Prevent sampleless speaker identities

MeetingAssistant/Speakers/SpeakerIdentityService.cs

@@ -82,6 +82,15 @@ public sealed class SpeakerIdentityService : ISpeakerIdentificationService
 
         if (target is null)
         {
+            if (sourceCandidate is null && snippet.Length == 0)
+            {
+                logger.LogWarning(
+                    "Skipping speaker override from {SourceSpeaker} to {TargetSpeaker} because no source sample could be resolved",
+                    sourceLabel,
+                    targetName);
+                return;
+            }
+
             target = sourceCandidate ?? new SpeakerIdentity
             {
                 CreatedAt = now,

MeetingAssistant/Workflow/WorkflowRulesEditorChatPipeline.cs

@@ -317,7 +317,7 @@ public sealed class WorkflowRulesEditorChatPipeline : IWorkflowRulesEditorChatPi
                 AIFunctionFactory.Create(
                     tools.CreateIdentity,
                     "create_identity",
-                    "Create a speaker identity with optional canonicalName, aliases, and candidateNames. Returns the created identity JSON."),
+                    "Refuse sampleless speaker identity creation and explain that identities must be created from an existing transcript speaker sample."),
                 AIFunctionFactory.Create(
                     tools.UpdateIdentity,
                     "update_identity",

MeetingAssistant/Workflow/WorkflowRulesEditorInstructionBuilder.cs

@@ -61,7 +61,7 @@ public sealed class WorkflowRulesEditorInstructionBuilder : IWorkflowRulesEditor
             "Project tools can create project folders and read, write, list, and search files in configured projects." + Environment.NewLine + Environment.NewLine +
             "Meeting artifact tools can list recent summaries and read/search/write summaries, transcripts, meeting notes, and assistant context files for note post-processing and repair. Prefer frontmatter-specific write tools for metadata-only fixes." + Environment.NewLine + Environment.NewLine +
             "Diagnostic tools mirror the local health, recording status, Outlook metadata, speaker identity merge, workflow reload, and ASR diagnostic endpoints without requiring HTTP." + Environment.NewLine + Environment.NewLine +
-            "Speaker identity tools can search/list/read/create/update/delete/merge identities, list/read/delete identity samples, and queue a sample for local playback." + Environment.NewLine + Environment.NewLine +
+            "Speaker identity tools can search/list/read/update/delete/merge identities, refuse sampleless identity creation, list/read/delete identity samples, and queue a sample for local playback. Do not delete the last sample from an identity; delete the identity instead." + Environment.NewLine + Environment.NewLine +
             "Workflow rules reference documentation:" + Environment.NewLine +
             "```markdown" + Environment.NewLine +
             docs.Trim() + Environment.NewLine +

MeetingAssistant/Workflow/WorkflowRulesEditorTools.cs

@@ -723,36 +723,14 @@ public sealed class WorkflowRulesEditorTools
         }
     }
 
-    public async Task<string> CreateIdentity(
+    public Task<string> CreateIdentity(
         string? canonicalName = null,
         string[]? aliases = null,
         string[]? candidateNames = null)
     {
-        var context = await CreatePreparedIdentityContextAsync(CancellationToken.None);
-        if (context is null)
-        {
-            return "Speaker identity database is not configured.";
-        }
-
-        await using (context)
-        {
-            var now = DateTimeOffset.UtcNow;
-            var identity = new SpeakerIdentity
-            {
-                CanonicalName = NormalizeNullable(canonicalName),
-                CreatedAt = now,
-                UpdatedAt = now,
-                Aliases = NormalizeNames(aliases)
-                    .Select(name => new SpeakerAlias { Name = name })
-                    .ToList(),
-                CandidateNames = NormalizeNames(candidateNames)
-                    .Select(name => new SpeakerCandidateName { Name = name })
-                    .ToList()
-            };
-            context.SpeakerIdentities.Add(identity);
-            await context.SaveChangesAsync();
-            return ToJson(ToIdentityDetail(identity));
-        }
+        return Task.FromResult(
+            "Refused: speaker identities require at least one audio sample. " +
+            "Use a speaker override from an existing transcript speaker sample, or update/merge an existing sampled identity.");
     }
 
     public async Task<string> UpdateIdentity(
@@ -902,6 +880,13 @@ public sealed class WorkflowRulesEditorTools
                 return $"Sample {sampleId} was not found.";
             }
 
+            var sampleCount = await context.SpeakerSnippets.CountAsync(candidate =>
+                candidate.SpeakerIdentityId == sample.SpeakerIdentityId);
+            if (sampleCount <= 1)
+            {
+                return $"Refused: sample {sampleId} is the last sample for identity {sample.SpeakerIdentityId}. Delete the identity instead.";
+            }
+
             context.SpeakerSnippets.Remove(sample);
             await context.SaveChangesAsync();
             return $"Deleted sample {sampleId}.";