Purpose
Generate a tight, engineering-ready feature brief for a retail trading capability that a product team can hand to design and engineering without a second drafting pass. Solves the recurring problem of trading features stalling in ambiguity — unclear buying-power math, unhandled market states, and missing regulatory flags that surface late in the build.
When to Use
Invoke this skill when the user asks to:
- Write a feature brief or PRD for a trading capability (options chain, charting, order ticket, margin tools)
- Spec a buying power, margin, or settlement display for a brokerage app
- Document requirements for a new watchlist, quote, or portfolio feature
- Turn a rough feature idea into user stories and acceptance criteria for engineering handoff
- Define edge cases and market-state behavior for a trading UI before a sprint
- Capture regulatory and risk requirements for a new investing feature
Inputs Required
Before starting, collect:
- Feature: The trading capability to spec (e.g., options chain, candlestick chart, buying power widget, margin call flow)
- Platform context: Web / iOS / Android / all; self-directed brokerage, robo, or hybrid
- Target user: Novice retail, active trader, options trader, or margin user
- Account types in scope: Cash / margin / IRA / options-approval levels
- Market data source: Real-time, delayed 15-min, or provider name if known
- Regulatory jurisdiction: US (FINRA/SEC), and whether PDT, Reg T, or options suitability rules apply
- Integration surface: Existing systems it touches (order management, clearing, quote feed, funding)
If account types or jurisdiction are missing, default to US self-directed brokerage with cash and margin accounts and note the assumption. Assume real-time data unless stated otherwise.
Instructions
Step 1: Problem Statement & Objective
Open with a 2–3 sentence problem statement: who the user is, what they currently can't do or do painfully, and the outcome the feature delivers. Pair it with one measurable objective (e.g., "reduce order-entry errors on multi-leg options," "surface accurate buying power before order submission"). Avoid restating the feature name as the problem — name the underlying job.
Step 2: User Stories
Write 4–6 user stories in the format "As a [specific trader type], I want to [action] so that [outcome]." Cover the primary happy path plus at least one story for a constrained user (e.g., cash-account user hitting a settlement rule, options user below the required approval level). Each story must map to a real trading decision, not a UI interaction for its own sake.
Step 3: Functional Requirements
List numbered functional requirements grouped under:
- Display & data: What values render, at what precision, refresh cadence, and source (real-time vs. delayed)
- Interactions: Inputs the user can take, defaults, and any confirmations
- Calculations: Any math must be stated explicitly — buying power, margin requirement, options P/L, cost basis. Show the formula or reference the governing rule (e.g., Reg T 50% initial margin).
- States: Loading, empty, error, halted-security, pre/post-market, and disabled states
Step 4: Edge Cases & Market States
Enumerate the trading-specific conditions that break naive implementations:
- Market closed, pre-market, after-hours, and holiday sessions
- Halted or restricted securities; hard-to-borrow or non-marginable names
- Zero or negative buying power; unsettled funds; PDT flag triggered
- Options expiration day, assignment/exercise, and pin risk near strike
- Stale or missing quote data and reconnection behavior For each, state the expected behavior — what the user sees and what actions are blocked or warned.
Step 5: Regulatory & Risk Flags
Call out compliance requirements the build must satisfy:
- Suitability and approval gating (options levels, margin agreement, PDT acknowledgment)
- Required disclosures and risk warnings, and where they must appear
- Real-time vs. delayed data labeling obligations
- Any recordkeeping, audit-trail, or best-execution touchpoints Flag anything requiring legal/compliance sign-off explicitly.
Step 6: Data Dependencies & Integrations
List upstream and downstream systems: quote feed, order management, clearing/settlement, funding/balance service, and any third-party market data. Note latency expectations and what happens on dependency failure.
Step 7: Acceptance Criteria
Write acceptance criteria in Given/When/Then format — one set per user story minimum, plus criteria covering the top 3 edge cases. Each must be testable by QA without interpretation (specific values, states, and expected outputs).
Output Format
- Structure: Single structured brief with labeled sections in the order below
- Length: 700–1,000 words
- Format: Structured document — prose for problem statement, numbered/bulleted lists for requirements and criteria
- Sections: Problem Statement & Objective → User Stories → Functional Requirements → Edge Cases & Market States → Regulatory & Risk Flags → Data Dependencies & Integrations → Acceptance Criteria
- Tone: Senior fintech PM — precise, decision-forcing, no hedging; assumes a technical reader
Quality Checklist
Before delivering output, verify:
- [ ] 4–6 user stories, at least one covering a constrained or restricted user
- [ ] Every calculation states its formula or references the governing rule (Reg T, PDT, etc.)
- [ ] At least 5 distinct market-state or edge-case conditions are covered with expected behavior
- [ ] Regulatory section names specific approval, disclosure, or data-labeling requirements — not "ensure compliance"
- [ ] Acceptance criteria are in Given/When/Then and testable without interpretation
- [ ] No unresolved bracket placeholders; assumptions are stated where inputs were missing
Notes
- The most common failure in trading briefs is under-specifying buying power and margin math — make those formulas explicit even when they feel obvious.
- Market-state handling (halts, pre/post-market, expiration) is where trading features diverge most from generic fintech UI; never skip Step 4.
- When the feature touches options or margin, treat the regulatory flags as gating, not decoration — the build likely needs a compliance review before shipping.
- If the user only has a rough idea, ask one clarifying question: "What decision is the user trying to make in the moment they use this?"
How to use this skill
This file is a Claude Code skill in Anthropic's standard format — markdown with YAML frontmatter at the top.
Installing in Claude Code:
~/.claude/skills/<folder-name>/SKILL.md— auto-loads in every session anywhere on your machine (recommended for skills you'll use across multiple projects)<your-project>/.claude/skills/<folder-name>/SKILL.md— auto-loads only when working in that project (recommended for project-specific skills)
Restart Claude Code or open a new session to register.
Using in Claude.ai, ChatGPT, Gemini, or other AI tools:
- Drag this file into a new chat, or copy and paste its contents
- Send your task or request as your next message — the AI will apply the skill where it fits
For Claude Code skill details: https://docs.anthropic.com/en/docs/claude-code/skills