Glossary

A Working Vocabulary for AI Agents and Runtime Governance

Terms
50
Categories
8
Published
50

Why we built this glossary

AI agents have introduced a growing vocabulary: tool calls, traces, guardrails, memory, identity, drift, and execution boundaries.

Each term describes something useful. But they don't all answer the same question.

An agent can be authenticated, authorized to use a tool, and operating exactly as designed, yet still take an action that has little to do with the objective it was given.

That is the question behind Sentience Governor: how do we evaluate an agent's actions against its declared objective, scope, and policy while it executes?

This glossary brings together established industry concepts and the vocabulary we use to describe runtime governance. Each entry explains what a concept means, how it applies to agent execution, what it is often confused with, and where its explanatory limits lie.

The aim is to build a useful reference for people building, operating, and governing AI agents.

As the field evolves, so will these definitions.

Sentience concept · Runtime and execution Agent action A single operation an agent attempts at the execution boundary, recorded as structured metadata: the tool used, the type of operation (read, write, delete or execute) and the system it targets. The record describes the attempt, not the content of prompts or completions. Read article Sentience concept · Evidence and observability Agent drift The divergence of an agent's behavior from its declared objective or scope over the course of execution, distinct from model drift and data drift. Sentience Governor records signals relevant to such divergence, including scope mismatches, unexpected operations and policy violations, but does not provide a single comprehensive drift measurement. Read article Industry concept · Evidence and observability Agent evaluation Measuring how well an agent performs against defined tasks or criteria, either offline on test sets or online by scoring real runs. Because agents take many steps, an evaluation can assess the final result, the path taken, or both. Read article Industry concept · Runtime and execution Agent harness The software wrapped around a language model that turns it into a working agent: it assembles the context, runs the loop, dispatches tool calls, applies permissions and handles results. Two agents using the same model can behave very differently because their harnesses differ. Read article Industry concept · Runtime and execution Agent loop The repeating cycle at the center of an agent: the model reads the current context, chooses an action, the action runs, and the result is added to the context for the next turn. The loop ends when the model decides the task is complete or an external limit stops it. Read article Industry concept · Cost and context Agent memory The mechanisms that let an agent retain and retrieve information beyond the context immediately available to the model, using resources such as notes, files, databases or vector stores. Depending on the design, this information may persist across steps, tasks or sessions and influence later behavior. Read article Industry concept · Evidence and observability Agent observability The ability to inspect and understand an agent's execution through recorded data such as traces, tool calls, inputs, outputs, timing and errors. It provides visibility into what occurred and the surrounding execution context, while judging an action's appropriateness requires criteria against which to evaluate it. Read article Industry concept · Protocols and frameworks Agent orchestration The coordination of agents, tools and execution steps within a larger process, including routing work, ordering operations, managing state and handling handoffs. It defines how the parts of an agent system work together to complete a task. Read article Industry concept · Runtime and execution Agent runtime The execution environment that hosts an agent while it works: the processes, tools, credentials, state and resource limits available to it. It determines what the agent's actions can actually reach. Read article Industry concept · Evidence and observability Agent tracing Recording an agent run as a structured sequence of steps, typically nested spans covering model calls, tool calls and their timing. A trace shows the path an agent took through a task. Read article Industry concept · Protocols and frameworks Agent-to-agent (A2A) protocol An open protocol for communication and collaboration between independent AI agents, allowing them to discover capabilities, exchange messages, delegate tasks and receive results without requiring access to one another's internal state or tools. Read article Industry concept · Foundations Agentic AI A broad term for AI systems designed to pursue goals with some autonomy: planning, choosing actions, using tools and adjusting to results, rather than producing a single response to a single prompt. It names the approach, while an AI agent is a specific system built that way. Read article Industry concept · Foundations Agentic workflow A process in which some or all steps are carried out by AI agents, with the model deciding at least part of the sequence at run time rather than following a fixed script. The degree of model control ranges from one decision point inside a scripted pipeline to a fully open-ended loop. Read article Industry concept · Foundations AI agent An AI system that pursues a goal by selecting and carrying out actions, often through tools and over multiple steps. Unlike a system limited to producing responses, an agent can interact with software or external systems as part of its work. Read article Industry concept · Identity and authorization AI agent authorization and permissions The rules and mechanisms that determine what an identified agent may access or do, such as scoped credentials, delegated authority and least-privilege access. Authorization establishes what an agent is allowed to do, and does not by itself establish whether a permitted action serves the task it was