Binding Management

Binding Management

Intro

A Binding is an entity that connects two other entities with optional scope, temporality, and conditions. It is the junction-table pattern promoted to a primitive, and it is the right choice whenever a relationship is more than a simple "A references B" — for example "Alice is the tech lead on project X for 2026," or "the security gate applies to the release process only on the main branch."

MCP server. This skill ships a self-contained MCP server at mcp/server.py (PEP 723 script — requires uv and Python ≥ 3.10 on PATH). Agent harnesses reach its tools by reading a single MCP config file at startup, so the contents of mcp/mcp-config.json must be merged into the harness's MCP config and placed at the harness-specific path before this skill is usable. If processkit was installed by an installer, that wiring is the installer's responsibility; if processkit was installed manually, the project owner must do it by hand.

Overview

When to use a Binding vs a cross-reference

Rule: if a relationship has scope, time, or its own attributes → Binding. If it is just "A relates to B" → cross-reference in frontmatter.

If in doubt, prefer the cross-reference. Promote to a Binding only when you actually need the extra dimensions.

Binding types

spec.type is freeform; conventions emerge per project. Common ones:

Shape

---
apiVersion: processkit.projectious.work/v1
kind: Binding
metadata:
  id: BIND-bright-falcon
  created: 2026-04-06T00:00:00Z
spec:
  type: role-assignment
  subject: ACTOR-alice
  target: ROLE-tech-lead
  scope: SCOPE-project-x
  valid_from: 2026-01-01
  valid_until: 2026-12-31
  conditions:
    approval_required: false
  description: "Alice fills the tech-lead role on project X for 2026."
---

Optional body: context for why this binding exists, related discussion, etc.

Workflow

1. Pick the type — match an existing convention if possible.
2. Set subject (the entity "receiving" the relationship) and target (the entity "being bound to").
3. Set scope if the binding only applies within a particular scope.
4. Set valid_from / valid_until if the binding is time-bounded.
5. Add conditions for arbitrary constraints.
6. Save to context/bindings/.
7. Log binding.created.

Ending a binding

To end a binding:

• Preferred: set valid_until to the current date, log binding.ended.
• Alternative: delete the Binding file (only if it was created in error).

Do NOT edit subject or target of an existing binding — write a new one and end the old one. The history is what makes Bindings useful.

Resolving "who currently fills role X in scope Y?"

1. Find Bindings where type: role-assignment and target: ROLE-x and (scope: SCOPE-y or scope: null).
2. Filter to those active at the current time (valid_from ≤ now ≤ valid_until or either unset).
3. Return the subject IDs.

The Phase 3 MCP server provides resolve_bindings_for(entity_id, type?, at_time?).

Gotchas

Agent-specific failure modes — provider-neutral pause-and-self-check items:

• Using a Binding when a simple cross-reference would do. If the relationship has no scope, no time bounds, and no attributes of its own ("this workitem relates to that decision"), use a frontmatter cross-reference, not a Binding. Bindings are overhead — reserve them for relationships that genuinely need their own lifecycle.
• Using a cross-reference when scope or time matters. The inverse trap: "Alice owns this for sprint 42 only" or "the security gate applies on the main branch only" must be a Binding, not an assignee field. Cross-references can't carry temporal validity.
• Forgetting valid_from / valid_until on temporal Bindings. A Binding without time bounds reads as "forever". If the relationship is bounded ("until end of quarter"), set the bounds at creation. Otherwise queries like "who owns X right now" return stale results.
• Forgetting to end a Binding when the relationship ends. Open Bindings accumulate as orphans. When the underlying relationship ends, call end_binding (or set valid_until) — don't just delete the entity, since the historical record matters.
• Hallucinating subject or target IDs. Always verify both the subject and the target exist via index-management.get_entity before creating a Binding. A Binding pointing at a non-existent entity is structurally invalid and breaks every later resolve query.
• Querying current bindings without a time filter. When asking "who is the tech lead now", filter by current time (valid_from ≤ now ≤ valid_until). A naive query returns every Binding ever, including expired ones.
• Treating Bindings as RBAC enforcement. Bindings are descriptive, not restrictive. They record who has which role, not who is allowed to do what. Authorization is out of scope — do not use Bindings as a permission check.

Full reference

Fields

Why Binding is generalized from RoleBinding

DISC-001 introduced RoleBinding as the 18th primitive. DISC-002 §11 investigated whether this should be generalized. The pattern of "put a third thing between two things so either can change independently" is fundamental in software design (GoF patterns, DI, junction tables) and appears in at least 7 relationship types in processkit. Generalizing keeps the primitive count at 18 while covering more cases. See DEC-023.

No enforcement

Bindings are descriptive. processkit does not prevent actions based on bindings — e.g., a WorkItem doesn't refuse to transition if the actor isn't bound to the required role. Enforcement is a governance concern (DEC-017).

Indexing

In Phase 3, the index MCP server maintains a bindings table:

bindings(id, type, subject, subject_kind, target, target_kind,
         scope, valid_from, valid_until, active)

with active computed from valid_from/valid_until vs current time. This makes "who currently holds role X" a single SQL query.

Idempotency for "current state" bindings

When the same effective state is re-asserted (e.g. "Alice is still tech lead"), prefer extending valid_until on the existing Binding rather than creating a new one. This keeps history clean. If the underlying situation changed and just happened to end up in the same place, that's a new Binding.