Why

Investigate the motivation and intent behind code. The companion how skill answers what the code does and how it works. why answers what forces led to its shape.

Every subagent below is read-only. Its brief carries the filled prompt template and the reference files it needs, pasted in or as absolute paths, and says: read-only, inspect only, no writes, no git commands that change state. Start each one with the same tool access you have: an investigator without its MCP can't search its source. Take each subagent's model from ~/.config/ox/models.md, using the role its step names, and pass that line's model and effort to your subagent tool. If the line is inherit, is missing, or the file's # harness line names a different harness, omit both so the subagent runs on your model; if the file is missing, also suggest the user run /setup-ox models. If the tool rejects an entry, use the closest model it lists and say so. If the harness has no subagent tool, do each step yourself, in order.

Operating posture

Operate as a careful, cautious, and precise investigator. Be honest about what you know vs what you're inferring. Read EPISTEMICS.md for the full confidence framework and phrasing guide. The synthesizer must follow it.

Step 1. Understand the target and the question

The target is usually a chunk of code, a pattern, a feature, or a named design decision. The question is usually a design rationale, a tradeoff, a motivating edge case, an external constraint, dead code, or a broad history sweep.

If the target is vague ("why do we do it this way?" with no clear referent), make your best guess from conversation context (open files, recent edits, what was just discussed). State your interpretation briefly so the user can redirect if you're off, then proceed.

Step 2. Establish the code anchor

Before starting investigators, build the seed context inline: file paths and line ranges, key symbols (functions, tables, events, exports), the last few commits touching the target, PR numbers from merge commits (pattern (#1234) in the subject line), and any linked issue IDs. Run git blame -L <start>,<end> <file> for last-touch commits, git log --follow -p -- <file> for full history with patches through renames, git log --oneline -20 -- <file> for recent commits with PR numbers visible, and git log -1 --format=%B <commit> to extract PR numbers. Then pull the PR bodies and discussion for any substantive commit: gh pr view <number> --json title,body,author,createdAt,mergedAt,labels,closingIssuesReferences,comments,reviews.