given. Read article Industry concept · Cost and context AI agent cost The total expense of operating an AI agent, including model usage, tool execution, infrastructure and retries. Unlike the cost of a single model request, it depends on how many steps the agent takes, how much context each step consumes and which external resources it uses. Read article Industry concept · Protocols and frameworks AI agent framework A software library that provides the components for creating agents, such as model interfaces, tool definitions, the agent loop, memory and state handling. It shapes how an agent is built, while how the agent is hosted and run is the concern of the runtime. Read article Industry concept · Governance and policy AI agent governance Governance applied to AI systems that act: deciding what agents may do and under whose authority, evaluating what they actually do, and keeping evidence of both. It extends AI governance from models and their outputs to actions and their effects. Read article Industry concept · Identity and authorization AI agent identity An identity associated with an AI agent so that it can be distinguished from other agents, users and services, and its actions can be attributed to it. Where the identity is verifiable, it also supports authentication and authorization decisions. Read article Industry concept · Evidence and observability AI agent monitoring The ongoing observation of agents in operation against expected behavior, using measures such as error rates, latency, cost and task outcomes, usually with alerts when they move out of range. It tells operators that something has changed, while diagnosing why usually falls to tracing and observability. Read article Industry concept · Security AI agent sandbox An isolated execution environment that restricts the files, network resources, processes or credentials an agent's code and tools can access. It limits the reach of an agent's actions according to its configured isolation boundaries, but does not by itself determine whether a permitted action serves the intended task. Read article Industry concept · Security AI agent security The protection of agents, and of the systems they can reach, against misuse and attack, including prompt injection, credential and tool abuse, data exfiltration and excessive privileges. It treats the agent both as something to defend and as a potential path to everything it has access to. Read article Industry concept · Evidence and observability AI audit trail A chronological record of an AI system's actions and decisions, maintained so that its behavior can be reviewed and attributed later. Its evidentiary value depends on the coverage, integrity and provenance of the recorded events. Read article Industry concept · Governance and policy AI governance The policies, roles, processes and controls used to direct and oversee the development, deployment and operation of AI systems. It addresses accountability, risk, compliance and oversight across the AI lifecycle, from organizational decisions to the behavior of individual systems. Read article Industry concept · Security AI guardrails Controls placed around an AI system to constrain or check its inputs, outputs or actions, such as content filters, schema validation, allow-lists and rule-based checks. They apply limits that someone defined in advance, and sit at different points depending on the product: before the model, after it, or around tool use. Read article Industry concept · Foundations Coding agent An AI agent that works inside a software project: it reads and edits files, runs commands and tests, and uses the results to continue. Because it acts through a shell and the filesystem, its actions can have effects well beyond the code it was asked to change. Read article Sentience concept · Cost and context Context cost The portion of an agent's model usage cost attributable to supplying accumulated context, such as conversation history, instructions and tool results, across successive turns. Cached inputs may reduce the price of repeated context, but they do not eliminate its cost. Read article Industry concept · Cost and context Context window The maximum amount of context a language model can process in a single invocation, measured in tokens and subject to the model's input and output limits. An agent that accumulates more context than the model can accommodate must select, summarize or store material outside the active window. Read article Sentience concept · Governance and policy Declared intent A statement, made before an agent acts, of the objective it is working toward and the scope within which it will pursue it. In Sentience Governor it is written to the record as its own event and applies only to the activity that follows it. Read article Sentience concept · Governance and policy Declared scope The set of operation targets, such as the filesystem, a shell or the web, that are stated as within an agent's task boundaries. Each attempted action's target is compared against that set, and a mismatch is recorded. Read article Sentience concept · Runtime and execution Execution boundary The point at which an agent's decision is about to become an operation on a real system: a tool call, a file write, a shell command, a write to persistent memory. It is where an attempted action can be captured and evaluated, whether or not the operation then succeeds. Read article Sentience concept · Evidence and observability Flag and violation A flag identifies a condition or behavior that warrants attention during an AI agent's execution, while a policy violation indicates that an action meets the conditions of a rule defining prohibited or noncompliant behavior. The distinction separates observations about agent behavior from judgments against applicable policy, without necessarily determining what response should follow. Read article Industry concept · Runtime and execution Function calling A model capability in which the developer describes functions with typed parameters, and the model returns a function name and structured arguments instead of prose. The