Add milestones capability

docs/README.skills.md

@@ -213,7 +213,7 @@ See [CONTRIBUTING.md](../CONTRIBUTING.md#adding-skills) for guidelines on how to
 | [github-actions-runtime-upgrade-conventions](../skills/github-actions-runtime-upgrade-conventions/SKILL.md)<br />`gh skills install github/awesome-copilot github-actions-runtime-upgrade-conventions` | Upgrade GitHub Actions to supported runtimes by selecting safe action versions, preserving workflow behavior, and validating post-upgrade execution. | None |
 | [github-codespaces-efficiency](../skills/github-codespaces-efficiency/SKILL.md)<br />`gh skills install github/awesome-copilot github-codespaces-efficiency` | Audit and improve GitHub Codespaces efficiency. Use this skill when a user wants faster Codespaces startup, lower Codespaces spend, slim devcontainers, right-size machines, tune idle timeout, or scope prebuilds to branches with sustained usage. | `references/codespaces.md`<br />`references/review-rubric.md` |
 | [github-copilot-starter](../skills/github-copilot-starter/SKILL.md)<br />`gh skills install github/awesome-copilot github-copilot-starter` | Set up complete GitHub Copilot configuration for a new project based on technology stack | None |
-| [github-issues](../skills/github-issues/SKILL.md)<br />`gh skills install github/awesome-copilot github-issues` | Create, update, and manage GitHub issues using MCP tools. Use this skill when users want to create bug reports, feature requests, or task issues, update existing issues, add labels/assignees/milestones, set issue fields (dates, priority, custom fields), set issue types, manage issue workflows, link issues, add dependencies, or track blocked-by/blocking relationships. Triggers on requests like "create an issue", "file a bug", "request a feature", "update issue X", "set the priority", "set the start date", "link issues", "add dependency", "blocked by", "blocking", or any GitHub issue management task. | `references/dependencies.md`<br />`references/images.md`<br />`references/issue-fields.md`<br />`references/issue-types.md`<br />`references/projects.md`<br />`references/search.md`<br />`references/sub-issues.md`<br />`references/templates.md` |
+| [github-issues](../skills/github-issues/SKILL.md)<br />`gh skills install github/awesome-copilot github-issues` | Create, update, and manage GitHub issues using MCP tools. Use this skill when users want to create bug reports, feature requests, or task issues, update existing issues, add labels/assignees/milestones, set issue fields (dates, priority, custom fields), set issue types, manage issue workflows, link issues, add dependencies, or track blocked-by/blocking relationships. Triggers on requests like "create an issue", "file a bug", "request a feature", "update issue X", "set the priority", "set the start date", "link issues", "add dependency", "blocked by", "blocking", or any GitHub issue management task. | `references/dependencies.md`<br />`references/images.md`<br />`references/issue-fields.md`<br />`references/issue-types.md`<br />`references/milestones.md`<br />`references/projects.md`<br />`references/search.md`<br />`references/sub-issues.md`<br />`references/templates.md` |
 | [github-release](../skills/github-release/SKILL.md)<br />`gh skills install github/awesome-copilot github-release` | Guides IA through releasing a new version of a GitHub library end-to-end. Handles SemVer versioning and Keep a Changelog formatting automatically. | `references/commit-classification.md`<br />`references/semver-rules.md` |
 | [gitmoji](../skills/gitmoji/SKILL.md)<br />`gh skills install github/awesome-copilot gitmoji` | Generates commit messages following the gitmoji convention (https://gitmoji.dev) — picks the right emoji for the intent of the change and writes a well-formed message. Use when asked to "write a gitmoji commit", "add an emoji to my commit message", "which gitmoji should I use", "gitmoji this change", or when a project uses gitmoji-style commit messages. Works from a git diff, staged changes, or a plain description of the change. Generates the message only — does not run git commands. | `references/gitmoji-reference.md` |
 | [go-mcp-server-generator](../skills/go-mcp-server-generator/SKILL.md)<br />`gh skills install github/awesome-copilot go-mcp-server-generator` | Generate a complete Go MCP server project with proper structure, dependencies, and implementation using the official github.com/modelcontextprotocol/go-sdk. | None |

