diff --git a/.changeset/spawn-model-picker.md b/.changeset/spawn-model-picker.md
new file mode 100644
index 0000000..010d0cb
--- /dev/null
+++ b/.changeset/spawn-model-picker.md
@@ -0,0 +1,5 @@
+---
+"@jmfederico/pi-web": patch
+---
+
+Let agents pick a model when delegating work: `spawn_session` and `spawn_subsession` accept an optional `model` parameter as an exact `provider/model-id` (an unknown value is rejected; omitting it keeps the inherited model). In the chat composer, typing `#` opens a model completion menu that inserts a `#provider/model-id` reference into the draft, which agents forward as that parameter.
diff --git a/docs/config.html b/docs/config.html
index 47b2dfd..17314f4 100644
--- a/docs/config.html
+++ b/docs/config.html
@@ -103,6 +103,7 @@
Model catalog refresh
Session tools
Extension dialogs
+ Prompt completions
Completion tools
@@ -805,6 +806,15 @@
available when the child stops. Included output and transcripts follow a labeled marker and come last,
after PI WEB guidance.
+
+ Both spawn_session and spawn_subsession accept an optional
+ model parameter, given as an exact provider/model-id such as
+ anthropic/claude-sonnet-4-5. When set, the new session starts on that model instead of
+ inheriting the dispatching session's model. The match is strict: an unknown or malformed value is
+ rejected with an error. A #provider/model-id reference in the prompt (see
+ Prompt completions) is how users ask for a specific model; agents
+ forward that reference as this parameter.
+
In Settings → Session daemon, these keys are saved on the selected machine. Restart the
session daemon on that machine after changing them.
@@ -879,6 +889,25 @@
+
+ Prompt completions
+ The chat composer opens completion menus on three trigger characters:
+
+ / at the very start of the draft completes session commands.
+ -
+
@ completes file paths: @ for tracked files, @ (at, then
+ space) or !@ for all files. Picking one inserts an @path reference into the
+ draft, quoted automatically when the path contains spaces.
+
+ -
+
# completes the models available to the session, filtered case-insensitively as you type
+ (at most 12 entries). Picking one inserts a #provider/model-id reference into the draft,
+ which tells agents the request should run on that model — for example as the model
+ parameter of spawn_session.
+
+
+
+
Optional completion tools
diff --git a/docs/config.md b/docs/config.md
index 515f912..e9d7fe8 100644
--- a/docs/config.md
+++ b/docs/config.md
@@ -273,6 +273,8 @@ A completion notice wakes an idle parent or queues behind in-flight work. Each n
`list_subsessions`, `check_subsession`, and `read_subsession` never yield or change control flow. They are for deliberate inspection or recovery, not completion polling. While a child works, agent-facing `check_subsession` and `read_subsession` withhold partial output and direct the parent to continue independent work or yield at the join point. Output becomes available when the child stops. Included output and transcripts follow a labeled marker and come last, after PI WEB guidance.
+Both `spawn_session` and `spawn_subsession` accept an optional `model` parameter, given as an exact `provider/model-id` such as `anthropic/claude-sonnet-4-5`. When set, the new session starts on that model instead of inheriting the dispatching session's model. The match is strict: an unknown or malformed value is rejected with an error. A `#provider/model-id` reference in the prompt (see [Prompt completions](#prompt-completions)) is how users ask for a specific model; agents forward that reference as this parameter.
+
In **Settings → Session daemon**, these keys are saved on the selected machine. Restart the session daemon on that machine after changing them.
#### `askUser` and `ask_user`
@@ -331,6 +333,14 @@ Shortcut values are keyed by action id. Values are shortcut strings such as `mod
Prefer Settings → Keyboard for editing shortcuts interactively.
+## Prompt completions
+
+The chat composer opens completion menus on three trigger characters:
+
+- `/` at the very start of the draft completes session commands.
+- `@` completes file paths: `@` for tracked files, `@ ` (at, then space) or `!@` for all files. Picking one inserts an `@path` reference into the draft, quoted automatically when the path contains spaces.
+- `#` completes the models available to the session, filtered case-insensitively as you type (at most 12 entries). Picking one inserts a `#provider/model-id` reference into the draft, which tells agents the request should run on that model — for example as the `model` parameter of `spawn_session`.
+
## Optional completion tools
File and path `@` completions work without extra tools. If `fzf` is available on the PI WEB server's `PATH`, PI WEB uses it to improve completion filtering/ranking; otherwise it falls back to built-in ranking.
diff --git a/src/client/src/components/PromptEditor.modelCompletion.test.ts b/src/client/src/components/PromptEditor.modelCompletion.test.ts
new file mode 100644
index 0000000..9a15f91
--- /dev/null
+++ b/src/client/src/components/PromptEditor.modelCompletion.test.ts
@@ -0,0 +1,81 @@
+import { afterEach, describe, expect, it, vi } from "vitest";
+import { api, type SessionModel } from "../api";
+import { PromptEditor } from "./PromptEditor";
+
+const sonnet: SessionModel = { provider: "anthropic", id: "claude-sonnet-4-5", name: "Claude Sonnet 4.5" };
+const gpt: SessionModel = { provider: "openai", id: "gpt-5.2" };
+
+afterEach(() => {
+ vi.restoreAllMocks();
+});
+
+describe("PromptEditor model completions", () => {
+ it("requests models for the session and maps a # token to model completions", async () => {
+ const models = vi.spyOn(api, "models").mockResolvedValue({ models: [sonnet, gpt] });
+ const editor = new PromptEditor();
+ editor.sessionId = "session-1";
+ editor.cwd = "/repo";
+ editor.machineId = "remote-a";
+
+ await refreshCompletions(editor, "please use #cla");
+
+ expect(models).toHaveBeenCalledWith({ id: "session-1", cwd: "/repo" }, "remote-a");
+ expect(currentCompletions(editor)).toEqual([
+ { kind: "model", replaceFrom: 11, replaceTo: 15, insertText: "#anthropic/claude-sonnet-4-5", detail: "anthropic", description: "Claude Sonnet 4.5" },
+ ]);
+ expect(Reflect.get(editor, "selectedIndex")).toBe(0);
+ });
+
+ it("lists every model for a bare # token", async () => {
+ vi.spyOn(api, "models").mockResolvedValue({ models: [sonnet, gpt] });
+ const editor = new PromptEditor();
+ editor.sessionId = "session-1";
+ editor.cwd = "/repo";
+
+ await refreshCompletions(editor, "#");
+
+ expect(currentCompletions(editor)).toEqual([
+ { kind: "model", replaceFrom: 0, replaceTo: 1, insertText: "#anthropic/claude-sonnet-4-5", detail: "anthropic", description: "Claude Sonnet 4.5" },
+ { kind: "model", replaceFrom: 0, replaceTo: 1, insertText: "#openai/gpt-5.2", detail: "openai" },
+ ]);
+ });
+
+ it("clears completions when the models request fails", async () => {
+ vi.spyOn(api, "models").mockRejectedValue(new Error("models unavailable"));
+ const editor = new PromptEditor();
+ editor.sessionId = "session-1";
+ editor.cwd = "/repo";
+
+ await refreshCompletions(editor, "#cla");
+
+ expect(currentCompletions(editor)).toEqual([]);
+ });
+
+ it("does not request models without session context", async () => {
+ const models = vi.spyOn(api, "models").mockResolvedValue({ models: [sonnet] });
+ const editor = new PromptEditor();
+
+ await refreshCompletions(editor, "#cla");
+
+ expect(models).not.toHaveBeenCalled();
+ expect(currentCompletions(editor)).toEqual([]);
+ });
+});
+
+// refreshCompletions is private and driven by CodeMirror updates in production;
+// invoking it through Reflect mirrors the PromptEditor.draft.test.ts seam and
+// keeps the wiring test at the component boundary without a DOM harness.
