feat(opencode): task signals — structured returns, terse completion, sparse context, wake-on-message

Four controls over what flows in and out of a Task dispatch, all defaulting
to today's behavior.

task_return lets a subagent set a free-form JSON result on its own session
row, delivered in the completion frame and on the task.completed event, so a
coordinator can read a machine result instead of parsing prose.

Terse completion replaces a background child's full completion body with a
digest plus a pointer to the child session, which stops large returns from
rewriting the parent's cache tail on every completion.

Sparse dispatch context drops global instruction files, the skills block, and
the MCP block, and skips assembling them rather than discarding the output.

Wake-on-message wakes an idle child to drain its inbox when a sibling or
coordinator message lands, budgeted per run and never waking a child whose
ancestor chain is gone.

Terse and sparse read from a task config family with precedence global →
project → agent frontmatter → dispatch param.

Author: iceteaSA

packages/core/schema.json

@@ -1,9 +1,9 @@
 {
   "version": "7",
   "dialect": "sqlite",
-  "id": "d3f3a5db-0f01-49de-827d-cce528d30460",
+  "id": "e6ecea79-5939-40bd-9e2d-606016753258",
   "prevIds": [
-    "f14a9b18-8207-487e-a3d3-227e629ba9ad"
+    "b1dd5863-f1ea-4f16-8aac-0134c692891c"
   ],
   "ddl": [
     {
@@ -1384,6 +1384,16 @@
       "entityType": "columns",
       "table": "session"
     },
+    {
+      "type": "text",
+      "notNull": false,
+      "autoincrement": false,
+      "default": null,
+      "generated": null,
+      "name": "result",
+      "entityType": "columns",
+      "table": "session"
+    },
     {
       "type": "real",
       "notNull": true,
@@ -1524,6 +1534,16 @@
       "entityType": "columns",
       "table": "session"
     },
+    {
+      "type": "text",
+      "notNull": false,
+      "autoincrement": false,
+      "default": null,
+      "generated": null,
+      "name": "context_mode",
+      "entityType": "columns",
+      "table": "session"
+    },
     {
       "type": "text",
       "notNull": true,

packages/core/src/database/migration.gen.ts

@@ -0,0 +1,11 @@
+import { Effect } from "effect"
+import type { DatabaseMigration } from "../migration"
+
+export default {
+  id: "20260705045947_productive_masque",
+  up(tx) {
+    return Effect.gen(function* () {
+      yield* tx.run(`ALTER TABLE \`session\` ADD \`result\` text;`)
+    })
+  },
+} satisfies DatabaseMigration.Migration

packages/core/src/database/migration/20260705045947_productive_masque.ts

@@ -0,0 +1,11 @@
+import { Effect } from "effect"
+import type { DatabaseMigration } from "../migration"
+
+export default {
+  id: "20260705061319_silly_the_hood",
+  up(tx) {
+    return Effect.gen(function* () {
+      yield* tx.run(`ALTER TABLE \`session\` ADD \`context_mode\` text;`)
+    })
+  },
+} satisfies DatabaseMigration.Migration

packages/core/src/database/migration/20260705061319_silly_the_hood.ts

@@ -224,6 +224,7 @@ export default {
           \`summary_files\` integer,
           \`summary_diffs\` text,
           \`metadata\` text,
+          \`result\` text,
           \`cost\` real DEFAULT 0 NOT NULL,
           \`tokens_input\` integer DEFAULT 0 NOT NULL,
           \`tokens_output\` integer DEFAULT 0 NOT NULL,
@@ -238,6 +239,7 @@ export default {
           \`time_updated\` integer NOT NULL,
           \`time_compacting\` integer,
           \`time_archived\` integer,
+          \`context_mode\` text,
           CONSTRAINT \`fk_session_project_id_project_id_fk\` FOREIGN KEY (\`project_id\`) REFERENCES \`project\`(\`id\`) ON DELETE CASCADE
         );
       `)

