Decision Record

Decision Record

Intro

A DecisionRecord captures a single consequential choice: what was decided, why, what alternatives were rejected, and what consequences are expected. This is the classic Architecture Decision Record (ADR) pattern, promoted to a first-class primitive in processkit.

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 record a decision

Record a decision when the choice:

• Has consequences someone will ask about in six months ("why are we using X?").
• Rules out real alternatives that took thought to reject.
• Affects more than one file, component, or person.
• Is the kind of thing that "we decided in a meeting" but nobody wrote down.

Don't record: trivial choices made inside a single function, preference calls with no downside, decisions already documented somewhere authoritative.

Shape

---
apiVersion: processkit.projectious.work/v2
kind: DecisionRecord
metadata:
  id: DEC-steady-river
  created: 2026-04-06T00:00:00Z
spec:
  title: "Use official Python MCP SDK with uv PEP 723 inline dependencies"
  state: accepted
  context: "Skill MCP servers need a runtime. Options vary from zero-dep stdlib to full SDK."
  decision: "Use the official mcp Python SDK, distributed as standalone scripts with PEP 723 inline deps, launched via uv."
  rationale: |
    - The SDK is the standard; rolling our own JSON-RPC means maintaining protocol code.
    - PEP 723 + uv eliminates per-skill env setup; uv caching amortizes first-run cost.
    - Container already has Python ≥3.10 and uv — no base image change.
  alternatives:
    - option: "Raw JSON-RPC with zero dependencies"
      rejected_because: "Reimplements the protocol, fragile for complex servers."
    - option: "Pydantic-only minimal server"
      rejected_because: "Kept as escape hatch if container size becomes critical; not default."
  consequences: |
    - +300-400 MB image size per skill with MCP server.
    - First-run 5-10s for uv resolution; cached thereafter.
    - Escape hatch documented if size becomes an issue.
  deciders: [ACTOR-owner, ACTOR-claude]
  decided_at: 2026-04-05T00:00:00Z
---

Optional body: longer narrative, links to the discussion, related research.

Workflow

1. Pick an ID: DEC-<generated-id>.
2. Write a declarative title — state the decision itself, not a question.
3. Fill in context (what prompted this), decision (the chosen option), rationale (why).
4. List alternatives with explicit rejected_because — this is the part future-you will thank present-you for.
5. Write consequences — what follows from this decision, positive and negative.
6. Set state: proposed if still under discussion, accepted if finalized.
7. Save to context/decisions/.
8. Log decision.proposed or decision.accepted.

Superseding

When a decision is replaced by a later one:

1. In the new DecisionRecord, set spec.supersedes: DEC-<old-id>.
2. In the old DecisionRecord, set spec.state: superseded and spec.superseded_by: DEC-<new-id>.
3. Log decision.superseded referencing both IDs.

Never delete or edit the old record. Its existence is why we can trace the evolution of the decision.

This skill also provides the /decision-record-write slash command for direct invocation — see commands/decision-record-write.md. This skill also provides the /decision-record-query slash command for direct invocation — see commands/decision-record-query.md.

Gotchas

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

• Recording a decision before it has actually been made. A proposal in a discussion is not a DecisionRecord. Open a Discussion if reasoning is still in flight; only record when the choice is settled. Recording too early creates a fictional history.
• Capturing WHAT but not WHY. A DecisionRecord without rationale is just a workitem in the wrong directory. The whole value of the ADR pattern is the reasoning trail — what was considered, why this was picked, what was rejected.
• Omitting the rejected alternatives. "We decided X" is half a decision; "We picked X over Y and Z because …" is a decision. Future-you needs the alternatives to know whether the call still holds when context changes.
• Editing an old DecisionRecord instead of superseding it. Decisions are immutable history. If the call needs to change, write a NEW DecisionRecord with supersedes: pointing at the old one and set the old one's state to superseded. Never overwrite — the old reasoning is part of the audit trail.
• Recording trivial choices as DecisionRecords. A DecisionRecord is overhead; reserve it for choices a future agent or human will ask about in six months. Variable naming inside one function is not a DecisionRecord.
• Putting the rationale in the Discussion body instead of the DecisionRecord. Discussions are pre-decisional reasoning; DecisionRecords are post-decisional summary. The rationale must be copied (not linked) into the DecisionRecord so the latter is self-contained when read in isolation.
• Hallucinating decision history when the user asks "what did we decide about X". Run query_decisions and search_entities against the actual store before answering. Do not synthesize an answer from memory; it will be wrong.

Full reference

State machine

See src/primitives/state-machines/decisionrecord.yaml:

proposed → accepted → superseded (terminal)
    ↓
  rejected (terminal)

rejected is for decisions considered and declined — kept for history. superseded is for decisions replaced by a later one.

Full field list

See src/primitives/schemas/decisionrecord.yaml. Notable fields:

• deciders: list of Actor IDs. Who agreed.
• supersedes / superseded_by: DEC IDs. Replacement chain.
• related_workitems: BACK IDs. Work that prompted or implements the decision.
• decided_at: when the decision was finalized. Distinct from metadata.created (when the file was written).

Distinguishing decisions from discussions

A Discussion (separate primitive) is a multi-turn conversation exploring a question. A DecisionRecord is the crisp outcome. Workflow:

1. Open a Discussion when a question arises.
2. Explore, debate, research.
3. When the group converges on an answer, write a DecisionRecord.
4. Link the Discussion via spec.related_discussions (cross-reference).

Not every discussion produces a decision; not every decision is preceded by a discussion.

Writing good titles

Good titles are declarative, active, and concrete:

• ✓ "Use official Python MCP SDK with uv PEP 723 inline dependencies"
• ✓ "Two-repo split: aibox + processkit"
• ✗ "Which MCP library to use?" (question, not decision)
• ✗ "Tooling update" (too vague)
• ✗ "Alice's proposal" (credits the person, not the decision)

Consequences that are honest

Future readers trust the decision record more when you write the real consequences, including the uncomfortable ones. "Costs 300-400 MB image size" builds more credibility than "some increase in container size."

Linking to workitems

When a decision prompts work to happen, link via spec.related_workitems:

spec:
  related_workitems: [BACK-calm-fox, BACK-swift-oak]

This lets queries find "all work that implements DEC-foo" and "all decisions that motivated BACK-bar."