# Changelog

{% updates format="full" %}
{% update date="2026-04-13" %}

##

**Added**

* **Prompt Optimizations (GEPA-powered)** — Automatically improve system prompts using FastRouter’s Genetic-Pareto optimization engine with iterative reflection, mutation, and scoring
* **Run prompt experiments from your own data** — Import datasets from files or Activity Logs, evaluate against custom metrics, and compare optimized prompts against baseline performance
* **LLM-as-a-Judge evaluations** — Score prompts across metrics like Accuracy, Helpfulness, Safety, Completeness, or your own custom criteria using a shared evaluator model
* **Optimization Insights** — Review improvement %, final scores, accepted iterations, and the full optimized prompt in a dedicated results view

<https://docs.fastrouter.ai/prompt-optimizations>
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{% update date="2026-04-03" %}

##

**Added**

* **MCP Gateway** — Register any MCP-compatible server (GitHub, Linear, Gmail, or your own APIs) and expose its tools to any model routed through FastRouter, with centralized credential management, project-level scoping, and selective tool exposure
* **OAuth 2.0 & Static Header authentication for MCP servers** — Securely store and inject credentials server-side across all tool calls, with support for No Auth, Static Header, and full OAuth 2.0 authorization code flow
* **Auto-execution mode** — Set `auto_execute_tools: true` to let FastRouter handle the complete tool-call loop and return a final text response directly, with a configurable `max_tool_rounds` cap (maximum 5)

<https://docs.fastrouter.ai/mcp-gateway>
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{% updates format="full" %}
{% update date="2026-03-27" %}

##

**Added**

* **Priority Routing** — Route requests through models in a fixed priority order, with automatic sequential fallback for deterministic, predictable routing
* **Category-Based Routing** — Direct requests to different model groups based on detected prompt category, with per-category sub-strategies and a configurable default fallback

<https://docs.fastrouter.ai/explore-features/virtual-model-aliases>

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{% update date="2026-03-20" %}

##

#### Added

* **Tracing (W3C `traceparent` support)** — Group multiple LLM API calls into a single trace with ordered spans
* **Traces view in Activity** — Visualize execution timelines, latency, tokens, and cost across spans

<https://docs.fastrouter.ai/tracing>
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