01
Constraint Solving
Definition
Finding an action plan that satisfies limits such as budget, time, permissions, dependencies, policies, or resource availability.
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Agentic AI Glossary
Agent Planning & Reasoning
Agent Planning & Reasoning terms and explanations from the Agentic AI Glossary.
118 terms in this chapter
02
Critic Agent
Definition
A Critic Agent reviews another agent's plan, answer, or tool trajectory and points out errors, risks, or missing evidence.
03
Decision Tree
Definition
A branching structure that represents choices and outcomes, helping agents or systems select actions under different conditions.
04
Dependency Graph
Definition
A map of tasks or components that shows which items must happen before others can safely run.
05
Dynamic Planning
Definition
Planning that changes during execution as the agent receives new observations, tool results, failures, or user constraints.
06
Execution Trace
Definition
A recorded timeline of execution activity that helps engineers debug behavior and understand execution history.
07
Executor Agent
Definition
An Executor Agent carries out the steps created by a planner, usually by calling tools, APIs, or workflow actions.
08
Goal Decomposition
Definition
Breaking a broad objective into smaller subgoals that can be planned, assigned, executed, and evaluated.
09
Graph of Thoughts
Definition
A reasoning approach that explores connected ideas or partial solutions as a graph instead of a single linear chain.
10
Hierarchical Planning
Definition
Planning in layers, where a high-level goal is divided into phases, tasks, and concrete execution steps.
11
Long-Horizon Planning
Definition
Planning across many steps, tools, or time periods where memory, checkpoints, and recovery become important.
12
Milestone
Definition
A meaningful checkpoint that shows progress toward a larger goal and helps decide whether to continue, revise, or stop.
13
Plan-and-Execute
Definition
A pattern where one component creates a plan and another component follows the plan while reporting progress and failures.
14
Plan Execution
Definition
Carrying out planned steps through model calls, tools, APIs, retrieval, human approvals, or workflow actions.
15
Plan Revision
Definition
Changing a plan after discovering missing information, failed assumptions, blocked tools, or better available options.
16
Plan Validation
Definition
Checking that a plan is feasible, safe, complete, and aligned with the user's goal before execution.
17
Planner Agent
Definition
A Planner Agent breaks a high-level goal into ordered steps, dependencies, and checkpoints before execution begins.
18
Search-Based Planning
Definition
Using search over possible states or actions to find a path from the current situation to a desired goal.
19
Short-Horizon Planning
Definition
Planning only the next few steps, useful when the environment changes quickly or uncertainty is high.
20
Step Planning
Definition
Turning a task into clear ordered steps that can be executed, checked, retried, or delegated.
21
Subtask
Definition
A smaller unit of work inside a larger task, often assigned to a tool, worker agent, or workflow step.
22
Task Decomposition
Definition
Splitting a complex request into manageable subtasks with clear order, dependencies, and completion criteria.
23
Tree of Thoughts
Definition
A reasoning approach that explores multiple possible solution paths and chooses the most promising branch.
24
Verifier Agent
Definition
A Verifier Agent checks whether an output, tool result, or completed task satisfies the requirements and quality criteria.
25
Backoff
Definition
A retry strategy that waits longer after repeated failures, reducing pressure on rate-limited or unstable services.
26
Checkpoint Recovery
Definition
Restoring a workflow from a saved state so an agent can resume after failure without starting over.
27
Concurrency
Definition
The ability to process multiple sessions, tasks, or tool calls at the same time.
28
Dead Letter Queue
Definition
A queue that stores failed messages or tasks for later inspection, repair, replay, or manual handling.
29
Degraded Mode
Definition
A reduced-capability operating state used when a model, tool, data source, or service is unavailable.
30
Determinism
Definition
The degree to which the same input and configuration produce the same result, important for testing and auditability.
31
Error Handling
Definition
Logic that detects exceptions, communicates failures clearly, retries when safe, and prevents uncontrolled agent behavior.
32
Exception Handling
Definition
Code-level handling of unexpected runtime problems such as bad inputs, unavailable APIs, or invalid tool outputs.
33
Failure Mode
Definition
A specific way an agent or system can fail, such as hallucination, wrong tool use, timeout, or unsafe escalation.
34
Fallback
Definition
An alternate path used when the preferred model, tool, retrieval source, or workflow cannot complete safely.
35
Fault Tolerance
Definition
The ability to continue operating safely when components fail, slow down, or return partial results.
36
Graceful Degradation
Definition
Reducing functionality in a controlled way instead of failing completely when resources or services are limited.
37
Idempotency
Definition
A design property where repeating the same action does not create duplicate or harmful side effects.
38
Non-Determinism
Definition
Behavior where the same request may produce different outputs because of sampling, model updates, tool state, or timing.
39
Rate Limit Handling
Definition
Managing provider or API limits through throttling, queuing, backoff, caching, or routing to alternatives.
