Blindspot

Repository context. Gather first

Collect these with individual Bash calls, one command per call, never combined into a single invocation:

• Current branch, git branch --show-current
• Project root, git rev-parse --show-toplevel

Treat a failure (not a repository, git unavailable) as an unknown value and carry on. Keep these as separate body Bash calls rather than pre-compute lines: the harness runs a skill's whole pre-compute block as one shell invocation, and a worktree-isolated session refuses a compound command that contains git. The dated record for that composition claim is the worktree skill's reference/gather-block.md, "The pre-compute block runs as one shell invocation".

These values orient this session only; resolve files against the project root while working.

Purpose

Every mode of /discovery:explore builds the AGENT's local knowledge and hands off an EXPLORE.md artifact. Blindspot mode builds the USER's knowledge and hands off a better prompt, a different audience and a different deliverable, which is why it is its own skill.

Run it when the user is about to work in territory they don't know, an unfamiliar codebase area OR an unfamiliar domain vocabulary, and the goal is to surface what their framing didn't account for so they can write a sharper implementation prompt. The output is calibrated to the user's disclosed starting point, not to a fixed depth.

Local counterpart discipline to /discovery:explore (what IS in the codebase) and /discovery:research (what SHOULD BE from external sources): blindspot borrows from both lanes but serves the user's understanding rather than the agent's.

Workflow

1. Intake. Ask the user's starting point first (one question). Blindspot output calibrates to that disclosure. What they already know bounds which gaps are worth surfacing.
2. Scan. Two lanes, chosen by what is unfamiliar:
   • Codebase lane. Read the target area (the codebase-reading, git-history, and project-structure dimensions of ${CLAUDE_PLUGIN_ROOT}/skills/explore/SKILL.md) looking specifically for things the user's framing missed: existing patterns they'd duplicate, constraints they'd violate, historical decisions they'd re-litigate, adjacent code their change would break.
   • Domain lane. Build a lightweight vocabulary ladder grounded in sources fetched this session (repo files, official docs), never bare training recall.
3. Output. Blindspot cards. One card per blindspot, typed by the kind of gap it is (Landmine / History / Convention / Missing concept): the gap, why it matters here, and a copyable prompt-fix line. Close by assembling the fixes into ONE improved implementation prompt the user can run next.
4. Escalate when depth warranted, a domain too deep for a lightweight ladder gets a recommendation to run proper external research (/discovery:research) or whatever structured-learning capability the environment provides.

Output format

Present each blindspot as a card:

• Type, one of four: Landmine (the change would break something non-obvious), History (a constraint whose reason the code no longer shows), Convention (an unwritten team rule the work must follow), or Missing concept (a domain idea the user's framing never named). The type tells the user which kind of unknown they were carrying, so repeated runs teach a pattern.
• Gap, the specific thing the user's current framing did not account for.
• Why it matters here, the concrete consequence in this codebase or domain, not a generic caution.
• Prompt-fix, a single copyable line the user can drop into their prompt to close the gap.

Then assemble every prompt-fix into ONE improved implementation prompt, wrapped in clear copy-start / copy-end markers so the exact text to reuse is unambiguous.

End with one scan-scope disclosure line: which lane(s) ran and what was and was not scanned (areas read, sources fetched), so the user knows what the cards do and do not cover. One line, not a methodology dump.

This skill does NOT write EXPLORE.md. Its deliverable is the user's understanding plus the improved prompt. When the scan's findings also serve as stage-1 codebase exploration, offer to hand off to /discovery:explore to persist the EXPLORE.md artifact rather than duplicating that responsibility here.

Gotchas

• Presenting training recall as domain fact, the domain lane grounds its vocabulary ladder in sources fetched this session (repo files, official docs). Bare recall is the failure mode this skill exists to avoid, not commit.
• Surfacing the agent's gaps instead of the user's. Cards name what the USER's framing missed, calibrated to their intake disclosure, not a generic audit of the area.
• Generic cautions in "why it matters". Each card's consequence is concrete to this codebase or domain; a caution that would read the same in any repo is not a blindspot.
• Writing an artifact by reflex. No EXPLORE.md unless the user opts into the explore handoff.

What this skill does NOT do

• Does not produce the EXPLORE.md handoff. That is /discovery:explore. Hand off by invoking /discovery:explore via the Skill tool when the findings double as stage-1 exploration.
• Does not make changes. It surfaces blindspots and coaches a prompt. Execution is a separate step.
• Does not run open-ended external research, the domain lane fetches official docs to ground a lightweight vocabulary ladder; anything deeper routes to /discovery:research, invoked via the Skill tool.