Airtable Base Audit Skill

You are an expert at analyzing Airtable bases for health issues. Help users identify problems across field usage, performance, and schema design.

When to Use This Skill

• User explicitly invokes /airtable-base-audit
• User asks to "audit my base", "check base health", or "analyze my Airtable"

Overview

This skill performs comprehensive base health analysis:

• Field Health (~35% of score) - Unused fields, low fill rates, duplicates, "(copy)" fields
• Performance (~35% of score) - Record counts, attachment storage, TODAY() formulas, complex formulas
• Schema Quality (~30% of score) - Repeated data, relationship patterns, normalization

Produces a letter grade (A-F) with percentage breakdown and actionable recommendations.

---

Step 1: Determine Airtable Plan

Ask the user's plan to set correct limits:

What Airtable plan are you on?
  1. Teams (50K records/base, 20GB attachments)
  2. Business (125K records/base, 100GB attachments)
  3. Enterprise (500K records/base, 1TB attachments)
  4. I don't know (will use Business defaults)

Plan Limits Reference

Plan	Records/Base	Attachment Storage
Teams	50,000	20GB
Business	125,000	100GB
Enterprise	500,000	1TB

---

Step 2: Select Base to Audit

List available bases and let user choose:

# Get bases using MCP
mcp__airtable__list_bases

Present numbered list:

Which base would you like to audit?
  1. Projects (appXXX)
  2. CRM (appYYY)
  3. Inventory (appZZZ)

---

Step 3: Gather Data

3.1 Fetch Tables and Fields

# Get all tables
mcp__airtable__list_tables
  baseId: "appXXX"
  detailLevel: "fullSchema"

# For each table, get detailed field info
mcp__airtable__describe_table
  baseId: "appXXX"
  tableId: "tblXXX"

3.2 Sample Records for Analysis

To calculate fill rates and uniqueness, sample records from each table:

# Sample records (first 100-1000 depending on table size)
mcp__airtable__list_records
  baseId: "appXXX"
  tableIdOrName: "tblXXX"
  maxRecords: 100

For large tables (>1000 records), sample in chunks to get representative data.

Rate Limiting

Airtable API has a 5 requests/second limit. For bases with many tables:

• Add 200ms delay between API calls
• This prevents rate limit errors during large audits

Progress Indication

Analyzing "Projects" base...
  - Fetching tables (5 found)
  - Analyzing fields (47 total)
    - Tasks: 24 fields, sampling records...
    - Milestones: 12 fields, sampling records...
    - ...
  - Checking performance metrics
  - Evaluating schema patterns

---

Step 4: Analyze Field Health

Check 1: Unused Fields (0% fill rate)

Detection: Field has no data in any sampled records.

fill_rate = (records_with_value / total_records) * 100
unused = fill_rate === 0

Severity: Warning (may be new field or intentionally empty)

Auto-Fix: Can hide field (reversible)

Check 2: Low Fill Rate (<10%)

Detection: Field has data in less than 10% of records.

Severity: Info (flag for review)

Auto-Fix: None (requires human judgment)

Check 3: Uniqueness Analysis

Detection: Fields with names containing "email", "id", "key", "code" should have high uniqueness.

uniqueness = (unique_values / total_non_empty_values) * 100

Expected uniqueness:

• Email fields: >95%
• ID/Key/Code fields: >99%

Severity: Warning if below threshold

Auto-Fix: None (data quality issue)

Check 4: "(copy)" Fields

Detection: Field name contains "(copy)" - indicates UI duplication never renamed.

/\(copy\)/i.test(fieldName)

Severity: Warning

Auto-Fix: Suggest rename (removing "(copy)")

Check 5: Duplicate Data Patterns

Detection: Same non-trivial values appearing across multiple fields or tables.

Look for:

• Identical text appearing in 2+ fields
• Same select options duplicated across tables
• Repeated company names, emails, etc. (suggests missing link)

Severity: Info (may be intentional)

Auto-Fix: None (requires schema redesign)

---

Step 5: Analyze Performance

Check 1: Record Count vs Plan Limit

usage_percent = (record_count / plan_limit) * 100

Thresholds:

• <50%: Good
• 50-75%: Info (plan ahead)
• 75-90%: Warning

• 90%: Critical

Check 2: Attachment Storage

Note: Attachment size cannot be directly queried via API. Estimate by:

• Counting attachment fields
• Sampling attachment records
• Noting if storage warnings are mentioned

Thresholds: Same as record count

Check 3: TODAY() Formula Detection

Detection: Search formula fields for performance-impacting functions.

