Preset root. A preset is a directory holding agent.cordis.yml; the roster (@deepseek-ai/dsh-agent-presets) only scans its configured roots. This package ships the preset at preset/dashr/, so expose it to the roster by adding that directory as a root — the same mechanism the CLI uses for its own shipped set (apps/cli/src/profile-boot.ts pins config/agent-presets/ with trust: system via a boot overlay). With a --patch overlay (or the profile's cordis.patch.yml):

  # dashr-preset-root.yml — passed as `--patch dashr-preset-root.yml`
  - id: agent-presets
    config:
      roots:
        - path: <profile-dir>/node_modules/dsh-rlm-mode/preset
          trust: system
  

  roots entries are scanned in order (earlier wins a duplicate id), each path may expand a leading ~, and trust marks shipped (system) vs locally authored (user) presets — display-only, not a capability boundary. The roster always appends its own user root (<dshHome>/.agent-presets) unless includeUserRoot: false.

Once the root is configured, the preset appears in the roster and can be picked for a session (dashr), copied for local authoring, or set as the agent-presets default.

The dashr preset

preset/dashr/agent.cordis.yml (display metadata in preset.yml) is an AGENT-PLANE composition in the shape of the upstream code preset. Its rows:

Row	Package	Notes
persona	@deepseek-ai/dsh-persona	Same shape as code; describes the persistent-kernel mode.
agent-instructions	@deepseek-ai/dsh-agent-instructions	Same as code.
dashr-kernel (group, isolate: { rlmRuntime: true })	dsh-rlm-mode + dsh-rlm-mode	The provider publishes ctx.rlmRuntime behind an entry-local realm; the presentation row sits INSIDE the group because realm-private services resolve only for rows sharing the realm.
filesystem (group, isolate: { fs: true })	@deepseek-ai/dsh-fs-local + @deepseek-ai/dsh-tool-fs	The minimal preset's bare-local pattern (the code preset instead uses the host's sandboxed fs). read/write/edit register on a bare host; read_image waits for an attachments service the host owns.
tool-todo	@deepseek-ai/dsh-tool-todo	Registers into the registry's preset layer; also the binding-bridge material (todo_write(...) inside a cell).

Deliberately absent, with reasons (the upstream code preset carries them):

• dsh-tool-bash / dsh-tool-pwsh — their executors (bash-sandbox / pwsh-sandbox) are host-plane services a bare host does not supply, and shell work belongs inside the kernel anyway.
• dsh-tool-fs-search — its ripgrep/subprocess/spill stack is host-plane weight with a native dependency; kernel-side Python covers search.
• The jobs/skills/goals/plan/compaction/delegation sections — each either owns host-plane singletons or adds host services; a DASHR deployment composes them on the host when wanted.

The provider row's config carries only the tunables worth overriding from a preset: python (from DASHR_KERNEL_PYTHON, else python3), snapshotDir (unset → no snapshots). The kernel's working directory is NOT a tunable: it is per-session state, resolved at kernel boot from the run principal through the host's sessions service (session.header.cwd — the same source the {{cwd}} prompt variable reads), so each session's kernel starts in that session's workspace. A principal with no resolvable session (agentless runs) falls back to inheriting the host process cwd. See the sibling package's README for the full table.

Realm semantics (read this before relying on isolation)

An entry-local realm (isolate: { rlmRuntime: true }) is one instance per mounted composition, not per session. The roster mounts a preset ONCE per process under a standing scope and every session joins it, so under the roster all dashr sessions share one provider instance. That is the upstream roster's documented model ("its plugins key their state by Session/Agent, so sessions stay apart inside one shared instance") — and since M3-A the provider honors exactly that: it keys one kernel per Session/Agent inside the shared instance (the run's principal, threaded from the calling agent's id by this package's bridge), spawns each lazily on that session's first ipython, and tears it down on agent/disposed. State set by session A is therefore NOT visible to session B under either mount granularity; mounting per agent (the exported mountPreset primitive) additionally gives each session its own realm instance. test/preset.spec.ts proves both directions (shared instance + keyed kernels under the roster; separate instances under per-agent mounting).

