feat: add portable PR attachment skill

Author: none23

skills/attach-github-pr-files/SKILL.md

@@ -0,0 +1,10 @@
+---
+name: attach-github-pr-files
+description: Upload local images or files and embed them in a GitHub pull request body or comment. Use when a PR needs a screenshot, log, PDF, or other attachment that GitHub CLI, Codex, or Claude Code cannot upload directly.
+---
+
+Run this skill's `scripts/upload.sh FILE [ALT]`; paste its Markdown output into the PR.
+
+Require `GITHUB_ATTACHMENTS_TOKEN`. Give images meaningful alt text.
+
+Never upload secrets: anyone with the URL can read the file until it expires.

skills/attach-github-pr-files/agents/openai.yaml

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+interface:
+  display_name: "Attach GitHub PR Files"
+  short_description: "Upload files for GitHub pull request Markdown"
+  default_prompt: "Use $attach-github-pr-files to attach this file to the GitHub pull request."

skills/attach-github-pr-files/scripts/upload.sh

@@ -0,0 +1,27 @@
+#!/bin/sh
+set -eu
+
+file=${1:?"usage: upload.sh FILE [ALT]"}
+alt=${2-}
+: "${GITHUB_ATTACHMENTS_TOKEN:?GITHUB_ATTACHMENTS_TOKEN is required}"
+test -f "$file"
+
+output=$(mktemp)
+trap 'rm -f "$output"' EXIT HUP INT TERM
+
+set -- \
+  --fail-with-body --silent --show-error \
+  --request POST \
+  --header "Authorization: Bearer $GITHUB_ATTACHMENTS_TOKEN" \
+  --header "X-Filename: $(basename "$file")" \
+  --header "Content-Type: $(file --brief --mime-type -- "$file")" \
+  --data-binary "@$file" \
+  --output "$output"
+[ -z "$alt" ] || set -- "$@" --header "X-Alt-Text: $alt"
+
+if ! curl "$@" https://github-pr-attachments.none23.workers.dev/v1/attachments; then
+  cat "$output" >&2
+  exit 1
+fi
+
+node -e 'const x=JSON.parse(require("fs").readFileSync(process.argv[1]));if(typeof x.markdown!=="string")throw Error("invalid response");console.log(x.markdown)' "$output"