v1.4.0-beta.1

🎉 Welcome to the 1.4.0-beta.1 release of the agentgateway project!

## Artifacts

**Docker images** are available:
* `cr.agentgateway.dev/agentgateway:v1.4.0-beta.1`
* `cr.agentgateway.dev/controller:v1.4.0-beta.1`

**Helm charts** are available:
* `cr.agentgateway.dev/charts/agentgateway:v1.4.0-beta.1`
* `cr.agentgateway.dev/charts/agentgateway-crds:v1.4.0-beta.1`
* `cr.agentgateway.dev/charts/agentgateway-standalone:v1.4.0-beta.1`

**Binaries** for `agentgateway` and the `agctl` CLI are available below.

## Quick Start

Follow the [Kubernetes](https://agentgateway.dev/docs/kubernetes/latest/quickstart/) or [Standalone](https://agentgateway.dev/docs/standalone/latest/quickstart/) quick start guide to get started!


## What's Changed
* feat(oauth): support custom token types and OAuth 2.1 exchange defaults by @markuskobler in https://github.com/agentgateway/agentgateway/pull/2580
* chore: Add Gateway-TCP conformance profile by @davidjumani in https://github.com/agentgateway/agentgateway/pull/2604
* S390x support by @satyamg1620 in https://github.com/agentgateway/agentgateway/pull/2149
* build(deps): bump js-yaml from 4.2.0 to 4.3.0 in /ui in the npm_and_yarn group across 1 directory by @dependabot[bot] in https://github.com/agentgateway/agentgateway/pull/2611
* controller: add Cross App Access auth support by @markuskobler in https://github.com/agentgateway/agentgateway/pull/2534
* cel: do not expose body when exceeds buffer by @howardjohn in https://github.com/agentgateway/agentgateway/pull/2615
* aws auth: per-backend SigV4 signing region by @stevenctl in https://github.com/agentgateway/agentgateway/pull/2610
* add delay policy for fault injection by @stevenctl in https://github.com/agentgateway/agentgateway/pull/2613
* helm: scrape proxy metrics with PodMonitor by @mmmommm in https://github.com/agentgateway/agentgateway/pull/2591
* feat(transformation): add CEL replace mode for headers by @piyushbag in https://github.com/agentgateway/agentgateway/pull/2589
* standalone: support writing config to database by @howardjohn in https://github.com/agentgateway/agentgateway/pull/2603
* build(deps): bump the cargo-weekly group across 1 directory with 4 updates by @dependabot[bot] in https://github.com/agentgateway/agentgateway/pull/2612
* proxy: avoid double poll on Body by @howardjohn in https://github.com/agentgateway/agentgateway/pull/2582
* auth: make crossAppAccess subject token source configurable by @sladkani in https://github.com/agentgateway/agentgateway/pull/2558
* controller: Narrow prompt guard auxiliary backend auth by @markuskobler in https://github.com/agentgateway/agentgateway/pull/2614
* build(deps): bump pyasn1 from 0.6.3 to 0.6.4 in /examples/traffic-a2a/strands-agents in the uv group across 1 directory by @dependabot[bot] in https://github.com/agentgateway/agentgateway/pull/2632
* build(deps-dev): bump fast-uri from 3.1.2 to 3.1.4 in /ui in the npm_and_yarn group across 1 directory by @dependabot[bot] in https://github.com/agentgateway/agentgateway/pull/2631
* Decompress request body on model router path by @howardjohn in https://github.com/agentgateway/agentgateway/pull/2635
* feat(mcp): add Microsoft Entra ID as a native MCP authentication provider by @asaliyog in https://github.com/agentgateway/agentgateway/pull/2408
* controller: expose cross-app subject token source by @markuskobler in https://github.com/agentgateway/agentgateway/pull/2629
* feat(llm): configurable webhook guardrail headers and path via CEL by @robin-fiddler in https://github.com/agentgateway/agentgateway/pull/2595
* llm: allow logging user AND prompt by @howardjohn in https://github.com/agentgateway/agentgateway/pull/2638
* auth: add default cloud auth fetch timeout by @howardjohn in https://github.com/agentgateway/agentgateway/pull/2637
* feat(ui): add passthrough backend auth policy editor by @jbohanon in https://github.com/agentgateway/agentgateway/pull/2601
* standalone: do not default expose admin interface by @howardjohn in https://github.com/agentgateway/agentgateway/pull/2642
* ui: remove redundant pnpm lock by @howardjohn in https://github.com/agentgateway/agentgateway/pull/2653
* ui: remove diff on delete button by @howardjohn in https://github.com/agentgateway/agentgateway/pull/2652