skills/github-issues/SKILL.md

@@ -194,6 +194,7 @@ The following features require REST or GraphQL APIs beyond the basic MCP tools.
 |------------|-------------|-----------|
 | Advanced search | Complex queries with boolean logic, date ranges, cross-repo search, issue field filters (`field.name:value`) | [references/search.md](references/search.md) |
 | Sub-issues & parent issues | Breaking work into hierarchical tasks | [references/sub-issues.md](references/sub-issues.md) |
+| Milestones | Create, read, update, close, reopen, delete milestones and manage milestone issues | [references/milestones.md](references/milestones.md) |
 | Issue dependencies | Tracking blocked-by / blocking relationships | [references/dependencies.md](references/dependencies.md) |
 | Issue types (advanced) | GraphQL operations beyond MCP `list_issue_types` / `type` param | [references/issue-types.md](references/issue-types.md) |
 | Projects V2 | Project boards, progress reports, field management | [references/projects.md](references/projects.md) |

skills/github-issues/references/milestones.md

@@ -0,0 +1,110 @@
+# Milestones
+
+Use milestones to group related issues into a deliverable unit of work.
+
+Milestones can be read and managed through the GitHub REST API.
+
+## List Milestones
+
+```bash
+gh api "repos/{owner}/{repo}/milestones?state=all&per_page=100" \
+  --paginate \
+  --jq '.[] | {number, title, state, open_issues, closed_issues, due_on}'
+```
+
+## Get Milestone
+
+```bash
+gh api repos/{owner}/{repo}/milestones/{milestone_number}
+```
+
+## Create Milestone
+
+```bash
+gh api repos/{owner}/{repo}/milestones \
+  -X POST \
+  -f title="Milestone title" \
+  -f description="Milestone description"
+```
+
+Optional due date:
+
+```bash
+gh api repos/{owner}/{repo}/milestones \
+  -X POST \
+  -f title="Milestone title" \
+  -f description="Milestone description" \
+  -f due_on="2026-09-01T00:00:00Z"
+```
+
+## Update Milestone
+
+```bash
+gh api repos/{owner}/{repo}/milestones/{milestone_number} \
+  -X PATCH \
+  -f title="Updated title" \
+  -f description="Updated description"
+```
+
+## Close Milestone
+
+```bash
+gh api repos/{owner}/{repo}/milestones/{milestone_number} \
+  -X PATCH \
+  -f state=closed
+```
+
+## Reopen Milestone
+
+```bash
+gh api repos/{owner}/{repo}/milestones/{milestone_number} \
+  -X PATCH \
+  -f state=open
+```
+
+## List Issues in Milestone
+
+Use the milestone number, not the milestone title.
+
+```bash
+gh api "repos/{owner}/{repo}/issues?milestone={milestone_number}&state=all&per_page=100" \
+  --paginate \
+  --jq '.[] | select(.pull_request == null) | {number, title, state}'
+```
+
+The Issues REST endpoint can also return pull requests, so exclude entries
+containing `pull_request` when the caller specifically requests milestone issues.
+
+## Assign Issue to Milestone
+
+```bash
+gh api repos/{owner}/{repo}/issues/{issue_number} \
+  -X PATCH \
+  -F milestone={milestone_number}
+```
+
+## Remove Issue from Milestone
+
+```bash
+gh api repos/{owner}/{repo}/issues/{issue_number} \
+  -X PATCH \
+  -F milestone=null
+```
+
+## Delete Milestone
+
+Delete a milestone only when explicitly requested.
+
+```bash
+gh api repos/{owner}/{repo}/milestones/{milestone_number} \
+  -X DELETE
+```
+
+## Usage Rules
+
+- Use milestone numbers for API operations.
+- A milestone groups work; it does not define issue execution order.
+- Use native issue dependencies for execution ordering.
+- Do not infer dependencies merely because issues belong to the same milestone.
+- Listing a milestone for an automated workflow should include all open and
+  closed issues unless the caller explicitly requests otherwise.