Implement support for passing a session_id variable to scriptorium to support sticky routing

docs/config.md

@@ -225,7 +225,9 @@ For each `pipeline.scriptorium.artifacts.<name>`:
 | `output_path` | string | Conditional | required when enabled; also required when referenced by publish/output/input rules |
 | `timeout` | duration | No | artifact override |
 | `inputs` | map | No | input key names must be non-empty |
-| `vars` | map | No | values must be string or bool |
+| `vars` | map | No | values must be string or bool; `session_id` is reserved and overwritten by Narratio |
+
+Narratio adds `session_id=narratio-session-<session_id>` to every Scriptorium request for sticky upstream LLM routing. If an artifact config sets `vars.session_id`, Narratio replaces that value before invoking Scriptorium. Use a different variable name if a prompt needs the raw Narratio session ID as content.
 
 For each artifact input `pipeline.scriptorium.artifacts.<name>.inputs.<input_name>`:
 

docs/integrations/scriptorium.md

@@ -55,6 +55,7 @@ Render behavior:
 
 ## Deterministic Behavior
 - input and var maps are sorted into deterministic `--input` and `--var` CLI args.
+- stage wiring adds `session_id=narratio-session-<session_id>` to every Scriptorium request for sticky upstream routing, overriding any configured `vars.session_id`.
 - generated invocation YAML (`scriptorium.generated.v1`) is emitted when requested.
 - adapter is stateless and does not own artifact-selection policy.
 

internal/config/defaults.go

@@ -34,9 +34,11 @@ const (
 	DefaultAuditaTimeout = "3h"
 	DefaultAuditaReport  = true
 
-	DefaultScriptoriumBinary             = "scriptorium"
-	DefaultScriptoriumTimeout            = "10m"
-	DefaultScriptoriumArtifactOutputRoot = "artifacts"
+	DefaultScriptoriumBinary                 = "scriptorium"
+	DefaultScriptoriumTimeout                = "10m"
+	DefaultScriptoriumArtifactOutputRoot     = "artifacts"
+	DefaultScriptoriumStickySessionVarName   = "session_id"
+	DefaultScriptoriumStickySessionVarPrefix = "narratio-session-"
 
 	DefaultTrimEnabled                   = true
 	DefaultTrimOutputPath                = artifactmodel.TranscriptPathFinalTrimmed

internal/stage/analyze.go

@@ -347,6 +347,7 @@ func executeAnalyzeArtifact(
 	if err != nil {
 		return nil, fmt.Errorf("analyze: resolve vars for artifact %q: %w", artifactName, err)
 	}
+	vars = withScriptoriumStickySessionVar(vars, sessionID)
 
 	canonicalOutputPath, err := resolveScriptoriumOutputPath(paths, artifactCfg.OutputPath)
 	if err != nil {

internal/stage/analyze_test.go

@@ -54,6 +54,9 @@ func TestAnalyzeGeneratesSessionRecapFromTrimmedTranscript(t *testing.T) {
 	if req.Timeout != 2*time.Minute {
 		t.Fatalf("timeout = %s, want 2m", req.Timeout)
 	}
+	if req.Vars["session_id"] != "narratio-session-2026-05-03" {
+		t.Fatalf("session_id var = %q, want sticky narratio session id", req.Vars["session_id"])
+	}
 
 	if len(result.Outputs) != 1 || result.Outputs[0].Kind != "session_recap" {
 		t.Fatalf("outputs = %#v, want one session_recap output", result.Outputs)
@@ -69,6 +72,34 @@ func TestAnalyzeGeneratesSessionRecapFromTrimmedTranscript(t *testing.T) {
 	}
 }
 
