Evaluate New Port Agent Skill

Evaluate New Port

When to Use

• Reviewing a newly added or substantially updated port
• Auditing whether a port's declared license metadata matches what it installs
• Checking for vendored third-party code or optional dependencies that are not modeled in vcpkg.json
• Looking for packaging or review issues after a real local install

Overview

This skill takes a single port name, reads the port's metadata and build recipe, performs a clean local install, and writes a structured audit report. The audit focuses on:

• Declared license metadata from ports/{port-name}/vcpkg.json, including feature-scoped declarations
• Build invocation and feature toggles from ports/{port-name}/portfile.cmake
• Real build output after vcpkg x-ci-clean and vcpkg install {port-name}
• Extracted source tree under buildtrees/{port-name}/src
• Installed package contents under packages/{port-name}_{target-triplet}
• Code review suggestions for the port's packaging logic and metadata

If the install reports that the port is unsupported on the current platform or triplet, stop there and recommend a more appropriate platform instead of continuing the audit.

Required Inputs

• A valid port name present under ports/{port-name}

Detailed Workflow

Step 1: Read the Port Metadata

Open these files first:

• ports/{port-name}/vcpkg.json
• ports/{port-name}/portfile.cmake

Extract at least the following:

From vcpkg.json:

• top-level license, if present
• any feature-scoped license declarations, including explicit null
• homepage
• features
• dependencies
• supports, if present

From portfile.cmake:

• The primary build helper used (vcpkg_cmake_configure, vcpkg_configure_make, vcpkg_cmake_build, Meson helpers, raw cmake, etc.)
• Feature-to-build-option mappings
• Explicit enable/disable flags for optional upstream components
• Any platform guards, fatal errors, or unsupported conditions
• Any bundling, patching, or file-pruning logic relevant to installed content

Step 2: Clean the Local Working State

Run the repository-local vcpkg executable from the repository root:

Windows:

.\vcpkg.exe x-ci-clean

Linux/macOS:

./vcpkg x-ci-clean

Do not skip this step. The audit should be based on a fresh source extraction and package install.

Step 3: Install the Port

Run a normal install of the requested port:

Windows:

.\vcpkg.exe install {port-name}

Linux/macOS:

./vcpkg install {port-name}

Capture the output. If it contains an unsupported-platform message, stop the workflow and report:

• That the current platform cannot evaluate this port meaningfully
• The reason quoted from the install output or portfile.cmake
• A suggested alternate platform, chosen from evidence in supports, platform guards, or fatal-error text

Common examples:

• only supports Windows → suggest Windows
• only supports Linux → suggest Linux
• only supports x64 and x86 Windows → suggest an x64 Windows host
• Building for {TARGET_TRIPLET} on {HOST_TRIPLET} is unsupported → suggest the native target platform instead of cross-building

If the install succeeds, continue.

If the install hit a binary cache and you need to rerun the port to force a local rebuild for inspection, remove and reinstall the affected port directly rather than running x-ci-clean followed by install --no-binarycaching. That preserves cache hits for unedited dependencies while still rebuilding the port under review.

Step 4: Determine the Installed Triplet Directory

Find the installed package directory under:

packages/{port-name}_{target-triplet}

Use the package directory that was created by the install you just ran. The triplet is normally the system default target triplet (for example x64-windows, arm64-windows, or x64-linux).

If multiple matching directories exist, prefer the one whose timestamp matches the current install output. Record the chosen triplet in the report.

Step 5: Audit the Extracted Source Tree

Inspect buildtrees/{port-name}/src and identify the extracted source directory or directories for the current build. Review them for vendoring and undeclared optional dependencies.

5a. Vendored Dependencies

Look for signs of bundled third-party code, such as directories or files named:

• third_party
• third-party
• vendor
• vendors
• extern
• external
• deps
• dependencies
• subprojects
• nested copies of well-known libraries

For each candidate:

• identify the bundled project if possible
• determine whether it is built or installed
• check whether the same dependency is already modeled in vcpkg.json
• note whether the portfile patches it out, replaces it with a vcpkg dependency, or leaves it vendored

5b. Optional Dependencies Not Explicitly Controlled

Look for optional integrations that are present upstream but not clearly controlled in packaging. Sources of evidence include:

• find_package(...)
• pkg_check_modules(...)
• option(...)
• WITH_*, ENABLE_*, USE_*, BUILD_*
• Meson feature or dependency(...)
• Autotools --with-* / --enable-*

Flag an issue when an optional dependency:

• appears in upstream build logic,
• is not declared in vcpkg.json, and
• is not explicitly enabled or disabled by portfile.cmake

The point is to find dependencies that may be auto-detected from the host environment, leading to non-reproducible builds.

Step 6: Audit Installed Content Against the Declared License Metadata

Inspect the package contents under packages/{port-name}_{target-triplet}. Focus on:

• share/{port-name}/copyright
• installed license files
• headers, sources, examples, tools, or assets originating from bundled third-party code
• any embedded notices for code under additional licenses

Treat explicit "license": null as intentional metadata meaning "no SPDX expression is provided here; inspect the installed copyright file." Do not report that case as missing metadata by itself.

Flag content when:

• the installed files include third-party components under licenses not covered by the declared license metadata,
• multiple upstream licenses appear to require a more precise SPDX expression,
• or the package installs bundled code whose license is absent from the declared metadata and copyright file

Do not assume every extra notice is a bug. Record the evidence and explain whether it appears compatible, incomplete, or suspicious.

Step 7: Review the Portfile for Packaging Suggestions

While auditing ports/{port-name}/portfile.cmake, look for common review items such as:

• missing explicit disable flags for tests, docs, examples, benchmarks, or tools
• optional dependencies that should be feature-gated
• vendored libraries that could be replaced with vcpkg dependencies
• install steps that might ship unnecessary files
• missing cleanup of debug-only or duplicate artifacts
• support restrictions that should move into supports in vcpkg.json
• license metadata that is too broad or incomplete after considering top-level and feature-scoped declarations

Only report suggestions supported by evidence from the files or the install result.

Output Requirements

Generate a markdown report with these sections:

• Port Summary
• Declared Metadata
• Build Invocation Summary
• Install Result
• Vendored Dependencies
• Optional Dependency Risks
• License / Installed Content Findings
• Other Port Review Suggestions
• Recommended Follow-ups

Be specific. Cite file paths and brief snippets when they support a finding.

If there are no findings for a section, write None found instead of omitting the section.

Suggested Report Template

See references/report-template.md.

Execution Notes

• Run from the repository root
• Prefer repository-local paths in all findings
• Do not continue source/package inspection after an unsupported install result
• Base conclusions on the actual installed package directory created by this run
• Keep the final report focused on actionable review feedback rather than restating raw command output