023 Assumption Analysis Agent Skill
Use when a framed and root-caused problem needs its assumptions made explicit before design or planning begins — explicit Assumptions, Unknowns, and a Validation plan. This should trigger when an issue's Assumption Analysis point of view needs evaluation, or when a maintainer directly asks to surface hidden assumptions and unknowns before committing to an approach. Part of Plinth Toolkit
Install
one command, takes just this skill from the repositorynpx skills add https://github.com/jabrena/plinth --skill 023-assumption-analysisThe instruction itself
5 sections, as written by the authorAssumption Analysis
Guide production of explicit Assumptions, a list of Unknowns, and a Validation plan for a problem under exploration. This is an interactive SKILL.
What is covered in this Skill?
- Surfacing assumptions implicit in the problem frame and root-cause findings
- Distinguishing an assumption (believed true, not yet verified) from an unknown (not yet known either way)
- Ranking assumptions and unknowns by impact and confidence
- Defining a validation plan that names how and when each risky assumption or unknown will be checked
- Feeding assumption and unknown findings into
024-context-mappingand the remaining Functional Specification lenses
Constraints
Make assumptions and unknowns explicit before they become undiscussed risk. When this technique is orchestrated by another workflow, the orchestrator owns clarifying-question sequencing; when applied standalone, ask directly.
- MUST read
references/023-assumption-analysis.mdbefore applying Assumption Analysis guidance - MUST state each assumption as a falsifiable claim believed true but not yet verified
- MUST distinguish assumptions (believed true) from unknowns (not yet known either way)
- MUST rank assumptions and unknowns by impact if wrong and by current confidence
- MUST define a validation plan naming how and when each high-impact, low-confidence assumption or unknown will be checked
- MUST NOT invent an assumption, unknown, or validation step when the available content is vague or ambiguous; flag the gap for a clarifying question instead
When to use this skill
- Surface the assumptions behind this problem
- List the unknowns for this issue
- Build a validation plan for these assumptions
- Apply assumption analysis before design begins
- Draft the Assumption Analysis section of a Functional Specification
Workflow
- Read the Reference
Read references/023-assumption-analysis.md, then review the problem frame and root-cause findings for implicit beliefs.
- Surface Explicit Assumptions
State each assumption as a falsifiable claim believed true but not yet verified.
- List Unknowns
List facts that are not yet known either way, distinct from assumptions.
- Rank by Impact and Confidence
Rank assumptions and unknowns by impact if wrong and by current confidence, prioritizing high-impact, low-confidence items.
- Define the Validation Plan
Name how and when each high-priority assumption or unknown will be validated.
- Report the Assumption Analysis
Report the Assumptions, Unknowns, and Validation plan, and flag any item left open pending a clarifying answer.
Reference
For detailed guidance, examples, and constraints, see references/023-assumption-analysis.md.
Other skills for the same job
different authors, same section of the catalogue
Guide users through a structured workflow for co-authoring documentation. Use when user wants to write documentation, proposals, technical specs, decision docs, or similar structured content. This workflow helps users efficiently transfer context, refine content through iteration, and verify the doc works for readers. Trigger when user mentions writing docs, creating proposals, drafting specs, or similar documentation tasks.
Intelligently organizes your files and folders across your computer by understanding context, finding duplicates, suggesting better structures, and automating cleanup tasks. Reduces cognitive load and keeps your digital workspace tidy without manual effort.
Generates creative domain name ideas for your project and checks availability across multiple TLDs (.com, .io, .dev, .ai, etc.). Saves hours of brainstorming and manual checking.
You MUST use this before any creative work - creating features, building components, adding functionality, or modifying behavior. Explores user intent, requirements and design before implementation.
Implements Manus-style file-based planning for complex tasks. Creates task_plan.md, findings.md, and progress.md. Use when starting complex multi-step tasks, research projects, or any task requiring >5 tool calls.
Creative research ideation and exploration. Use for open-ended brainstorming sessions, exploring interdisciplinary connections, challenging assumptions, or identifying research gaps. Best for early-stage research planning when you do not have specific observations yet. For formulating testable hypotheses from data use hypothesis-generation.
Comprehensive GitHub project management with swarm-coordinated issue tracking, project board automation, and sprint planning
Interview the user relentlessly about a plan or design until reaching shared understanding, resolving each branch of the decision tree. Use when user wants to stress-test a plan, get grilled on their design, or mentions "grill me".
How to use it
Take jabrena/023-assumption-analysis from the repository into ~/.claude/skills for personal
use, or into .claude/skills inside a project.
The agent identifies a skill by the name field in its header. Two skills with the
same name cannot sit side by side — one of them will be ignored.