Terms starting with S

26 of 250 glossary terms. Each entry links to its own page with why it matters and where it fits.

Definitions here are written for engineers, not grammarians: what the term means, why it matters when it comes up, and where it sits in the curriculum — most term pages name the lessons that lean on the concept, so you can jump from a definition straight to the teaching. Use the letter bar below to move through the alphabet, or press the slash key to search the whole corpus directly.

Every entry carries three things besides the definition: the plain aliases it travels under (listed as “also”), a category tag for which stretch of the curriculum it belongs to, and the cross-references that place it next to its neighbors — the terms you would meet in the same lesson. A term earns a page here only when a lesson in the curriculum actually uses it, so the corpus stays the shape of the material instead of the shape of a dictionary.

One honest way to use this page: read down the list of entries below and note every term you could not define in a sentence if a colleague asked. That list — not the whole letter — is your revision list, and each entry links to the reading that closes the gap.

SFT (Supervised Fine-Tuning)
Math & training
Fine-tuning a pretrained model on paired inputs and desired responses so it learns the demonstrated behavior under the training distribution.
Sandbox
Agents & tools
An isolated execution environment that restricts an agent's access to files, processes, network destinations, credentials, and host resources.
Saturation
Reliability & operations
The degree to which a constrained resource or service has exhausted its capacity, including queued work that cannot begin promptly.
Scope Contract
AI-native development
A concrete agreement that defines a task's goal, allowed and forbidden surfaces, expected artifacts, verification requirements, and stopping conditions.
Self-Attention
Models & inference
Attention in which queries, keys, and values are derived from the same sequence representation. Scaled similarity scores are normalized and used to combine values, subject to causal, padding, local, or other masks.
Semantic Cache
AI-native development
A cache that reuses a previous result when a new request is judged sufficiently similar under a chosen representation and threshold.
Semantic Search
Retrieval & generation
Retrieval that represents a query and candidates in an embedding space and ranks candidates using a vector-similarity function.
Separation of Duties
Security & governance
Dividing conflicting responsibilities or authority across independent roles so one principal cannot complete a high-risk action without another authorized decision.
Service Level Indicator (SLI)
Reliability & operations
A quantitative measure of service behavior at a defined user-relevant boundary, such as successful request ratio or latency below a threshold.
Service Level Objective (SLO)
Reliability & operations
A target range or threshold for a service-level indicator over a stated population and measurement window.
Shadow Traffic
Reliability & operations
A copy of live request traffic sent to a candidate system for observation while the candidate response remains outside the primary user response path. Because the copied request still executes, its side effects must be isolated.
Shared Embedding Space
Multimodal systems
A common vector space in which representations from different modalities can be compared with the same similarity function.
Skill Bundle
Agents & tools
The complete installable skill directory, including `SKILL.md` and every reference, script, asset, fixture, or companion file required by the workflow.
Skill Catalog
Agents & tools
The compact model-visible inventory of eligible skills, usually containing routing metadata such as name, description, and an internal source identifier rather than every skill body.
Skill Discovery
Agents & tools
A runtime pipeline that searches configured roots, identifies candidate skill directories, validates their package contract, attaches scope and provenance, resolves collisions, and publishes eligible catalog entries.
Skill Invocation
Agents & tools
The runtime-mediated process in which an eligible human, model, application, or other skill selects a skill and causes its instructions to enter the working context.
Softmax
Math & training
A function defined by `softmax(x_i) = exp(x_i) / sum(exp(x_j))`, implemented with numerical stabilization. Its outputs are positive and sum to one, so they can parameterize a categorical distribution.
Software Bill of Materials (SBOM)
also: SBOM
Security & governance
A structured inventory of software components and relationships associated with a product or artifact, often including versions, suppliers, licenses, and identifiers.
Speculative Decoding
Models & inference
An inference method in which a cheaper draft process proposes several tokens and the target model scores those draft positions in parallel. In exact sampling variants, an acceptance and correction rule preserves the target model's output distribution.
Stateless MCP
Agents & tools
The MCP 2026-07-28 request model in which every request carries the protocol version and client capabilities in `params._meta`, while results carry an explicit `resultType`; no protocol state is keyed by an initialization handshake, connection, or `Mcp-Session-Id`.
Stochastic Gradient Descent (SGD)
also: SGD
Math & training
An optimizer family that updates parameters from a gradient estimated on a sampled example or minibatch rather than the complete training dataset.
Stop Sequence
Models & inference
An application-specified token or text pattern that causes generation to stop when the decoding system encounters it.
Streaming
Models & inference
Delivering incremental response events before the complete result is ready. A stream may contain token text, structured deltas, tool-call arguments, usage metadata, or status events depending on the API.
Structured Output
Agents & tools
Model output constrained or validated against a machine-readable schema so application code can consume fields without parsing free-form prose.
Swarm
Agents & tools
A loosely coordinated multi-agent pattern in which local agent decisions and message exchange produce system-level behavior. The term is used inconsistently, so the actual topology, state ownership, and termination rules must be specified.
System Prompt
Prompting & context
A provider-defined instruction message or configuration supplied by the application to establish behavior and constraints within that provider's instruction hierarchy.