+async function refreshCompletions(editor: PromptEditor, draft: string): Promise {
+ Reflect.set(editor, "draft", draft);
+ const refresh: unknown = Reflect.get(editor, "refreshCompletions");
+ if (!isRefreshCompletions(refresh)) throw new Error("PromptEditor.refreshCompletions is not callable");
+ await refresh.call(editor);
+}
+
+function isRefreshCompletions(value: unknown): value is (this: PromptEditor) => Promise {
+ return typeof value === "function";
+}
+
+function currentCompletions(editor: PromptEditor): unknown {
+ return Reflect.get(editor, "completions");
+}
diff --git a/src/client/src/components/PromptEditor.ts b/src/client/src/components/PromptEditor.ts
index d504c40..68f7493 100644
--- a/src/client/src/components/PromptEditor.ts
+++ b/src/client/src/components/PromptEditor.ts
@@ -5,12 +5,12 @@ import { EditorView, keymap, placeholder } from "@codemirror/view";
import { defaultHighlightStyle, indentOnInput, indentUnit, syntaxHighlighting } from "@codemirror/language";
import { LitElement, html, type PropertyValues } from "lit";
import { customElement, property, query, state } from "lit/decorators.js";
-import { api, type FileSuggestion, type PromptAttachment, type SessionStatus, type SlashCommand } from "../api";
+import { api, type FileSuggestion, type PromptAttachment, type SessionModel, type SessionStatus, type SlashCommand } from "../api";
import type { PromptAttachmentDelivery } from "../../../shared/apiTypes";
import { capturePromptAttachments, effectivePromptAttachmentDelivery, isInlinePromptAttachment, promptAttachmentsCanUseInlineDelivery, type CapturedAttachment } from "../promptAttachmentCapture";
import { inputModeForDraft, inputModesEqual, type InputMode } from "../inputModes";
import { machineSessionKey } from "../machineKeys";
-import { detectPromptCompletionTrigger, fileCompletionInsertText, type PromptCompletionTrigger } from "../promptCompletions";
+import { detectPromptCompletionTrigger, fileCompletionInsertText, modelCompletionChoices, type PromptCompletionTrigger } from "../promptCompletions";
import { clearDraft, loadDraft, saveDraft } from "../promptDraftStorage";
import { loadAttachmentDelivery, saveAttachmentDelivery } from "../attachmentPreferences";
import { createMobilePromptEnterMedia, readPromptEnterPreference, shouldSendPromptOnEnterShortcut, shouldUsePromptEnterShiftShortcut } from "../promptEnterBehavior";
@@ -283,7 +283,7 @@ export class PromptEditor extends LitElement {
keyup: (event) => this.handleEditorKeyUp(event),
blur: () => this.resetEditorModifierState(),
}),
- placeholder("Message pi... Use / for commands, @ for tracked files, @ space for all files"),
+ placeholder("Message pi... Use / for commands, @ for tracked files, @ space for all files, # for models"),
this.editableCompartment.of(EditorView.editable.of(!this.disabled)),
this.readOnlyCompartment.of(EditorState.readOnly.of(this.disabled)),
EditorView.updateListener.of((update) => {
@@ -372,6 +372,15 @@ export class PromptEditor extends LitElement {
...(file.path.endsWith("/") && insertText.endsWith("\"") ? { cursorOffset: insertText.length - 1 } : {}),
};
});
+ } else if (trigger.kind === "model" && this.sessionId !== undefined && this.sessionId !== "" && this.cwd !== undefined && this.cwd !== "") {
+ const models = await api.models({ id: this.sessionId, cwd: this.cwd }, this.machineId).then((response) => response.models).catch(emptySessionModels);
+ if (version !== this.requestVersion) return;
+ this.completions = modelCompletionChoices(models, trigger.query).map((choice) => ({
+ kind: "model",
+ replaceFrom: trigger.from,
+ replaceTo: trigger.to,
+ ...choice,
+ }));
}
}
@@ -516,6 +525,10 @@ function emptyFileSuggestions(): FileSuggestion[] {
return [];
}
+function emptySessionModels(): SessionModel[] {
+ return [];
+}
+
function filesFromDataTransfer(data: DataTransfer | null): File[] {
if (data === null) return [];
return Array.from(data.files);
diff --git a/src/client/src/components/shared.ts b/src/client/src/components/shared.ts
index 41b93c4..67d48f3 100644
--- a/src/client/src/components/shared.ts
+++ b/src/client/src/components/shared.ts
@@ -72,7 +72,7 @@ export interface ChatLine {
}
export interface CompletionItem {
- kind: "command" | "file";
+ kind: "command" | "file" | "model";
replaceFrom: number;
replaceTo: number;
insertText: string;
diff --git a/src/client/src/inputModes.test.ts b/src/client/src/inputModes.test.ts
index 20e84df..ac0380f 100644
--- a/src/client/src/inputModes.test.ts
+++ b/src/client/src/inputModes.test.ts
@@ -31,4 +31,11 @@ describe("input mode helpers", () => {
expect(inputModeForDraft("open !@\"vendor/file.ts")).toEqual({ kind: "file" });
expect(inputModeForDraft("open \"src/main.ts")).toEqual({ kind: "normal" });
});
+
+ it("collapses # model completion tokens to model mode", () => {
+ expect(inputModeForDraft("#anthropic/claude-opus")).toEqual({ kind: "model" });
+ expect(inputModeForDraft("use #gpt-5.2")).toEqual({ kind: "model" });
+ expect(inputModeForDraft("use #gpt-5.2 please")).toEqual({ kind: "normal" });
+ expect(inputModeForDraft("# ")).toEqual({ kind: "normal" });
+ });
});
diff --git a/src/client/src/inputModes.ts b/src/client/src/inputModes.ts
index bfeb755..afe06d2 100644
--- a/src/client/src/inputModes.ts
+++ b/src/client/src/inputModes.ts
@@ -4,6 +4,7 @@ export type InputMode =
| { kind: "normal" }
| { kind: "command" }
| { kind: "file" }
+ | { kind: "model" }
| { kind: "shell"; excludeFromContext: boolean };
export function inputModeForDraft(draft: string): InputMode {
@@ -11,7 +12,9 @@ export function inputModeForDraft(draft: string): InputMode {
if (trimmed.startsWith("!@")) return { kind: "file" };
if (trimmed.startsWith("!")) return { kind: "shell", excludeFromContext: trimmed.startsWith("!!") };
if (currentToken(draft).startsWith("/")) return { kind: "command" };
- if (detectPromptCompletionTrigger(draft)?.kind === "file") return { kind: "file" };
+ const trigger = detectPromptCompletionTrigger(draft);
+ if (trigger?.kind === "file") return { kind: "file" };
+ if (trigger?.kind === "model") return { kind: "model" };
return { kind: "normal" };
}
diff --git a/src/client/src/promptCompletions.test.ts b/src/client/src/promptCompletions.test.ts
index 59bb8ed..1cb1989 100644