40
Recovery Strategy
Definition
Recovery Strategy is a planned approach for recovery. It guides design, deployment, measurement, governance, and continuous improvement.
41
Reliability
Definition
The ability of an AI system to deliver correct, safe, and available behavior across normal and edge-case conditions.
42
Reproducibility
Definition
The ability to rerun an evaluation or agent trace and obtain comparable behavior for debugging and compliance.
43
Resilience
Definition
The system's ability to absorb failures, adapt, and keep delivering acceptable service.
44
Retry
Definition
Repeating a failed request or tool call under controlled limits, often with backoff and idempotency protection.
45
Robustness
Definition
The ability to handle noisy inputs, edge cases, bad retrieval, ambiguous requests, or tool errors without breaking.
46
Root Cause Analysis
Definition
Investigating the underlying reason for a failure, such as bad data, prompt design, tool errors, or infrastructure limits.
47
Safe Failure
Definition
A failure state that avoids harm, data leakage, unsafe actions, or misleading output even when the task cannot finish.
48
Scalability
Definition
The ability to maintain quality, reliability, and cost control as usage grows.
49
Self-Healing
Definition
Automatic detection, retry, repair, or rerouting after an execution failure.
50
Session Management
Definition
Securely managing the lifecycle and context of individual user or task sessions.
51
State Recovery
Definition
Restoring task variables, memory, progress, and context after interruption or system failure.
52
Timeout
Definition
A maximum wait time for a model, tool, or workflow step before the system stops, retries, or falls back.
53
Agent Graph
Definition
Agent Graph is a workflow pattern for agent graph. It coordinates agent steps, tools, state, approvals, handoffs, or recovery paths.
54
Agentic Workflow
Definition
Agentic Workflow is a workflow pattern for agentic workflow. It coordinates agent steps, tools, state, approvals, handoffs, or recovery paths.
55
Checkpointing
Definition
Checkpointing is a workflow pattern for checkpointing. It coordinates agent steps, tools, state, approvals, handoffs, or recovery paths.
56
Critic-Reviewer
Definition
Critic-Reviewer is a workflow pattern for critic-reviewer. It coordinates agent steps, tools, state, approvals, handoffs, or recovery paths.
57
DAG
Definition
DAG is a workflow pattern for dag. It coordinates agent steps, tools, state, approvals, handoffs, or recovery paths.
58
Directed Acyclic Graph
Definition
Directed Acyclic Graph is a workflow pattern for directed acyclic graph. It coordinates agent steps, tools, state, approvals, handoffs, or recovery paths.
59
Durable Execution
Definition
Durable Execution is a workflow pattern for durable execution. It coordinates agent steps, tools, state, approvals, handoffs, or recovery paths.
60
Escalation Flow
Definition
Escalation Flow is a workflow pattern for escalation flow. It coordinates agent steps, tools, state, approvals, handoffs, or recovery paths.
61
Evaluator-Optimizer
Definition
Evaluator-Optimizer is a workflow pattern for evaluator-optimizer. It coordinates agent steps, tools, state, approvals, handoffs, or recovery paths.
62
Event-Driven Architecture
Definition
A design where systems react to events, triggers, messages, or state changes rather than only direct user requests.
63
Event-Driven Workflow
Definition
Event-Driven Workflow is a workflow pattern for event-driven workflow. It coordinates agent steps, tools, state, approvals, handoffs, or recovery paths.
64
Human Approval Flow
Definition
Human Approval Flow is a workflow pattern for human approval flow. It coordinates agent steps, tools, state, approvals, handoffs, or recovery paths.
65
Multi-Step Workflow
Definition
Multi-Step Workflow is a workflow pattern for multi-step workflow. It coordinates agent steps, tools, state, approvals, handoffs, or recovery paths.
66
Orchestration
Definition
Coordinating models, tools, agents, state, policies, and workflows into one reliable execution path.
67
Orchestrator-Worker
Definition
Orchestrator-Worker is a workflow pattern for orchestrator-worker. It coordinates agent steps, tools, state, approvals, handoffs, or recovery paths.
68
Parallelization
Definition
Parallelization is a workflow pattern for parallelization. It coordinates agent steps, tools, state, approvals, handoffs, or recovery paths.
69
Planner-Executor
Definition
Planner-Executor is a workflow pattern for planner-executor. It coordinates agent steps, tools, state, approvals, handoffs, or recovery paths.
70
RAG Workflow
Definition
RAG Workflow is a workflow pattern for rag workflow. It coordinates agent steps, tools, state, approvals, handoffs, or recovery paths.
71
Routing
Definition
Routing is a workflow pattern for routing. It coordinates agent steps, tools, state, approvals, handoffs, or recovery paths.