What the realm does guarantee, and what the tests assert: the provider is invisible to the host plane (ctx.get/root realm never resolve it), a mount publishing an un-realm'd service is rejected by dsh-agent-presets, and a PTC Code-Mode session in the same process still resolves the host's codeRuntime.

Coexistence with a PTC Code-Mode session

ipython is our own transport name (the registry reserves run_code), so a Code-Mode preset (@deepseek-ai/dsh-agent-tool-presentation with mode: code over the host-plane worker-thread codeRuntime) composes beside the dashr preset in one process: the PTC agent's assembly shows run_code plus the TS tools:sdk section, the dashr agent's shows ipython plus the Python dashr:tool-catalog, and neither execution path touches the other's runtime. One environmental caveat: the worker-thread provider strips TypeScript in-process, so a Node build without TS support (process.features.typescript === false, e.g. this dev box's v22 binary) runs Python cells fine but answers a run_code with the provider's documented "Node.js is not compiled with TypeScript support" error — the same spec passes the real-run branch under a TS-capable Node 24.

Composition

import Presentation from 'dsh-rlm-mode'

// Inside a preset's standing scope context:
scope.ctx.plugin(Presentation, { maxParallelSubCalls: 10 })

The row waits for ctx.rlmRuntime at mount (ctx.inject) and re-reads it at use time: a preset against a runtime-less deployment fails at mount, named in the preset's activation audit, instead of at the first prompt.

Delegation and messaging (rlm, agent_message, agent_list, rlm_workflow, rlm_ralph)

The upstream delegation tools stay REGISTERED and executable but are masked from the model's surface (presentation-only, ADR-0002): subagent, subagent_fork, send_message, list_agents, interrupt_agent, workflow, ralph, and the child-scoped report appear in neither the Tool Catalog text nor the kernel binding names. The bridge callables re-expose them with the cell's ergonomics, dispatching through the SAME nested sub-dispatch pipeline (and agent_message({"receiver": "parent", ...}) over the service layer for report), so the upstream enforcement surface (approval, sandbox, maxDepth, per-instance config) is inherited wholesale. Every bridge callable takes the SAME one-object form as the registry tools — await name({...}):

• child = await rlm({"mode": "spawn" | "fork" | "interrupt", ...}) — mode dispatch over the subagent tools: "spawn" bridges subagent (a fresh child); "fork" bridges subagent_fork (a child seeded from this conversation's completed turns); "interrupt" (with agent_id) bridges interrupt_agent. Children run in the BACKGROUND by default — admission returns a durable subagent id immediately and the child reports up when it settles (a wakeup notice). Pass {"run_in_background": false} only when the next step depends on the child's result: that call blocks and returns the child's output. There is no rlm_await (the pre-v0.1.5 polling wrapper is gone — foreground mode covers blocking fan-in, and asyncio.gather fans out).
• await agent_message({"receiver": "child" | "parent", "message": ..., "subagent_id": ...}) — the dual-use A2A channel. "receiver": "child" (with the spawn's subagent_id) bridges the send_message tool downlink; "receiver": "parent" reports up through the SERVICE layer (ctx.subagents.reportFrom(exec.agent, ...)) — the single child->parent channel, replacing the masked report tool. The uplink works only for a live continuable child — a root agent gets a structured UNAUTHORIZED instead.
• await agent_list({"scope": "children" | "descendants"}) — bridges list_agents ("children" is the default).
• await rlm_workflow({"meta": ..., "script": ...}) — bridges workflow: a JavaScript orchestration script plus its meta identity block.
• await rlm_ralph({"objective": ..., "max_rounds": ...}) — bridges ralph: iterative fresh-agent rounds toward an objective.

Child-model selection is deployment-level, not per-call: the pre-v0.1.5 model key is gone, and the preset pins agentOptions.model on the tool-subagent/tool-subagent-fork rows (default: parent-model inheritance). Every binding returns structured JSON; errors are a FIELD on the result, never a host crash — a missing ctx.subagents service, an unsupported capability, a depth cap, an unknown id, or an infrastructure rejection all map to an error string.

