feat: add graph-backed orchestration topology

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
This commit is contained in:
David Kaya
2026-03-24 22:44:17 +01:00
co-authored by Copilot
parent 5ab0b22d15
commit 2e2caf78f9
13 changed files with 1871 additions and 39 deletions
@@ -12,6 +12,34 @@ public sealed class PatternAgentDefinitionDto
public string? ReasoningEffort { get; init; }
}
public sealed class PatternGraphPositionDto
{
public double X { get; init; }
public double Y { get; init; }
}
public sealed class PatternGraphNodeDto
{
public string Id { get; init; } = string.Empty;
public string Kind { get; init; } = string.Empty;
public PatternGraphPositionDto Position { get; init; } = new();
public string? AgentId { get; init; }
public int? Order { get; init; }
}
public sealed class PatternGraphEdgeDto
{
public string Id { get; init; } = string.Empty;
public string Source { get; init; } = string.Empty;
public string Target { get; init; } = string.Empty;
}
public sealed class PatternGraphDto
{
public IReadOnlyList<PatternGraphNodeDto> Nodes { get; init; } = [];
public IReadOnlyList<PatternGraphEdgeDto> Edges { get; init; } = [];
}
public sealed class PatternDefinitionDto
{
public string Id { get; init; } = string.Empty;
@@ -23,6 +51,7 @@ public sealed class PatternDefinitionDto
public int MaxIterations { get; init; }
public ApprovalPolicyDto? ApprovalPolicy { get; init; }
public IReadOnlyList<PatternAgentDefinitionDto> Agents { get; init; } = [];
public PatternGraphDto? Graph { get; init; }
public string CreatedAt { get; init; } = string.Empty;
public string UpdatedAt { get; init; } = string.Empty;
}
@@ -94,9 +94,9 @@ internal sealed class CopilotAgentBundle : IAsyncDisposable
{
return pattern.Mode switch
{
"single" => AgentWorkflowBuilder.BuildSequential(pattern.Name, Agents),
"sequential" => AgentWorkflowBuilder.BuildSequential(pattern.Name, Agents),
"concurrent" => AgentWorkflowBuilder.BuildConcurrent(pattern.Name, Agents),
"single" => AgentWorkflowBuilder.BuildSequential(pattern.Name, ResolveOrderedAgents(pattern)),
"sequential" => AgentWorkflowBuilder.BuildSequential(pattern.Name, ResolveOrderedAgents(pattern)),
"concurrent" => AgentWorkflowBuilder.BuildConcurrent(pattern.Name, ResolveOrderedAgents(pattern)),
"handoff" => BuildHandoffWorkflow(pattern),
"group-chat" => BuildGroupChatWorkflow(pattern),
"magentic" => throw new NotSupportedException(
@@ -116,30 +116,30 @@ internal sealed class CopilotAgentBundle : IAsyncDisposable
private Workflow BuildHandoffWorkflow(PatternDefinitionDto pattern)
{
AIAgent firstAgent = Agents[0];
PatternAgentDefinitionDto triageDefinition = pattern.Agents[0];
IReadOnlyList<(AIAgent Agent, PatternAgentDefinitionDto Definition)> specialists =
Agents.Skip(1)
.Zip(pattern.Agents.Skip(1), (agent, definition) => (agent, definition))
.ToList();
Dictionary<string, AIAgent> agentMap = BuildAgentMap(pattern);
Dictionary<string, PatternAgentDefinitionDto> definitionMap = pattern.Agents.ToDictionary(
definition => definition.Id,
definition => definition,
StringComparer.Ordinal);
PatternHandoffTopology topology = PatternGraphResolver.ResolveHandoff(pattern);
AIAgent entryAgent = agentMap.GetValueOrDefault(topology.EntryAgentId) ?? Agents[0];
HandoffsWorkflowBuilder builder = AgentWorkflowBuilder.CreateHandoffBuilderWith(firstAgent)
HandoffsWorkflowBuilder builder = AgentWorkflowBuilder.CreateHandoffBuilderWith(entryAgent)
.WithHandoffInstructions(HandoffWorkflowGuidance.CreateWorkflowInstructions());
foreach ((AIAgent specialist, PatternAgentDefinitionDto definition) in specialists)
foreach (PatternHandoffRoute route in topology.Routes)
{
builder = builder.WithHandoff(
firstAgent,
specialist,
HandoffWorkflowGuidance.CreateForwardReason(definition));
}
if (!agentMap.TryGetValue(route.SourceAgentId, out AIAgent? sourceAgent)
|| !agentMap.TryGetValue(route.TargetAgentId, out AIAgent? targetAgent)
|| !definitionMap.TryGetValue(route.TargetAgentId, out PatternAgentDefinitionDto? targetDefinition))
{
continue;
}
foreach ((AIAgent specialist, _) in specialists)
{
builder = builder.WithHandoff(
specialist,
firstAgent,
HandoffWorkflowGuidance.CreateReturnReason(triageDefinition));
sourceAgent,
targetAgent,
HandoffWorkflowGuidance.CreateForwardReason(targetDefinition));
}
return builder.Build();
@@ -155,7 +155,30 @@ internal sealed class CopilotAgentBundle : IAsyncDisposable
{
MaximumIterationCount = maximumIterations,
})
.AddParticipants(Agents.ToArray())
.AddParticipants(ResolveOrderedAgents(pattern).ToArray())
