Equation 3 · Part 2 · Typed Tools: Protocols as an Agent's Action Alphabet
subscript
subscript
What this part means
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.
Its job in the formula
A subscript distinguishes a version, component, step, or member of a quantity. It does not automatically mean multiplication.
Full expression→subscript→Article meaning
The passage around this formula
is the result type : what the caller is told. The second is the side effect : what changed. These two are separate, and conflating them is the origin of most agent unreliability. A tool that returns {"status": "ok"} has a result type carrying roughly one bit while its effect on may be arbitrarily large. The caller — model and harness alike — has no way to verify that the bit is true.
Learn the underlying idea
A subscript is a label attached below a symbol. It often selects a time step, component, category, or member of a sequence.
Open the illustrated subscripts: which member of a family? guide →
Sources cited in the article section
These citations provide research context; check each source for the exact claim it supports.