--- a/src/client/src/promptCompletions.test.ts
+++ b/src/client/src/promptCompletions.test.ts
@@ -1,5 +1,6 @@
import { describe, expect, it } from "vitest";
-import { detectPromptCompletionTrigger, fileCompletionInsertText } from "./promptCompletions";
+import type { SessionModel } from "../../shared/apiTypes";
+import { detectPromptCompletionTrigger, fileCompletionInsertText, modelCompletionChoices } from "./promptCompletions";
describe("detectPromptCompletionTrigger", () => {
it("keeps all-file suggestions active when an @ space query contains spaces", () => {
@@ -54,6 +55,73 @@ describe("detectPromptCompletionTrigger", () => {
});
expect(detectPromptCompletionTrigger("/model")).toEqual({ kind: "command", query: "model", from: 0, to: 6 });
});
+
+ it("detects model queries for tokens starting with #", () => {
+ expect(detectPromptCompletionTrigger("#")).toEqual({ kind: "model", query: "", from: 0, to: 1 });
+ expect(detectPromptCompletionTrigger("use #anthropic/claude-opus")).toEqual({ kind: "model", query: "anthropic/claude-opus", from: 4, to: 26 });
+ });
+
+ it("detects model queries at any cursor position but not inside other tokens or quotes", () => {
+ expect(detectPromptCompletionTrigger("use #claude now", 10)).toEqual({ kind: "model", query: "claud", from: 4, to: 10 });
+ expect(detectPromptCompletionTrigger("say hello#world")).toBeUndefined();
+ expect(detectPromptCompletionTrigger('say "#claude')).toBeUndefined();
+ });
+
+ it("shows model completion for a markdown header only on the bare # keystroke", () => {
+ expect(detectPromptCompletionTrigger("#")).toEqual({ kind: "model", query: "", from: 0, to: 1 });
+ expect(detectPromptCompletionTrigger("# ")).toBeUndefined();
+ expect(detectPromptCompletionTrigger("# Title")).toBeUndefined();
+ });
+});
+
+describe("modelCompletionChoices", () => {
+ const models: SessionModel[] = [
+ { provider: "anthropic", id: "claude-opus-4-5", name: "Claude Opus 4.5" },
+ { provider: "anthropic", id: "claude-sonnet-4-5", name: "Claude Sonnet 4.5" },
+ { provider: "openai", id: "gpt-5.2", name: "GPT-5.2" },
+ { provider: "google", id: "gemini-3-pro" },
+ ];
+
+ it("lists all models for an empty query, mapped to #provider/id insert texts", () => {
+ expect(modelCompletionChoices(models, "")).toEqual([
+ { insertText: "#anthropic/claude-opus-4-5", detail: "anthropic", description: "Claude Opus 4.5" },
+ { insertText: "#anthropic/claude-sonnet-4-5", detail: "anthropic", description: "Claude Sonnet 4.5" },
+ { insertText: "#openai/gpt-5.2", detail: "openai", description: "GPT-5.2" },
+ { insertText: "#google/gemini-3-pro", detail: "google" },
+ ]);
+ });
+
+ it("filters case-insensitively across provider/id, id, and display name", () => {
+ expect(modelCompletionChoices(models, "OPUS-4")).toEqual([
+ { insertText: "#anthropic/claude-opus-4-5", detail: "anthropic", description: "Claude Opus 4.5" },
+ ]);
+ expect(modelCompletionChoices(models, "openai")).toEqual([
+ { insertText: "#openai/gpt-5.2", detail: "openai", description: "GPT-5.2" },
+ ]);
+ expect(modelCompletionChoices(models, "sonnet 4.5")).toEqual([
+ { insertText: "#anthropic/claude-sonnet-4-5", detail: "anthropic", description: "Claude Sonnet 4.5" },
+ ]);
+ });
+
+ it("omits the description when the display name matches the id", () => {
+ expect(modelCompletionChoices([{ provider: "ollama", id: "qwen3", name: "qwen3" }], "")).toEqual([
+ { insertText: "#ollama/qwen3", detail: "ollama" },
+ ]);
+ });
+
+ it("skips models without a provider or id since they cannot form a #provider/id reference", () => {
+ expect(modelCompletionChoices([{ id: "orphan" }, { provider: "ghost" }, { provider: "openai", id: "gpt-5.2" }], "")).toEqual([
+ { insertText: "#openai/gpt-5.2", detail: "openai" },
+ ]);
+ });
+
+ it("caps the list at 12 models, preserving server order", () => {
+ const many = Array.from({ length: 20 }, (_, index) => ({ provider: "p", id: `m${String(index)}` }));
+ const choices = modelCompletionChoices(many, "");
+ expect(choices).toHaveLength(12);
+ expect(choices[0]?.insertText).toBe("#p/m0");
+ expect(choices[11]?.insertText).toBe("#p/m11");
+ });
});
describe("fileCompletionInsertText", () => {
diff --git a/src/client/src/promptCompletions.ts b/src/client/src/promptCompletions.ts
index 1a0fc7b..c18742d 100644
--- a/src/client/src/promptCompletions.ts
+++ b/src/client/src/promptCompletions.ts
@@ -1,6 +1,9 @@
+import type { SessionModel } from "../../shared/apiTypes";
+
export type PromptCompletionTrigger =
| { kind: "command"; query: string; from: number; to: number }
- | { kind: "file"; query: string; from: number; to: number; fileScope?: "tracked" | "all" | undefined; allPrefix?: "@ " | "!@" | undefined; quoted?: boolean };
+ | { kind: "file"; query: string; from: number; to: number; fileScope?: "tracked" | "all" | undefined; allPrefix?: "@ " | "!@" | undefined; quoted?: boolean }
+ | { kind: "model"; query: string; from: number; to: number };
export function detectPromptCompletionTrigger(draft: string, cursor = draft.length): PromptCompletionTrigger | undefined {
const beforeCursor = draft.slice(0, cursor);
@@ -17,9 +20,46 @@ export function detectPromptCompletionTrigger(draft: string, cursor = draft.leng
if (token.startsWith("/") && tokenStart === 0) return { kind: "command", query: token.slice(1), from: tokenStart, to: cursor };
if (token.startsWith("!@")) return { kind: "file", query: token.slice(2), from: tokenStart, to: cursor, fileScope: "all", allPrefix: "!@" };
if (token.startsWith("@")) return { kind: "file", query: token.slice(1), from: tokenStart, to: cursor, fileScope: "tracked" };
+ if (token.startsWith("#")) return { kind: "model", query: token.slice(1), from: tokenStart, to: cursor };
return undefined;
}
+export interface ModelCompletionChoice {
+ insertText: string;
+ detail: string;
+ description?: string;
+}
+
+const MODEL_COMPLETION_LIMIT = 12;
+
+export function modelCompletionChoices(models: readonly SessionModel[], query: string): ModelCompletionChoice[] {
+ const needle = query.toLowerCase();
+ const choices: ModelCompletionChoice[] = [];
+ for (const model of models) {
+ // A completion must produce a strict provider/model-id reference, so models
+ // missing either half of the identity can never be inserted.