.Build();
}
private IReadOnlyList<AIAgent> ResolveOrderedAgents(PatternDefinitionDto pattern)
{
Dictionary<string, AIAgent> agentMap = BuildAgentMap(pattern);
List<AIAgent> orderedAgents = PatternGraphResolver.ResolveOrderedAgentIds(pattern)
.Select(agentId => agentMap.TryGetValue(agentId, out AIAgent? agent) ? agent : null)
.Where(agent => agent is not null)
.Cast<AIAgent>()
.ToList();
return orderedAgents.Count == Agents.Count ? orderedAgents : Agents;
}
private Dictionary<string, AIAgent> BuildAgentMap(PatternDefinitionDto pattern)
{
Dictionary<string, AIAgent> agentMap = new(StringComparer.Ordinal);
foreach ((PatternAgentDefinitionDto definition, AIAgent agent) in pattern.Agents.Zip(Agents))
{
agentMap[definition.Id] = agent;
}
return agentMap;
}
}
@@ -0,0 +1,345 @@
using Eryx.AgentHost.Contracts;
namespace Eryx.AgentHost.Services;
internal sealed record PatternHandoffRoute(string SourceAgentId, string TargetAgentId);
internal sealed record PatternHandoffTopology(string EntryAgentId, IReadOnlyList<PatternHandoffRoute> Routes);
internal static class PatternGraphResolver
{
private const string UserInputKind = "user-input";
private const string UserOutputKind = "user-output";
private const string AgentKind = "agent";
private const string DistributorKind = "distributor";
private const string CollectorKind = "collector";
private const string OrchestratorKind = "orchestrator";
private static readonly StringComparer Comparer = StringComparer.OrdinalIgnoreCase;
public static PatternGraphDto Resolve(PatternDefinitionDto pattern)
=> pattern.Graph ?? CreateDefault(pattern);
public static IReadOnlyList<string> ResolveOrderedAgentIds(PatternDefinitionDto pattern)
{
PatternGraphDto graph = Resolve(pattern);
return pattern.Mode switch
{
"single" or "sequential" or "magentic" => ResolveLinearAgentIds(pattern, graph),
"concurrent" or "group-chat" or "handoff" => ResolveAgentOrder(pattern, graph),
_ => pattern.Agents.Select(agent => agent.Id).ToList()
};
}
public static PatternHandoffTopology ResolveHandoff(PatternDefinitionDto pattern)
{
return TryResolveHandoff(pattern, Resolve(pattern))
?? TryResolveHandoff(pattern, CreateDefault(pattern))
?? new PatternHandoffTopology(
pattern.Agents.FirstOrDefault()?.Id ?? string.Empty,
[]);
}
public static PatternGraphDto CreateDefault(PatternDefinitionDto pattern)
{
return pattern.Mode switch
{
"single" or "sequential" or "magentic" => CreateLinearGraph(pattern.Agents),
"concurrent" => CreateConcurrentGraph(pattern.Agents),
"handoff" => CreateHandoffGraph(pattern.Agents),
"group-chat" => CreateGroupChatGraph(pattern.Agents),
_ => CreateLinearGraph(pattern.Agents)
};
}
private static IReadOnlyList<string> ResolveLinearAgentIds(PatternDefinitionDto pattern, PatternGraphDto graph)
{
PatternGraphNodeDto? inputNode = GetNodeByKind(graph, UserInputKind);
PatternGraphNodeDto? outputNode = GetNodeByKind(graph, UserOutputKind);
if (inputNode is null || outputNode is null)
{
return pattern.Agents.Select(agent => agent.Id).ToList();
}
Dictionary<string, PatternGraphNodeDto> nodesById = graph.Nodes.ToDictionary(node => node.Id, node => node);
Dictionary<string, List<PatternGraphEdgeDto>> outgoing = BuildOutgoingLookup(graph);
List<string> orderedAgentIds = [];
HashSet<string> visitedNodeIds = [];
string currentNodeId = inputNode.Id;
while (visitedNodeIds.Add(currentNodeId))
{
if (!outgoing.TryGetValue(currentNodeId, out List<PatternGraphEdgeDto>? edges) || edges.Count != 1)
{
break;
}
string nextNodeId = edges[0].Target;
if (!nodesById.TryGetValue(nextNodeId, out PatternGraphNodeDto? nextNode))
{
break;
}
if (Comparer.Equals(nextNode.Id, outputNode.Id))
{
break;
}
if (Comparer.Equals(nextNode.Kind, AgentKind) && !string.IsNullOrWhiteSpace(nextNode.AgentId))
{
orderedAgentIds.Add(nextNode.AgentId);
}
currentNodeId = nextNodeId;
}
return orderedAgentIds.Count == pattern.Agents.Count
? orderedAgentIds
: pattern.Agents.Select(agent => agent.Id).ToList();
}
private static IReadOnlyList<string> ResolveAgentOrder(PatternDefinitionDto pattern, PatternGraphDto graph)
{
Dictionary<string, int> fallbackOrder = pattern.Agents
.Select((agent, index) => new { agent.Id, Index = index })
.ToDictionary(item => item.Id, item => item.Index);
List<string> orderedAgentIds = graph.Nodes
.Where(node => Comparer.Equals(node.Kind, AgentKind) && !string.IsNullOrWhiteSpace(node.AgentId))
.OrderBy(node => node.Order ?? int.MaxValue)
.ThenBy(node => fallbackOrder.GetValueOrDefault(node.AgentId!, int.MaxValue))
.Select(node => node.AgentId!)
