[Bug Report / v0.1.2-rc.1] Missing re-export of assertNever in dsh-llm & missing subagent-model-selection-settings in dsh-base

[iron-water]

Overview

In @deepseek-ai/dsh@0.1.2-rc.1, two breaking regressions were identified when running custom or CLI profiles with the shipped base bundles and presets:

---

1. @deepseek-ai/dsh-llm omitted re-exporting assertNever

Issue:

SyntaxError: The requested module '@deepseek-ai/dsh-llm' does not provide an export named 'assertNever'

Root Cause:
In 0.1.2-rc.1, assertNever was moved to @deepseek-ai/dsh-util-values. In @deepseek-ai/dsh-llm/lib/index.js, assertNever is imported at the top from @deepseek-ai/dsh-util-values, but it was omitted from the module's export { ... } block at the end of dsh-llm/lib/index.js.
Any downstream package or plugin relying on @deepseek-ai/dsh-llm's historical export of assertNever fails with an ESM SyntaxError at module linking time.

Suggested Fix:
Add assertNever back to the export list in @deepseek-ai/dsh-llm/lib/index.js:

- export { APP_IDENTITY, BlockAssembler, ...
+ export { assertNever, APP_IDENTITY, BlockAssembler, ...

---

2. @deepseek-ai/dsh-base omitted subagent-model-selection-settings host row

Issue:
When creating a session under a base-backed profile (such as the conventional CLI profile) with the default standard preset:

⨯ session creation failed: agent-presets: preset "standard" failed to mount: failed to apply loader entry delegation (cordis:group): failed to apply loader entry tool-subagent (tool-subagent: `modelSelectionSettings` requires @deepseek-ai/dsh-tool-subagent/model-selection-settings in the Host scope)

Root Cause:
The shipped standard preset (agent-presets/presets/standard/agent.cordis.yml) now defaults modelSelectionSettings: true:

    - id: tool-subagent
      name: '@deepseek-ai/dsh-tool-subagent'
      config:
        provider: spawn
        toolName: subagent
        modelSelectionSettings: true
        backgroundMode: continuable

In @deepseek-ai/dsh-tool-subagent/lib/index.js:580:

if (config.modelSelectionSettings === true) {
  const settings = ctx.get("subagentModelSelection");
  if (settings === undefined) throw new Error("tool-subagent: `modelSelectionSettings` requires @deepseek-ai/dsh-tool-subagent/model-selection-settings in the Host scope");
}

This host row was mounted in @deepseek-ai/dsh-web-app/cordis.patch.yml, but omitted from @deepseek-ai/dsh-base/cordis.patch.yml. As a result, non-web compositions using the shipped standard preset fail to mount during session creation.

Suggested Fix:
Mount @deepseek-ai/dsh-tool-subagent/model-selection-settings in @deepseek-ai/dsh-base/cordis.patch.yml:

    - id: subagent-model-selection-settings
      name: '@deepseek-ai/dsh-tool-subagent/model-selection-settings'

[argszero]

Verified both reports against master d347e70390 (current 0.1.3-alpha.1 line) and against the published npm artifacts. Neither is fixed by moving off rc.1 — both persist on the current line.

1. assertNever re-export — confirmed, and it was a silent removal of a published export

I compared the published artifacts:

• @deepseek-ai/dsh-llm@0.1.1-rc.2 (lib/index.js): defines assertNever (a local helper) and lists it in the named export block — export { APP_IDENTITY, ..., assertNever, assertUsableApiKey, ... }. It was a real public named export of this package at that release.
• @deepseek-ai/dsh-llm@0.1.2-alpha.5 and 0.1.2-rc.1: the top now reads import { assertNever, deepFreeze } from "@deepseek-ai/dsh-util-values", and assertNever is gone from the export block. Any import { assertNever } from '@deepseek-ai/dsh-llm' therefore fails at ESM link time with exactly the SyntaxError you quoted.

So the sequence was: helper consolidated into dsh-util-values, the internal imports updated, but the re-export was dropped without a signal in the same change — a named export that shipped in 0.1.1-rc.2 silently vanished in the 0.1.2 line. On master (packages/llm/llm/src/index.ts) there is still no re-export, so the current line has the same gap. No in-tree consumer imports it from dsh-llm (only from dsh-util-values), which is why no CI/test caught it — the blast radius is exactly downstream/plugin authors like yourself.

Your suggested fix is the right shape and is genuinely one line in packages/llm/llm/src/index.ts:

export { assertNever } from '@deepseek-ai/dsh-util-values'

This fits a broader pattern this repo has seen several times: public exports removed without signal (public APIs are documented as pre-stable, so removal is legal, but it must be announced). The structural remedy would be a release gate that diffs each package's public export surface against the previous published version — that would have flagged this drop automatically, the same way it would flag the other members of that family.

2. subagent-model-selection-settings host row — confirmed, persists on master

All three shipped presets (standard, ptc, cordis) configure the delegation tool with modelSelectionSettings: true (presets/*/agent.cordis.yml). The guard in packages/subagent/tool-subagent/src/index.ts:601-615 throws at composition time when the settings service is absent from the Host scope — the exact error you hit. The row that satisfies it:

- id: subagent-model-selection-settings
  name: '@deepseek-ai/dsh-tool-subagent/model-selection-settings'

is mounted only in packages/bundle/web-app/cordis.patch.yml:46-47 (plus an SDK loader test fixture). packages/bundle/base/cordis.patch.yml does not carry it, and master is unchanged. The preset default, the web-app row, and the throw guard were introduced together in #2663 (f76a225a7d), so the shipped non-web bundles (headless/acp/sdk) are internally consistent only because they never mount dsh-agent-presets at all. The trap is that the preset artifacts themselves are generic: any non-web composition that legitimately composes @deepseek-ai/dsh-agent-presets with a shipped preset — your CLI profile, and any embedded/desktop/BFF product following the same docs — fails at session creation, and the error names the missing package but not where the row belongs (the only in-repo example is inside web-app's patch).

Immediate workaround for your profile: add the row above to your profile's cordis.patch.yml (id must match; subagentModelSelection is read by name at index.ts:605).

Upstream-fix candidates, in order of my preference:

1. Mount the row in bundle/base so every base-backed profile hosts the service, making the shipped presets composition-independent (mirrors how other preset-sampled host rows are handled in base).
2. Keep base untouched but document the host requirement on the agent-presets package (which shipped presets require which host rows), and/or make the throw's message state that the row goes in the profile composition that mounts dsh-agent-presets.

Thanks for the precise write-up — both items are reproducible from the shipped artifacts and both are actionable on the current line.