application, not the model, executes the function, and the term is often used interchangeably with tool calling, which is the broader concept. Read article Sentience concept · Evidence and observability Governance evidence The recorded account of what an agent declared, what it attempted, which policy applied and what the evaluation concluded, including what could not be determined. Its value lies in gaps and unknowns being recorded explicitly rather than left out. Read article Sentience concept · Governance and policy Governance profile An operator-defined configuration that establishes the expectations, boundaries, and oversight requirements against which an AI agent's execution is evaluated. It helps determine what behavior deserves attention, which operations carry greater consequence, and how governance findings should be recorded or acted upon. Read article Sentience concept · Security High-consequence operation A high-consequence operation is an agent action whose consequences, if mistaken, would be costly, difficult to reverse, or widely felt, and which therefore warrants more scrutiny than routine actions. Which operations qualify is a judgment about the action in its context, typically made by the operator responsible for the environment. Read article Industry concept · Governance and policy Human in the loop A design in which a person participates in an AI system's decision or execution process by reviewing, approving, correcting or providing input at a defined stage. Human involvement may occur before consequential actions, during execution or when reviewing results, depending on the system's purpose and risk. Read article Sentience concept · Governance and policy Local-first governance An approach in which agent actions are evaluated, and the resulting record is kept by default, on the operator's own machine, with no account, service or network connection required. It describes where governance runs, not what the agent itself connects to. Read article Industry concept · Foundations Long-running agent An agent that works on a task over an extended period, across many steps and sometimes multiple sessions. It may use notes, memory or checkpoints to preserve working state, making continuity of purpose and scope important throughout execution. Read article Industry concept · Protocols and frameworks MCP server A program that exposes tools, resources or prompts to AI applications over the Model Context Protocol, running either locally alongside the client or as a remote service. Each server extends what a connected agent is able to do. Read article Industry concept · Protocols and frameworks Model Context Protocol (MCP) An open standard for connecting AI applications to external systems through a common client-server interface. MCP servers can expose tools, resources and prompts, allowing compatible clients to discover and use those capabilities. Read article Industry concept · Foundations Multi-agent system A system in which several agents, each with its own role, instructions or tools, work on a task by delegating, exchanging results or acting in parallel. It raises questions a single agent does not, such as which agent acted, under whose authority and with what shared state. Read article Industry concept · Governance and policy Policy as code The practice of writing policies in a machine-readable form that is version-controlled, tested and evaluated automatically, instead of keeping them only as documents. It makes a policy's application repeatable and its changes reviewable. Read article Sentience concept · Governance and policy Policy resolution Policy resolution is the process of determining which governance policies apply to an AI agent or execution context. It establishes how policies are selected, combined, or prioritized, and provides the basis for evaluating agent behavior against the appropriate expectations and boundaries. Read article Industry concept · Security Prompt injection An attack in which an adversary uses crafted input to redirect an AI system away from its intended instructions or task. It may arrive directly through a user prompt or indirectly through material such as documents, web pages and tool results, potentially causing an agent to take unintended actions. Read article Sentience concept · Governance and policy Runtime governance The evaluation of an AI agent's actions against its declared intent, scope and policy while the agent is executing, with the results recorded as evidence. Sentience Governor implements it as observation and recording: actions are evaluated and flagged, and execution is not interrupted. Read article Sentience concept · Runtime and execution Semantic action classification Describing the potential effects of a shell command by its domain, action and destructive character, rather than recording only that a command was run. Sentience Governor currently applies deterministic classification to Claude Code shell commands and records unknown or incomplete classifications rather than assuming an effect it cannot establish. Read article Sentience concept · Evidence and observability Sentience Agent Execution Record The local, append-only stream of structured events that Sentience Governor writes for each governed agent session. It uses one schema across every supported integration and stays on the operator's machine by default. Read article Sentience concept · Foundations The Governor Model The architecture proposed in the Sentience Governor white paper, in which governance is a continuous control loop that jointly manages an agent's scope, its memory, and the identities and policies that constrain both. It describes an architecture and a direction, not the current capabilities of Sentience Governor. Read article Industry concept · Runtime and execution Tool calling The mechanism by which a language model requests an external function, API or command through a structured interface, with the surrounding application responsible for invoking it and returning the result. A tool call represents a requested operation, not proof that the operation succeeded. Read article

