HTML Feature Mocks
imbue-ai/bouncer
Explores a feature idea through HTML mocks that match the project's existing UI, keeping every earlier version and logging each requested tweak in a context file.
Identify risky assumptions for a feature idea in an existing product across Value, Usability, Viability, and Feasibility.
Install Identify Assumptions Existing
$ npx skills add phuryn/pm-skills --skill identify-assumptions-existing -a claude-codeProject install by default; add -g for ~/.claude/skills/.
$ gh skill install phuryn/pm-skills identify-assumptions-existing --agent claude-codeProject scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).
$ git clone --depth 1 https://github.com/phuryn/pm-skills.git skills-src && mkdir -p .claude/skills && cp -r skills-src/pm-product-discovery/skills/identify-assumptions-existing .claude/skills/identify-assumptions-existing && rm -rf skills-srcUse ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.
Claude Code skills documentation · loads skills from .claude/skills/
Install the "identify-assumptions-existing" agent skill from https://github.com/phuryn/pm-skills/tree/main/pm-product-discovery/skills/identify-assumptions-existing into .claude/skills/identify-assumptions-existing/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "identify-assumptions-existing", then confirm the skill loads.Claude Code copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$skill-installer install https://github.com/phuryn/pm-skills/tree/main/pm-product-discovery/skills/identify-assumptions-existingType this inside Codex. $skill-installer <name> installs a curated skill from openai/skills. The installer writes to $CODEX_HOME/skills (default ~/.codex/skills). Restart Codex if the skill does not show up.
$ npx skills add phuryn/pm-skills --skill identify-assumptions-existing -a codexProject install goes to .agents/skills/; add -g for ~/.codex/skills/.
$ gh skill install phuryn/pm-skills identify-assumptions-existing --agent codexProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/phuryn/pm-skills.git skills-src && mkdir -p .agents/skills && cp -r skills-src/pm-product-discovery/skills/identify-assumptions-existing .agents/skills/identify-assumptions-existing && rm -rf skills-srcUse ~/.agents/skills/ instead of .agents/skills for a personal install.
Codex skills documentation · loads skills from .agents/skills/
Install the "identify-assumptions-existing" agent skill from https://github.com/phuryn/pm-skills/tree/main/pm-product-discovery/skills/identify-assumptions-existing into .agents/skills/identify-assumptions-existing/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "identify-assumptions-existing", then confirm the skill loads.Codex copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ npx skills add phuryn/pm-skills --skill identify-assumptions-existing -a cursorProject install goes to .agents/skills/; add -g for ~/.cursor/skills/.
$ gh skill install phuryn/pm-skills identify-assumptions-existing --agent cursorProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/phuryn/pm-skills.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/pm-product-discovery/skills/identify-assumptions-existing .cursor/skills/identify-assumptions-existing && rm -rf skills-srcUse ~/.cursor/skills/ instead of .cursor/skills for a personal install.
Cursor skills documentation · loads skills from .cursor/skills/, .agents/skills/, .claude/skills/, .codex/skills/
Install the "identify-assumptions-existing" agent skill from https://github.com/phuryn/pm-skills/tree/main/pm-product-discovery/skills/identify-assumptions-existing into .cursor/skills/identify-assumptions-existing/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "identify-assumptions-existing", then confirm the skill loads.Cursor copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ gemini skills install https://github.com/phuryn/pm-skills.git --path pm-product-discovery/skills/identify-assumptions-existing--scope user (default) or --scope workspace; --path is the subfolder of the repo that holds the skill; --consent skips the security confirmation prompt.
$ npx skills add phuryn/pm-skills --skill identify-assumptions-existing -a gemini-cliProject install goes to .agents/skills/; add -g for ~/.gemini/skills/.
$ gh skill install phuryn/pm-skills identify-assumptions-existing --agent gemini-cliProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/phuryn/pm-skills.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/pm-product-discovery/skills/identify-assumptions-existing .gemini/skills/identify-assumptions-existing && rm -rf skills-srcUse ~/.gemini/skills/ instead of .gemini/skills for a personal install, then run /skills reload.
Gemini CLI skills documentation · loads skills from .gemini/skills/, .agents/skills/
Install the "identify-assumptions-existing" agent skill from https://github.com/phuryn/pm-skills/tree/main/pm-product-discovery/skills/identify-assumptions-existing into .gemini/skills/identify-assumptions-existing/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "identify-assumptions-existing", then confirm the skill loads.Gemini CLI copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ gh skill install phuryn/pm-skills identify-assumptions-existingInstalls for Copilot at project scope by default; add --scope user for a personal install. Preview a skill first with gh skill preview. Needs GitHub CLI 2.90.0 or later (public preview).
$ npx skills add phuryn/pm-skills --skill identify-assumptions-existing -a github-copilotProject install goes to .agents/skills/; add -g for ~/.copilot/skills/.