+ if (!hasQualifiedModelId(model)) continue;
+ if (!modelMatchesQuery(model, needle)) continue;
+ choices.push({
+ insertText: `#${model.provider}/${model.id}`,
+ detail: model.provider,
+ ...(model.name !== undefined && model.name !== "" && model.name !== model.id ? { description: model.name } : {}),
+ });
+ if (choices.length >= MODEL_COMPLETION_LIMIT) break;
+ }
+ return choices;
+}
+
+function hasQualifiedModelId(model: SessionModel): model is SessionModel & { provider: string; id: string } {
+ return typeof model.provider === "string" && model.provider !== "" && typeof model.id === "string" && model.id !== "";
+}
+
+function modelMatchesQuery(model: SessionModel & { provider: string; id: string }, needle: string): boolean {
+ return `${model.provider}/${model.id}`.toLowerCase().includes(needle)
+ || model.id.toLowerCase().includes(needle)
+ || (model.name?.toLowerCase().includes(needle) ?? false);
+}
+
export function fileCompletionInsertText(path: string, quoted: boolean, allPrefix?: "@ " | "!@"): string {
const prefix = allPrefix ?? "@";
if (!quoted && !path.includes(" ")) return `${prefix}${path}`;
diff --git a/src/server/sessions/piSessionService.delegationTools.test.ts b/src/server/sessions/piSessionService.delegationTools.test.ts
index 247b3d3..4cb4854 100644
--- a/src/server/sessions/piSessionService.delegationTools.test.ts
+++ b/src/server/sessions/piSessionService.delegationTools.test.ts
@@ -1,6 +1,7 @@
import { mkdtemp, rm, writeFile } from "node:fs/promises";
import { tmpdir } from "node:os";
import { join } from "node:path";
+import type { ExtensionContext } from "@earendil-works/pi-coding-agent";
import { afterEach, describe, expect, it, vi } from "vitest";
import { createPiWebCustomToolDefinitions, sessionAllowsDelegationTools, type PiSessionManager } from "./piSessionService.js";
import type { SubsessionToolDeps } from "./spawnSubsessionTool.js";
@@ -14,13 +15,14 @@ afterEach(async () => {
function delegationDeps() {
const spawn = vi.fn(() => Promise.resolve({ sessionId: "independent-1", cwd: "/workspace" }));
+ const subsessionSpawn = vi.fn(() => Promise.resolve({ sessionId: "child-1", cwd: "/workspace" }));
const subsessions: SubsessionToolDeps = {
- spawn: vi.fn(() => Promise.resolve({ sessionId: "child-1", cwd: "/workspace" })),
+ spawn: subsessionSpawn,
list: vi.fn(() => Promise.resolve([])),
check: vi.fn(() => Promise.resolve({ sessionId: "child-1", cwd: "/workspace", status: "idle" as const, finalText: "", messageCount: 0 })),
read: vi.fn(() => Promise.resolve({ sessionId: "child-1", cwd: "/workspace", status: "idle" as const, entries: [], total: 0, matched: 0, start: 0, hasMore: false })),
};
- return { spawn, subsessions };
+ return { spawn, subsessions, subsessionSpawn };
}
function toolNames(definitions: ReturnType): string[] {
@@ -35,6 +37,20 @@ function manager(id: string, file: string | undefined, entries: readonly unknown
});
}
+const dispatchModel = { provider: "anthropic", id: "claude-sonnet" };
+
+function ctxFor(sessionId: string, sessionFile: string | undefined, model?: unknown): ExtensionContext {
+ // The delegation tools only read sessionManager and model from the context.
+ // eslint-disable-next-line @typescript-eslint/consistent-type-assertions -- test stub with the minimal surface the tools read.
+ return { sessionManager: manager(sessionId, sessionFile), ...(model === undefined ? {} : { model }) } as unknown as ExtensionContext;
+}
+
+function findTool(definitions: ReturnType, name: string) {
+ const tool = definitions.find((definition) => definition.name === name);
+ if (tool === undefined) throw new Error(`missing tool ${name}`);
+ return tool;
+}
+
describe("delegation tool capability boundary", () => {
it("provides every globally enabled delegation tool to unrestricted sessions", () => {
const { spawn, subsessions } = delegationDeps();
@@ -63,6 +79,39 @@ describe("delegation tool capability boundary", () => {
expect(toolNames(createPiWebCustomToolDefinitions("/workspace", false, spawn, subsessions))).toEqual(["edit"]);
});
+ it("wires the dispatching session identity, inherited model, and model spec into spawn_session", async () => {
+ const { spawn, subsessions } = delegationDeps();
+ const spawnTool = findTool(createPiWebCustomToolDefinitions("/workspace", true, spawn, subsessions), "spawn_session");
+
+ await spawnTool.execute("call-1", { prompt: "go", model: "openai/gpt-5" }, undefined, undefined, ctxFor("spawner-7", "/sessions/spawner-7.jsonl", dispatchModel));
+
+ expect(spawn).toHaveBeenCalledWith({
+ spawningCwd: "/workspace",
+ spawningSessionId: "spawner-7",
+ prompt: "go",
+ cwd: undefined,
+ model: dispatchModel,
+ modelSpec: "openai/gpt-5",
+ });
+ });
+
+ it("wires the parent identity, inherited model, and model spec into spawn_subsession", async () => {
+ const { spawn, subsessions, subsessionSpawn } = delegationDeps();
+ const spawnTool = findTool(createPiWebCustomToolDefinitions("/workspace", true, spawn, subsessions), "spawn_subsession");
+
+ await spawnTool.execute("call-2", { prompt: "go", model: "openai/gpt-5" }, undefined, undefined, ctxFor("parent-9", "/sessions/parent-9.jsonl", dispatchModel));
+
+ expect(subsessionSpawn).toHaveBeenCalledWith({
+ spawningCwd: "/workspace",
+ parentSessionId: "parent-9",
+ parentSessionFile: "/sessions/parent-9.jsonl",
+ prompt: "go",
+ cwd: undefined,
+ model: dispatchModel,
+ modelSpec: "openai/gpt-5",
+ });
+ });
+
it.each(["human-created", "spawn_session-created"])("allows delegation for a %s session without tracked-child provenance", async () => {
const sessionManager = manager("session-1", undefined);
const open = vi.fn(() => { throw new Error("no parent session should be opened"); });
diff --git a/src/server/sessions/piSessionService.spawnSession.test.ts b/src/server/sessions/piSessionService.spawnSession.test.ts
index 0d10106..439f724 100644
--- a/src/server/sessions/piSessionService.spawnSession.test.ts
+++ b/src/server/sessions/piSessionService.spawnSession.test.ts
@@ -4,6 +4,7 @@ import type { SpawnTargetDecision } from "./spawnTargetResolver.js";
