Reasoning Routing

Reasoning routing rules extend the existing model and combo routing. When no active rule matches, the existing thinking, suffix, connection-default, and provider-translation behavior remains unchanged.

Management

Rule management is available under Settings → Global Routing. The API-key editor provides the same management UI filtered to the selected key.

The management API is exposed by these routes:

• GET and POST at /api/settings/reasoning-routing-rules
• GET, PATCH, and DELETE at /api/settings/reasoning-routing-rules/[id]
• POST at /api/settings/reasoning-routing-rules/simulate

All routes use requireManagementAuth. Inputs are validated with the schemas in src/shared/validation/schemas/reasoningRouting.ts. The simulator never makes an upstream call.

Rule Resolution

The early evaluation selects exactly one rule. Scopes are checked in this order:

1. apiKey
2. combo
3. model
4. global

Within a scope, higher priority wins first, followed by an exact model match over a glob pattern, then stable createdAt and id ordering. requestTags are read exclusively from metadata.tags and support any or all matching.

A connection rule is evaluated only when no early rule won and a concrete provider connection has already been selected. It may change effort and budget only.

Effort and Budget

sourceEffort accepts any, missing, none, low, medium, high, xhigh, max, and ultra. missing means that the request contains neither a discrete effort nor a thinking toggle or thinking budget. A budget-only signal is therefore matched only by any.

effortMode has three variants:

• inherit keeps the client effort while still allowing the model or combo to change.
• default sets targetEffort only when no explicit reasoning signal is present.
• force replaces the discrete effort with targetEffort.

Independently, budgetAction can be preserve, remove, or set. force with none removes all recognized effort and budget fields. none together with set is invalid.

Requests targeting known-incompatible models are rejected before the upstream call. For combo targets, incompatible entries are removed; if none remain, the request returns status 400. Unknown capability data produces a warning and leaves the rule active.

Security and Transports

The source and target model, or source and target combo, remain subject to the existing API-key policy. A reasoning rule never expands model, combo, or quota permissions.

The engine is integrated into Chat Completions, Responses, Anthropic Messages, and the internal Codex WebSocket path. The WebSocket path accepts Codex target models only; combo targets cannot be executed there. The rule decision is stored in the existing route trace without secrets.

Persistence

The migration src/lib/db/migrations/126_reasoning_routing_rules.sql creates the reasoning_routing_rules table. Rules reference stored API keys, combos, and provider connections. Deletes clean up related rules. The database access layer in src/lib/db/reasoningRoutingRules.ts maintains an invalidatable cache for the request path.

Rules are included in SQLite backups, the full database export, and the config-sync bundle. reconcileReasoningRulesForSync disables imported rules with missing references and reports those conflicts.

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