.Distinct()
.ToList();
return orderedAgentIds.Count == pattern.Agents.Count
? orderedAgentIds
: pattern.Agents.Select(agent => agent.Id).ToList();
}
private static PatternHandoffTopology? TryResolveHandoff(PatternDefinitionDto pattern, PatternGraphDto graph)
{
Dictionary<string, PatternGraphNodeDto> nodesById = graph.Nodes.ToDictionary(node => node.Id, node => node);
PatternGraphNodeDto? inputNode = GetNodeByKind(graph, UserInputKind);
string? entryAgentId = null;
if (inputNode is not null)
{
entryAgentId = graph.Edges
.Where(edge => Comparer.Equals(edge.Source, inputNode.Id))
.Select(edge => nodesById.TryGetValue(edge.Target, out PatternGraphNodeDto? targetNode)
? targetNode.AgentId
: null)
.FirstOrDefault(agentId => !string.IsNullOrWhiteSpace(agentId));
}
List<PatternHandoffRoute> routes = graph.Edges
.Select(edge => (SourceNode: nodesById.GetValueOrDefault(edge.Source), TargetNode: nodesById.GetValueOrDefault(edge.Target)))
.Where(item =>
item.SourceNode is not null
&& item.TargetNode is not null
&& Comparer.Equals(item.SourceNode.Kind, AgentKind)
&& Comparer.Equals(item.TargetNode.Kind, AgentKind)
&& !string.IsNullOrWhiteSpace(item.SourceNode.AgentId)
&& !string.IsNullOrWhiteSpace(item.TargetNode.AgentId))
.Select(item => new PatternHandoffRoute(item.SourceNode!.AgentId!, item.TargetNode!.AgentId!))
.Distinct()
.ToList();
if (string.IsNullOrWhiteSpace(entryAgentId) || routes.Count == 0)
{
return null;
}
return new PatternHandoffTopology(entryAgentId!, routes);
}
private static Dictionary<string, List<PatternGraphEdgeDto>> BuildOutgoingLookup(PatternGraphDto graph)
{
Dictionary<string, List<PatternGraphEdgeDto>> lookup = new(StringComparer.Ordinal);
foreach (PatternGraphNodeDto node in graph.Nodes)
{
lookup[node.Id] = [];
}
foreach (PatternGraphEdgeDto edge in graph.Edges)
{
if (!lookup.TryGetValue(edge.Source, out List<PatternGraphEdgeDto>? edges))
{
edges = [];
lookup[edge.Source] = edges;
}
edges.Add(edge);
}
return lookup;
}
private static PatternGraphNodeDto? GetNodeByKind(PatternGraphDto graph, string kind)
=> graph.Nodes.FirstOrDefault(node => Comparer.Equals(node.Kind, kind));
private static PatternGraphDto CreateLinearGraph(IReadOnlyList<PatternAgentDefinitionDto> agents)
{
PatternGraphNodeDto inputNode = CreateSystemNode("system-user-input", UserInputKind, 0, 0);
PatternGraphNodeDto outputNode = CreateSystemNode("system-user-output", UserOutputKind, 220 * Math.Max(agents.Count + 1, 2), 0);
List<PatternGraphNodeDto> agentNodes = agents
.Select((agent, index) => CreateAgentNode(agent, index, 220 * (index + 1), 0))
.ToList();
List<PatternGraphEdgeDto> edges = [];
List<string> path = [inputNode.Id, .. agentNodes.Select(node => node.Id), outputNode.Id];
for (int index = 0; index < path.Count - 1; index += 1)
{
edges.Add(CreateEdge(path[index], path[index + 1]));
}
return new PatternGraphDto
{
Nodes = [inputNode, .. agentNodes, outputNode],
Edges = edges
};
}
private static PatternGraphDto CreateConcurrentGraph(IReadOnlyList<PatternAgentDefinitionDto> agents)
{
PatternGraphNodeDto inputNode = CreateSystemNode("system-user-input", UserInputKind, 0, 0);
PatternGraphNodeDto distributorNode = CreateSystemNode("system-distributor", DistributorKind, 190, 0);
PatternGraphNodeDto collectorNode = CreateSystemNode("system-collector", CollectorKind, 650, 0);
PatternGraphNodeDto outputNode = CreateSystemNode("system-user-output", UserOutputKind, 860, 0);
List<PatternGraphNodeDto> agentNodes = agents
.Select((agent, index) => CreateAgentNode(agent, index, 430, SpreadY(index, Math.Max(agents.Count, 1), 170)))
.ToList();
return new PatternGraphDto
{
Nodes = [inputNode, distributorNode, .. agentNodes, collectorNode, outputNode],
Edges =
[
CreateEdge(inputNode.Id, distributorNode.Id),
.. agentNodes.Select(node => CreateEdge(distributorNode.Id, node.Id)),
.. agentNodes.Select(node => CreateEdge(node.Id, collectorNode.Id)),
CreateEdge(collectorNode.Id, outputNode.Id)
]
};
}
private static PatternGraphDto CreateHandoffGraph(IReadOnlyList<PatternAgentDefinitionDto> agents)
{
PatternGraphNodeDto inputNode = CreateSystemNode("system-user-input", UserInputKind, 0, 0);
PatternGraphNodeDto outputNode = CreateSystemNode("system-user-output", UserOutputKind, 860, 0);
PatternAgentDefinitionDto? entryAgent = agents.FirstOrDefault();
PatternGraphNodeDto? entryNode = entryAgent is null
? null
: CreateAgentNode(entryAgent, 0, 220, 0);
List<PatternGraphNodeDto> specialistNodes = agents
.Skip(1)