import { CapturingSessionEventHub, fakeRuntime, runtimeCreator, sessionGateway, testModel, testModelRuntime, type RuntimeCreator } from "./piSessionService.testSupport.js";
const TEST_AGENT_DIR = "/tmp/pi-web-test-agent";
+const TEST_MODEL_SPEC = "anthropic/claude-sonnet-4-5-20250929";
describe("PiSessionService", () => {
describe("spawnSession", () => {
@@ -25,7 +26,7 @@ describe("PiSessionService", () => {
it("starts a session at the resolved target, delivers the prompt, and logs the spawn", async () => {
const { fake, service, log } = spawnService({ allowed: true, cwd: "/workspace-feature" });
- const result = await service.spawnSession({ spawningCwd: "/workspace", prompt: "continue the plan", cwd: "/workspace-feature" });
+ const result = await service.spawnSession({ spawningCwd: "/workspace", spawningSessionId: "spawner-1", prompt: "continue the plan", cwd: "/workspace-feature" });
expect(result).toEqual({ sessionId: "spawned-1", cwd: "/workspace-feature" });
expect(fake.calls.prompt).toEqual([{ text: "continue the plan", options: undefined }]);
@@ -53,17 +54,34 @@ describe("PiSessionService", () => {
heartbeatIntervalMs: 60_000,
});
- await service.spawnSession({ spawningCwd: "/workspace", prompt: "continue", cwd: "/workspace-feature", model });
+ await service.spawnSession({ spawningCwd: "/workspace", spawningSessionId: "spawner-1", prompt: "continue", cwd: "/workspace-feature", model });
expect(initialModel).toBe(model);
expect(delegationToolsEnabled).toBe(true);
await service.dispose();
});
+ it("names the spawned session's model in the result", async () => {
+ const spawned = fakeRuntime("spawned-1", { sessionFile: "/tmp/spawned-1.jsonl", model: testModel() });
+ const service = new PiSessionService(new CapturingSessionEventHub(), {
+ agentDir: TEST_AGENT_DIR,
+ modelRuntime: testModelRuntime,
+ createAgentRuntime: runtimeCreator(spawned.runtime),
+ sessionManager: sessionGateway([]),
+ spawnTargets: { resolveSpawnTarget: () => Promise.resolve({ allowed: true, cwd: "/workspace-feature" }) },
+ heartbeatIntervalMs: 60_000,
+ });
+
+ const result = await service.spawnSession({ spawningCwd: "/workspace", spawningSessionId: "spawner-1", prompt: "continue", cwd: "/workspace-feature" });
+
+ expect(result).toEqual({ sessionId: "spawned-1", cwd: "/workspace-feature", model: TEST_MODEL_SPEC });
+ await service.dispose();
+ });
+
it("rejects an out-of-project target without starting a session", async () => {
const { fake, service } = spawnService({ allowed: false, reason: "out-of-project", allowedCwds: ["/workspace"] });
- await expect(service.spawnSession({ spawningCwd: "/workspace", prompt: "go", cwd: "/elsewhere" }))
+ await expect(service.spawnSession({ spawningCwd: "/workspace", spawningSessionId: "spawner-1", prompt: "go", cwd: "/elsewhere" }))
.rejects.toThrow("cwd must be a workspace of this project. Allowed: /workspace");
expect(fake.calls.prompt).toEqual([]);
expect(service.activeCount()).toBe(0);
@@ -73,7 +91,7 @@ describe("PiSessionService", () => {
it("rejects when the spawning session is not in a registered project", async () => {
const { service } = spawnService({ allowed: false, reason: "not-registered" });
- await expect(service.spawnSession({ spawningCwd: "/workspace", prompt: "go", cwd: undefined }))
+ await expect(service.spawnSession({ spawningCwd: "/workspace", spawningSessionId: "spawner-1", prompt: "go", cwd: undefined }))
.rejects.toThrow("Spawning session is not in a registered project");
await service.dispose();
});
@@ -88,9 +106,120 @@ describe("PiSessionService", () => {
heartbeatIntervalMs: 60_000,
});
- await expect(service.spawnSession({ spawningCwd: "/workspace", prompt: "go", cwd: undefined }))
+ await expect(service.spawnSession({ spawningCwd: "/workspace", spawningSessionId: "spawner-1", prompt: "go", cwd: undefined }))
.rejects.toThrow("Spawning sessions is disabled");
await service.dispose();
});
+
+ describe("model spec resolution", () => {
+ /**
+ * Harness: the spawner comes online via `service.start`, then the spawn
+ * creates the next queued runtime. `initialModels` records every
+ * creation-time model so tests can see exactly what the spawned session
+ * was started with.
+ */
+ function specService(spawnerPatch: Parameters[1] = {}) {
+ const spawner = fakeRuntime("spawner-1", { sessionFile: "/tmp/spawner-1.jsonl", ...spawnerPatch });
+ const spawned = fakeRuntime("spawned-2", { sessionFile: "/tmp/spawned-2.jsonl", model: testModel() });
+ const initialModels: PiAgentSession["model"][] = [];
+ const runtimes = [spawner.runtime, spawned.runtime];
+ let index = 0;
+ const createAgentRuntime: RuntimeCreator = async (_createRuntime, options) => {
+ await Promise.resolve();
+ initialModels.push(options.initialModel);
+ const runtime = runtimes[index] ?? spawned.runtime;
+ index += 1;
+ return runtime;
+ };
+ const service = new PiSessionService(new CapturingSessionEventHub(), {
+ agentDir: TEST_AGENT_DIR,
+ modelRuntime: testModelRuntime,
+ createAgentRuntime,
+ sessionManager: sessionGateway([]),
+ spawnTargets: { resolveSpawnTarget: () => Promise.resolve({ allowed: true, cwd: "/workspace-feature" }) },
+ heartbeatIntervalMs: 60_000,
+ });
+ return { service, spawner, spawned, initialModels };
+ }
+
+ it("resolves the spec against the spawning session's scoped models and names it in the result", async () => {
+ const scoped = testModel();
+ const { service, initialModels } = specService({ scopedModels: [{ model: scoped }] });
+ await service.start("/workspace");
+
+ const result = await service.spawnSession({ spawningCwd: "/workspace", spawningSessionId: "spawner-1", prompt: "go", cwd: "/workspace-feature", modelSpec: TEST_MODEL_SPEC });
+
+ expect(initialModels).toHaveLength(2);
+ expect(initialModels[0]).toBeUndefined();
+ expect(initialModels[1]).toBe(scoped);
+ expect(result).toEqual({ sessionId: "spawned-2", cwd: "/workspace-feature", model: TEST_MODEL_SPEC });
+ await service.dispose();
+ });
+
+ it("falls back to a direct runtime lookup when the spec is not among the available candidates", async () => {
+ // The shared test runtime has no configured auth, so its available
+ // snapshot is empty; only the getModel fallback can resolve the spec.
