ES — Executable Specification v1.0

 

ES — Executable Specification v1.0

Theoretical foundations: Grant C. Sterling (Eastern Illinois University). Analysis and synthesis: Dave Kelly. Prose rendering: Claude (Anthropic). 2026.

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The Term

Corpus term. Derived from “English as Code: Natural Language in the Era of Large Language Models”, from that essay’s phrase precision at the level of executable specification.

An Executable Specification is a natural-language document written to the standard of code. It answers the question the essay raises but does not name: in “English as Code,” code is not a programming language. It is prose meeting a standard of correctness that was formerly required only of formal code.

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The Standard

A document qualifies as an Executable Specification when it satisfies the following:

• Terms defined before use.
• Procedures specified in full.
• Failure modes named and guarded against.
• Output formats determined in advance.
• Verification steps written in at every transition point where drift can occur.

Prose meeting this standard governs a large language model’s output with logical force. Prose failing it leaves gaps, and the model fills those gaps from its training distribution rather than from the author’s intentions. Vagueness is therefore not a stylistic defect in this context but a functional one: the underspecified sentence does not merely communicate poorly, it executes poorly.

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The Mode of Execution

Execution here is semantic, not computational. The model interprets a constrained specification and produces behavior systematically conditioned by it. It does not transform the specification under machine-level semantics, and identical inputs are not guaranteed identical outputs.

This qualification is established in “The Project as the Corpus’s Own Instantiation” and travels with the term. Any use of “Executable Specification” that implies determinism in the programming-language sense is a misuse of the term.

The claim retained is still substantive. Most natural-language documents do not condition an executor’s behavior with anything approaching this degree of systematicity. What makes the conditioning tight enough to warrant the name is the presence of the five structural features above.

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The Correspondences

Within the corpus, the mapping holds as follows. The corpus is the codebase. Instrument definitions are functions. Self-audits are assertions. Mandatory checkpoints at step transitions halt execution pending verification. Prohibitions on named failure modes are guard clauses. Closed verdict categories are enumerated types. The six commitments are constants against which variables are evaluated.

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Derivation Note

The acronym is drawn from the essay’s own wording rather than coined independently. Four alternatives were considered and set aside: SOC, from “built to the standard of code,” which defines code by code; SPEL, from “sufficient precision to function as executable logic,” which carries more of the thesis at the cost of a looser derivation; NLS, Natural Language Specification, which names the object rather than the standard, since a vague document is also a natural-language specification; and SBE, Specification Before Execution, which names the ordering discipline only.

ES was selected because it is the essay’s own noun for the thing, it is a term rather than a slogan, and it does not smuggle in the computational reading.

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Theoretical foundations: Grant C. Sterling (Eastern Illinois University). Analysis and synthesis: Dave Kelly. Prose rendering: Claude (Anthropic). 2026.