.Select((agent, index) => CreateAgentNode(agent, index + 1, 540, SpreadY(index, Math.Max(agents.Count - 1, 1), 220)))
.ToList();
List<PatternGraphEdgeDto> edges = [];
if (entryNode is not null)
{
edges.Add(CreateEdge(inputNode.Id, entryNode.Id));
edges.Add(CreateEdge(entryNode.Id, outputNode.Id));
foreach (PatternGraphNodeDto specialistNode in specialistNodes)
{
edges.Add(CreateEdge(entryNode.Id, specialistNode.Id));
edges.Add(CreateEdge(specialistNode.Id, entryNode.Id));
edges.Add(CreateEdge(specialistNode.Id, outputNode.Id));
}
}
List<PatternGraphNodeDto> nodes = [inputNode];
if (entryNode is not null)
{
nodes.Add(entryNode);
}
nodes.AddRange(specialistNodes);
nodes.Add(outputNode);
return new PatternGraphDto
{
Nodes = nodes,
Edges = edges
};
}
private static PatternGraphDto CreateGroupChatGraph(IReadOnlyList<PatternAgentDefinitionDto> agents)
{
PatternGraphNodeDto inputNode = CreateSystemNode("system-user-input", UserInputKind, 0, 0);
PatternGraphNodeDto orchestratorNode = CreateSystemNode("system-orchestrator", OrchestratorKind, 250, 0);
PatternGraphNodeDto outputNode = CreateSystemNode("system-user-output", UserOutputKind, 900, 0);
const double centerX = 560;
const double centerY = 0;
const double radiusX = 190;
const double radiusY = 170;
List<PatternGraphNodeDto> agentNodes = agents
.Select((agent, index) =>
{
double angle = agents.Count <= 1
? 0
: (Math.PI * 2 * index) / agents.Count - (Math.PI / 2);
return CreateAgentNode(
agent,
index,
Math.Round(centerX + Math.Cos(angle) * radiusX),
Math.Round(centerY + Math.Sin(angle) * radiusY));
})
.ToList();
return new PatternGraphDto
{
Nodes = [inputNode, orchestratorNode, .. agentNodes, outputNode],
Edges =
[
CreateEdge(inputNode.Id, orchestratorNode.Id),
.. agentNodes.SelectMany(node => new[]
{
CreateEdge(orchestratorNode.Id, node.Id),
CreateEdge(node.Id, orchestratorNode.Id)
}),
CreateEdge(orchestratorNode.Id, outputNode.Id)
]
};
}
private static PatternGraphNodeDto CreateSystemNode(string id, string kind, double x, double y)
=> new()
{
Id = id,
Kind = kind,
Position = new PatternGraphPositionDto
{
X = x,
Y = y
}
};
private static PatternGraphNodeDto CreateAgentNode(PatternAgentDefinitionDto agent, int order, double x, double y)
=> new()
{
Id = $"agent-node-{agent.Id}",
Kind = AgentKind,
AgentId = agent.Id,
Order = order,
Position = new PatternGraphPositionDto
{
X = x,
Y = y
}
};
private static PatternGraphEdgeDto CreateEdge(string source, string target)
=> new()
{
Id = $"edge-{source}-to-{target}",
Source = source,
Target = target
};
private static double SpreadY(int index, int count, double gap)
=> (index - ((count - 1) / 2d)) * gap;
}
@@ -4,6 +4,8 @@ namespace Eryx.AgentHost.Services;
public sealed class PatternValidator
{
private static readonly StringComparer Comparer = StringComparer.OrdinalIgnoreCase;
public IReadOnlyList<PatternValidationIssueDto> Validate(PatternDefinitionDto pattern)
{
List<PatternValidationIssueDto> issues = [];
@@ -93,6 +95,479 @@ public sealed class PatternValidator
}
}
ValidateGraph(pattern, PatternGraphResolver.Resolve(pattern), issues);
return issues;
}
private static void ValidateGraph(
PatternDefinitionDto pattern,
PatternGraphDto graph,
List<PatternValidationIssueDto> issues)
{
if (graph.Nodes.Count == 0)
{
AddGraphIssue(issues, "Pattern graph must include nodes.");
return;
}
HashSet<string> nodeIds = new(StringComparer.Ordinal);
HashSet<string> edgeIds = new(StringComparer.Ordinal);
HashSet<string> agentIds = pattern.Agents.Select(agent => agent.Id).ToHashSet(StringComparer.Ordinal);
HashSet<string> seenAgentIds = new(StringComparer.Ordinal);
HashSet<int> seenAgentOrders = [];
Dictionary<string, PatternGraphNodeDto> nodesById = new(StringComparer.Ordinal);
foreach (PatternGraphNodeDto node in graph.Nodes)
{
if (!nodeIds.Add(node.Id))
{
AddGraphIssue(issues, $"Pattern graph contains duplicate node \"{node.Id}\".");
}
nodesById[node.Id] = node;
if (Comparer.Equals(node.Kind, "agent"))
{
if (string.IsNullOrWhiteSpace(node.AgentId) || !agentIds.Contains(node.AgentId))
{
AddGraphIssue(issues, $"Agent node \"{node.Id}\" must reference a known agent.");
}
if (!string.IsNullOrWhiteSpace(node.AgentId) && !seenAgentIds.Add(node.AgentId))
{
AddGraphIssue(issues, $"Pattern graph contains multiple nodes for agent \"{node.AgentId}\".");
}
if (!node.Order.HasValue)
{
AddGraphIssue(issues, $"Agent node \"{node.Id}\" must define an order.");
}
else if (!seenAgentOrders.Add(node.Order.Value))
{
AddGraphIssue(issues, $"Pattern graph contains duplicate agent order \"{node.Order.Value}\".");