+ const { service, initialModels } = specService();
+ await service.start("/workspace");
+
+ const result = await service.spawnSession({ spawningCwd: "/workspace", spawningSessionId: "spawner-1", prompt: "go", cwd: "/workspace-feature", modelSpec: TEST_MODEL_SPEC });
+
+ expect(initialModels[1]).toMatchObject({ provider: "anthropic", id: "claude-sonnet-4-5-20250929" });
+ expect(result).toEqual({ sessionId: "spawned-2", cwd: "/workspace-feature", model: TEST_MODEL_SPEC });
+ await service.dispose();
+ });
+
+ it.each(["no-slash", "anthropic/", "/id"])("rejects the malformed spec %s without starting a session", async (modelSpec) => {
+ const { service, spawned, initialModels } = specService({ scopedModels: [{ model: testModel() }] });
+ await service.start("/workspace");
+
+ await expect(service.spawnSession({ spawningCwd: "/workspace", spawningSessionId: "spawner-1", prompt: "go", cwd: "/workspace-feature", modelSpec }))
+ .rejects.toThrow(`Unknown model "${modelSpec}". Pass an exact "provider/model-id".`);
+ expect(initialModels).toEqual([undefined]);
+ expect(spawned.calls.prompt).toEqual([]);
+ expect(service.activeCount()).toBe(1);
+ await service.dispose();
+ });
+
+ it("rejects an unknown spec without starting a session", async () => {
+ const { service, spawned, initialModels } = specService({ scopedModels: [{ model: testModel() }] });
+ await service.start("/workspace");
+
+ await expect(service.spawnSession({ spawningCwd: "/workspace", spawningSessionId: "spawner-1", prompt: "go", cwd: "/workspace-feature", modelSpec: "anthropic/does-not-exist" }))
+ .rejects.toThrow('Unknown model "anthropic/does-not-exist". Pass an exact "provider/model-id".');
+ expect(initialModels).toEqual([undefined]);
+ expect(spawned.calls.prompt).toEqual([]);
+ expect(service.activeCount()).toBe(1);
+ await service.dispose();
+ });
+
+ it("rejects an unknown spec even when the spawning session has no available models", async () => {
+ const { service } = specService();
+ await service.start("/workspace");
+
+ await expect(service.spawnSession({ spawningCwd: "/workspace", spawningSessionId: "spawner-1", prompt: "go", cwd: "/workspace-feature", modelSpec: "ghost/model" }))
+ .rejects.toThrow('Unknown model "ghost/model". Pass an exact "provider/model-id".');
+ await service.dispose();
+ });
+
+ it("does not look up the spawning session when no model spec is given", async () => {
+ const spawned = fakeRuntime("spawned-2", { sessionFile: "/tmp/spawned-2.jsonl", model: testModel() });
+ const service = new PiSessionService(new CapturingSessionEventHub(), {
+ agentDir: TEST_AGENT_DIR,
+ modelRuntime: testModelRuntime,
+ createAgentRuntime: runtimeCreator(spawned.runtime),
+ sessionManager: sessionGateway([]),
+ spawnTargets: { resolveSpawnTarget: () => Promise.resolve({ allowed: true, cwd: "/workspace-feature" }) },
+ heartbeatIntervalMs: 60_000,
+ });
+
+ // "ghost" is not a resolvable session, and the default path must not care.
+ const result = await service.spawnSession({ spawningCwd: "/workspace", spawningSessionId: "ghost", prompt: "go", cwd: "/workspace-feature" });
+
+ expect(result).toEqual({ sessionId: "spawned-2", cwd: "/workspace-feature", model: TEST_MODEL_SPEC });
+ expect(spawned.calls.prompt).toEqual([{ text: "go", options: undefined }]);
+ await service.dispose();
+ });
+ });
});
});
diff --git a/src/server/sessions/piSessionService.spawnSubsession.test.ts b/src/server/sessions/piSessionService.spawnSubsession.test.ts
index 13177eb..4a43468 100644
--- a/src/server/sessions/piSessionService.spawnSubsession.test.ts
+++ b/src/server/sessions/piSessionService.spawnSubsession.test.ts
@@ -98,6 +98,38 @@ describe("PiSessionService", () => {
await service.dispose();
});
+ it("resolves a model spec against the parent's models and names it in the result", async () => {
+ const scoped = testModel();
+ const parent = fakeRuntime("parent-1", { sessionFile: "/tmp/parent-1.jsonl", scopedModels: [{ model: scoped }] });
+ const child = fakeRuntime("child-1", { sessionFile: "/tmp/child-1.jsonl", sessionManager: fakeSessionManager("/workspace-feature"), model: scoped });
+ const initialModels: PiAgentSession["model"][] = [];
+ const runtimes = [parent.runtime, child.runtime];
+ let index = 0;
+ const createAgentRuntime: RuntimeCreator = async (_createRuntime, options) => {
+ await Promise.resolve();
+ initialModels.push(options.initialModel);
+ const runtime = runtimes[index] ?? child.runtime;
+ index += 1;
+ return runtime;
+ };
+ const service = new PiSessionService(new CapturingSessionEventHub(), {
+ agentDir: TEST_AGENT_DIR,
+ modelRuntime: testModelRuntime,
+ createAgentRuntime,
+ sessionManager: sessionGateway([]),
+ archiveStore: emptyArchiveStore(),
+ spawnTargets: { resolveSpawnTarget: () => Promise.resolve({ allowed: true, cwd: "/workspace-feature" }) },
+ heartbeatIntervalMs: 60_000,
+ });
+
+ await service.start("/workspace");
+ const result = await service.spawnSubsession({ spawningCwd: "/workspace", parentSessionId: "parent-1", parentSessionFile: "/tmp/parent-1.jsonl", prompt: "do the slice", cwd: "/workspace-feature", modelSpec: "anthropic/claude-sonnet-4-5-20250929" });
+
+ expect(initialModels[1]).toBe(scoped);
+ expect(result).toEqual({ sessionId: "child-1", cwd: "/workspace-feature", model: "anthropic/claude-sonnet-4-5-20250929" });
+ await service.dispose();
+ });
+
it("persists tracked child links in the parent and child sessions", async () => {
const parentPersisted: { customType: string; data?: unknown }[] = [];
const childPersisted: { customType: string; data?: unknown }[] = [];
diff --git a/src/server/sessions/piSessionService.ts b/src/server/sessions/piSessionService.ts
index f8f7552..d85de27 100644
--- a/src/server/sessions/piSessionService.ts
+++ b/src/server/sessions/piSessionService.ts
@@ -120,6 +120,30 @@ function spawnTargetError(decision: Extract {
+ await session.modelRuntime.refresh();
+ return session.scopedModels.length > 0
+ ? session.scopedModels.map((scoped) => scoped.model)
+ : session.modelRuntime.getAvailableSnapshot();
+ }
+
+ /**
+ * Resolve a strict `provider/model-id` spec from a spawn tool against the
+ * *spawning* session's model runtime, using the same candidates
+ * {@link setModel} offers plus a direct runtime lookup as fallback. Unknown
+ * or malformed specs throw; the agent loop turns that into an error tool
+ * result the spawning agent can retry from.
