Software Development Skills

Set up and administer Git infrastructure and behavior — self-hosting a Git server (protocol choice, SSH/git-daemon/Smart HTTP setup, access restriction), server-side config, Git hooks (client and server), enforcing policies like commit-message formats and per-path ACLs, and repository/team configuration such as line endings, whitespace, attributes (binary diffs, clean/smudge filters, export rules, per-file merge strategy), and credential storage. Use when the user wants to host repos themselves, add hooks, block force pushes, enforce commit rules, fix CRLF/whitespace issues, diff binary files, or configure Git for a team — even if they only say "our pushes should be rejected when..." or "line endings are a mess". Not for GitHub/GitLab account-level UI administration.

Manage Git branches and integrate work — merge vs rebase decisions, tracking/remote branches, renaming branches (including master/main), and resolving merge conflicts including hard cases (whitespace conflicts, binary files, recurring conflicts with rerere, picking sides, subtree merges). Use when the user hits a merge conflict, asks "merge or rebase?", needs to rename or clean up branches, or must integrate diverged branches — even if they just paste conflict markers or a failed-merge error. Not for undoing already-made merges or recovering lost commits (use git-history-repair).

Undo, rewrite, and recover Git history safely — amend, reset vs restore vs revert, interactive rebase (reorder/squash/split/drop), undoing bad merges, recovering "lost" commits via reflog/fsck, and purging secrets or huge files from all history. Use when something in a repo went wrong or history must be reshaped — "undo this commit", "I lost my work", "remove this password/file from history", "clean up my commits before pushing", "botched merge/rebase" — even if the user doesn't say "rewrite history". Also covers finding when/where a bug or change was introduced (bisect, blame, pickaxe). Not for routine branching/merging or resolving fresh merge conflicts.

Migrate repositories from other version-control systems into Git, or use Git as a client against them — SVN (git svn clone + full post-import cleanup, ongoing git-svn workflow rules), Mercurial (hg-fast-export), Perforce (git-p4 / Git Fusion), and custom sources via git fast-import. Use when the user wants to "convert/import/migrate a repo to git", keep working against a Subversion server with git, fix author names during an import, or write an importer for an unusual source (backups, another VCS) — even if they just say "we're moving off SVN". Not for cloning/mirroring between plain Git remotes.

Work with Git submodules correctly — adding, cloning, updating, committing inside, publishing, switching branches, converting directories, and merging diverged submodule pointers. Use for any task touching a repo that contains (or should contain) another Git repo — "submodule is empty after clone", "detached HEAD in my submodule", "update all submodules", "my teammate can't see my submodule changes", ".gitmodules conflict" — even if the user just reports a subdirectory mysteriously empty or 'modified (new commits)'. Not for vendoring via subtree merge (see git-branching-and-merging).

Design, generate, and consume RFC 9457 problem details for HTTP APIs (application/problem+json, application/problem+xml). Use when implementing or reviewing API error responses, standardizing error bodies, defining new error/problem types, or parsing errors in an HTTP client — including "return a proper JSON error", "structure our API errors", or any mention of RFC 7807, RFC 9457, or problem+json, even if the user doesn't say "problem details". Not for choosing HTTP status codes in general or debugging application logic.

Convert PDF documents into one or more high-quality reusable Agent Skills. Use when the user wants the knowledge, procedures, rules, standards, or methods in a PDF turned into agent capabilities — "skill-ify this PDF", "turn this manual into a skill", "make yourself able to do what this document teaches" — even when they don't use the word "skill". Not for merely summarizing, translating, or answering questions about a PDF.

Expert Git knowledge distilled from the Pro Git book (2nd edition, Chacon & Straub). Use when working with Git version control: everyday commands (add/commit/log/diff), branching and merging, rebasing, undoing mistakes, rewriting history, recovering lost commits, resolving merge conflicts, remotes and collaboration workflows, tags, stashing, bisect/blame debugging, submodules, hooks, git configuration and attributes, setting up a Git server, or understanding Git internals (objects, refs, packfiles, refspecs).

Design and review HTTP API error responses using RFC 9457 Problem Details (application/problem+json, application/problem+xml). Use when implementing API error handling, defining new problem types, validating error response payloads, or migrating from RFC 7807.