}
}
else if (!string.IsNullOrWhiteSpace(node.AgentId))
{
AddGraphIssue(issues, $"System node \"{node.Id}\" cannot reference an agent.");
}
}
foreach (PatternAgentDefinitionDto agent in pattern.Agents)
{
if (!seenAgentIds.Contains(agent.Id))
{
AddGraphIssue(issues, $"Pattern graph is missing node metadata for agent \"{agent.Id}\".");
}
}
foreach (PatternGraphEdgeDto edge in graph.Edges)
{
if (!edgeIds.Add(edge.Id))
{
AddGraphIssue(issues, $"Pattern graph contains duplicate edge \"{edge.Id}\".");
}
if (!nodesById.ContainsKey(edge.Source) || !nodesById.ContainsKey(edge.Target))
{
AddGraphIssue(issues, $"Pattern graph edge \"{edge.Id}\" must connect known nodes.");
}
}
switch (pattern.Mode)
{
case "single":
case "sequential":
case "magentic":
ValidateLinearGraph(pattern, graph, issues);
break;
case "concurrent":
ValidateConcurrentGraph(pattern, graph, issues);
break;
case "handoff":
ValidateHandoffGraph(graph, issues);
break;
case "group-chat":
ValidateGroupChatGraph(pattern, graph, issues);
break;
}
}
private static void ValidateLinearGraph(
PatternDefinitionDto pattern,
PatternGraphDto graph,
List<PatternValidationIssueDto> issues)
{
ValidateSystemNodeCounts(graph, ["user-input", "user-output"], issues);
PatternGraphNodeDto? inputNode = GetNodeByKind(graph, "user-input");
PatternGraphNodeDto? outputNode = GetNodeByKind(graph, "user-output");
if (inputNode is null || outputNode is null)
{
return;
}
Dictionary<string, List<PatternGraphEdgeDto>> incoming = BuildIncomingLookup(graph);
Dictionary<string, List<PatternGraphEdgeDto>> outgoing = BuildOutgoingLookup(graph);
List<PatternGraphNodeDto> agentNodes = GetAgentNodes(graph);
if (graph.Edges.Count != pattern.Agents.Count + 1)
{
AddGraphIssue(issues, "Linear orchestration graphs must be a single path from user input through every agent to user output.");
}
if (incoming.GetValueOrDefault(inputNode.Id, []).Count != 0 || outgoing.GetValueOrDefault(inputNode.Id, []).Count != 1)
{
AddGraphIssue(issues, "User input must start exactly one path.");
}
if (incoming.GetValueOrDefault(outputNode.Id, []).Count != 1 || outgoing.GetValueOrDefault(outputNode.Id, []).Count != 0)
{
AddGraphIssue(issues, "User output must terminate exactly one path.");
}
foreach (PatternGraphNodeDto node in agentNodes)
{
if (incoming.GetValueOrDefault(node.Id, []).Count != 1 || outgoing.GetValueOrDefault(node.Id, []).Count != 1)
{
AddGraphIssue(issues, "Each agent in a linear orchestration must have exactly one incoming and one outgoing edge.");
break;
}
}
HashSet<string> visited = new(StringComparer.Ordinal);
string currentNodeId = inputNode.Id;
while (visited.Add(currentNodeId))
{
List<PatternGraphEdgeDto> nextEdges = outgoing.GetValueOrDefault(currentNodeId, []);
if (nextEdges.Count == 0)
{
break;
}
if (nextEdges.Count != 1)
{
AddGraphIssue(issues, "Linear orchestration nodes may only branch to one next step.");
break;
}
currentNodeId = nextEdges[0].Target;
if (Comparer.Equals(currentNodeId, outputNode.Id))
{
visited.Add(currentNodeId);
break;
}
}
HashSet<string> expectedVisited = new(StringComparer.Ordinal)
{
inputNode.Id,
outputNode.Id
};
foreach (PatternGraphNodeDto node in agentNodes)
{
expectedVisited.Add(node.Id);
}
if (!expectedVisited.SetEquals(visited))
{
AddGraphIssue(issues, "Linear orchestration graphs must visit every agent exactly once.");
}
}
private static void ValidateConcurrentGraph(
PatternDefinitionDto pattern,
PatternGraphDto graph,
List<PatternValidationIssueDto> issues)
{
ValidateSystemNodeCounts(graph, ["user-input", "distributor", "collector", "user-output"], issues);
PatternGraphNodeDto? inputNode = GetNodeByKind(graph, "user-input");
PatternGraphNodeDto? distributorNode = GetNodeByKind(graph, "distributor");
PatternGraphNodeDto? collectorNode = GetNodeByKind(graph, "collector");
PatternGraphNodeDto? outputNode = GetNodeByKind(graph, "user-output");
if (inputNode is null || distributorNode is null || collectorNode is null || outputNode is null)
{
return;
}
Dictionary<string, List<PatternGraphEdgeDto>> incoming = BuildIncomingLookup(graph);
Dictionary<string, List<PatternGraphEdgeDto>> outgoing = BuildOutgoingLookup(graph);
List<PatternGraphNodeDto> agentNodes = GetAgentNodes(graph);
HashSet<string> distributorTargets = outgoing.GetValueOrDefault(distributorNode.Id, []).Select(edge => edge.Target).ToHashSet(StringComparer.Ordinal);
HashSet<string> collectorSources = incoming.GetValueOrDefault(collectorNode.Id, []).Select(edge => edge.Source).ToHashSet(StringComparer.Ordinal);