// Flag these in formulas
/TODAY\(\)/i
/NOW\(\)/i

Why it matters: These formulas recalculate on every base load, causing performance issues at scale.

Severity: Warning (suggest alternatives)

Alternatives to suggest:

• Use a "Last Updated" field instead
• Move calculation to automation that runs periodically
• Use DATEADD from a fixed reference date

Check 4: Complex Formulas

Detection: Formula text longer than 500 characters.

Severity: Info (may indicate formula should be split or simplified)

Check 5: Deep Lookup/Rollup Chains

Detection: Lookups that reference other lookups, or rollups of lookups.

Severity: Warning (performance impact, harder to debug)

---

Step 6: Analyze Schema Quality

Check 1: Repeated Data Across Tables

Detection: Same text values appearing in multiple tables without linked records.

Example: "Acme Corp" appears as text in Contacts, Projects, and Invoices tables.

Recommendation: Create a Companies table and link to it.

Severity: Warning

Check 2: Too Many Single-Select Fields

Detection: Table has >10 single-select fields.

Severity: Info

Recommendation: Consider grouping related selects or extracting to separate table.

Check 3: Missing Relationships

Detection: Data patterns suggesting need for linked records:

• Same field names across tables (e.g., "Company Name" in multiple tables)
• Foreign key patterns (fields ending in "ID", "Code")
• Repeated text that could be normalized

Severity: Info

Check 4: Join Table Candidates

Detection: Many-to-many relationship patterns without junction table.

Look for:

• Multiple link fields to same table
• Long text fields containing comma-separated values
• Multiselect fields with many options

Severity: Info

Check 5: Denormalization

Detection: Fields that could be lookups instead of duplicated data.

Example: "Client Email" in Projects table when there's already a Client link field.

Severity: Info

---

Step 7: Calculate Scores

Scoring Formula

// Weight by category
fieldHealthWeight = 0.35;
performanceWeight = 0.35;
schemaQualityWeight = 0.30;

// Each category scores 0-100
overallScore = (fieldHealth * fieldHealthWeight) +
               (performance * performanceWeight) +
               (schemaQuality * schemaQualityWeight);

Category Scoring

Deduct points for issues:

Field Health (100 base):

• Unused field: -5 per field
• Low fill rate: -2 per field
• "(copy)" field: -3 per field
• Low uniqueness on ID field: -5 per field

Performance (100 base):

• Record usage >75%: -10
• Record usage >90%: -25
• Each TODAY() formula: -10
• Each complex formula: -3
• Deep lookup chains: -5 each

Schema Quality (100 base):

• Repeated data pattern: -10 per pattern

• 10 single-selects: -5

• Missing obvious relationship: -5 per pattern
• Denormalization detected: -3 per instance

Letter Grades

Score	Grade
90-100	A
80-89	B
70-79	C
60-69	D
<60	F

---

Step 8: Present Report

Report Format

═══════════════════════════════════════════════
         Base Health Report: [Base Name]
═══════════════════════════════════════════════
Overall Score: [Grade] ([Score]/100)

📊 Field Health: [Grade] ([Score]/100)
  ✓ [N] fields analyzed
  ✓ [N] fields have good fill rates (>10%)
  ⚠ [N] fields with <10% fill rate
  ⚠ [N] fields appear unused (0% fill)
  ⚠ "[Field Name]" should be renamed (has "(copy)")
  ℹ "[Field]" field: [N]% unique (good!/needs review)

📈 Performance: [Grade] ([Score]/100)
  ✓ [N] records ([N]% of [Limit] limit)
  ⚠ [N] formulas use TODAY() - consider alternatives
  ⚠ [N] complex formulas (>[N] chars)
  ⚠ Attachment storage approaching limit

🔗 Schema Quality: [Grade] ([Score]/100)
  ⚠ "[Value]" repeated in [N] tables - consider linked record
  ⚠ [Table] has [N] single-select fields
  💡 Consider extracting "[Pattern]" to separate table

───────────────────────────────────────────────
Safe fixes available:
  • Hide [N] unused fields

How would you like to proceed?
  [1] Apply safe fixes
  [2] Export full report
  [3] View detailed recommendations
═══════════════════════════════════════════════

---

Step 9: Remediation Options

Option 1: Apply Safe Fixes

Safe fixes are low-risk, reversible changes:

Can auto-fix:

• Hide unused fields (can be unhidden later)

Cannot auto-fix (too risky):

• Delete fields
• Modify formulas
• Restructure schema
• Change field types

Applying safe fixes...
  ✓ Hidden "Old Status" in Tasks (was unused)
  ✓ Hidden "Notes Backup" in Projects (was unused)

Done! 2 fields hidden.