+func TestAnalyzeStickySessionVarOverridesConfiguredAndPreservesArbitraryVars(t *testing.T) {
+	env, m, fake := setupAnalyzeEnv(t)
+	paths := sessionPathsForEnv(env, m.SessionID)
+	writeAnalyzeFile(t, filepath.Join(paths.TranscriptsDir, "final.trimmed.json"), `{"segments":[]}`)
+
+	artifact := env.Config.Pipeline.Scriptorium.Artifacts["session_recap"]
+	artifact.Vars = map[string]any{
+		"session_id":      "configured-session",
+		"character_name":  "Hrank",
+		"character_class": "Fighter",
+	}
+	env.Config.Pipeline.Scriptorium.Artifacts["session_recap"] = artifact
+
+	if _, err := (analyzeStage{}).Run(context.Background(), env, m); err != nil {
+		t.Fatalf("Run() error = %v", err)
+	}
+	req := fake.RunRequests[0]
+	if req.Vars["session_id"] != "narratio-session-2026-05-03" {
+		t.Fatalf("session_id var = %q, want sticky value", req.Vars["session_id"])
+	}
+	if req.Vars["character_name"] != "Hrank" {
+		t.Fatalf("character_name var = %q, want Hrank", req.Vars["character_name"])
+	}
+	if req.Vars["character_class"] != "Fighter" {
+		t.Fatalf("character_class var = %q, want Fighter", req.Vars["character_class"])
+	}
+}
+
 func TestAnalyzeRenderDebugFalseDoesNotCallRenderArtifact(t *testing.T) {
 	env, m, fake := setupAnalyzeEnv(t)
 	paths := sessionPathsForEnv(env, m.SessionID)
@@ -142,6 +173,12 @@ func TestAnalyzeRenderOutputPathIsRecorded(t *testing.T) {
 	if len(fake.RenderRequests) != 1 {
 		t.Fatalf("render requests = %d, want 1", len(fake.RenderRequests))
 	}
+	if fake.RenderRequests[0].Vars["session_id"] != "narratio-session-2026-05-03" {
+		t.Fatalf("render session_id var = %q, want sticky narratio session id", fake.RenderRequests[0].Vars["session_id"])
+	}
+	if fake.RunRequests[0].Vars["session_id"] != "narratio-session-2026-05-03" {
+		t.Fatalf("run session_id var = %q, want sticky narratio session id", fake.RunRequests[0].Vars["session_id"])
+	}
 	if result.Metadata["render_output_path"] != filepath.Join(paths.ArtifactsDir, "session_recap.render.json") {
 		t.Fatalf("render_output_path = %#v, want session_recap.render.json path", result.Metadata["render_output_path"])
 	}

internal/stage/scriptorium_vars.go

@@ -0,0 +1,21 @@
+package stage
+
+import (
+	"strings"
+
+	"gitea.maximumdirect.net/eric/narratio/internal/config"
+)
+
+func withScriptoriumStickySessionVar(vars map[string]string, sessionID string) map[string]string {
+	out := make(map[string]string, len(vars)+1)
+	for k, v := range vars {
+		out[k] = v
+	}
+	if trimmedSessionID := strings.TrimSpace(sessionID); trimmedSessionID != "" {
+		out[config.DefaultScriptoriumStickySessionVarName] = config.DefaultScriptoriumStickySessionVarPrefix + trimmedSessionID
+	}
+	if len(out) == 0 {
+		return nil
+	}
+	return out
+}

internal/stage/trim.go

@@ -150,7 +150,7 @@ func (trimStage) Run(ctx context.Context, env *Env, m *manifest.Manifest) (*Stag
 	inputPaths := map[string]string{
 		boundsCfg.TranscriptInputName: normalizedPath,
 	}
-	vars := map[string]string{}
+	vars := withScriptoriumStickySessionVar(nil, sessionID)
 
 	metadata["bounds_prompt_id"] = boundsCfg.PromptID
 	metadata["bounds_profile_id"] = boundsCfg.ProfileID

internal/stage/trim_test.go

@@ -34,6 +34,9 @@ func TestTrimStageConsumesNormalizedAndProducesTrimmedTranscript(t *testing.T) {
 	if len(scr.RunRequests) != 1 {
 		t.Fatalf("scriptorium run requests = %d, want 1", len(scr.RunRequests))
 	}
+	if scr.RunRequests[0].Vars["session_id"] != "narratio-session-2026-05-03" {
+		t.Fatalf("session_id var = %q, want sticky narratio session id", scr.RunRequests[0].Vars["session_id"])
+	}
 	if len(ser.TrimRequests) != 1 {
 		t.Fatalf("seriatim trim requests = %d, want 1", len(ser.TrimRequests))
 	}
@@ -129,6 +132,12 @@ func TestTrimStageRenderDebugDiagnosticsAreNotStageOutputs(t *testing.T) {
 	if len(scr.RenderRequests) != 1 {
 		t.Fatalf("scriptorium render requests = %d, want 1", len(scr.RenderRequests))
 	}
+	if scr.RenderRequests[0].Vars["session_id"] != "narratio-session-2026-05-03" {
+		t.Fatalf("render session_id var = %q, want sticky narratio session id", scr.RenderRequests[0].Vars["session_id"])
+	}
+	if scr.RunRequests[0].Vars["session_id"] != "narratio-session-2026-05-03" {
+		t.Fatalf("run session_id var = %q, want sticky narratio session id", scr.RunRequests[0].Vars["session_id"])
+	}
 	for _, out := range result.Outputs {
 		if out.Kind == "session_bounds_render" {
 			t.Fatalf("render diagnostics should not be stage outputs: %#v", result.Outputs)