bear-case

bear-case is a skill for Claude Code, Codex from yennanliu/InvestSkill. It costs 33 tokens per session (2,946 once invoked), scanned A, original, MIT.

A stock-analysis guide that argues the case for not owning a company’s shares, like a short seller reviewing risks and counterevidence.

In plain words
What is it for?
It is for building a bearish investment case around a stock, including recent figures, valuation measures, business risks, and evidence against the bullish view.
Why use it?
It helps challenge an optimistic investment view and uncover reasons a stock could perform poorly. It also requires checking current market data before analysis.

Skill for Claude CodeCodex

Part of the us-stock-analysis plugin — 27 skills shipped together

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add skills/yennanliu/investskill/bear-case
Any agent
npx skills add yennanliu/InvestSkill --skill bear-case
Clone the repo
git clone --depth 1 https://github.com/yennanliu/InvestSkill

Made for: Claude Code, Codex.

Or install us-stock-analysis, the plugin that ships this one along with the rest of its 27 skills.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for bear-case

README.md
[![agentmods](https://agentmods.dev/badge/skills/yennanliu/investskill/bear-case.svg)](https://agentmods.dev/skills/yennanliu/investskill/bear-case)
Your own site
<a href="https://agentmods.dev/skills/yennanliu/investskill/bear-case"><img src="https://agentmods.dev/badge/skills/yennanliu/investskill/bear-case.svg" alt="Measured on agentmods" height="20"></a>
Per session 33 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,946 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00033 $0.02946
Opus 5 $0.00016 $0.01473
Sonnet 5 $0.00007 $0.00589
Haiku 4.5 $0.00003 $0.00295

Measured 5d ago against content hash 5e5df91aa6ab, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

bear-case scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 5d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

plugins/us-stock-analysis/skills/bear-case/SKILL.md · 214 lines

How it starts

The opening of the file, as written. The whole thing — 214 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Bear Case (Bearish Investor)

⚠️ Data Verification — Do This Before Any Analysis

Before running any analysis, always retrieve the latest market data for the ticker:

  1. Fetch current price — use web search or ask the user for the live price, 52-week range, and market cap. Never assume a price from training data.
  2. Confirm key figures — recent earnings, revenue, key ratios (P/E, P/S, etc.) as applicable to this skill.
  3. State your data source — note where the numbers came from (e.g., "Google Finance, June 19 2026") at the top of the output.
  4. Flag stale data explicitly — if live data is unavailable, display this warning before proceeding:

⚠️ Live data unavailable. The following analysis uses training-data estimates which may be significantly out of date. Verify all prices and metrics before making any decisions.

Never silently substitute training-data estimates for current prices. When in doubt, ask the user to paste the latest quote.


⚠️ Read This First — This Analysis Is Intentionally One-Sided

You are a skeptical short-seller and professional bear. Your single mandate is to construct the strongest, most intellectually honest case for why this stock should NOT be held — and, in the extreme, why it should be sold or shorted.

This is a red-team / devil's-advocate tool by design. It is deliberately biased to the downside. Its value comes from being one-sided: it forces the counterevidence to the surface so the user can stress-test a bullish thesis and see the stock from the inverse direction. It is not a balanced call and must never be presented as one.

  • Always open the output with: "This is a deliberately one-sided bear case. Pair it with /stock-eval (or a bull-case analysis) for a balanced view."
  • Argue the bear side with conviction, but never fabricate. Every claim must be grounded in real data, a real risk, or an explicitly labeled assumption/hypothesis.
  • Steelman the bear thesis, then be honest about what would break it (the "Thesis-Killers" section is mandatory).

Read the full file on GitHub · 214 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 5d ago First seen · 214 lines · 33 tokens per session scan A 5e5df91aa6ab

Subscribe to this mod's changes

bear-case is a skill published in the GitHub repository yennanliu/InvestSkill (198 stars, last pushed yesterday), licensed MIT. It adds 33 tokens to every session and 2,946 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.