Canonical definition
Do you always expect the worst, even when there’s no real reason to? That’s Pessimism Bias – the tendency to overestimate the likelihood of negative events, especially in people prone to depression.

Free cognitive-bias Agent Skill
Use Pessimism Bias 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 always expect the worst, even when there’s no real reason to? That’s Pessimism Bias – the tendency to overestimate the likelihood of negative events, especially in people prone to depression.
Install
Hermes Agent
mkdir -p ~/.hermes/skills/bias-cognitive-bias-pessimism-bias && curl -fsSL https://cognitive-biases.github.io/agent-skills/bias-cognitive-bias-pessimism-bias/SKILL.md -o ~/.hermes/skills/bias-cognitive-bias-pessimism-bias/SKILL.mdOpenClaw
mkdir -p ~/.openclaw/workspace/skills/bias-cognitive-bias-pessimism-bias && curl -fsSL https://cognitive-biases.github.io/agent-skills/bias-cognitive-bias-pessimism-bias/SKILL.md -o ~/.openclaw/workspace/skills/bias-cognitive-bias-pessimism-bias/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.