fix(kernel,inference): reliable artifact emission for local models

Two fixes that together let the freestyle analyst/architect stages actually
produce valid artifacts on a local model (verified end-to-end: analyst passed
first try, architect produced a validated plan):

1. Tools-less final emission (SessionOrchestrator): producing the artifact
   while tools are in the request is unreliable — llama.cpp's Gemma template
   switches to a channel format and leaks <|channel> markers into the text, and
   models keep tool-calling until the round cap without ever emitting. After the
   tool loop, fire ONE tools-less inference to get clean JSON (also re-enables
   the JSON grammar, since grammar+tools is rejected). Gated on the artifact not
   already being produced via emit_artifact.

2. GBNF grammar handles arrays/objects (GbnfGrammarConverter): array-typed
   properties fell through to a 'string' rule, so the grammar forced a string
   where the schema demanded an array — an unwinnable grammar-vs-validator
   disagreement. Add generic value/object/array rules and map types correctly.

Note: also needs schema 'items' on array props (runtime schemas updated; mirror
to repo schemas/*.json).

core/kernel/src/main/kotlin/com/correx/core/kernel/orchestration/ReplayOrchestrator.kt

@@ -182,6 +182,7 @@ class ReplayOrchestrator(
         timeoutMs: Long,
         responseFormat: ResponseFormat,
         effectives: RunEffectives,
+        withTools: Boolean,
     ): InferenceResult = when (strategy) {
         is ReplayStrategy.SkipInference -> {
             // bypass router entirely — use recorded artifact
@@ -210,7 +211,9 @@ class ReplayOrchestrator(
                     },
                 )
         }
-        else -> super.runInference(sessionId, stageId, contextPack, stageConfig, timeoutMs, responseFormat, effectives)
+        else -> super.runInference(
+            sessionId, stageId, contextPack, stageConfig, timeoutMs, responseFormat, effectives, withTools,
+        )
     }
 
     override suspend fun mapValidationOutcome(

core/kernel/src/main/kotlin/com/correx/core/kernel/orchestration/SessionOrchestrator.kt