* RIP StarHistory by @howardjohn in https://github.com/agentgateway/agentgateway/pull/2654
* fix(mcp): emit explicit SSE message events by @haowu1234 in https://github.com/agentgateway/agentgateway/pull/2644
* ui: align status on logs by @howardjohn in https://github.com/agentgateway/agentgateway/pull/2639
* hybrid mode: allow writing policies to the database by @howardjohn in https://github.com/agentgateway/agentgateway/pull/2651
* Fallback to custom UUID generation by @howardjohn in https://github.com/agentgateway/agentgateway/pull/2657
* Add support for notify for multi-replica postgres by @howardjohn in https://github.com/agentgateway/agentgateway/pull/2656
* feat(monitoring): add support for metrics service and ServiceMonitor configuration in agentgateway-standalone helm chart by @yanir75 in https://github.com/agentgateway/agentgateway/pull/2647
* test: fix flake in dtrace tests by @howardjohn in https://github.com/agentgateway/agentgateway/pull/2660
* add cli commands to support config migrations by @nfuden in https://github.com/agentgateway/agentgateway/pull/2617
* Update readme diagram by @howardjohn in https://github.com/agentgateway/agentgateway/pull/2655
* feat(backendAuth): support injecting multiple secret-sourced headers by @yordis in https://github.com/agentgateway/agentgateway/pull/2316
* chore: updates to README by @jbohanon in https://github.com/agentgateway/agentgateway/pull/2666
* feat(a2a): add response telemetry by @haowu1234 in https://github.com/agentgateway/agentgateway/pull/2646
* ui: fix the port mode for mcp in standalone ui by @jbohanon in https://github.com/agentgateway/agentgateway/pull/2669
* New `AgentgatewayModel` API by @keithmattix in https://github.com/agentgateway/agentgateway/pull/2583
* standalone: more hybrid mode revamps by @howardjohn in https://github.com/agentgateway/agentgateway/pull/2670
* feat(llm): use Gemini native generateContent/streamGenerateContent endpoints on Vertex by @htimur in https://github.com/agentgateway/agentgateway/pull/2023
* llm: make the error parsing permissive for completions by @howardjohn in https://github.com/agentgateway/agentgateway/pull/2673
* standalone: revamp helm chart for v1.4 by @howardjohn in https://github.com/agentgateway/agentgateway/pull/2671
* add tool calls in telemetry by @lcopi in https://github.com/agentgateway/agentgateway/pull/2233
* perf(jwks): parallelize JWKS fetches with bounded concurrency by @dongjiang1989 in https://github.com/agentgateway/agentgateway/pull/2594
* build(deps): bump postcss from 8.5.15 to 8.5.23 in /ui in the npm_and_yarn group across 1 directory by @dependabot[bot] in https://github.com/agentgateway/agentgateway/pull/2675
* docs: recommend against Deny policies by @howardjohn in https://github.com/agentgateway/agentgateway/pull/2677
* Bump deps ahead of v1.4 by @howardjohn in https://github.com/agentgateway/agentgateway/pull/2674
* cel: if the body exceeds the buffer size, expose it as a separate attribute by @howardjohn in https://github.com/agentgateway/agentgateway/pull/2678
* standalone: rename configStore to storage by @howardjohn in https://github.com/agentgateway/agentgateway/pull/2679
* chore: add max length to certain policy fields by @keithmattix in https://github.com/agentgateway/agentgateway/pull/2680

## New Contributors
* @davidjumani made their first contribution in https://github.com/agentgateway/agentgateway/pull/2604
* @satyamg1620 made their first contribution in https://github.com/agentgateway/agentgateway/pull/2149
* @mmmommm made their first contribution in https://github.com/agentgateway/agentgateway/pull/2591
* @sladkani made their first contribution in https://github.com/agentgateway/agentgateway/pull/2558
* @asaliyog made their first contribution in https://github.com/agentgateway/agentgateway/pull/2408
* @robin-fiddler made their first contribution in https://github.com/agentgateway/agentgateway/pull/2595
* @haowu1234 made their first contribution in https://github.com/agentgateway/agentgateway/pull/2644
* @htimur made their first contribution in https://github.com/agentgateway/agentgateway/pull/2023
* @lcopi made their first contribution in https://github.com/agentgateway/agentgateway/pull/2233

**Full Changelog**: https://github.com/agentgateway/agentgateway/compare/v1.4.0-alpha.2...v1.4.0-beta.1