[release] Release Highlights: v0.4.0

[github-actions]

🌟 Release Highlights

v0.4.0 brings significant security hardening through enhanced guard policy enforcement, improved OpenTelemetry tracing, and a large round of internal quality improvements across the codebase.

✨ What's New

🔒 Sink-Visibility Guard Policy (#8895, #8903, #8907)
The write-sink guard now enforces sink-visibility checks to prevent GitLost-style exfiltration attacks. Data that reaches a write sink is validated against visibility rules before the operation proceeds, giving you stronger guarantees that agents cannot exfiltrate secrets through write operations. Integration tests verify the behavior end-to-end.

🔍 Load-Time WASM Guard ABI Checks (#8779)
WASM guards are now validated at gateway startup rather than at first use. Misconfigured or incompatible guard modules are rejected early with clear error messages, eliminating silent failures at runtime.

📡 OpenTelemetry Tracing Improvements (#8841)
Span handling and trace propagation have been refined based on go-fan review feedback, improving observability for distributed deployments that rely on OTLP traces.

🛡️ gh codespace stop Modeled as Guarded Write (#8764)
The gh codespace stop operation is now classified as a guarded write, ensuring it is subject to the same DIFC label checks as other state-modifying operations.

🐛 Bug Fixes & Improvements

• ToolAnnotations preserved in routed mode (Fix ToolAnnotations drop in routed mode; document SDK upgrade gate #8567): MCP ToolAnnotations metadata was silently dropped when requests passed through the routed-mode handler. This is now fixed, and an SDK upgrade canary test documents the assumption so future SDK bumps won't regress it.
• OpenTelemetry headers field added to JSON stdin config ([Repo Assist] fix(config): add headers field to JSON stdin opentelemetry config #8587): The headers field was missing from the stdin JSON schema for the opentelemetry block, causing silent config failures when users specified custom OTLP headers via stdin.

⚡ Performance

• Logger payload sanitization ([Repo Assist] perf(logger): sanitize RPC payload once for text+markdown previews #8722): RPC payloads are now sanitized once and reused for both the text log and Markdown preview, eliminating redundant work on every logged response.
• jq filter compile/cache deduplication (Deduplicate jq filter compile/cache pipeline in jqschema without changing public behavior #8565): The jqschema middleware pipeline no longer recompiles identical jq filters; cached results are reused without any behavior change.

📚 Documentation

• Fixed incorrect headers example in the JSON stdin OpenTelemetry config reference and clarified that MCP_GATEWAY_PORT is used for environment validation only — not as a listen-address override (#8564).
• SDK upgrade gate procedure is now documented alongside the two canary tests that guard critical MCP SDK assumptions (#8567).

🐳 Docker Image

The Docker image for this release is available at:

docker pull ghcr.io/github/gh-aw-mcpg:v0.4.0
# or
docker pull ghcr.io/github/gh-aw-mcpg:latest

Supported platforms: linux/amd64, linux/arm64

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For complete details, see the full release notes.

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Generated by the Release Highlights workflow for v0.4.0

Warning

Firewall blocked 1 domain

The following domain was blocked by the firewall during workflow execution:

• awmgmcpg

To allow these domains, add them to the network.allowed list in your workflow frontmatter:

network:
  allowed:
    - defaults
    - "awmgmcpg"

See Network Configuration for more information.

Generated by Release · 29.4 AIC · ⊞ 6.2K · ◷

[leemeador]

I get the same error message about awmgmcpg being missing somehow. I cannot find the original log message in the huge output of the agentic locked workflow. If I add the network entry to my agentic workflow front matter, it breaks the workflow. Copilot suggests something else as the name but it doesn't remove the error. However, I can find nothing that is NOT working in the workflow.