Name agents by their first prompt line instead of an LLM summary (#1563)

* Name agents by their first prompt line instead of an LLM summary

The workspace title already captures the task; the LLM-generated agent
title just restated the same prompt. Drop the generator and keep the
provisional title (first prompt line), so the agent label stays
deterministic and explicit titles still win.

* Remove the no-op agent-title setting and leftover generator plumbing

Deleting the agent-title generator left its whole surface dangling: a
configurable "Agent titles" project setting that no longer did anything,
dead create-path plumbing, generator-only import/MCP deps, and the mock
provider's agent-title parser. Remove all of it, plus a dead test mock
and timing sleeps that guarded the deleted background job. Replace them
with a no-mock lifecycle test asserting the title stays the first prompt
line across create and settle.

Old paseo.json files with metadataGeneration.agentTitle still parse via
schema passthrough — see COMPAT(projectMetadataAgentTitle).

packages/protocol/src/agent-title-limits.ts

@@ -1,2 +1 @@
 export const MAX_EXPLICIT_AGENT_TITLE_CHARS = 200;
-export const MAX_AUTO_AGENT_TITLE_CHARS = 40;

packages/protocol/src/paseo-config-schema.test.ts

@@ -37,7 +37,6 @@ describe("paseo config schema", () => {
     expect(
       PaseoConfigSchema.parse({
         metadataGeneration: {
-          agentTitle: { instructions: "Use concise titles." },
           branchName: { instructions: "Prefix branches with feat/." },
           commitMessage: { instructions: "Use imperative mood." },
           pullRequest: { instructions: "Include risk notes." },
@@ -45,7 +44,6 @@ describe("paseo config schema", () => {
       }),
     ).toEqual({
       metadataGeneration: {
-        agentTitle: { instructions: "Use concise titles." },
         branchName: { instructions: "Prefix branches with feat/." },
         commitMessage: { instructions: "Use imperative mood." },
         pullRequest: { instructions: "Include risk notes." },
@@ -56,29 +54,40 @@ describe("paseo config schema", () => {
   it("parses partial metadata generation instructions with missing entries undefined", () => {
     const parsed = PaseoConfigSchema.parse({
       metadataGeneration: {
-        agentTitle: { instructions: "Keep it short." },
+        branchName: { instructions: "Keep it short." },
       },
     });
 
     expect(parsed.metadataGeneration).toEqual({
-      agentTitle: { instructions: "Keep it short." },
+      branchName: { instructions: "Keep it short." },
     });
-    expect(parsed.metadataGeneration?.branchName).toBeUndefined();
     expect(parsed.metadataGeneration?.commitMessage).toBeUndefined();
     expect(parsed.metadataGeneration?.pullRequest).toBeUndefined();
   });
 
+  it("preserves legacy agentTitle metadata instructions as passthrough", () => {
+    expect(
+      PaseoConfigSchema.parse({
+        metadataGeneration: {
+          agentTitle: { instructions: "Use concise titles." },
+        },
+      }),
+    ).toEqual({
+      metadataGeneration: {
+        agentTitle: { instructions: "Use concise titles." },
+      },
+    });
+  });
+
   it("passes through unknown metadata generation fields", () => {
     expect(
       PaseoConfigSchema.parse({
         metadataGeneration: {
-          agentTitle: { instructions: "Use concise titles." },
           futureField: 42,
         },
       }),
     ).toEqual({
       metadataGeneration: {
-        agentTitle: { instructions: "Use concise titles." },
         futureField: 42,
       },
     });
@@ -88,7 +97,7 @@ describe("paseo config schema", () => {
     expect(
       PaseoConfigSchema.parse({
         metadataGeneration: {
-          agentTitle: {
+          branchName: {
             instructions: "Use concise titles.",
             model: "haiku",
           },
@@ -96,7 +105,7 @@ describe("paseo config schema", () => {
       }),
     ).toEqual({
       metadataGeneration: {
-        agentTitle: {
+        branchName: {
           instructions: "Use concise titles.",
           model: "haiku",
         },
@@ -108,17 +117,17 @@ describe("paseo config schema", () => {
     expect(
       PaseoConfigSchema.parse({
         metadataGeneration: {
-          agentTitle: { instructions: 42 },
+          branchName: { instructions: 42 },
         },
       }),
     ).toEqual({
       metadataGeneration: {
-        agentTitle: {},
+        branchName: {},
       },
     });
   });
 
-  it("raw schema preserves old-style config while accepting metadata generation", () => {
+  it("raw schema preserves old-style config while accepting legacy agentTitle", () => {
     const config = {
       worktree: {
         setup: "npm install",
@@ -132,6 +141,7 @@ describe("paseo config schema", () => {
       },
       metadataGeneration: {
         agentTitle: { instructions: "Use concise titles." },
+        branchName: { instructions: "Use concise branches." },
       },
     };
 
@@ -142,12 +152,12 @@ describe("paseo config schema", () => {
     expect(
       PaseoConfigRawSchema.parse({
         metadataGeneration: {
-          agentTitle: { instructions: 42 },
+          branchName: { instructions: 42 },
         },
       }),
     ).toEqual({
       metadataGeneration: {
-        agentTitle: {},
+        branchName: {},
       },
     });
   });

packages/protocol/src/paseo-config-schema.ts

@@ -39,11 +39,12 @@ export const PaseoMetadataGenerationEntrySchema = z
 
 export const PaseoMetadataGenerationSchema = z
   .object({
-    agentTitle: PaseoMetadataGenerationEntrySchema.optional(),
     branchName: PaseoMetadataGenerationEntrySchema.optional(),
     commitMessage: PaseoMetadataGenerationEntrySchema.optional(),
     pullRequest: PaseoMetadataGenerationEntrySchema.optional(),
   })
+  // COMPAT(projectMetadataAgentTitle): `agentTitle` project metadata prompts were removed
+  // in v0.1.96; keep legacy paseo.json parseable until 2026-12-16.
   .passthrough()
   .catch({});