Nexus Model Updates

Nexus Model Updates

Use this skill whenever a task changes Nexus model availability, model prices, context windows, capabilities, defaults, or live provider compatibility.

Research First

Verify new or changed cloud models against primary sources before editing. Prefer official provider docs, model pages, pricing pages, or API model listings. For OpenAI model work, use the openai-docs skill or official OpenAI domains. For OpenRouter, use the model page, for example https://openrouter.ai/openai/<model-id>.

Capture these facts before editing:

• Provider-facing model ID.
• Display name.
• Context window and max output tokens.
• Input and output price per 1M tokens.
• Whether text, image input, functions/tools, streaming, JSON/structured outputs, and reasoning are supported.
• Whether the model should become the provider default.

Edit Model Registries

Provider model registries live under:

src/services/llm/adapters/<provider>/<Provider>Models.ts

Common files:

src/services/llm/adapters/openai/OpenAIModels.ts
src/services/llm/adapters/openrouter/OpenRouterModels.ts
src/services/llm/adapters/openai-codex/OpenAICodexModels.ts
src/services/llm/adapters/github-copilot/GithubCopilotModels.ts
src/services/llm/adapters/anthropic/AnthropicModels.ts
src/services/llm/adapters/google/GoogleModels.ts

For each model, add or update a ModelSpec with:

{
  provider: 'openai',
  name: 'GPT-5.5',
  apiName: 'gpt-5.5',
  contextWindow: 1050000,
  maxTokens: 128000,
  inputCostPerMillion: 5.00,
  outputCostPerMillion: 30.00,
  capabilities: {
    supportsJSON: true,
    supportsImages: true,
    supportsFunctions: true,
    supportsStreaming: true,
    supportsThinking: true
  }
}

If changing defaults, update the provider default export in the same file, and update any adapter constructor fallback that hard-codes a default model. Search with:

rg -n "gpt-|claude-|gemini-|DEFAULT_MODEL|super\\(" src/services/llm/adapters tests

OpenRouter model IDs usually include the upstream namespace, for example openai/gpt-5.5. The reusable smoke test accepts either gpt-5.5 or openai/gpt-5.5 for OpenRouter and normalizes un-namespaced IDs to openai/<id>.

Codex OAuth models are defined in OpenAICodexModels.ts. Only add models that are available through the Codex/ChatGPT OAuth endpoint. Do not assume a Pro model is available in Codex just because it exists in ChatGPT or the OpenAI API.

Update Behavior

Some models need code-path updates beyond registry entries:

• OpenAI Pro or long-running Responses API models may need DeepResearchHandler routing if streaming chat is unsupported or background polling is recommended.
• OAuth-backed Codex may reject some standard Responses API parameters. The generic live smoke test intentionally omits maxTokens for Codex because the endpoint has rejected max_output_tokens.
• If a provider adapter has a stale fallback model in its constructor, update it with the same default as the registry.
• If tests assert a previous default model, update those expectations.

Test Locally

Run focused static tests after changing registries or defaults:

npx jest tests/unit/ModelRegistry.test.ts tests/unit/OpenAICodexAdapter.test.ts --runInBand

Run the build before finishing:

npm run build

If npm run build only changes src/utils/connectorContent.ts generated timestamp, revert that generated churn unless connector source actually changed:

git restore -- src/utils/connectorContent.ts

Live Smoke Test

Use the reusable smoke test for arbitrary provider/model checks:

RUN_MODEL_SMOKE=1 MODEL_SMOKE_PROVIDER=openai MODEL_SMOKE_MODEL=gpt-5.5 npx jest tests/debug/provider-model-live-smoke.test.ts --runInBand --no-coverage --verbose
RUN_MODEL_SMOKE=1 MODEL_SMOKE_PROVIDER=openrouter MODEL_SMOKE_MODEL=gpt-5.5 npx jest tests/debug/provider-model-live-smoke.test.ts --runInBand --no-coverage --verbose
RUN_MODEL_SMOKE=1 MODEL_SMOKE_PROVIDER=openai-codex MODEL_SMOKE_MODEL=gpt-5.5 npx jest tests/debug/provider-model-live-smoke.test.ts --runInBand --no-coverage --verbose

Run all provider defaults:

RUN_MODEL_SMOKE=1 npx jest tests/debug/provider-model-live-smoke.test.ts --runInBand --no-coverage --verbose

Provider-specific overrides when running all:

OPENAI_SMOKE_MODEL=gpt-5.5
OPENROUTER_SMOKE_MODEL=openai/gpt-5.5
CODEX_SMOKE_MODEL=gpt-5.5

The live smoke suite is skipped unless RUN_MODEL_SMOKE=1 is set. In Codex sandboxed sessions, live API calls may fail with DNS or network errors; rerun the same Jest command with escalated permissions when needed.

The smoke test loads OpenAI/OpenRouter API keys from environment variables or repo .env, and Codex OAuth tokens from data.json. Never print or copy credentials into chat.