if (graph.Edges.Count != pattern.Agents.Count * 2 + 2)
{
AddGraphIssue(issues, "Concurrent orchestration graphs must fan out from the distributor and fan back into the collector.");
}
if (incoming.GetValueOrDefault(inputNode.Id, []).Count != 0 || outgoing.GetValueOrDefault(inputNode.Id, []).Count != 1)
{
AddGraphIssue(issues, "User input must connect only to the distributor.");
}
if (incoming.GetValueOrDefault(distributorNode.Id, []).Count != 1)
{
AddGraphIssue(issues, "Distributor must receive exactly one edge from user input.");
}
if (outgoing.GetValueOrDefault(collectorNode.Id, []).Count != 1 || incoming.GetValueOrDefault(outputNode.Id, []).Count != 1)
{
AddGraphIssue(issues, "Collector must forward exactly one edge to user output.");
}
foreach (PatternGraphNodeDto agentNode in agentNodes)
{
if (!distributorTargets.Contains(agentNode.Id))
{
AddGraphIssue(issues, $"Distributor must connect to agent \"{agentNode.AgentId}\".");
}
if (!collectorSources.Contains(agentNode.Id))
{
AddGraphIssue(issues, $"Agent \"{agentNode.AgentId}\" must connect to the collector.");
}
}
}
private static void ValidateHandoffGraph(
PatternGraphDto graph,
List<PatternValidationIssueDto> issues)
{
ValidateSystemNodeCounts(graph, ["user-input", "user-output"], issues);
PatternGraphNodeDto? inputNode = GetNodeByKind(graph, "user-input");
PatternGraphNodeDto? outputNode = GetNodeByKind(graph, "user-output");
if (inputNode is null || outputNode is null)
{
return;
}
Dictionary<string, List<PatternGraphEdgeDto>> incoming = BuildIncomingLookup(graph);
Dictionary<string, List<PatternGraphEdgeDto>> outgoing = BuildOutgoingLookup(graph);
List<PatternGraphNodeDto> agentNodes = GetAgentNodes(graph);
HashSet<string> agentNodeIds = agentNodes.Select(node => node.Id).ToHashSet(StringComparer.Ordinal);
List<PatternGraphEdgeDto> entryEdges = outgoing.GetValueOrDefault(inputNode.Id, []);
List<PatternGraphEdgeDto> completionEdges = incoming.GetValueOrDefault(outputNode.Id, []);
if (entryEdges.Count != 1)
{
AddGraphIssue(issues, "Handoff graphs must connect user input to exactly one entry agent.");
return;
}
if (!agentNodeIds.Contains(entryEdges[0].Target))
{
AddGraphIssue(issues, "Handoff entry edges must target an agent node.");
}
if (completionEdges.Count == 0)
{
AddGraphIssue(issues, "Handoff graphs must allow at least one agent to complete back to user output.");
}
bool hasAgentToAgentRoute = false;
foreach (PatternGraphEdgeDto edge in graph.Edges)
{
if (Comparer.Equals(edge.Source, inputNode.Id))
{
continue;
}
if (Comparer.Equals(edge.Target, outputNode.Id))
{
if (!agentNodeIds.Contains(edge.Source))
{
AddGraphIssue(issues, "Only agent nodes may complete to user output.");
}
continue;
}
if (!agentNodeIds.Contains(edge.Source) || !agentNodeIds.Contains(edge.Target))
{
AddGraphIssue(issues, "Handoff routes may only connect agents to agents or agents to user output.");
continue;
}
if (Comparer.Equals(edge.Source, edge.Target))
{
AddGraphIssue(issues, "Handoff routes cannot target the same agent node.");
}
hasAgentToAgentRoute = true;
}
if (!hasAgentToAgentRoute && agentNodes.Count > 1)
{
AddGraphIssue(issues, "Handoff graphs must include at least one agent-to-agent handoff route.");
}
HashSet<string> reachable = new(StringComparer.Ordinal);
Stack<string> stack = new Stack<string>([entryEdges[0].Target]);
while (stack.Count > 0)
{
string nodeId = stack.Pop();
if (!reachable.Add(nodeId))
{
continue;
}
foreach (PatternGraphEdgeDto edge in outgoing.GetValueOrDefault(nodeId, []))
{
if (agentNodeIds.Contains(edge.Target) && !reachable.Contains(edge.Target))
{
stack.Push(edge.Target);
}
}
}
foreach (PatternGraphNodeDto agentNode in agentNodes)
{
if (!reachable.Contains(agentNode.Id))
{
AddGraphIssue(issues, $"Handoff entry agent must be able to reach \"{agentNode.AgentId}\".");
}
}
if (incoming.GetValueOrDefault(inputNode.Id, []).Count != 0 || outgoing.GetValueOrDefault(outputNode.Id, []).Count != 0)
{
AddGraphIssue(issues, "User input cannot have incoming edges and user output cannot have outgoing edges.");
}
}
private static void ValidateGroupChatGraph(
PatternDefinitionDto pattern,
PatternGraphDto graph,
List<PatternValidationIssueDto> issues)
{
ValidateSystemNodeCounts(graph, ["user-input", "orchestrator", "user-output"], issues);
PatternGraphNodeDto? inputNode = GetNodeByKind(graph, "user-input");
PatternGraphNodeDto? orchestratorNode = GetNodeByKind(graph, "orchestrator");
PatternGraphNodeDto? outputNode = GetNodeByKind(graph, "user-output");
