Formula Resolution Architecture

> Where formulas live, how they're found, and how they'll scale to Mol Mall

The Problem

Formulas currently exist in multiple locations with no clear precedence:

  • .beads/formulas/ (source of truth for a project)
  • internal/formula/formulas/ (embedded copy for go install)
  • Crew directories have their own .beads/formulas/ (diverging copies)

When an agent runs bd cook mol-polecat-work, which version do they get?

Design Goals

  1. Predictable resolution - Clear precedence rules
  2. Local customization - Override system defaults without forking
  3. Project-specific formulas - Committed workflows for collaborators
  4. Mol Mall ready - Architecture supports remote formula installation
  5. Federation ready - Formulas are shareable across towns via HOP (Highway Operations Protocol)

Three-Tier Resolution

┌─────────────────────────────────────────────────────────────────┐
│                     FORMULA RESOLUTION ORDER                     │
│                    (most specific wins)                          │
└─────────────────────────────────────────────────────────────────┘

TIER 1: PROJECT (rig-level)
  Location: <project>/.beads/formulas/
  Source:   Committed to project repo
  Use case: Project-specific workflows (deploy, test, release)
  Example:  ~/gt/gastown/.beads/formulas/mol-gastown-release.formula.toml

TIER 2: TOWN (user-level)
  Location: ~/gt/.beads/formulas/
  Source:   Mol Mall installs, user customizations
  Use case: Cross-project workflows, personal preferences
  Example:  ~/gt/.beads/formulas/mol-polecat-work.formula.toml (customized)

TIER 3: SYSTEM (embedded)
  Location: Compiled into gt binary
  Source:   gastown/mayor/rig/.beads/formulas/ at build time
  Use case: Defaults, blessed patterns, fallback
  Example:  mol-polecat-work.formula.toml (factory default)

Resolution Algorithm

func ResolveFormula(name string, cwd string) (Formula, Tier, error) {
    // Tier 1: Project-level (walk up from cwd to find .beads/formulas/)
    if projectDir := findProjectRoot(cwd); projectDir != "" {
        path := filepath.Join(projectDir, ".beads", "formulas", name+".formula.toml")
        if f, err := loadFormula(path); err == nil {
            return f, TierProject, nil
        }
    }

    // Tier 2: Town-level
    townDir := getTownRoot() // ~/gt or $GT_HOME
    path := filepath.Join(townDir, ".beads", "formulas", name+".formula.toml")
    if f, err := loadFormula(path); err == nil {
        return f, TierTown, nil
    }

    // Tier 3: Embedded (system)
    if f, err := loadEmbeddedFormula(name); err == nil {
        return f, TierSystem, nil
    }

    return nil, 0, ErrFormulaNotFound
}

Why This Order

Project wins because:
  • Project maintainers know their workflows best
  • Collaborators get consistent behavior via git
  • CI/CD uses the same formulas as developers
Town is middle because:
  • User customizations override system defaults
  • Mol Mall installs don't require project changes
  • Cross-project consistency for the user
System is fallback because:
  • Always available (compiled in)
  • Factory reset target
  • The "blessed" versions

Formula Identity

Current Format

formula = "mol-polecat-work"
version = 4
description = "..."

Extended Format (Mol Mall Ready)

[formula]
name = "mol-polecat-work"
version = "4.0.0"                          # Semver
author = "steve@gastown.io"                # Author identity
license = "MIT"
repository = "https://github.com/steveyegge/gastown"

[formula.registry]
uri = "hop://molmall.gastown.io/formulas/mol-polecat-work@4.0.0"
checksum = "sha256:abc123..."              # Integrity verification
signed_by = "steve@gastown.io"             # Optional signing

[formula.capabilities]
# What capabilities does this formula exercise? Used for agent routing.
primary = ["go", "testing", "code-review"]
secondary = ["git", "ci-cd"]

Version Resolution

When multiple versions exist: 

bd cook mol-polecat-work          # Resolves per tier order
bd cook mol-polecat-work@4        # Specific major version
bd cook mol-polecat-work@4.0.0    # Exact version
bd cook mol-polecat-work@latest   # Explicit latest

Crew Directory Problem

Current State

Crew directories (gastown/crew/max/) are sparse checkouts of gastown. They have:

  • Their own .beads/formulas/ (from the checkout)
  • These can diverge from mayor/rig/.beads/formulas/

The Fix

Crew should NOT have their own formula copies. Options:

Option A: Symlink/Redirect 

# crew/max/.beads/formulas -> ../../mayor/rig/.beads/formulas
All crew share the rig's formulas.

Option B: Provision on Demand

Crew directories don't have .beads/formulas/. Resolution falls through to:

  1. Town-level (~/gt/.beads/formulas/)
  2. System (embedded)
Option C: Sparse Checkout Exclusion

Exclude .beads/formulas/ from crew sparse checkouts entirely.

Recommendation: Option B - Crew shouldn't need project-level formulas. They work on the project, they don't define its workflows.

Commands

Existing

bd formula list              # Available formulas (should show tier)
bd formula show <name>       # Formula details
bd cook <formula>            # Formula → Proto

Enhanced

# List with tier information
bd formula list
  mol-polecat-work          v4    [project]
  mol-polecat-code-review   v1    [town]
  mol-witness-patrol        v2    [system]

# Show resolution path
bd formula show mol-polecat-work --resolve
  Resolving: mol-polecat-work
  ✓ Found at: ~/gt/gastown/.beads/formulas/mol-polecat-work.formula.toml
  Tier: project
  Version: 4

  Resolution path checked:
  1. [project] ~/gt/gastown/.beads/formulas/ ← FOUND
  2. [town]    ~/gt/.beads/formulas/
  3. [system]  <embedded>

# Override tier for testing
bd cook mol-polecat-work --tier=system    # Force embedded version
bd cook mol-polecat-work --tier=town      # Force town version

Future (Mol Mall)

# Install from Mol Mall
gt formula install mol-code-review-strict
gt formula install mol-code-review-strict@2.0.0
gt formula install hop://acme.corp/formulas/mol-deploy

# Manage installed formulas
gt formula list --installed              # What's in town-level
gt formula upgrade mol-polecat-work      # Update to latest
gt formula pin mol-polecat-work@4.0.0    # Lock version
gt formula uninstall mol-code-review-strict

Migration Path

Phase 1: Resolution Order (Now)

  1. Implement three-tier resolution in bd cook
  2. Add --resolve flag to show resolution path
  3. Update bd formula list to show tiers
  4. Fix crew directories (Option B)

Phase 2: Town-Level Formulas

  1. Establish ~/gt/.beads/formulas/ as town formula location
  2. Add gt formula commands for managing town formulas
  3. Support manual installation (copy file, track in .installed.json)

Phase 3: Mol Mall Integration

  1. Define registry API (see mol-mall-design.md)
  2. Implement gt formula install from remote
  3. Add version pinning and upgrade flows
  4. Add integrity verification (checksums, optional signing)

Phase 4: Federation (HOP)

  1. Add capability tags to formula schema
  2. Track formula execution for agent accountability
  3. Enable federation (cross-town formula sharing via Highway Operations Protocol)
  4. Author attribution and validation records

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