Note: Hidden fields can be restored via Field menu → "Show hidden fields"

Option 2: Export Full Report

Generate detailed markdown report:

# Base Health Audit Report

**Base:** [Name]
**Generated:** [Date]
**Plan:** [Plan Type]

## Summary

| Category | Score | Grade |
|----------|-------|-------|
| Overall | [N]/100 | [Grade] |
| Field Health | [N]/100 | [Grade] |
| Performance | [N]/100 | [Grade] |
| Schema Quality | [N]/100 | [Grade] |

## Field Health Issues

### Unused Fields (0% fill rate)

| Table | Field | Type | Recommendation |
|-------|-------|------|----------------|
| Tasks | Old Status | Single Select | Hide or delete |
| ... | ... | ... | ... |

### Low Fill Rate Fields (<10%)

| Table | Field | Fill Rate | Recommendation |
|-------|-------|-----------|----------------|
| ... | ... | ... | ... |

### Fields Needing Rename

| Table | Current Name | Suggested Name |
|-------|--------------|----------------|
| Tasks | Status (copy) | [User decides] |

## Performance Issues

### TODAY() Formulas

| Table | Field | Formula | Alternative |
|-------|-------|---------|-------------|
| Tasks | Days Open | TODAY()-{Created} | Use automation to update daily |

### Complex Formulas

| Table | Field | Length | Recommendation |
|-------|-------|--------|----------------|
| ... | ... | ... | Consider splitting |

## Schema Quality Issues

### Repeated Data

| Value | Found In | Recommendation |
|-------|----------|----------------|
| "Acme Corp" | Contacts, Projects, Invoices | Create Companies table with links |

### Relationship Opportunities

| Pattern | Tables | Suggestion |
|---------|--------|------------|
| Company Name | Contacts, Projects | Link to shared Companies table |

## Manual Action Checklist

- [ ] Review and delete/keep unused fields
- [ ] Rename "(copy)" fields appropriately
- [ ] Replace TODAY() formulas with alternatives
- [ ] Consider schema changes for repeated data

Option 3: Detailed Recommendations

Interactive drill-down for each issue:

Issue 1 of [N]: TODAY() Formula in "Days Open"

📍 Location: Tasks table → Days Open field
📝 Current formula: TODAY()-{Created}

⚠ Why this matters:
  TODAY() recalculates every time the base loads.
  With [N] records, this causes noticeable slowdown.

💡 Recommended alternatives:

  1. Automation approach:
     - Create a "Days Open Snapshot" number field
     - Set up daily automation to update: TODAY()-{Created}
     - Runs once per day instead of on every load

  2. Script approach:
     - Run a script weekly to update stale values
     - Better for bases with less frequent access

  3. Keep as-is:
     - Acceptable if real-time accuracy is critical
     - Consider if <1000 records

Would you like step-by-step instructions for any approach?
  [1] Automation setup
  [2] Script setup
  [3] Skip to next issue

---

Edge Cases

MCP Not Available

Airtable MCP tools not available. To use this skill:

Option 1: Configure Airtable MCP
  - Add AIRTABLE_PAT to your environment
  - Restart Claude Code

Option 2: Manual audit (limited)
  - Open your base in Airtable
  - Go to Help → API documentation
  - Share field lists for analysis

Very Large Base

For bases with >20 tables or >100 fields:

This base has [N] tables and [N] fields.
A full audit may take several minutes.

How would you like to proceed?
  1. Full audit (recommended for first-time)
  2. Quick scan (field health only)
  3. Audit specific tables

Permission Errors

⚠ Unable to access some tables. You may need:
  - schema.bases:read scope on your token
  - Access permissions to all tables

Continuing with accessible tables...

---

Best Practices

1. Run quarterly - Bases accumulate cruft over time; regular audits prevent debt
2. Start with report mode - Review findings before applying any fixes
3. Coordinate with team - Notify collaborators before hiding fields
4. Back up first - Export base to CSV before structural changes
5. Address performance first - TODAY() formulas have immediate impact
6. Schema changes last - These require the most planning

---

Relationship to Other Skills

• airtable-field-audit - Focuses on field naming issues (duplicates, whitespace, casing)
• airtable-base-audit - Broader health check (this skill)

Consider running both for comprehensive base maintenance:

1. /airtable-base-audit first for overall health
2. /airtable-field-audit after for naming cleanup