dsh-model-advanced

Per-model default reasoning level and image handoff for text-only models — added to the existing Settings → Models page.

Model adapters describe a model once, provider-wide and statically. Two things an agent actually needs cannot be expressed that way:

• The level a conversation should start at, per model. A fast model and a reasoning model on the same provider usually want different defaults, but an adapter exposes a single provider-wide effort.
• What happens when a text-only model is handed an image. Today the image is dropped or the turn fails. It should be read by a model that can see, and the reading should stay in the conversation.

This plugin adds a card at the bottom of the Models page that configures both, and implements the runtime behaviour behind them.

The card this plugin adds, at the bottom of Settings → Models: a starting reasoning level for each model, and — for a model that cannot see — the model that reads images on its behalf.

Install

Requires a DeepSeek Harness install with the plugin manager.

dsh plugin --profile desktop add github:drm-nz/dsh-model-advanced

Then restart the app. This plugin has a host half (lib/index.js) and a browser half (lib/client.js); the host half loads at boot, and the browser half is served from the installed package, so neither picks up without a restart.

From a local checkout

dsh plugin --profile desktop add link:/absolute/path/to/dsh-model-advanced

or add the link: dependency to the profile's package.json, run pnpm install there, and restart. A linked package resolves its dependencies and peers from its own directory, so they must be installed there too.

The shipped cordis.patch.yml names its entry bare (dsh-model-advanced), not relatively. A link: install's real directory sits outside node_modules, and this plugin imports Harness packages, so a bare name resolves through the profile's dependency mapping — a relative name would bypass it and the import would fail.

To remove it:

dsh plugin --profile desktop remove dsh-model-advanced

Requires the Harness packages it builds on (@deepseek-ai/dsh-llm, @deepseek-ai/dsh-tools, @deepseek-ai/schemastery) to resolve from the profile, and they should match the running Harness version — the plugin decorates runtime prototypes, so it is version-coupled by nature. See Compatibility below.

The card

One row per configured model, under the model list:

Column	What it sets
Model	The model's name, provider, and id
Default reasoning level	The level a conversation starts at when it has not picked one. Empty option = no override
Image understanding	For a model that cannot read images: the configured model that reads them on its behalf

Both choices are stored in this plugin's own settings namespace (model-advanced), keyed provider/model — not in the adapters'. That is what keeps two models on one provider independent, and what lets a model the adapters cannot describe still get a default.

How the default reasoning level is applied

Four seams, because a level can be chosen — or never chosen — in several places:

1. resolveModelInfo is decorated so the model catalogue states the configured level, and so the composer's Effort menu opens on it.
2. resolveCallConfig is decorated so selecting a model without naming a level saves the configured level instead of the adapter's own default.
3. An agent/request waterfall covers entry points that never pick a level at all.
4. A startup reconciliation (once, after the composition transaction settles) aligns the global default selection with the configured level.

Both prototype decorations are restored on dispose.

How image handoff works

Configure a delegate for a model that does not read images. Then, when a turn carries an image:

1. The delegate is called once, with a layout-preserving transcription instruction: a one-line summary, reading order, every text region with its approximate bounding box on a 0–1000 scale, tables as GFM, and notes for diagrams and UI state.
2. The result is appended to the step as an image transcript note naming the image id.
3. That note carries a [dsh-image-handoff:<id>] marker which is read back from session history, so retries and later turns never re-bill the delegate.
4. The image itself stays in the conversation; the wire to the text-only model still carries a placeholder, never the image. The transcript is what the model reads.

For follow-up questions the model calls:

inspect_image(image_id, question)

which hands the same image to the delegate again with the question. This exists so a text-only model is not stuck with a single fixed reading of an image forever.

A delegate failure does not end the turn — it becomes a note in the transcript saying what could not be read.