$ git clone --depth 1 https://github.com/phuryn/pm-skills.git skills-src && mkdir -p .github/skills && cp -r skills-src/pm-product-discovery/skills/identify-assumptions-existing .github/skills/identify-assumptions-existing && rm -rf skills-srcUse ~/.copilot/skills/ instead of .github/skills for a personal install. Commit .github/skills so cloud agent and code review can use it.
GitHub Copilot skills documentation · loads skills from .github/skills/, .claude/skills/, .agents/skills/
Install the "identify-assumptions-existing" agent skill from https://github.com/phuryn/pm-skills/tree/main/pm-product-discovery/skills/identify-assumptions-existing into .github/skills/identify-assumptions-existing/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "identify-assumptions-existing", then confirm the skill loads.GitHub Copilot copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ npx skills add phuryn/pm-skills --skill identify-assumptions-existing -a opencodeOpenCode documents no install command of its own. Project install goes to .agents/skills/; add -g for ~/.config/opencode/skills/.
$ gh skill install phuryn/pm-skills identify-assumptions-existing --agent opencodeProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/phuryn/pm-skills.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/pm-product-discovery/skills/identify-assumptions-existing .opencode/skills/identify-assumptions-existing && rm -rf skills-srcUse ~/.config/opencode/skills/ instead of .opencode/skills for a personal install.
OpenCode skills documentation · loads skills from .opencode/skills/, .claude/skills/, .agents/skills/
Install the "identify-assumptions-existing" agent skill from https://github.com/phuryn/pm-skills/tree/main/pm-product-discovery/skills/identify-assumptions-existing into .opencode/skills/identify-assumptions-existing/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "identify-assumptions-existing", then confirm the skill loads.OpenCode copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
Facts
- Skill name
identify-assumptions-existing- GitHub stars
- 27k
- Token cost
- ~525 tokens
- SKILL.md length
- 207 words
- Files
- 1
- Skills in repo
- 67
- Repo updated
- First seen
- Licence
- MIT
At a glance
Identify risky assumptions for a feature idea in an existing product across Value, Usability, Viability, and Feasibility.
- Works in 3 steps: Think from three perspectives about why… → Identify assumptions across four risk… → For each assumption, note
- Stress-testing a feature idea
- Instructions only: no scripts, shell commands, URLs or credentials in SKILL.md
- Doing risk assessment
What it does
Identify Assumptions Existing is an agent skill from phuryn/pm-skills. Identify risky assumptions for a feature idea in an existing product across Value, Usability, Viability, and Feasibility. Uses multi-perspective devil's advocate thinking. Use when stress-testing a feature idea, doing risk assessment, or preparing for assumption mapping.
Its SKILL.md is about 530 tokens, which your agent loads only when the skill is triggered. It is a single SKILL.md file with no bundled scripts.
It sits in Frontend & Design, covering UX design and Load testing. The repository describes itself as: PM Skills Marketplace: 100+ agentic skills, commands, and plugins — from discovery to strategy, execution, launch, and growth. The licence is MIT.
When your agent uses it
- Stress-testing a feature idea
- Doing risk assessment
- Preparing for assumption mapping
Example prompts
- “/identify-assumptions-existing”
Workflow steps
3 steps, taken from the first numbered list in SKILL.md.
- Think from three perspectives about why this feature might fail
- Identify assumptions across four risk areas
- For each assumption, note
What it can do on your machine
Read from SKILL.md and the folder at commit 6058e29. It shows what the files ask for, not the result of running them.
Tool permissions
Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.
From allowed-tools in the SKILL.md frontmatter.
Runs code
No scripts in the folder and no shell commands in SKILL.md.
From the folder's file list and the shell code blocks in SKILL.md.
Network
Links to these hosts (documentation or services it may open):
productcompass.pm
From URLs in SKILL.md, links to its own repository left out.
Credentials
Names no API keys, tokens, secrets or passwords.
From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.
Context cost
Identify Assumptions Existing loads about 525 tokens when it runs. Until then it costs about 75 tokens; SKILL.md has 207 words of instructions outside code blocks.
Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.
Safety
Auto-check passed
The automated check found no risky patterns in SKILL.md.
Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.
SKILL.md
The full file from phuryn/pm-skills at commit 6058e29, republished under its MIT licence (© phuryn). 207 words, ~525 tokens.
Download SKILL.mdSave it as
.claude/skills/identify-assumptions-existing/SKILL.md (or your agent's skills folder).- name
- identify-assumptions-existing
- description
- Identify risky assumptions for a feature idea in an existing product across Value, Usability, Viability, and Feasibility. Uses multi-perspective devil's advocate thinking. Use when stress-testing a feature idea, doing risk assessment, or preparing for assumption mapping.
Identify Assumptions (Existing Product)
Devil's advocate analysis to surface risky assumptions across four risk areas.
Context
You are stress-testing a feature idea for $ARGUMENTS.
If the user provides files (designs, PRDs, research), read them first.