+ */
+ private async resolveSpawnModel(spawningSessionId: string, modelSpec: string): Promise {
+ const session = await this.getOrOpen(spawningSessionId);
+ const parsed = parseModelSpec(modelSpec);
+ const candidates = await this.sessionModelCandidates(session);
+ const model = parsed === undefined
+ ? undefined
+ : candidates.find((candidate) => candidate.provider === parsed.provider && candidate.id === parsed.modelId)
+ ?? session.modelRuntime.getModel(parsed.provider, parsed.modelId);
+ if (model === undefined) throw unknownSpawnModelError(modelSpec);
+ return model;
}
/**
@@ -1822,10 +1897,7 @@ export class PiSessionService implements SessionRouteService {
async availableModels(ref: PiSessionLookup): Promise {
const session = await this.getOrOpen(ref);
- await session.modelRuntime.refresh();
- const models = session.scopedModels.length > 0
- ? session.scopedModels.map((scoped) => scoped.model)
- : session.modelRuntime.getAvailableSnapshot();
+ const models = await this.sessionModelCandidates(session);
return models.map(modelToClientModel);
}
@@ -1833,11 +1905,8 @@ export class PiSessionService implements SessionRouteService {
await this.assertWritable(ref);
const session = await this.getOrOpen(ref);
this.assertTreeNavigationInactive(session, "change models");
- await session.modelRuntime.refresh();
+ const candidates = await this.sessionModelCandidates(session);
this.assertTreeNavigationInactive(session, "change models");
- const candidates = session.scopedModels.length > 0
- ? session.scopedModels.map((scoped) => scoped.model)
- : session.modelRuntime.getAvailableSnapshot();
const model = candidates.find((candidate) => candidate.provider === provider && candidate.id === modelId)
?? session.modelRuntime.getModel(provider, modelId);
if (model === undefined) throw new Error(`Model not found: ${provider}/${modelId}`);
diff --git a/src/server/sessions/spawnSessionTool.test.ts b/src/server/sessions/spawnSessionTool.test.ts
index f2fa1c6..58dc660 100644
--- a/src/server/sessions/spawnSessionTool.test.ts
+++ b/src/server/sessions/spawnSessionTool.test.ts
@@ -2,20 +2,23 @@ import type { ExtensionContext } from "@earendil-works/pi-coding-agent";
import { describe, expect, it, vi } from "vitest";
import { createSpawnSessionToolDefinition } from "./spawnSessionTool.js";
-// eslint-disable-next-line @typescript-eslint/consistent-type-assertions -- test stub with the minimal surface the tool reads.
-const ctx = {} as ExtensionContext;
const dispatchModel = { provider: "anthropic", id: "claude-sonnet" };
-// eslint-disable-next-line @typescript-eslint/consistent-type-assertions -- test stub with the minimal surface the tool reads.
-const ctxWithModel = { model: dispatchModel } as ExtensionContext;
+
+function ctxFor(sessionId: string, model?: unknown): ExtensionContext {
+ const sessionManager = { getSessionId: () => sessionId };
+ // The spawn tool only reads sessionManager.getSessionId and model.
+ // eslint-disable-next-line @typescript-eslint/consistent-type-assertions -- test stub with the minimal surface the tool reads.
+ return { sessionManager, ...(model === undefined ? {} : { model }) } as unknown as ExtensionContext;
+}
describe("createSpawnSessionToolDefinition", () => {
- it("passes the spawning cwd, explicit cwd, dispatching model, and prompt to spawn callback", async () => {
+ it("passes the spawning identity, explicit cwd, dispatching model, and prompt to spawn callback", async () => {
const spawn = vi.fn(() => Promise.resolve({ sessionId: "new-1", cwd: "/repos/a-feature" }));
const tool = createSpawnSessionToolDefinition("/repos/a", { spawn });
- const result = await tool.execute("call-1", { prompt: "do the thing", cwd: "/repos/a-feature" }, undefined, undefined, ctxWithModel);
+ const result = await tool.execute("call-1", { prompt: "do the thing", cwd: "/repos/a-feature" }, undefined, undefined, ctxFor("spawner-1", dispatchModel));
- expect(spawn).toHaveBeenCalledWith({ spawningCwd: "/repos/a", prompt: "do the thing", cwd: "/repos/a-feature", model: dispatchModel });
+ expect(spawn).toHaveBeenCalledWith({ spawningCwd: "/repos/a", spawningSessionId: "spawner-1", prompt: "do the thing", cwd: "/repos/a-feature", model: dispatchModel });
expect(result.details).toEqual({ sessionId: "new-1", cwd: "/repos/a-feature" });
expect(result.content[0]).toMatchObject({ type: "text", text: "Started independent session new-1 in /repos/a-feature." });
});
@@ -32,16 +35,45 @@ describe("createSpawnSessionToolDefinition", () => {
const spawn = vi.fn(() => Promise.resolve({ sessionId: "new-2", cwd: "/repos/a" }));
const tool = createSpawnSessionToolDefinition("/repos/a", { spawn });
- await tool.execute("call-2", { prompt: "continue" }, undefined, undefined, ctx);
+ await tool.execute("call-2", { prompt: "continue" }, undefined, undefined, ctxFor("spawner-1"));
- expect(spawn).toHaveBeenCalledWith({ spawningCwd: "/repos/a", prompt: "continue", cwd: undefined });
+ expect(spawn).toHaveBeenCalledWith({ spawningCwd: "/repos/a", spawningSessionId: "spawner-1", prompt: "continue", cwd: undefined });
+ });
+
+ it("forwards an explicit model as a model spec alongside the inherited model", async () => {
+ const spawn = vi.fn(() => Promise.resolve({ sessionId: "new-3", cwd: "/repos/a", model: "openai/gpt-5" }));
+ const tool = createSpawnSessionToolDefinition("/repos/a", { spawn });
+
+ const result = await tool.execute("call-3", { prompt: "continue", model: "openai/gpt-5" }, undefined, undefined, ctxFor("spawner-1", dispatchModel));
+
+ expect(spawn).toHaveBeenCalledWith({
+ spawningCwd: "/repos/a",
+ spawningSessionId: "spawner-1",
+ prompt: "continue",
+ cwd: undefined,
+ model: dispatchModel,
+ modelSpec: "openai/gpt-5",
+ });
+ expect(result.details).toEqual({ sessionId: "new-3", cwd: "/repos/a", model: "openai/gpt-5" });
+ expect(result.content[0]).toMatchObject({ type: "text", text: "Started independent session new-3 in /repos/a using model openai/gpt-5." });
+ });
+
+ it("teaches the model parameter format and the #provider/model-id reference convention", () => {
+ const tool = createSpawnSessionToolDefinition("/repos/a", { spawn: vi.fn() });
+
+ expect(tool.parameters).toMatchObject({
+ properties: {
+ // eslint-disable-next-line @typescript-eslint/no-unsafe-assignment -- stringMatching yields `any` against the loosely typed tool schema.