Realm boundary: ctx.subagents is a HOST-PLANE root-realm singleton (the dashr preset deliberately does not carry the subagent rows), while this row sits inside the preset's isolate: { rlmRuntime: true } realm. Cordis resolves outer-realm services for names the inner realm does NOT isolate, so this row reaches ctx.subagents outward through ctx.get('subagents') while the realm-private rlmRuntime stays invisible to the root. The agent_message uplink callback lives HERE because it is the one layer that can simultaneously see ctx.subagents (outward), the reporting child Agent (exec.agent), and the run's abort signal; every DOWNLINK bridges the tool layer instead, so the delegation tools' policy surface stays in force.

Continual Harness + refine() (M4-B)

The Continual Harness is per-agent DURABLE PROMPT STATE — notes, memories, and skills carried into every future system prompt of the same agent id. It is prompt-as-variable: the dashr:harness prompt section (order 200, the first slot after the 100–199 tool-guidance band) re-renders from the CURRENT store at EVERY assembly, so a refine() that lands mid-turn is visible to the very next model request with no restart. An empty harness renders an empty section (renderPrompt drops it), and entries are brace-neutralized at render time so a literal {{var}} inside a memory can never throw (or silently interpolate) the prompt-variable machinery.

Each cell exposes summary = await refine({"instruction": "..."}) — one bare callable global:

• The host resolves the aux model route: refineModel config ('provider/model', or a bare model id paired with the calling agent's own provider) or, unset, the agent's own provider+model (refinement writes durable state, so the default is the agent's own model).
• One hand-built ctx.llm.stream call (NOT markAgentLoopRequest-marked — that identity belongs to loop-built requests) carries the full current harness, the instruction, and a strict op-schema directive.
• The answer is parsed under an all-or-nothing schema (add {kind,title,content} | update {id,title?,content?} | delete {id}); anything unparseable or invalid leaves the store UNTOUCHED and returns a structured error field.
• Validated ops apply atomically and the cell gets {refined: true, applied: [...], entries_before, entries_after, model}.

Storage: harnessDir set → one JSON file per agent (<harnessDir>/<agent>/harness.json), written tmp-sibling + rename (atomic), restored by the next composition serving the same agent id; agent/disposed drops only the in-memory cache — the file survives by design ("continual"). harnessDir unset → memory-only, dying with the composition (the same opt-in posture as the runtime's snapshotDir; a silent default location would persistently alter future prompts without a deployment decision). Soft caps: 64 entries, 200-char titles, 8000-char content. Entry text is foreign model output; the caps bound what a runaway refine can add to every future prompt. The await blocks the cell until the aux call settles, under the kernel run's own wall budget (runTimeoutMs), and the abort chain follows exec.signal — an aborted refine is a structured error, never a partial store mutation.

compact() (M4-B)

result = await compact() (or compact({"reason": "..."})) exposes the PA check-usage→summarize→keep-working semantics over the compaction seam. It first attaches the session's current pressure as context_tokens when a ctx.tokenMeter is mounted (the probe is advisory — a failing meter never masks compaction), then resolves an engine:

• compactModel SET → a DASHR-scoped BasicCompactionEngine is lazily mounted once per composition under ctx.isolate('compaction') (a proper plugin fiber so the engine's own llm/tokenMeter/sessions injects resolve OUTWARD to the host singletons) with summarizationProvider/Model derived from the key ('provider/model' explicit; a bare model id pairs with the first calling agent's provider) and auto: false — the host engine, if any, keeps the automatic pressure/overflow listeners and is never disturbed (cordis keys service registration by isolation label, so the scoped provide cannot collide with it and never resolves outside this composition). The dynamic import keeps the optional peer @deepseek-ai/dsh-compaction-basic unloaded for deployments that never set the key.
• compactModel UNSET → the host-mounted ctx.compaction engine, inheriting its model chain (configured ?? latest-request ?? agent — "follows the session model"). No engine mounted → a structured unavailable error (with context_tokens still reported), never a crash.

Execution is a two-step ladder, because the seam's compactNow requires an IDLE agent and an in-cell call always runs inside a live agent turn: it tries compactNow first (an idle-path deployment or a future seam change benefits), and on the expected busy falls through to compactIfNeeded('pressure') — the same policy entry the engine itself runs between steps: below threshold an honest {status: 'no-op'}, above it the selected range is summarized NOW and the model's next request in the SAME turn already rides the compacted history.