@@ -606,6 +606,40 @@ abstract class SessionOrchestrator(
             )
             toolRounds++
         }
+        // Final clean emission. Producing the artifact while tools are in the request is unreliable on
+        // some local chat templates (Gemma leaks `<|channel>` markers into the text; other models keep
+        // tool-calling until the round cap and never emit). For an LLM-emitted stage that hasn't already
+        // produced its artifact via the emit_artifact tool, fire ONE tools-less inference — verified to
+        // yield clean JSON deterministically. Skipped when the model already emitted clean final text.
+        if (inferenceResult is InferenceResult.Success && llmEmittedSlots.isNotEmpty() && llmArtifactOverride == null) {
+            val last = inferenceResult.response
+            val needsCleanEmission = last.finishReason is FinishReason.ToolCall ||
+                last.text.isBlank() || last.text.contains("<|channel")
+            if (needsCleanEmission && !isCancelled(sessionId)) {
+                val nudge = "Stop calling tools. Output the required '${llmEmittedSlots.first().name.value}' " +
+                    "artifact now as a single JSON object matching the schema — no tool calls, no commentary."
+                accumulatedEntries = accumulatedEntries + ContextEntry(
+                    id = ContextEntryId(UUID.randomUUID().toString()),
+                    layer = ContextLayer.L2,
+                    sourceType = "toolResult",
+                    sourceId = UUID.randomUUID().toString(),
+                    content = nudge,
+                    tokenEstimate = estimateTokens(nudge),
+                    role = EntryRole.TOOL,
+                )
+                currentContext = contextPackBuilder.build(
+                    id = ContextPackId(UUID.randomUUID().toString()),
+                    sessionId = sessionId,
+                    stageId = stageId,
+                    entries = accumulatedEntries,
+                    budget = TokenBudget(limit = stageConfig.tokenBudget),
+                )
+                inferenceResult = runInference(
+                    sessionId, stageId, currentContext, stageConfig, config.stageTimeoutMs,
+                    responseFormat, effectives, withTools = false,
+                )
+            }
+        }
         return when (inferenceResult) {
             is InferenceResult.Cancelled -> StageExecutionResult.Failure("CANCELLED", retryable = false)
             is InferenceResult.Failed ->
@@ -1853,12 +1887,17 @@ abstract class SessionOrchestrator(
         timeoutMs: Long,
         responseFormat: ResponseFormat = ResponseFormat.Text,
         effectives: RunEffectives = RunEffectives(toolRegistry, toolExecutor, workspacePolicy),
+        // When false, send NO tools. Some local chat templates (e.g. llama.cpp's Gemma) switch to a
+        // tool-calling/reasoning-channel format when tools are present and leak `<|channel>` markers
+        // into the artifact text; a tools-less call yields clean JSON deterministically (and lets the
+        // JSON grammar constraint re-apply, since grammar+tools is rejected by llama.cpp).
+        withTools: Boolean = true,
     ): InferenceResult {
         // A stage that grants tools needs a tool-calling model, so request ToolCalling on top of any
         // declared capabilities — the capability-aware strategy then ranks eligible providers by their
         // ToolCalling score and routes the stage to the best tool-caller.
         val requiredCapabilities = stageConfig.requiredCapabilities +
-            if (stageConfig.allowedTools.isNotEmpty()) setOf(ModelCapability.ToolCalling) else emptySet()
+            if (withTools && stageConfig.allowedTools.isNotEmpty()) setOf(ModelCapability.ToolCalling) else emptySet()
         val provider = inferenceRouter.route(stageId, requiredCapabilities, stageConfig.modelId)
         log.debug(
             "[Orchestrator] inference session={} stage={} provider={} timeoutMs={}",
@@ -1872,28 +1911,32 @@ abstract class SessionOrchestrator(
             contextPack = contextPack,
             generationConfig = stageConfig.generationConfig,
             responseFormat = responseFormat,
-            tools = stageConfig.allowedTools
-                .mapNotNull { effectives.registry?.resolve(it) }
-                .filter { tool ->
-                    // ponytail: filter write tools while read-before-write block is active; restored once a read completes
-                    !isReadOnlyMode(sessionId) || ToolCapability.FILE_WRITE !in tool.requiredCapabilities
-                }
-                .map { tool ->
-                    ToolDefinition(
+            tools = if (!withTools) {
+                emptyList()
+            } else {
+                stageConfig.allowedTools
+                    .mapNotNull { effectives.registry?.resolve(it) }
+                    .filter { tool ->
+                        // ponytail: filter write tools while read-before-write block is active; restored once a read completes
+                        !isReadOnlyMode(sessionId) || ToolCapability.FILE_WRITE !in tool.requiredCapabilities
+                    }
+                    .map { tool ->
+                        ToolDefinition(
+                            function = ToolFunction(
+                                name = tool.name,
+                                description = tool.description,
+                                parameters = tool.parametersSchema,
+                            ),
+                        )
+                    } + ToolDefinition(
                         function = ToolFunction(
-                            name = tool.name,
-                            description = tool.description,
-                            parameters = tool.parametersSchema,
+                            name = STAGE_COMPLETE_TOOL,
+                            description = "Call this tool when the stage's goal is fully met and no further tool calls are needed. " +
+                                    "The orchestrator will proceed to the next stage.",
+                            parameters = JsonObject(emptyMap()),
                         ),
-                    )
-                } + ToolDefinition(
-                    function = ToolFunction(
-                        name = STAGE_COMPLETE_TOOL,
-                        description = "Call this tool when the stage's goal is fully met and no further tool calls are needed. " +
-                                "The orchestrator will proceed to the next stage.",
-                        parameters = JsonObject(emptyMap()),
-                    ),
-                ) + emitArtifactTool(stageConfig),
+                    ) + emitArtifactTool(stageConfig)
+            },
         )
 
         val renderedMessages = PromptRenderer.render(contextPack)

infrastructure/inference/llama_cpp/src/main/kotlin/com/correx/infrastructure/inference/llama/cpp/GbnfGrammarConverter.kt

