Canonical definition
Sunk Cost Effect is the tendency for money, time, or effort that cannot be recovered to influence what you choose next, even when the future costs and benefits should be enough to make the decision.

Free cognitive-bias Agent Skill
Use Sunk Cost 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
Sunk Cost Effect is the tendency for money, time, or effort that cannot be recovered to influence what you choose next, even when the future costs and benefits should be enough to make the decision.
Install
Hermes Agent
mkdir -p ~/.hermes/skills/bias-cognitive-bias-sunk-cost-effect && curl -fsSL https://cognitive-biases.github.io/agent-skills/bias-cognitive-bias-sunk-cost-effect/SKILL.md -o ~/.hermes/skills/bias-cognitive-bias-sunk-cost-effect/SKILL.mdOpenClaw
mkdir -p ~/.openclaw/workspace/skills/bias-cognitive-bias-sunk-cost-effect && curl -fsSL https://cognitive-biases.github.io/agent-skills/bias-cognitive-bias-sunk-cost-effect/SKILL.md -o ~/.openclaw/workspace/skills/bias-cognitive-bias-sunk-cost-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.