Context Recency Window (Feature 1)

recencyWindowTokens adds an operator-set, model-independent trigger on top of the upstream ratio threshold. The preset ships it commented out (opt-in; default behavior matches a plain dsh deployment exactly). Enable it in the preset row with a full-form compactModel:

config:
  compactModel: deepseek/deepseek-v4-flash   # full provider/model form
  recencyWindowTokens: 500000                # ~1-2 MB of mixed text
  retainTokens: 50000                        # post-compaction tail

Semantics: at every agent step the session's measured pressure is compared against BOTH ceilings — recencyWindowTokens and the upstream thresholdRatio × model contextWindow — and whichever is lower fires first. On a 250K-context model with a 500K recency ceiling the upstream ~200K threshold triggers; on a 1M model the 500K recency ceiling triggers. When recency fires, the engine selects the range from the newest surface node backward until retainTokens are kept (never splitting a tool-call/result pair) and hands it to the upstream compactRegion — region validation, the durable compaction lock, summarization, and the surface replacement are all native. Below the recency ceiling the check delegates wholesale to the upstream engine; context-overflow recovery keeps its maximum-reduction semantics untouched.

Success reports {status: 'compacted', path, compaction_id, summary_seq, shadowed_items, shadowed_tokens, compact_model}; non-busy failures are structured error fields.

Config

Field	Default	Meaning
maxParallelSubCalls	10	Cap on one cell's overlapping sub-calls (native scheduler contract; 1 = strictly serial).
harnessDir	unset	Root for the Continual Harness store: one harness.json per agent, atomically written, restored by the next composition of the same agent id. Unset = memory-only (dies with the composition). Must be a non-empty string when set.
refineModel	unset	Aux model route for refine(): 'provider/model' explicit, a bare model id paired with the calling agent's provider, or unset for the agent's own route. Must be a non-empty string when set.
compactModel	unset	Summarization model for compact(): mounts a DASHR-scoped BasicCompactionEngine (design A — see above) under ctx.isolate('compaction') with this route and auto: false. Unset inherits the host engine and its model chain. Requires the optional peer @deepseek-ai/dsh-compaction-basic when set. Must be a non-empty string when set.
recencyWindowTokens	unset	Context Recency Window (Feature 1): an absolute token ceiling for passive pressure compaction. When set, a RecencyAwareCompactionEngine (a BasicCompactionEngine subclass) mounts under ctx.isolate('compaction') with auto: true — every agent step checks the session's measured pressure and compacts when it exceeds this ceiling, independent of the model's own context window. The upstream thresholdRatio × contextWindow threshold stays active as a second trigger arm (whichever ceiling is lower fires first). Requires compactModel in the full 'provider/model' form (the engine mounts before any agent exists to pair a bare model id) and an absolute retainTokens. Must be a positive integer when set.
retainTokens	unset	The absolute post-compaction retained tail in tokens (upstream's own key, passed through) for the recency engine. Must stay below recencyWindowTokens — the engine machine-checks that invariant at mount. Only meaningful with recencyWindowTokens; must be a positive integer when set.

Dependencies note: @deepseek-ai/dsh-compaction-basic is an OPTIONAL peer dependency (dev-installed for the design-A tests). Nothing loads it unless compactModel is set; a deployment that sets the key without the peer gets a structured error naming the missing package, never a crash at import time.

Tests

npm install
npm run typecheck
npm test        # pretest builds this package AND the sibling provider first
npm run build

The suite needs a Python interpreter with ipykernel for the real-kernel tiers. It resolves one from DASHR_KERNEL_PYTHON (the preset's own knob), then DASHR_TEST_PYTHON, then /tmp/dashr-kernel-venv/bin/python, then this package's or the sibling's .venv-kernel, then python3. test/preset.spec.ts mounts the shipped preset through the real roster, so npm test also requires the sibling package built (pretest handles the order).

Relationship to upstream

Structure mirrors @deepseek-ai/dsh-agent-tool-presentation and the Code Mode half of @deepseek-ai/dsh-tools (0.1.0-rc.6), re-pointed at the vendored rlmRuntime Service Definition. See the module docs in src/index.ts for the deliberate deltas (ipython vs run_code, ordinary scoped registration, guard-based collapse, mirrored tools/code-dispatch-log waterfall).