if (inputNode is null || orchestratorNode is null || outputNode is null)
{
return;
}
Dictionary<string, List<PatternGraphEdgeDto>> incoming = BuildIncomingLookup(graph);
Dictionary<string, List<PatternGraphEdgeDto>> outgoing = BuildOutgoingLookup(graph);
List<PatternGraphNodeDto> agentNodes = GetAgentNodes(graph);
HashSet<string> orchestratorTargets = outgoing.GetValueOrDefault(orchestratorNode.Id, []).Select(edge => edge.Target).ToHashSet(StringComparer.Ordinal);
HashSet<string> orchestratorSources = incoming.GetValueOrDefault(orchestratorNode.Id, []).Select(edge => edge.Source).ToHashSet(StringComparer.Ordinal);
if (graph.Edges.Count != pattern.Agents.Count * 2 + 2)
{
AddGraphIssue(issues, "Group chat graphs must connect the orchestrator to every participant and then back to user output.");
}
if (outgoing.GetValueOrDefault(inputNode.Id, []).Any(edge => !Comparer.Equals(edge.Target, orchestratorNode.Id)))
{
AddGraphIssue(issues, "User input must only connect to the orchestrator.");
}
if (!outgoing.GetValueOrDefault(orchestratorNode.Id, []).Any(edge => Comparer.Equals(edge.Target, outputNode.Id)))
{
AddGraphIssue(issues, "Group chat orchestrator must connect to user output.");
}
foreach (PatternGraphNodeDto agentNode in agentNodes)
{
if (!orchestratorTargets.Contains(agentNode.Id))
{
AddGraphIssue(issues, $"Orchestrator must connect to agent \"{agentNode.AgentId}\".");
}
if (!orchestratorSources.Contains(agentNode.Id))
{
AddGraphIssue(issues, $"Agent \"{agentNode.AgentId}\" must connect back to the orchestrator.");
}
}
}
private static void ValidateSystemNodeCounts(
PatternGraphDto graph,
IReadOnlyList<string> expectedKinds,
List<PatternValidationIssueDto> issues)
{
Dictionary<string, int> counts = graph.Nodes
.GroupBy(node => node.Kind, Comparer)
.ToDictionary(group => group.Key, group => group.Count(), Comparer);
HashSet<string> expected = expectedKinds.ToHashSet(Comparer);
foreach (string kind in expectedKinds)
{
if (counts.GetValueOrDefault(kind, 0) != 1)
{
AddGraphIssue(issues, $"Pattern graph must include exactly one \"{kind}\" node.");
}
}
foreach ((string kind, int count) in counts)
{
if (Comparer.Equals(kind, "agent"))
{
continue;
}
if (!expected.Contains(kind) && count > 0)
{
AddGraphIssue(issues, $"Pattern graph does not allow \"{kind}\" nodes in this mode.");
}
}
}
private static PatternGraphNodeDto? GetNodeByKind(PatternGraphDto graph, string kind)
=> graph.Nodes.FirstOrDefault(node => Comparer.Equals(node.Kind, kind));
private static List<PatternGraphNodeDto> GetAgentNodes(PatternGraphDto graph)
=> graph.Nodes.Where(node => Comparer.Equals(node.Kind, "agent")).ToList();
private static Dictionary<string, List<PatternGraphEdgeDto>> BuildIncomingLookup(PatternGraphDto graph)
{
Dictionary<string, List<PatternGraphEdgeDto>> incoming = new(StringComparer.Ordinal);
foreach (PatternGraphNodeDto node in graph.Nodes)
{
incoming[node.Id] = [];
}
foreach (PatternGraphEdgeDto edge in graph.Edges)
{
if (!incoming.TryGetValue(edge.Target, out List<PatternGraphEdgeDto>? edges))
{
edges = [];
incoming[edge.Target] = edges;
}
edges.Add(edge);
}
return incoming;
}
private static Dictionary<string, List<PatternGraphEdgeDto>> BuildOutgoingLookup(PatternGraphDto graph)
{
Dictionary<string, List<PatternGraphEdgeDto>> outgoing = new(StringComparer.Ordinal);
foreach (PatternGraphNodeDto node in graph.Nodes)
{
outgoing[node.Id] = [];
}
foreach (PatternGraphEdgeDto edge in graph.Edges)
{
if (!outgoing.TryGetValue(edge.Source, out List<PatternGraphEdgeDto>? edges))
{
edges = [];
outgoing[edge.Source] = edges;
}
edges.Add(edge);
}
return outgoing;
}
private static void AddGraphIssue(List<PatternValidationIssueDto> issues, string message)
=> issues.Add(new PatternValidationIssueDto
{
Field = "graph",
Message = message,
});
}
@@ -0,0 +1,127 @@
using Eryx.AgentHost.Contracts;
using Eryx.AgentHost.Services;
namespace Eryx.AgentHost.Tests;
public sealed class PatternGraphResolverTests
{
[Fact]
public void ResolveOrderedAgentIds_UsesSequentialGraphPath()
{
PatternDefinitionDto pattern = CreatePattern(
"sequential",
[
CreateAgent("agent-1", "Analyst"),
CreateAgent("agent-2", "Builder"),
CreateAgent("agent-3", "Reviewer"),
],
new PatternGraphDto
{
Nodes =
[
CreateSystemNode("system-user-input", "user-input"),
CreateAgentNode("agent-1", 0),
CreateAgentNode("agent-2", 1),
CreateAgentNode("agent-3", 2),
CreateSystemNode("system-user-output", "user-output"),
],
Edges =
[
CreateEdge("system-user-input", "agent-node-agent-3"),
