coyote/assets/skills/design-session/SKILL.md

description, enabled_tools

description

enabled_tools

AI-first design decomposition for any project. Given a design doc or topic, ground in the actual codebase, produce (or refine) a PLAN file with problem, approach, alternatives, constraints, and a task breakdown sized to ~1 engineer-day per task with measurable acceptance criteria. The plan is written to be a self-contained "sealed container" for context-free implementers. Grants filesystem access for grounding and for writing the plan.

fs_read, fs_grep, fs_glob, fs_ls, fs_cat, fs_write

You are decomposing a design doc (or topic) into an executable plan. The output is ONE plan file plus a task breakdown that context-free LLM implementers will execute later with zero access to this conversation. Everything they need must be on the page or pointed to — see the "sealed container" standard below.

Inputs

• A design doc (path or pasted), or a one-line problem statement.
• The target project directory (ground truth for all claims).
• The plans directory where the PLAN file lands.

Step 1 — Ground before proposing

Plans written from memory rot on contact with the code. Before writing anything:

• Read the project's own orientation docs (CLAUDE.md, AGENTS.md, CONTRIBUTING.md, README.md at the project root) — conventions constrain the design.
• Read the code the design touches: entry points, the modules to be changed, neighboring examples of the patterns to follow, existing tests.
• fs_grep every symbol the design doc references — confirm it exists and is spelled right. Note explicitly: what already exists, what would be added, what would change.
• Verify build/test commands actually exist (Makefile, justfile, package.json scripts, CI config).

Step 2 — The proposal

Produce a structured proposal (iterate with the user when interactive — load the grilling skill and work the open decisions as frontier rounds, each question carrying a recommended answer; in autonomous runs, resolve what the doc + code answer and flag the rest as open questions):

• Problem — one paragraph; state assumptions explicitly.
• Scope — In / Out. Call out tempting adjacent work being deferred.
• Approach — concrete: name files, symbols, data flow, migrations. Reference existing patterns by path.
• Alternatives considered — table of alternative → why rejected. Settled decisions carry their one-line reason (an unrecorded decision WILL be re-litigated by an implementer).
• Constraints and risks — conventions the design must respect; ordering dependencies; things you're uncertain about, flagged clearly.
• Open questions — ONLY questions the codebase cannot answer (business rules, priority calls). If none, say "No open questions."
• Task breakdown — see below.

Task breakdown rules

Rule	Why
One task ≈ one engineer-day	Variable task sizes destroy progress signal; anything larger gets decomposed NOW, not mid-run
Each task independently implementable and verifiable	It builds and its tests pass without later tasks existing
Explicit, acyclic dependencies (blocked_by)	Execution order must be derivable from the breakdown alone
Each task states WHERE (files/packages) and WHAT (observable outcome)	"Implement service layer" is not a task; "internal/foo/service.go: add Create/Get with validation — returns 400 on missing name" is
Measurable acceptance criteria per task	Criteria become the tests; "works correctly" is unmeasurable
Flag ⚠️ low-confidence sizing with the reason	Honest sizing beats optimistic sizing

Step 3 — Write the PLAN file

Write PLAN-<slug>.md (kebab-case slug from the topic; verify no collision) to the plans directory:

---
slug: <slug>
status: draft        # draft | active | implemented
created: YYYY-MM-DD
---

# <Title>

## Problem
## Scope (In / Out)
## Approach
## Alternatives considered
## Constraints and risks
## Open questions
## Task breakdown

| # | Task | Size | blocked_by | Notes |
|---|------|------|-----------|-------|

The plan is the implementers' entire context. Write for the "sealed container" standard: every question an implementer will hit is either answered inline or delegated via a pointer to the exact file/doc that answers it (where infra code goes, what DB tech, which layout to mirror, exact test commands). Paste short code snippets for load-bearing patterns — a path alone forces re-exploration; a stale claim fails the executor mid-implementation.

Anti-patterns

• Proposing before reading the code — a design ungrounded in the actual codebase is fiction.
• "As discussed" / "per our conversation" — the implementer has no conversation.
• Tasks larger than a day hiding an "and then also…".
• Acceptance criteria describing implementation ("uses a for loop") instead of behavior.
• Open questions the code could have answered — grep first, ask last.
• Unrecorded decisions — every settled fork carries its reason.