Instructions
The user will describe their product, objective, market segment, and feature idea. Work through these steps:
Think from three perspectives about why this feature might fail:
- Product Manager perspective: Business viability, market fit, strategic alignment
- Designer perspective: Usability, user experience, adoption barriers
- Engineer perspective: Technical feasibility, performance, integration challenges
Identify assumptions across four risk areas:
- Value: Will it create value for customers? Does it solve a real problem?
- Usability: Will users figure out how to use it? Is the learning curve acceptable?
- Viability: Can marketing, sales, finance, and legal support it?
- Feasibility: Can it be built with existing technology? Are there integration risks?
For each assumption, note:
- What specifically could go wrong
- How confident you are (High/Medium/Low)
- Suggested way to test it
Think step by step. Be thorough but constructive — the goal is to strengthen the idea, not kill it.
Further Reading
© phuryn, MIT. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file
Files
Just SKILL.md in pm-product-discovery/skills/identify-assumptions-existing of phuryn/pm-skills.
Open the folder on GitHubat commit 6058e29
Compare with similar skills
Identify Assumptions Existing next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.
| Skill | Stars | Used in | Tokens | Auto-check | Licence | Repo updated |
|---|---|---|---|---|---|---|
| Identify Assumptions Existing this skillphuryn/pm-skills | 27k | — | ~525 | Automated safety check: Pass | MIT | |
| HTML Feature Mocksimbue-ai/bouncer | 399 | — | ~677 | Automated safety check: Pass | AGPL-3.0 | |
| LobeHub UX Checklistslobehub/lobehub | 83k | — | ~2.6k | Automated safety check: Pass | Custom licence | |
| Lamina Evaluationaryaniyaps/lamina | 116 | — | ~432 | Automated safety check: Pass | Apache-2.0 | |
| Product Skillsalirezarezvani/claude-skills | 28k | — | ~2.6k | Automated safety check: Pass | MIT | |
| Nova Act UsabilityLeoYeAI/openclaw-master-skills | 2.2k | — | ~7.4k | Automated safety check: Pass | MIT |
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Related
Questions about Identify Assumptions Existing
What does Identify Assumptions Existing do?
Identify risky assumptions for a feature idea in an existing product across Value, Usability, Viability, and Feasibility. Identify Assumptions Existing is an agent skill from phuryn/pm-skills. Identify risky assumptions for a feature idea in an existing product across Value, Usability, Viability, and Feasibility.
When should I use Identify Assumptions Existing?
Identify Assumptions Existing fits situations like: stress-testing a feature idea; doing risk assessment; preparing for assumption mapping.
How do I install Identify Assumptions Existing in Claude Code?
Run `npx skills add phuryn/pm-skills --skill identify-assumptions-existing -a claude-code`. Or copy the skill folder (pm-product-discovery/skills/identify-assumptions-existing in phuryn/pm-skills) into .claude/skills/identify-assumptions-existing in your project. Claude Code loads it when a task matches its description.
How do I install Identify Assumptions Existing in Codex?
Run `npx skills add phuryn/pm-skills --skill identify-assumptions-existing -a codex`. Or copy the skill folder (pm-product-discovery/skills/identify-assumptions-existing in phuryn/pm-skills) into .agents/skills/identify-assumptions-existing in your project. Codex loads it when a task matches its description.
Can I use Identify Assumptions Existing in Cursor, Gemini CLI or GitHub Copilot?
Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add phuryn/pm-skills --skill identify-assumptions-existing -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/identify-assumptions-existing, .gemini/skills/identify-assumptions-existing, .github/skills/identify-assumptions-existing and .opencode/skills/identify-assumptions-existing in your project.
What does Identify Assumptions Existing need to run?
SKILL.md names no scripts, command-line tools or credentials: Identify Assumptions Existing is instructions for the agent only.
Does Identify Assumptions Existing access the network?
SKILL.md names 1 domain. As links in the text: productcompass.pm. This is read from the text; nothing was executed.
Is Identify Assumptions Existing safe to install?
Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. Review the folder before installing.
What licence does Identify Assumptions Existing use?
Identify Assumptions Existing is published under the MIT licence (the repository's licence). It allows redistribution, so the full SKILL.md is shown on this page.
How many tokens does Identify Assumptions Existing use?
About 525 tokens (SKILL.md is roughly 2.1k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full.
What are the alternatives to Identify Assumptions Existing?
Skills that share tags, products or a category with Identify Assumptions Existing: HTML Feature Mocks (imbue-ai/bouncer, 399 stars), LobeHub UX Checklists (lobehub/lobehub, 83k stars), Lamina Evaluation (aryaniyaps/lamina, 116 stars) and Product Skills (alirezarezvani/claude-skills, 28k stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.
Who maintains Identify Assumptions Existing?
phuryn (a GitHub user) maintains it in phuryn/pm-skills, which has 26,862 GitHub stars. The repository holds 67 skills in this directory. The repository was last updated on October 9, 2026.
Source: phuryn/pm-skills on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.