50 terms

Foundations

Agentic AI

Read article

A broad term for AI systems designed to pursue goals with some autonomy: planning, choosing actions, using tools and adjusting to results, rather than producing a single response to a single prompt. It names the approach, while an AI agent is a specific system built that way.

Agentic workflow

Read article

A process in which some or all steps are carried out by AI agents, with the model deciding at least part of the sequence at run time rather than following a fixed script. The degree of model control ranges from one decision point inside a scripted pipeline to a fully open-ended loop.

AI agent

Read article

An AI system that pursues a goal by selecting and carrying out actions, often through tools and over multiple steps. Unlike a system limited to producing responses, an agent can interact with software or external systems as part of its work.

Coding agent

Read article

An AI agent that works inside a software project: it reads and edits files, runs commands and tests, and uses the results to continue. Because it acts through a shell and the filesystem, its actions can have effects well beyond the code it was asked to change.

Long-running agent

Read article

An agent that works on a task over an extended period, across many steps and sometimes multiple sessions. It may use notes, memory or checkpoints to preserve working state, making continuity of purpose and scope important throughout execution.

Multi-agent system

Read article

A system in which several agents, each with its own role, instructions or tools, work on a task by delegating, exchanging results or acting in parallel. It raises questions a single agent does not, such as which agent acted, under whose authority and with what shared state.

The Governor Model

Read article

The architecture proposed in the Sentience Governor white paper, in which governance is a continuous control loop that jointly manages an agent's scope, its memory, and the identities and policies that constrain both. It describes an architecture and a direction, not the current capabilities of Sentience Governor.

Runtime and execution

Agent action

Read article

A single operation an agent attempts at the execution boundary, recorded as structured metadata: the tool used, the type of operation (read, write, delete or execute) and the system it targets. The record describes the attempt, not the content of prompts or completions.

Agent harness

Read article

The software wrapped around a language model that turns it into a working agent: it assembles the context, runs the loop, dispatches tool calls, applies permissions and handles results. Two agents using the same model can behave very differently because their harnesses differ.

Agent loop

Read article

The repeating cycle at the center of an agent: the model reads the current context, chooses an action, the action runs, and the result is added to the context for the next turn. The loop ends when the model decides the task is complete or an external limit stops it.

Agent runtime

Read article

The execution environment that hosts an agent while it works: the processes, tools, credentials, state and resource limits available to it. It determines what the agent's actions can actually reach.

Execution boundary

Read article

The point at which an agent's decision is about to become an operation on a real system: a tool call, a file write, a shell command, a write to persistent memory. It is where an attempted action can be captured and evaluated, whether or not the operation then succeeds.

Function calling

Read article

A model capability in which the developer describes functions with typed parameters, and the model returns a function name and structured arguments instead of prose. The application, not the model, executes the function, and the term is often used interchangeably with tool calling, which is the broader concept.

Semantic action classification

Read article

Describing the potential effects of a shell command by its domain, action and destructive character, rather than recording only that a command was run. Sentience Governor currently applies deterministic classification to Claude Code shell commands and records unknown or incomplete classifications rather than assuming an effect it cannot establish.