Discovering which models read images

Capability is resolved in this order, cheapest first:

1. The provider's own configuration — the model's declared input modalities in its settings namespace.
2. discoverModels, asked only for models the configuration does not describe, so an ordinary page load stays offline.
3. Inference from the same model id served by another configured route.
4. A checkbox — "This model reads images" — when all of the above are unknown, which pins the answer for that model.

Configure by hand

The card writes this namespace; it can also be edited directly.

- id: model-advanced
  config:
    modelDefaults:
      "deepseek/deepseek-chat": high
    imageDelegates:
      "deepseek/deepseek-chat": { provider: openai, model: gpt-5-mini }
    imageCapable:
      "openai/o4-mini": true

Key	Shape	Meaning
modelDefaults	provider/model → effort id	Starting reasoning level for that model
imageDelegates	provider/model → { provider, model }	The model that reads images on this one's behalf
imageCapable	provider/model → true	Pins image capability when it cannot be discovered

Effort ids must match the adapter's own level ids; the card lists them, so pick from there rather than guessing.

Startup self-check

Every boot, after the composition settles, the plugin appends one line to ~/.dsh/health.log — the one place a silent degradation becomes visible:

2026-11-01T02:00:42Z dsh-model-advanced ok   patch=live tool=live defaults=2/2
2026-11-01T02:00:42Z dsh-model-advanced warn patch=live tool=live defaults=1/2 stale=deepseek/old-model

• patch — the two prototype decorations are still the functions this plugin installed. dead means a Harness internal moved and the defaults stop applying.
• tool — inspect_image registered.
• defaults — how many configured defaults were read back from resolveModelInfo and found to name a level their model still offers. stale= names the ones that do not, which is what a renamed effort id looks like.

Read it with:

tail -n 2 ~/.dsh/health.log        # both plugins, when both are installed
grep -v ' ok ' ~/.dsh/health.log   # only problems

Set DSH_HEALTH_LOG to write somewhere else. A diagnostics failure never stops the plugin from loading.

Verified on a real boot of DeepSeek Harness 0.2.1-rc.5 (macOS desktop profile) on 2026-11-01, with five configured model defaults:

2026-11-01T02:03:32Z dsh-model-advanced ok   patch=live tool=live defaults=5/5

That line is the compatibility datapoint worth checking after you upgrade: it names the Harness version this plugin was last confirmed against.

Compatibility

This plugin reaches into Harness internals rather than wrapping a public extension point, which is a deliberate trade: there is no public seam for "change this model's default effort" or "read this image for a model that cannot".

What that means in practice:

• It fails soft, and silently. Every decoration and hook is wrapped so that a failure leaves the turn exactly as it would have been. If a future Harness release renames resolveModelInfo or resolveCallConfig, the card still renders and saves settings, but the defaults stop being applied — with no error in the UI. The startup self-check is the detector: look for patch=dead in ~/.dsh/health.log first.
• It is version-coupled. Tested against the Harness build it was developed on.
• No automated tests. The behaviour depends on a live composition (LLM runtime, settings documents, agent sessions) that is not practical to fake convincingly; the seams above are the thing to verify by hand after an upgrade.

Known limits

• DeepSeek's adapters register no model discovery, so their models report image capability only through provider configuration (API-key routes) or the adapter's own catalogue (account route, when the app has it). For a model whose capability is genuinely unknown, use the pin checkbox.
• The composer's Effort menu lists the adapter's level names. The card uses the same names deliberately, so the two never disagree.
• Defaults changed while the app runs align the global default selection at the next start (or after re-picking the model).
• Multi-model routes take reasoning-level names from each model, but the stored default is always per model.
• A delegate call is a real model call — it costs tokens. It is made once per image per session, plus once per inspect_image call.

Layout

Path	Purpose
lib/index.js	Host half: config schema, prototype decorations, handoff, inspect_image
lib/client.js	Browser half: the card in the Models page footer slot
cordis.patch.yml	Bundle patch that inserts the plugin row
docs/advanced-model-settings.png	Screenshot of the card, shown at the top

License

MIT.