+ model: { description: expect.stringMatching(/provider\/model-id.*#provider\/model-id.*Omit to inherit/s) },
+ },
+ });
});
it("propagates the spawn callback error so the agent loop reports it", async () => {
const spawn = vi.fn(() => Promise.reject(new Error("cwd must be a workspace of this project. Allowed: /repos/a")));
const tool = createSpawnSessionToolDefinition("/repos/a", { spawn });
- await expect(tool.execute("call-4", { prompt: "x", cwd: "/elsewhere" }, undefined, undefined, ctx))
+ await expect(tool.execute("call-4", { prompt: "x", cwd: "/elsewhere" }, undefined, undefined, ctxFor("spawner-1")))
.rejects.toThrow("cwd must be a workspace of this project. Allowed: /repos/a");
});
});
diff --git a/src/server/sessions/spawnSessionTool.ts b/src/server/sessions/spawnSessionTool.ts
index aad33ee..45c81e5 100644
--- a/src/server/sessions/spawnSessionTool.ts
+++ b/src/server/sessions/spawnSessionTool.ts
@@ -4,16 +4,22 @@ import { defineTool, type ExtensionContext } from "@earendil-works/pi-coding-age
export interface SpawnSessionResult {
sessionId: string;
cwd: string;
+ /** Model the spawned session runs with, as `provider/id`; absent when unknown. */
+ model?: string;
}
export type SpawnSessionModel = NonNullable;
export interface SpawnSessionInvocation {
spawningCwd: string;
+ /** Id of the dispatching session; used to resolve {@link modelSpec} against its model runtime. */
+ spawningSessionId: string;
prompt: string;
cwd: string | undefined;
/** Current model from the dispatching session, used as the spawned session's default. */
model?: SpawnSessionModel;
+ /** Strict `provider/model-id` requested by the dispatcher; overrides {@link model} when set. */
+ modelSpec?: string;
}
export interface SpawnSessionToolDeps {
@@ -29,6 +35,9 @@ const SpawnSessionParams = Type.Object({
cwd: Type.Optional(Type.String({
description: "Working directory for the new session. Must be a workspace (worktree, or root) of the same project as this session. Defaults to this session's working directory.",
})),
+ model: Type.Optional(Type.String({
+ description: 'Model for the new session, as an exact "provider/model-id" such as "anthropic/claude-sonnet-4-5". When the user references a model as #provider/model-id in their request, forward it here. An unknown value is rejected. Omit to inherit this session\'s model.',
+ })),
});
/**
@@ -50,12 +59,15 @@ export function createSpawnSessionToolDefinition(spawningCwd: string, deps: Spaw
// valid workspace) rather than crash.
const result = await deps.spawn({
spawningCwd,
+ spawningSessionId: ctx.sessionManager.getSessionId(),
prompt: params.prompt,
cwd: params.cwd,
...(ctx.model === undefined ? {} : { model: ctx.model }),
+ ...(params.model === undefined ? {} : { modelSpec: params.model }),
});
+ const modelNote = result.model === undefined ? "" : ` using model ${result.model}`;
return {
- content: [{ type: "text", text: `Started independent session ${result.sessionId} in ${result.cwd}.` }],
+ content: [{ type: "text", text: `Started independent session ${result.sessionId} in ${result.cwd}${modelNote}.` }],
details: result,
};
},
diff --git a/src/server/sessions/spawnSubsessionTool.test.ts b/src/server/sessions/spawnSubsessionTool.test.ts
index bf25ccb..da1f221 100644
--- a/src/server/sessions/spawnSubsessionTool.test.ts
+++ b/src/server/sessions/spawnSubsessionTool.test.ts
@@ -112,6 +112,36 @@ describe("createSubsessionToolDefinitions", () => {
});
});
+ it("spawn_subsession forwards an explicit model as a model spec and names the model used", async () => {
+ const spawn = vi.fn(() => Promise.resolve({ sessionId: "child-3", cwd: "/repos/a", model: "openai/gpt-5" }));
+ const { spawn: spawnTool } = tools({ spawn });
+
+ const result = await spawnTool.execute("call-model", { prompt: "do it", model: "openai/gpt-5" }, undefined, undefined, ctxFor("parent-1", "/sessions/parent-1.jsonl", dispatchModel));
+
+ expect(spawn).toHaveBeenCalledWith({
+ spawningCwd: "/repos/a",
+ parentSessionId: "parent-1",
+ parentSessionFile: "/sessions/parent-1.jsonl",
+ prompt: "do it",
+ cwd: undefined,
+ model: dispatchModel,
+ modelSpec: "openai/gpt-5",
+ });
+ expect(result.details).toEqual({ sessionId: "child-3", cwd: "/repos/a", model: "openai/gpt-5" });
+ expect(firstText(result.content)).toBe("Started tracked subsession child-3 in /repos/a using model openai/gpt-5. Continue other work, then join with yield_to_subsessions; do not poll.");
+ });
+
+ it("spawn_subsession teaches the model parameter format and the #provider/model-id reference convention", () => {
+ const { spawn: spawnTool } = tools({});
+
+ expect(spawnTool.parameters).toMatchObject({
+ properties: {
+ // eslint-disable-next-line @typescript-eslint/no-unsafe-assignment -- stringMatching yields `any` against the loosely typed tool schema.
+ model: { description: expect.stringMatching(/provider\/model-id.*#provider\/model-id.*Omit to inherit/s) },
+ },
+ });
+ });
+
it("list_subsessions reports the caller's subsessions and their status", async () => {
const list = vi.fn(() => Promise.resolve([
{ sessionId: "child-1", cwd: "/repos/a", status: "working" as const },
diff --git a/src/server/sessions/spawnSubsessionTool.ts b/src/server/sessions/spawnSubsessionTool.ts
index 0f9aec8..173679b 100644
--- a/src/server/sessions/spawnSubsessionTool.ts
+++ b/src/server/sessions/spawnSubsessionTool.ts
@@ -8,6 +8,8 @@ export type SubsessionStatus = "working" | "idle" | "error" | "unknown";
export interface SpawnSubsessionResult {
sessionId: string;
cwd: string;
+ /** Model the child session runs with, as `provider/id`; absent when unknown. */
+ model?: string;
}
export type SpawnSubsessionModel = NonNullable;
@@ -23,6 +25,8 @@ export interface SpawnSubsessionInvocation {
cwd: string | undefined;
/** Current model from the dispatching session, used as the spawned session's default. */
model?: SpawnSubsessionModel;
+ /** Strict `provider/model-id` requested by the parent; overrides {@link model} when set. */
+ modelSpec?: string;
}
export interface SubsessionSummary {
@@ -72,6 +76,9 @@ const SpawnSubsessionParams = Type.Object({
cwd: Type.Optional(Type.String({
description: "Child workspace in the same project (worktree or root); defaults to the parent's directory.",
})),
+ model: Type.Optional(Type.String({
+ description: 'Model for the child session, as an exact "provider/model-id" such as "anthropic/claude-sonnet-4-5". When the user references a model as #provider/model-id in their request, forward it here. An unknown value is rejected. Omit to inherit this session\'s model.',
+ })),
});
const ListSubsessionsParams = Type.Object({});
@@ -197,9 +204,11 @@ export function createSubsessionToolDefinitions(spawningCwd: string, deps: Subse
prompt: params.prompt,
cwd: params.cwd,
...(ctx.model === undefined ? {} : { model: ctx.model }),
+ ...(params.model === undefined ? {} : { modelSpec: params.model }),
});
+ const modelNote = result.model === undefined ? "" : ` using model ${result.model}`;
return {
- content: [{ type: "text", text: `Started tracked subsession ${result.sessionId} in ${result.cwd}. Continue other work, then join with yield_to_subsessions; do not poll.` }],
+ content: [{ type: "text", text: `Started tracked subsession ${result.sessionId} in ${result.cwd}${modelNote}. Continue other work, then join with yield_to_subsessions; do not poll.` }],
details: result,
};
},