feat(bedrock): make default model region-aware based on AWS_REGION

[Bl3f]

Problem

The default Bedrock model (us.anthropic.claude-sonnet-4-6) was hardcoded with a us. prefix. When users configure AWS_REGION to an EU or AP region (e.g. eu-west-1, ap-southeast-1), the default model ID still used the us. prefix, which doesn't work for cross-region inference.

While resolveBedrockModelId in providers.ts already handled rewriting model IDs at inference time, getDefaultModelId (used for fallback model selection, UI display, and project config initialization) always returned the raw us. prefixed ID.

Solution

• Moved resolveBedrockModelId, getBedrockRegionPrefix, and BEDROCK_REGION_PREFIXES from providers.ts to provider-meta.ts (no SDK imports — stays frontend-safe)
• getDefaultModelId now accepts an optional region parameter and resolves the correct geographic prefix (us./eu./ap.) for Bedrock models
• When no explicit region is passed, falls back to process.env.AWS_REGION
• Updated backend callers (agent.ts, llm.ts, project-llm-config.queries.ts) to pass the project config region where available

How it works

Scenario	Before	After
AWS_REGION=eu-west-1, no explicit region	us.anthropic.claude-sonnet-4-6	eu.anthropic.claude-sonnet-4-6
AWS_REGION=ap-southeast-1	us.anthropic.claude-sonnet-4-6	ap.anthropic.claude-sonnet-4-6
AWS_REGION=us-east-1 or unset	us.anthropic.claude-sonnet-4-6	us.anthropic.claude-sonnet-4-6 (unchanged)
Project config with region: 'eu-central-1'	us.anthropic.claude-sonnet-4-6	eu.anthropic.claude-sonnet-4-6

Files changed

• apps/backend/src/agents/provider-meta.ts — added Bedrock region helpers and region-aware getDefaultModelId
• apps/backend/src/agents/providers.ts — removed duplicate helpers, re-exports from provider-meta.ts
• apps/backend/src/services/agent.ts — passes project config region to getDefaultModelId
• apps/backend/src/utils/llm.ts — passes project config region to getDefaultModelId
• apps/backend/src/queries/project-llm-config.queries.ts — passes project config region to fallback model lookup

  

[github-actions]

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[cubic-dev-ai]

2 issues found across 5 files

Prompt for AI agents (unresolved issues)

Check if these issues are valid — if so, understand the root cause of each and fix them. If appropriate, use sub-agents to investigate and fix each issue separately.


<file name="apps/backend/src/agents/provider-meta.ts">

<violation number="1" location="apps/backend/src/agents/provider-meta.ts:318">
P1: Avoid direct `process.env` access in this frontend-consumed helper; it can crash Bedrock settings UI in the browser when no region argument is passed.</violation>
</file>

<file name="apps/backend/src/utils/llm.ts">

<violation number="1" location="apps/backend/src/utils/llm.ts:180">
P2: Region-aware Bedrock defaults should not be emitted here unless the model metadata table also includes those regional IDs; otherwise the UI and cost/context lookups lose metadata for EU/AP defaults.</violation>
</file>

_{Reply with feedback, questions, or to request a fix. Tag @cubic-dev-ai to re-run a review.}

[cubic-dev-ai]

P1: Avoid direct process.env access in this frontend-consumed helper; it can crash Bedrock settings UI in the browser when no region argument is passed.

Prompt for AI agents

Check if this issue is valid — if so, understand the root cause and fix it. At apps/backend/src/agents/provider-meta.ts, line 318:

<comment>Avoid direct `process.env` access in this frontend-consumed helper; it can crash Bedrock settings UI in the browser when no region argument is passed.</comment>

<file context>
@@ -310,10 +310,17 @@ export const PROVIDER_META: ProviderMetaMap = {
-	return defaultModel?.id ?? models[0]?.id ?? '';
+	const modelId = defaultModel?.id ?? models[0]?.id ?? '';
+	if (provider === 'bedrock') {
+		const effectiveRegion = region ?? process.env.AWS_REGION;
+		if (effectiveRegion) {
+			return resolveBedrockModelId(modelId, effectiveRegion);
</file context>

Suggested change

	const effectiveRegion = region ?? process.env.AWS_REGION;
	const effectiveRegion = region ?? (typeof process !== 'undefined' ? process.env.AWS_REGION : undefined);

[cubic-dev-ai]

P2: Region-aware Bedrock defaults should not be emitted here unless the model metadata table also includes those regional IDs; otherwise the UI and cost/context lookups lose metadata for EU/AP defaults.

Prompt for AI agents

Check if this issue is valid — if so, understand the root cause and fix it. At apps/backend/src/utils/llm.ts, line 180:

<comment>Region-aware Bedrock defaults should not be emitted here unless the model metadata table also includes those regional IDs; otherwise the UI and cost/context lookups lose metadata for EU/AP defaults.</comment>

<file context>
@@ -176,8 +176,8 @@ export const getProjectAvailableModels = async (
-			// If no models explicitly enabled, add the default
-			const defaultModelId = getDefaultModelId(provider);
+			const region = (config.credentials as Record<string, string> | null)?.region;
+			const defaultModelId = getDefaultModelId(provider, region);
 			models.push({ provider, modelId: defaultModelId, name: getModelName(provider, defaultModelId) });
 		} else {
</file context>