Thinking-Mode Token Budget

The smoke test default MODEL_SMOKE_MAX_TOKENS=16 is calibrated for non-reasoning models that emit a short "OK" echo. Reasoning/thinking-capable models (Gemini 3.x, Claude with extended thinking, OpenAI reasoning models) will return empty completions at this budget because the budget is exhausted on internal reasoning tokens before any visible text is emitted.

When testing a model with supportsThinking: true, raise the budget:

RUN_MODEL_SMOKE=1 MODEL_SMOKE_MAX_TOKENS=4096 \
  MODEL_SMOKE_PROVIDER=openrouter MODEL_SMOKE_MODEL=google/gemini-3.5-flash \
  npx jest tests/debug/provider-model-live-smoke.test.ts --runInBand --no-coverage --verbose

If a smoke test fails with empty response.text on a thinking-capable model, suspect token starvation before suspecting the model ID or API key.

Google Provider Env Var

The Google direct adapter reads GEMINI_API_KEY only — there is no GOOGLE_API_KEY fallback. If you see "GEMINI_API_KEY is required for Google smoke tests", set that exact var.

Worktree .env Access

The smoke test reads .env from process.cwd(), not by walking up the directory tree. When running from a git worktree (e.g., claudesidian-mcp-wt/<feature>/), the worktree has no .env of its own. Two options:

1. Symlink (preferred — no harness modification):

   ln -s /Users/jrosenbaum/Documents/Code/.obsidian/plugins/claudesidian-mcp/.env \
         /Users/jrosenbaum/Documents/Code/.obsidian/plugins/claudesidian-mcp-wt/<feature>/.env
   

2. Export the env vars inline before invoking jest.

Do NOT modify the harness to walk up the tree — that path has been flagged by the credential classifier as bypassing user deny rules. The symlink is the canonical workaround.

Run Against the Eval Harness (Tool-Calling Validation)

Smoke test is necessary but not sufficient. It only confirms the model returns text — it does NOT exercise tool calling, multi-turn flows, or any Nexus agent behavior. Before declaring a new model ready, run the LLM eval harness (tests/eval/), which drives the model through real Nexus tool schemas against a TestVault.

Step 1 — Add a config

Create tests/eval/configs/<model-slug>.yaml mirroring live.yaml with only the new model. Example (gemini-3.5-flash.yaml):

mode: live
testVaultPath: tests/eval/test-vault/

providers:
  openrouter:
    apiKeyEnv: OPENROUTER_API_KEY
    models:
      - google/gemini-3.5-flash
    enabled: true

defaults:
  temperature: 0
  maxRetries: 1
  retryDelayMs: 2000
  timeout: 120000
  systemPrompt: default

capture:
  enabled: true
  dumpOnFailure: true
  artifactsDir: test-artifacts/

scenarios: tests/eval/scenarios/**/*.eval.yaml

Use openrouter for cross-provider parity (it routes to the upstream model with a unified API surface). For provider-specific behavior (e.g., Google direct adapter quirks), add a second config pointing at the direct provider.

Step 2 — Run the harness

RUN_EVAL=1 EVAL_CONFIG=tests/eval/configs/<model-slug>.yaml \
  npx jest tests/eval/eval.test.ts --no-coverage --verbose

The harness drives 12 scenario files (tests/eval/scenarios/*.eval.yaml) covering: adversarial, basic-tool-call, content-operations, debug-multi-turn, multi-turn, provider-parity, search-variations, storage-operations, system-prompt, tool-discovery, two-tool-flow, vague-prompts. Total scenarios: ~27-30. Runtime: ~10-15 min per model.

The eval harness is skipped unless RUN_EVAL=1 is set.

Step 3 — Compare against baseline

Known prior-model pass rates (from the model-sweep, useful as a sanity baseline):

A new model in the 80%+ range is a healthy candidate for default; <60% suggests provider-specific prompt/tool-schema incompatibility that the smoke test would never have caught.

Step 4 — Decide based on results

• High pass rate (>80%): ship — consider promoting to provider default.
• Mid pass rate (60-80%): ship as opt-in, do NOT change defaults.
• Low pass rate (<60%): investigate failures before merging. Common causes: tool-schema rejection (some models choke on additionalProperties: false), context-window mismatch, thinking-mode response format quirks.
• Empty completions across scenarios: re-check thinking-mode token budgets in scenario configs, not the smoke-test defaults.

Final Checklist

Before answering:

• Cite or summarize the primary sources used for model facts.
• Confirm which providers and model IDs were added.
• State whether defaults changed.
• Report static tests, live smoke tests, and eval harness results (per-scenario pass/fail tally) and build results.
• Mention any skipped provider or known unsupported model variant.
• For reasoning/thinking models, confirm token budgets were raised in both smoke test and any custom eval config.

Source: ProfSynapse/nexus — distributed by TomeVault.