CreateEdge("agent-node-agent-3", "agent-node-agent-1"),
CreateEdge("agent-node-agent-1", "agent-node-agent-2"),
CreateEdge("agent-node-agent-2", "system-user-output"),
],
});
IReadOnlyList<string> orderedAgentIds = PatternGraphResolver.ResolveOrderedAgentIds(pattern);
Assert.Equal(["agent-3", "agent-1", "agent-2"], orderedAgentIds);
}
[Fact]
public void ResolveHandoff_UsesExplicitEntryAndRoutes()
{
PatternDefinitionDto pattern = CreatePattern(
"handoff",
[
CreateAgent("agent-1", "Triage"),
CreateAgent("agent-2", "UX"),
CreateAgent("agent-3", "Runtime"),
],
new PatternGraphDto
{
Nodes =
[
CreateSystemNode("system-user-input", "user-input"),
CreateSystemNode("system-user-output", "user-output"),
CreateAgentNode("agent-1", 0),
CreateAgentNode("agent-2", 1),
CreateAgentNode("agent-3", 2),
],
Edges =
[
CreateEdge("system-user-input", "agent-node-agent-3"),
CreateEdge("agent-node-agent-3", "agent-node-agent-2"),
CreateEdge("agent-node-agent-2", "agent-node-agent-1"),
CreateEdge("agent-node-agent-2", "system-user-output"),
],
});
PatternHandoffTopology topology = PatternGraphResolver.ResolveHandoff(pattern);
Assert.Equal("agent-3", topology.EntryAgentId);
Assert.Contains(new PatternHandoffRoute("agent-3", "agent-2"), topology.Routes);
Assert.Contains(new PatternHandoffRoute("agent-2", "agent-1"), topology.Routes);
Assert.DoesNotContain(new PatternHandoffRoute("agent-1", "agent-2"), topology.Routes);
}
private static PatternDefinitionDto CreatePattern(
string mode,
IReadOnlyList<PatternAgentDefinitionDto> agents,
PatternGraphDto graph)
=> new()
{
Id = $"{mode}-pattern",
Name = "Pattern",
Mode = mode,
Availability = "available",
Agents = agents,
Graph = graph,
};
private static PatternAgentDefinitionDto CreateAgent(string id, string name)
=> new()
{
Id = id,
Name = name,
Model = "gpt-5.4",
Instructions = "Help with the user's request.",
};
private static PatternGraphNodeDto CreateSystemNode(string id, string kind)
=> new()
{
Id = id,
Kind = kind,
Position = new PatternGraphPositionDto(),
};
private static PatternGraphNodeDto CreateAgentNode(string agentId, int order)
=> new()
{
Id = $"agent-node-{agentId}",
Kind = "agent",
AgentId = agentId,
Order = order,
Position = new PatternGraphPositionDto(),
};
private static PatternGraphEdgeDto CreateEdge(string source, string target)
=> new()
{
Id = $"edge-{source}-to-{target}",
Source = source,
Target = target,
};
}
@@ -73,12 +73,46 @@ public sealed class PatternValidatorTests
&& issue.Message.Contains("Unsupported", StringComparison.OrdinalIgnoreCase));
}
[Fact]
public void SequentialPattern_WithBranchedGraph_IsReportedAsInvalid()
{
IReadOnlyList<PatternValidationIssueDto> issues = _validator.Validate(
CreatePattern(
"sequential",
[
CreateAgent(id: "agent-1", name: "Analyst"),
CreateAgent(id: "agent-2", name: "Builder"),
],
graph: new PatternGraphDto
{
Nodes =
[
CreateSystemNode("system-user-input", "user-input"),
CreateAgentNode("agent-1", 0),
CreateAgentNode("agent-2", 1),
CreateSystemNode("system-user-output", "user-output"),
],
Edges =
[
CreateEdge("system-user-input", "agent-node-agent-1"),
CreateEdge("system-user-input", "agent-node-agent-2"),
CreateEdge("agent-node-agent-1", "agent-node-agent-2"),
CreateEdge("agent-node-agent-2", "system-user-output"),
],
}));
Assert.Contains(issues, issue =>
issue.Field == "graph"
&& issue.Message.Contains("single path", StringComparison.OrdinalIgnoreCase));
}
private static PatternDefinitionDto CreatePattern(
string mode,
IReadOnlyList<PatternAgentDefinitionDto> agents,
string availability = "available",
string? unavailabilityReason = null,
string name = "Pattern")
string name = "Pattern",
PatternGraphDto? graph = null)
{
return new PatternDefinitionDto
{
@@ -88,6 +122,7 @@ public sealed class PatternValidatorTests
Availability = availability,
UnavailabilityReason = unavailabilityReason,
Agents = agents,
Graph = graph,
};
}
@@ -105,4 +140,30 @@ public sealed class PatternValidatorTests
Instructions = instructions,
};
}
private static PatternGraphNodeDto CreateSystemNode(string id, string kind)
=> new()
{
Id = id,
Kind = kind,
Position = new PatternGraphPositionDto(),
};
private static PatternGraphNodeDto CreateAgentNode(string agentId, int order)
=> new()
{
Id = $"agent-node-{agentId}",
Kind = "agent",
AgentId = agentId,
Order = order,
Position = new PatternGraphPositionDto(),
};
private static PatternGraphEdgeDto CreateEdge(string source, string target)
=> new()
{
Id = $"edge-{source}-to-{target}",
Source = source,
Target = target,
};
}