@@ -19,7 +19,17 @@ internal object GbnfGrammarConverter {
         val escapeSeq = """"\\" (["\\/bfnrt] | $unicodeEscape)"""
         val stringRule = """string ::= "\"" ($charClass | $escapeSeq)* $closingQuote"""
         sb.appendLine(stringRule)
-        sb.appendLine("""number ::= "-"? [0-9]+""")
+        sb.appendLine("""number ::= "-"? [0-9]+ ("." [0-9]+)?""")
+        sb.appendLine("""boolean ::= "true" | "false"""")
+        sb.appendLine("""null   ::= "null"""")
+        // Generic JSON value/object/array rules so non-scalar properties are constrained to the right
+        // JSON shape. Without these, an `array` property fell through to `string`, so the grammar forced
+        // the model to emit a string where the schema (and post-hoc validation) demand an array — an
+        // unwinnable disagreement. Element/field *types* are left to schema validation; the grammar only
+        // enforces the JSON shape (brackets/braces).
+        sb.appendLine("""value  ::= string | number | boolean | null | object | array""")
+        sb.appendLine("""object ::= "{" ws (string ws ":" ws value (ws "," ws string ws ":" ws value)*)? ws "}"""")
+        sb.appendLine("""array  ::= "[" ws (value (ws "," ws value)*)? ws "]"""")
 
         // Build members rule:
         // - Required keys are always present, joined by commas.
@@ -58,7 +68,14 @@ internal object GbnfGrammarConverter {
     }
 
     private fun valueRuleFor(schema: JsonSchema, key: String): String {
-        val prop = schema.properties[key] ?: return "string"
-        return if (prop.type == "integer") "number" else "string"
+        val prop = schema.properties[key] ?: return "value"
+        return when (prop.type) {
+            "integer", "number" -> "number"
+            "boolean" -> "boolean"
+            "array" -> "array"
+            "object" -> "object"
+            "string" -> "string"
+            else -> "value"
+        }
     }
 }

infrastructure/inference/llama_cpp/src/test/kotlin/com/correx/infrastructure/inference/llama/cpp/GbnfGrammarConverterTest.kt

@@ -40,10 +40,31 @@ class GbnfGrammarConverterTest {
         required = emptyList(),
     )
 
+    @Test
+    fun `array property maps to the array rule, not string`() {
+        // Regression: an array-typed property used to fall through to `string`, so the grammar forced
+        // a string where the schema demands an array (analysis.requirements). It must map to `array`.
+        val schema = JsonSchema(
+            type = "object",
+            properties = mapOf(
+                "summary" to JsonSchemaProperty(type = "string"),
+                "requirements" to JsonSchemaProperty(type = "array", items = JsonSchemaProperty(type = "string")),
+            ),
+            required = listOf("summary", "requirements"),
+        )
+        val grammar = GbnfGrammarConverter.convert(schema)
+        assertTrue(grammar.contains("array  ::="), "grammar must declare an array rule")
+        val reqLine = grammar.lineSequence().first { it.contains("\\\"requirements\\\"") }
+        assertTrue(reqLine.trimEnd().endsWith("array"), "requirements must use the array rule, was: $reqLine")
+    }
+
     @Test
     fun `string rule does not contain quoted character class`() {
         val grammar = GbnfGrammarConverter.convert(allRequiredSchema)
-        assertFalse(grammar.contains("\"["), "string rule must not contain quoted character class (\"[)")
+        // Guard the original bug: the `string` rule's char class must stay unquoted. The `array` rule
+        // legitimately contains a quoted "[" literal, so scope the assertion to the string rule line.
+        val stringRuleLine = grammar.lineSequence().first { it.trimStart().startsWith("string ::=") }
+        assertFalse(stringRuleLine.contains("\"["), "string rule must not contain quoted character class (\"[)")
     }
 
     @Test