packages/core/src/database/schema.gen.ts

@@ -41,6 +41,8 @@ export function fromRow(row: typeof SessionTable.$inferSelect): SessionSchema.In
     }),
     subpath: row.path ? RelativePath.make(row.path) : undefined,
     revert: row.revert ? { ...row.revert, messageID: SessionMessage.ID.make(row.revert.messageID) } : undefined,
+    result: row.result ?? undefined,
+    contextMode: row.context_mode ?? undefined,
     time: {
       created: DateTime.makeUnsafe(row.time_created),
       updated: DateTime.makeUnsafe(row.time_updated),

packages/core/src/session/info.ts

@@ -60,6 +60,7 @@ function sessionRow(info: SessionV1.SessionInfo): typeof SessionTable.$inferInse
     summary_files: info.summary?.files,
     summary_diffs: info.summary?.diffs ? [...info.summary.diffs] : undefined,
     metadata: info.metadata,
+    result: info.result,
     cost: info.cost ?? 0,
     tokens_input: (info.tokens ?? { input: 0 }).input,
     tokens_output: (info.tokens ?? { output: 0 }).output,
@@ -72,6 +73,7 @@ function sessionRow(info: SessionV1.SessionInfo): typeof SessionTable.$inferInse
     time_updated: info.time.updated,
     time_compacting: info.time.compacting,
     time_archived: info.time.archived,
+    context_mode: info.contextMode,
   }
 }
 

packages/core/src/session/projector.ts

@@ -40,6 +40,7 @@ export const SessionTable = sqliteTable(
     summary_files: integer(),
     summary_diffs: text({ mode: "json" }).$type<Snapshot.LegacyFileDiff[]>(),
     metadata: text({ mode: "json" }).$type<Record<string, unknown>>(),
+    result: text({ mode: "json" }).$type<Record<string, unknown>>(),
     cost: real().notNull().default(0),
     tokens_input: integer().notNull().default(0),
     tokens_output: integer().notNull().default(0),
@@ -57,6 +58,7 @@ export const SessionTable = sqliteTable(
     ...Timestamps,
     time_compacting: integer(),
     time_archived: integer(),
+    context_mode: text().$type<"full" | "sparse">(),
   },
   (table) => [
     index("session_project_idx").on(table.project_id),

packages/core/src/session/sql.ts

@@ -35,6 +35,12 @@ const AgentSchema = Schema.StructWithRest(
       description: "Maximum number of agentic iterations before forcing text-only response",
     }),
     maxSteps: Schema.optional(PositiveInt).annotate({ description: "@deprecated Use 'steps' field instead." }),
+    completion: Schema.optional(Schema.Literals(["full", "terse"])).annotate({
+      description: "Completion display mode for task dispatches from this agent (default: full)",
+    }),
+    context: Schema.optional(Schema.Literals(["full", "sparse"])).annotate({
+      description: "Context display mode for task dispatches from this agent (default: full)",
+    }),
     permission: Schema.optional(ConfigPermissionV1.Info),
   }),
   [Schema.Record(Schema.String, Schema.Any)],
@@ -57,6 +63,8 @@ const KNOWN_KEYS = new Set([
   "permission",
   "disable",
   "tools",
+  "completion",
+  "context",
 ])
 
 const normalize = (agent: Schema.Schema.Type<typeof AgentSchema>): Schema.Schema.Type<typeof AgentSchema> => {

packages/core/src/v1/config/agent.ts

@@ -166,6 +166,16 @@ export const Info = Schema.Struct({
       }),
     }),
   ),
+  task: Schema.optional(
+    Schema.Struct({
+      completion: Schema.optional(Schema.Literals(["full", "terse"])).annotate({
+        description: "Completion display mode for task dispatches (default: full)",
+      }),
+      context: Schema.optional(Schema.Literals(["full", "sparse"])).annotate({
+        description: "Context display mode for task dispatches (default: full)",
+      }),
+    }),
+  ).annotate({ description: "Task dispatch configuration" }),
   experimental: Schema.optional(
     Schema.Struct({
       disable_paste_summary: Schema.optional(Schema.Boolean),