Tool calling

Read article

The mechanism by which a language model requests an external function, API or command through a structured interface, with the surrounding application responsible for invoking it and returning the result. A tool call represents a requested operation, not proof that the operation succeeded.

Governance and policy

AI agent governance

Read article

Governance applied to AI systems that act: deciding what agents may do and under whose authority, evaluating what they actually do, and keeping evidence of both. It extends AI governance from models and their outputs to actions and their effects.

AI governance

Read article

The policies, roles, processes and controls used to direct and oversee the development, deployment and operation of AI systems. It addresses accountability, risk, compliance and oversight across the AI lifecycle, from organizational decisions to the behavior of individual systems.

Declared intent

Read article

A statement, made before an agent acts, of the objective it is working toward and the scope within which it will pursue it. In Sentience Governor it is written to the record as its own event and applies only to the activity that follows it.

Declared scope

Read article

The set of operation targets, such as the filesystem, a shell or the web, that are stated as within an agent's task boundaries. Each attempted action's target is compared against that set, and a mismatch is recorded.

Governance profile

Read article

An operator-defined configuration that establishes the expectations, boundaries, and oversight requirements against which an AI agent's execution is evaluated. It helps determine what behavior deserves attention, which operations carry greater consequence, and how governance findings should be recorded or acted upon.

Human in the loop

Read article

A design in which a person participates in an AI system's decision or execution process by reviewing, approving, correcting or providing input at a defined stage. Human involvement may occur before consequential actions, during execution or when reviewing results, depending on the system's purpose and risk.

Local-first governance

Read article

An approach in which agent actions are evaluated, and the resulting record is kept by default, on the operator's own machine, with no account, service or network connection required. It describes where governance runs, not what the agent itself connects to.

Policy as code

Read article

The practice of writing policies in a machine-readable form that is version-controlled, tested and evaluated automatically, instead of keeping them only as documents. It makes a policy's application repeatable and its changes reviewable.

Policy resolution

Read article

Policy resolution is the process of determining which governance policies apply to an AI agent or execution context. It establishes how policies are selected, combined, or prioritized, and provides the basis for evaluating agent behavior against the appropriate expectations and boundaries.

Runtime governance

Read article

The evaluation of an AI agent's actions against its declared intent, scope and policy while the agent is executing, with the results recorded as evidence. Sentience Governor implements it as observation and recording: actions are evaluated and flagged, and execution is not interrupted.

Evidence and observability

Agent drift

Read article

The divergence of an agent's behavior from its declared objective or scope over the course of execution, distinct from model drift and data drift. Sentience Governor records signals relevant to such divergence, including scope mismatches, unexpected operations and policy violations, but does not provide a single comprehensive drift measurement.

Agent evaluation

Read article

Measuring how well an agent performs against defined tasks or criteria, either offline on test sets or online by scoring real runs. Because agents take many steps, an evaluation can assess the final result, the path taken, or both.

Agent observability

Read article

The ability to inspect and understand an agent's execution through recorded data such as traces, tool calls, inputs, outputs, timing and errors. It provides visibility into what occurred and the surrounding execution context, while judging an action's appropriateness requires criteria against which to evaluate it.

Agent tracing

Read article

Recording an agent run as a structured sequence of steps, typically nested spans covering model calls, tool calls and their timing. A trace shows the path an agent took through a task.

AI agent monitoring

Read article

The ongoing observation of agents in operation against expected behavior, using measures such as error rates, latency, cost and task outcomes, usually with alerts when they move out of range. It tells operators that something has changed, while diagnosing why usually falls to tracing and observability.

AI audit trail

Read article

A chronological record of an AI system's actions and decisions, maintained so that its behavior can be reviewed and attributed later. Its evidentiary value depends on the coverage, integrity and provenance of the recorded events.

Flag and violation

Read article

A flag identifies a condition or behavior that warrants attention during an AI agent's execution, while a policy violation indicates that an action meets the conditions of a rule defining prohibited or noncompliant behavior. The distinction separates observations about agent behavior from judgments against applicable policy, without necessarily determining what response should follow.