72
State Machine
Definition
State Machine is a workflow pattern for state machine. It coordinates agent steps, tools, state, approvals, handoffs, or recovery paths.
73
Supervisor-Worker
Definition
Supervisor-Worker is a workflow pattern for supervisor-worker. It coordinates agent steps, tools, state, approvals, handoffs, or recovery paths.
74
Tool-Use Flow
Definition
Tool-Use Flow is a workflow pattern for tool-use flow. It coordinates agent steps, tools, state, approvals, handoffs, or recovery paths.
75
Workflow
Definition
Workflow is a workflow pattern for workflow. It coordinates agent steps, tools, state, approvals, handoffs, or recovery paths.
76
Workflow Automation
Definition
Automating a multi-step business or technical process through tools, rules, and agent decisions.
77
Workflow Orchestration
Definition
Workflow Orchestration is a workflow pattern for workflow orchestration. It coordinates agent steps, tools, state, approvals, handoffs, or recovery paths.
78
A* Search
Definition
A best-first search method that combines path cost so far with a heuristic estimate of remaining cost.
79
Admissibility
Definition
A property of a search algorithm or heuristic that guarantees an optimal solution when its assumptions hold.
80
Best First Search
Definition
A search strategy that expands the most promising node first according to an evaluation function.
81
Bidirectional Search
Definition
A search strategy that works forward from the start and backward from the goal until the two searches meet.
82
Branching Factor
Definition
The average number of child nodes generated from each node in a search space.
83
Breadth-First Search
Definition
A search strategy that explores all nodes at the current depth before moving to the next level.
84
Brute-Force Search
Definition
A search approach that explores possible states without using problem-specific guidance.
85
Closed List
Definition
A collection of nodes that a search algorithm has already expanded.
86
Cut-Off Depth
Definition
A maximum search depth used to prevent depth-first search from exploring endlessly.
87
Depth-First Search
Definition
A search strategy that follows one path as deeply as possible before backtracking.
88
Depth of Problem
Definition
The length of the shortest sequence of operators from an initial state to a goal state.
89
Edge
Definition
A connection in a problem-space graph that represents an operator or transition between states.
90
FIFO Queue
Definition
A first-in, first-out data structure commonly used to implement breadth-first search.
91
Goal State
Definition
The desired state that a search algorithm is trying to reach.
92
Greedy Best First Search
Definition
A search strategy that expands the node estimated to be closest to the goal.
93
Heuristic Evaluation Function
Definition
A function that estimates how close a state is to a goal or how costly the remaining path may be.
94
Heuristic Search
Definition
A search approach that uses domain knowledge to choose more promising paths first.
95
Informed Search
Definition
A search strategy that uses heuristic information about the problem to improve efficiency.
96
Initial State
Definition
The starting state from which a search problem begins.
97
Iterative Deepening Depth-First Search
Definition
A search method that repeatedly runs depth-first search with increasing depth limits until it finds a solution.
98
LIFO Stack
Definition
A last-in, first-out data structure commonly used to implement depth-first search.
99
Local Beam Search
Definition
A local search method that keeps several candidate states and repeatedly selects the best successors.
100
Local Maximum
Definition
A state that is better than nearby states but may not be the best solution overall.
101
Local Search Algorithm
Definition
A search method that improves a candidate solution by moving to neighboring solutions.
102
Node
Definition
A point in a search graph that represents a state or partial solution.
103
Objective Function
Definition
A scoring function that measures how good a candidate solution is.
104
Open List
Definition
A collection of generated nodes that a search algorithm has not expanded yet.
105
Operator
Definition
An action or transition rule that changes one problem state into another.
106
Path Cost
Definition
The accumulated cost of moving through a sequence of states or actions.
107
Problem Instance
Definition
A specific search problem defined by an initial state and a goal state.
108
Problem Space
Definition
The set of states and operators in which a search problem is solved.
109
Problem Space Graph
Definition
A graph representation of a search problem where nodes are states and edges are operators.
110
Pure Heuristic Search
Definition
A search method that expands nodes according to heuristic values and manages open and closed lists.
111
Search Algorithm
Definition
A method for exploring states and actions to find a solution to a problem.
112
Simulated Annealing
Definition
A local search method that sometimes accepts worse moves early so it can escape poor local solutions.
113
Single-Agent Pathfinding Problem
Definition
A problem where one agent must find a sequence of moves from a start state to a goal state.
114
Space Complexity
Definition
The maximum amount of memory an algorithm needs while solving a problem.
115
Successor
Definition
A new state that results from applying an operator to a current state.
116
Time Complexity
Definition
The amount of computation or number of generated nodes an algorithm may require.
117
Travelling Salesman Problem
Definition
An optimization problem that seeks the lowest-cost tour visiting each city once and returning to the start.
118
Uniform Cost Search
Definition
A search strategy that expands the path with the lowest accumulated cost first.
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