forge-shape

name	forge-shape
description	Shape a vague idea into a clear plan through codebase investigation and convergent one-at-a-time questioning. Use when the user has a rough idea or problem that needs specifying before issue creation.
disable-model-invocation	true
allowed-tools	Read, Bash, Grep, Glob, WebSearch, AskUserQuestion

Shape

Shape a problem and converge on a plan before creating issues.

Input

The idea or problem to shape: $ARGUMENTS

Optional last parameter: -- <additional context>

If no argument is provided, ask the user what they'd like to shape.

Process

Step 1: Investigate Context

Before asking any questions, explore the codebase for related context:

• Find existing implementations, patterns, and constraints relevant to the idea
• Identify integration points, dependencies, and architectural boundaries
• Look for prior attempts or related work (git log, closed issues)

Check for related Issues in the project's Issue tracker — see issue-operations for search mechanics per provider.

Step 2: Shape the Problem

Converge on a shared design concept through one-at-a-time structured questioning. See shaping-methodology.md for why one-at-a-time beats batching, how to provide recommended answers without over-anchoring, walking the dependency tree of decisions, when to challenge, and when to stop.

If CONTEXT.md exists, read it — use its vocabulary when framing questions and challenging the user's language.

Loop until the design concept is clear:

1. Ground the next question in Step 1 findings — never ask what the codebase already answers
2. Ask one question with your recommended answer (phrase as "I'd suggest X because Y", not as a decision)
3. Wait for the user's response
4. Challenge when warranted — if the answer conflicts with CONTEXT.md vocabulary, call it out. If it contradicts what the code does, surface it. If it uses vague or overloaded terms, propose a precise canonical term. Invent concrete scenarios to stress-test fuzzy boundaries.
5. Adjust your understanding and pick the next question

Side effects during shaping — as terms and decisions crystallize:

• Resolved term? Update CONTEXT.md inline — don't batch. Add the term with a tight definition and _Avoid_ aliases if the user was using multiple words for the same concept.
• Load-bearing decision? If it's hard to reverse, surprising without context, and the result of a real trade-off — offer to record it as a short ADR in docs/adr/. Most decisions don't qualify. Create the directory lazily.

Stop when the user has accepted recommended answers for several consecutive questions, the remaining questions are taste-level (not decision-level), or the shared design concept is clear enough to summarize.

Use AskUserQuestion for each individual question. Do not bundle multiple questions into one prompt — that defeats the methodology.

Step 3: Explore Approaches (delegate, optional)

If shaping in Step 2 surfaced a clear approach, skip this step and go to Step 4.

If multiple plausible approaches remain after shaping (e.g., the design concept allows for several architectural shapes), delegate approach generation to 2-3 parallel sub-agents, each given a radically different design constraint. The value is in contrast — approaches must be structurally different, not variations on the same idea. If the runtime does not support sub-agents, generate the approaches sequentially yourself, deliberately adopting a different constraint lens for each.

Assign each sub-agent one constraint lens (adapt to the problem):

• Minimal — smallest change that addresses the core problem
• Reuse-first — maximize use of existing patterns and code
• Extensibility-first — optimize for future flexibility
• Performance-first — optimize for speed or resource efficiency

Sub-agent instructions:

You are designing one approach to a problem, constrained by a specific design lens. Follow your assigned constraint strictly — do not hedge toward a balanced middle ground.

Given the codebase findings and shaped design concept provided as input, propose one approach:

• One-line summary
• How it works, referencing specific files and patterns
• Tradeoffs (what you gain, what you give up)
• Relative complexity (Low / Medium / High)
• Risk factors

Inputs provided to each sub-agent:

• Codebase findings from Step 1
• Shaped design concept from Step 2
• The specific constraint lens to apply

Expected output: One approach per sub-agent, formatted as above.

Always include a minimal option. Present the contrasting approaches and let the user choose, combine, or reject all of them.

Step 4: Summarize Plan

Produce a structured summary using the output format below. This summary is the input for forge-create-issue.

The summary is evidence of alignment, not the alignment itself. If the user reads the summary and finds nothing surprising, the shaping worked.

Output Format

## Problem Statement
[1-2 sentences grounded in what was discussed]

## Chosen Approach
[Summary of the shaped design concept]

## Scope Boundaries
- In scope: [what this covers]
- Out of scope: [what this explicitly does not cover]

## Suggested Issue Breakdown
- [ ] Issue 1: <type>(<scope>): <description>
- [ ] Issue 2: <type>(<scope>): <description>

## Side Effects
- CONTEXT.md: <terms added or updated>
- ADRs: <decisions recorded, if any>

Guidelines

• One question at a time — convergence comes from depth per answer, not breadth per prompt
• Always recommend an answer — phrased as a recommendation, not a decision
• Challenge then converge — push back on terminology conflicts, code contradictions, and vague boundaries before accepting an answer
• Use the project's language — reference CONTEXT.md vocabulary; when new terms emerge, capture them immediately
• Problem over solution — clarify what's wrong before proposing how to fix it
• Stay grounded — reference specific code, files, and patterns, not abstractions
• Approach exploration is conditional — skip Step 3 when shaping already surfaced the approach

Related Skills

Next step: Use forge-create-issue to turn the plan into Issues.

Example Usage

/forge-shape the app is slow on mobile
/forge-shape we need better error handling
/forge-shape the authentication flow -- we've had security concerns, focus there