Canonical definition
Do you say you’re 99% sure about something, only to find out you were wrong? That’s Overconfidence Effect – the tendency to overestimate the accuracy of your knowledge and decisions, even when mistakes are likely.

Free cognitive-bias Agent Skill
Use Overconfidence Effect as a focused cognitive-bias lens. Explain the pattern, check whether it plausibly fits the situation, surface an alternative non-bias explanation, and return a practical counter-check without diagnosing people or claiming causation.
What the agent should do
Do you say you’re 99% sure about something, only to find out you were wrong? That’s Overconfidence Effect – the tendency to overestimate the accuracy of your knowledge and decisions, even when mistakes are likely.
Install
Hermes Agent
mkdir -p ~/.hermes/skills/bias-egocentric-bias-overconfidence-effect && curl -fsSL https://cognitive-biases.github.io/agent-skills/bias-egocentric-bias-overconfidence-effect/SKILL.md -o ~/.hermes/skills/bias-egocentric-bias-overconfidence-effect/SKILL.mdOpenClaw
mkdir -p ~/.openclaw/workspace/skills/bias-egocentric-bias-overconfidence-effect && curl -fsSL https://cognitive-biases.github.io/agent-skills/bias-egocentric-bias-overconfidence-effect/SKILL.md -o ~/.openclaw/workspace/skills/bias-egocentric-bias-overconfidence-effect/SKILL.mdOther Agent Skills-compatible tools
Download SKILL.md and put it in the skill directory or import surface supported by your agent.
Boundary
The skill must preserve uncertainty, surface a non-bias explanation and avoid turning a cognitive-bias label into a claim about a person's motives, intelligence or mental health.