Pre-Build Search: Grep Before You Build

Before building something new, check if a solution path already exists in the knowledge base. This prevents reinventing approaches that have already been tried, validated, or rejected.

When This Rule Activates

Before implementing any non-trivial feature, module, or integration:

• During /plan (Step 1.5: Prior Art Lookup)
• During /build_module (Step 2.5: Pre-Build Enrichment)
• When a developer asks "how should we implement X?"

What to Search

Search these locations in order:

1. Solution Paths (memory/projects/)

grep -ri "<domain keyword>" memory/projects/

Look for ## Solution Paths sections in project profiles. These document HOW projects solved specific problems — what was tried, what failed, and why the chosen approach won.

2. Known-Broken Approaches (memory/bugs/regression-ledger.md)

grep -i "<approach keyword>" memory/bugs/regression-ledger.md

Check the ## Known-Broken Approaches section. If an approach has been tried and found broken, don't repeat the mistake.

3. ADRs (docs/adr/)

grep -ri "<concept>" docs/adr/

Check if an architectural decision already covers this problem space.

4. Existing Patterns (memory/patterns/)

grep -ri "<pattern keyword>" memory/patterns/

Check if a promoted pattern addresses this need.

5. Captured Findings (metrics/evaluation.db)

Query non-noise findings by category or keyword to surface what prior reviews flagged:

import sqlite3
conn = sqlite3.connect("metrics/evaluation.db")
try:
    rows = conn.execute("""
        SELECT severity, category, summary, discussion_id
        FROM findings
        WHERE is_noise = 0
          AND (category LIKE '%<keyword>%' OR summary LIKE '%<keyword>%')
        ORDER BY created_at DESC
        LIMIT 20
    """).fetchall()
    for r in rows:
        print(f"[{r[0]}] {r[1]}: {r[2]}  ({r[3]})")
except sqlite3.OperationalError:
    # is_noise column absent (pre-migration DB) — retry without filter
    try:
        rows = conn.execute("""
            SELECT severity, category, summary, discussion_id
            FROM findings
            WHERE category LIKE '%<keyword>%' OR summary LIKE '%<keyword>%'
            ORDER BY created_at DESC LIMIT 20
        """).fetchall()
        for r in rows:
            print(f"[{r[0]}] {r[1]}: {r[2]}  ({r[3]})")
    except sqlite3.OperationalError:
        print("[info] findings table not available — skip")
conn.close()

6. Discussion Transcripts (discussions/)

Full-text search across all sealed discussion transcripts:

grep -ril "<keyword>" discussions/*/transcript.md

This surfaces discussions where the topic was debated, even if no finding was extracted.

How to Use Results

• Solution path found: Reference it in your plan or build. Explain why you're following or diverging from the documented path.
• Known-broken approach found: Do not use that approach. Document why you're using an alternative.
• No results found: Proceed normally. After implementation, capture the solution path via the commit protocol (Step 3.5).

What This Rule Does NOT Do

• It does not block builds if no prior art is found — absence of prior art is normal for novel work.
• It does not require exhaustive search — a quick grep is sufficient. If the first 2-3 searches yield nothing, move on.
• It does not replace architectural review — prior art informs decisions, it doesn't make them.