feat: add customizable fallback chains and improved model matching#1307
feat: add customizable fallback chains and improved model matching#1307wydrox wants to merge 1 commit intocode-yeongyu:devfrom
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- Add fallback_chain config option to agents and categories schema
- Implement model ID normalization to match prefixed models (e.g., antigravity-*)
- Add getEffectiveFallbackChain and getEffectiveCategoryFallbackChain functions
- Update resolveVariantForModel to use user-defined fallback chains
- Fall back to user config variant when model-based resolution fails
- Add comprehensive tests for new functionality
This allows users to define custom fallback chains in oh-my-opencode.json:
```json
{
"agents": {
"sisyphus": {
"fallback_chain": [
{ "providers": ["google"], "model": "gemini-3-pro", "variant": "max" }
]
}
}
}
```
|
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2 issues found across 4 files
Confidence score: 3/5
- There is a concrete logic risk in
src/shared/agent-variant.ts:findVariantInChaincan choose a provider match even when the model mismatches, which may apply an incompatible variant and skip later fallbacks. - Overall risk is moderate because the main issue could affect variant selection at runtime; the schema duplication in
src/config/schema.tsis low impact and mostly maintenance-related. - Pay close attention to
src/shared/agent-variant.ts- variant selection fallback may ignore model constraints.
Prompt for AI agents (all issues)
Check if these issues are valid — if so, understand the root cause of each and fix them.
<file name="src/config/schema.ts">
<violation number="1" location="src/config/schema.ts:133">
P2: `fallback_chain` schema is duplicated in two places; consider extracting a shared schema constant to avoid divergence when the shape changes.</violation>
</file>
<file name="src/shared/agent-variant.ts">
<violation number="1" location="src/shared/agent-variant.ts:120">
P2: findVariantInChain still falls back to the first provider match even when the model does not match. This ignores model constraints and can apply an incompatible variant, preventing later category/agent fallbacks from being tried.</violation>
</file>
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| /** Provider-specific options. Passed directly to OpenCode SDK. */ | ||
| providerOptions: z.record(z.string(), z.unknown()).optional(), | ||
| /** Custom fallback chain for model resolution. Overrides built-in agent fallback chains. */ | ||
| fallback_chain: z.array(z.object({ |
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P2: fallback_chain schema is duplicated in two places; consider extracting a shared schema constant to avoid divergence when the shape changes.
Prompt for AI agents
Check if this issue is valid — if so, understand the root cause and fix it. At src/config/schema.ts, line 133:
<comment>`fallback_chain` schema is duplicated in two places; consider extracting a shared schema constant to avoid divergence when the shape changes.</comment>
<file context>
@@ -129,6 +129,12 @@ export const AgentOverrideConfigSchema = z.object({
/** Provider-specific options. Passed directly to OpenCode SDK. */
providerOptions: z.record(z.string(), z.unknown()).optional(),
+ /** Custom fallback chain for model resolution. Overrides built-in agent fallback chains. */
+ fallback_chain: z.array(z.object({
+ providers: z.array(z.string()),
+ model: z.string(),
</file context>
| @@ -1,6 +1,44 @@ | |||
| import type { OhMyOpenCodeConfig } from "../config" | |||
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P2: findVariantInChain still falls back to the first provider match even when the model does not match. This ignores model constraints and can apply an incompatible variant, preventing later category/agent fallbacks from being tried.
Prompt for AI agents
Check if this issue is valid — if so, understand the root cause and fix it. At src/shared/agent-variant.ts, line 120:
<comment>findVariantInChain still falls back to the first provider match even when the model does not match. This ignores model constraints and can apply an incompatible variant, preventing later category/agent fallbacks from being tried.</comment>
<file context>
@@ -35,30 +73,61 @@ export function resolveVariantForModel(
providerID: string,
+ modelID?: string,
): string | undefined {
+ for (const entry of fallbackChain) {
+ if (entry.providers.includes(providerID)) {
+ if (modelID && entry.model) {
</file context>
|
Thank you for this contribution! Unfortunately, I need to close this PR for the following reasons:
That said, this is a valuable feature request! The idea of:
...are all excellent additions that would be useful for users with custom model routing setups. If you'd like to continue:
Feel free to reopen if you'd like to continue working on this! |
|
Sure! Let me work on it. I have read the CLA Document and I hereby sign the CLA |
|
I have addressed all the issues:
Verified with bun test v1.3.5 (1e86cebd). All 25 tests passed. |
2 participants
Summary
This PR adds support for customizable fallback chains and improves model ID matching to handle prefixed models (like
antigravity-*).Problem
model-requirements.tsantigravity-gemini-3-proSolution
oh-my-opencode.json:{ "agents": { "sisyphus": { "fallback_chain": [ { "providers": ["google"], "model": "gemini-3-pro", "variant": "max" } ] } }, "categories": { "ultrabrain": { "fallback_chain": [ { "providers": ["google"], "model": "gemini-3-pro", "variant": "high" } ] } } }Model ID normalization - Strips common routing prefixes (
antigravity-,proxy-,custom-) when matching models, soantigravity-gemini-3-promatchesgemini-3-proin fallback chains.Improved variant fallback - When model-based resolution fails, falls back to:
Changes
src/config/schema.ts: Addedfallback_chainoption toAgentOverrideConfigSchemaandCategoryConfigSchemasrc/shared/model-requirements.ts: AddedgetEffectiveFallbackChainandgetEffectiveCategoryFallbackChainfunctionssrc/shared/agent-variant.ts:normalizeModelIdandmodelMatchesfunctions for prefix-aware matchingresolveVariantForModelto use user-defined fallback chainssrc/shared/agent-variant.test.ts: Added comprehensive tests for new functionalityTesting
All 19 tests pass including 6 new tests:
antigravity-prefixSummary by cubic
Adds customizable fallback chains for agent/category variant resolution and prefix-aware model matching. Models routed via proxies (e.g., antigravity-gemini-3-pro) now resolve to the intended base model and variant.
New Features
Migration
Written for commit b4ef893. Summary will update on new commits.