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Equation 20 · Ten Failure Modes in Agentic Coding, from Prompt Injection to False Completion

What does this equation mean?

Ki=1−(1−pi)(1−di)(1−ci)(1−ri),K_i=1-(1-p_i)(1-d_i)(1-c_i)(1-r_i),

Read the formula alongside the article passage below. Each part has a deeper page with its role in the equation, the supporting passage and nearby citations.

Inputs and operations1-(1-p_i)(1-d_i)(1-c_i)(1-r_i)
Result or conditionK_i
How to read the two sides of this formula. Follow the article passage for the meaning of each quantity.

This equation states an equality: the expressions on both sides have the same value under the article’s assumptions. Read the equation part by part below; each part has a contextual explanation and a link to its mathematical background.

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KiK_i

Symbol K_i

KiK_i is part of the quantity the equation computes from the expression on the right.

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pip_i

Symbol p_i

effective prevention, detection, containment, and recovery probabilities under a simplified independence assumption.

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did_i

Symbol d_i

effective prevention, detection, containment, and recovery probabilities under a simplified independence assumption.

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cic_i

Symbol c_i

effective prevention, detection, containment, and recovery probabilities under a simplified independence assumption.

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rir_i

Symbol r_i

effective prevention, detection, containment, and recovery probabilities under a simplified independence assumption.

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=

=

The expressions on both sides represent the same quantity under the stated assumptions.

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subscript

subscript

The lower label selects a particular version, component, or indexed member of the quantity. For example, x₀ and xₜ can be values at different positions.

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How to interpret it

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What the article says around this equation

For failure mode i , define control coverage Ki=1−(1−pi)(1−di)(1−ci)(1−ri)K_i=1-(1-p_i)(1-d_i)(1-c_i)(1-r_i). where pip_i,did_i,cic_i,rir_i are effective prevention, detection, containment, and recovery probabilities under a simplified independence assumption. The equation should not be used to manufacture precise risk numbers; controls are correlated and measurements sparse. It communicates why a single impressive guardrail cannot justify broad authority.

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