Governance evidence

Read article

The recorded account of what an agent declared, what it attempted, which policy applied and what the evaluation concluded, including what could not be determined. Its value lies in gaps and unknowns being recorded explicitly rather than left out.

Sentience Agent Execution Record

Read article

The local, append-only stream of structured events that Sentience Governor writes for each governed agent session. It uses one schema across every supported integration and stays on the operator's machine by default.

Identity and authorization

AI agent authorization and permissions

Read article

The rules and mechanisms that determine what an identified agent may access or do, such as scoped credentials, delegated authority and least-privilege access. Authorization establishes what an agent is allowed to do, and does not by itself establish whether a permitted action serves the task it was given.

AI agent identity

Read article

An identity associated with an AI agent so that it can be distinguished from other agents, users and services, and its actions can be attributed to it. Where the identity is verifiable, it also supports authentication and authorization decisions.

Security

AI agent sandbox

Read article

An isolated execution environment that restricts the files, network resources, processes or credentials an agent's code and tools can access. It limits the reach of an agent's actions according to its configured isolation boundaries, but does not by itself determine whether a permitted action serves the intended task.

AI agent security

Read article

The protection of agents, and of the systems they can reach, against misuse and attack, including prompt injection, credential and tool abuse, data exfiltration and excessive privileges. It treats the agent both as something to defend and as a potential path to everything it has access to.

AI guardrails

Read article

Controls placed around an AI system to constrain or check its inputs, outputs or actions, such as content filters, schema validation, allow-lists and rule-based checks. They apply limits that someone defined in advance, and sit at different points depending on the product: before the model, after it, or around tool use.

High-consequence operation

Read article

A high-consequence operation is an agent action whose consequences, if mistaken, would be costly, difficult to reverse, or widely felt, and which therefore warrants more scrutiny than routine actions. Which operations qualify is a judgment about the action in its context, typically made by the operator responsible for the environment.

Prompt injection

Read article

An attack in which an adversary uses crafted input to redirect an AI system away from its intended instructions or task. It may arrive directly through a user prompt or indirectly through material such as documents, web pages and tool results, potentially causing an agent to take unintended actions.

Cost and context

Agent memory

Read article

The mechanisms that let an agent retain and retrieve information beyond the context immediately available to the model, using resources such as notes, files, databases or vector stores. Depending on the design, this information may persist across steps, tasks or sessions and influence later behavior.

AI agent cost

Read article

The total expense of operating an AI agent, including model usage, tool execution, infrastructure and retries. Unlike the cost of a single model request, it depends on how many steps the agent takes, how much context each step consumes and which external resources it uses.

Context cost

Read article

The portion of an agent's model usage cost attributable to supplying accumulated context, such as conversation history, instructions and tool results, across successive turns. Cached inputs may reduce the price of repeated context, but they do not eliminate its cost.

Context window

Read article

The maximum amount of context a language model can process in a single invocation, measured in tokens and subject to the model's input and output limits. An agent that accumulates more context than the model can accommodate must select, summarize or store material outside the active window.

Protocols and frameworks

Agent orchestration

Read article

The coordination of agents, tools and execution steps within a larger process, including routing work, ordering operations, managing state and handling handoffs. It defines how the parts of an agent system work together to complete a task.

Agent-to-agent (A2A) protocol

Read article

An open protocol for communication and collaboration between independent AI agents, allowing them to discover capabilities, exchange messages, delegate tasks and receive results without requiring access to one another's internal state or tools.

AI agent framework

Read article

A software library that provides the components for creating agents, such as model interfaces, tool definitions, the agent loop, memory and state handling. It shapes how an agent is built, while how the agent is hosted and run is the concern of the runtime.

MCP server

Read article

A program that exposes tools, resources or prompts to AI applications over the Model Context Protocol, running either locally alongside the client or as a remote service. Each server extends what a connected agent is able to do.

Model Context Protocol (MCP)

Read article

An open standard for connecting AI applications to external systems through a common client-server interface. MCP servers can expose tools, resources and prompts, allowing compatible clients to discover and use those capabilities.