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Hash-based IDs

Understanding beads' collision-resistant ID system.

The Problem​

Traditional sequential IDs (#1, #2, #3) break when:

  • Multiple agents create issues simultaneously
  • Different branches have independent numbering
  • Forks diverge and later merge

The Solution​

Beads uses hash-based IDs:

bd-a1b2c3    # Short hash
bd-f14c      # Even shorter
bd-a3f8e9.1  # Hierarchical (child of bd-a3f8e9)

Properties:

  • Globally unique (content-based hash)
  • No coordination needed between creators
  • Merge-friendly across branches
  • Predictable length (configurable)

How Hashes Work​

IDs are generated from:

  • Issue title
  • Creation timestamp
  • Random salt
# Create issue - ID assigned automatically
bd create "Fix authentication bug"
# Returns: bd-7x2f

# The ID is deterministic for same content+timestamp

Hierarchical IDs​

For epics and subtasks:

# Parent epic
bd create "Auth System" -t epic
# Returns: bd-a3f8e9

# Children auto-increment
bd create "Design UI" --parent bd-a3f8e9    # bd-a3f8e9.1
bd create "Backend" --parent bd-a3f8e9      # bd-a3f8e9.2
bd create "Tests" --parent bd-a3f8e9        # bd-a3f8e9.3

Benefits:

  • Clear parent-child relationship
  • No namespace collision (parent hash is unique)
  • Up to 3 levels of nesting

ID Configuration​

Configure ID prefix and length:

# Set prefix (default: bd)
bd config set id.prefix myproject

# Set hash length (default: 4)
bd config set id.hash_length 6

# New issues use new format
bd create "Test"
# Returns: myproject-a1b2c3

Collision Handling​

While rare, collisions are handled automatically:

  1. On import, if hash collision detected
  2. Beads appends disambiguator
  3. Both issues preserved
# Check for collisions
bd info --schema --json | jq '.collision_count'

Working with IDs​

# Partial ID matching
bd show a1b2     # Finds bd-a1b2...
bd show auth     # Fuzzy match by title

# Full ID required for ambiguous cases
bd show bd-a1b2c3d4

# List with full IDs
bd list --full-ids

Migration from Sequential IDs​

If migrating from a system with sequential IDs:

# Import preserves original IDs in metadata
bd import -i old-issues.json

# View original ID
bd show bd-new --json | jq '.original_id'

Best Practices​

  1. Use short references - bd-a1b2 is usually unique enough
  2. Use --json for scripts - Parse full ID programmatically
  3. Reference by hash in commits - Fixed bd-a1b2 in commit messages
  4. Let hierarchies form naturally - Create epics, add children as needed