Accept a full chat-completions URL as the base URL

plugins/thread-briefs/server.ts

@@ -38,7 +38,7 @@ export default async function plugin(bb: BbPluginApi) {
   const settings = bb.settings.define({
     baseUrl: {
       type: "string",
-      label: "API base URL",
+      label: "API base URL (root or full /chat/completions endpoint)",
       default: "https://api.openai.com/v1",
     },
     apiKey: { type: "string", label: "API key", secret: true },

plugins/thread-briefs/skills/thread-briefs/SKILL.md

@@ -16,7 +16,7 @@ Set these with `bb plugin config thread-briefs set <key> <value>`.
 
 | Key | Default | What it does |
 | --- | --- | --- |
-| `baseUrl` | `https://api.openai.com/v1` | OpenAI-compatible API root. `/chat/completions` is appended; a trailing slash is fine. |
+| `baseUrl` | `https://api.openai.com/v1` | OpenAI-compatible endpoint. Either the API root or the full `/chat/completions` URL works; trailing slashes are fine. |
 | `apiKey` | _(unset, secret)_ | Bearer token for that endpoint. The plugin reports `needs-configuration` until it is set. |
 | `model` | `gpt-4o-mini` | Model used for summarizing. Any small instruction-following model works. |
 | `jsonMode` | `true` | Send `response_format: {type: "json_object"}`. Turn **off** for endpoints that reject it (many local servers do). |
@@ -25,6 +25,18 @@ Set these with `bb plugin config thread-briefs set <key> <value>`.
 The key is a secret setting, so it stays on the server and is never sent to the
 frontend.
 
+Worked example, Fireworks:
+
+```sh
+bb plugin config thread-briefs set baseUrl "https://api.fireworks.ai/inference/v1"
+bb plugin config thread-briefs set model "accounts/fireworks/models/glm-5p3-flash"
+bb plugin config thread-briefs set apiKey "<key>"
+```
+
+A 404 naming a doubled path (`/chat/completions/chat/completions`) meant an older
+build appended the path to a `baseUrl` that already ended in it. Both spellings
+are accepted now.
+
 ## When a brief is regenerated
 
 1. `thread.idle` fires at every turn boundary and starts a `quietSeconds`

plugins/thread-briefs/summarize.test.ts

@@ -77,6 +77,12 @@ describe("parseSummary", () => {
 });
 
 describe("chatCompletionsUrl", () => {
+  it("appends the path to an API root", () => {
+    expect(chatCompletionsUrl("https://api.openai.com/v1")).toBe(
+      "https://api.openai.com/v1/chat/completions",
+    );
+  });
+
   it("tolerates a trailing slash", () => {
     expect(chatCompletionsUrl("https://api.openai.com/v1/")).toBe(
       "https://api.openai.com/v1/chat/completions",
@@ -88,6 +94,26 @@ describe("chatCompletionsUrl", () => {
       "https://x.test/v1/chat/completions",
     );
   });
+
+  // Providers document the full endpoint, so it gets pasted in as the base URL.
+  // Appending blindly produced /chat/completions/chat/completions and a 404.
+  it("leaves a full Fireworks endpoint alone", () => {
+    expect(
+      chatCompletionsUrl("https://api.fireworks.ai/inference/v1/chat/completions"),
+    ).toBe("https://api.fireworks.ai/inference/v1/chat/completions");
+  });
+
+  it("accepts the Fireworks API root too", () => {
+    expect(chatCompletionsUrl("https://api.fireworks.ai/inference/v1")).toBe(
+      "https://api.fireworks.ai/inference/v1/chat/completions",
+    );
+  });
+
+  it("leaves a full endpoint with a trailing slash alone", () => {
+    expect(chatCompletionsUrl("https://x.test/v1/chat/completions/")).toBe(
+      "https://x.test/v1/chat/completions",
+    );
+  });
 });
 
 describe("buildUserPrompt", () => {

plugins/thread-briefs/summarize.ts

@@ -131,9 +131,21 @@ export interface CompletionConfig {
   jsonMode: boolean;
 }
 
-/** Trailing slashes are the single most common way a base URL is mistyped. */
+/**
+ * Accept either the API root or the full chat-completions endpoint.
+ *
+ * Providers document the full URL — Fireworks publishes
+ * `https://api.fireworks.ai/inference/v1/chat/completions`, OpenAI the same
+ * shape — so pasting that into a setting labelled "base URL" is the natural
+ * mistake, and appending blindly produced
+ * `/v1/chat/completions/chat/completions` and a 404. Trailing slashes are the
+ * other common way to mistype it.
+ */
 export function chatCompletionsUrl(baseUrl: string): string {
-  return `${baseUrl.trim().replace(/\/+$/u, "")}/chat/completions`;
+  const trimmed = baseUrl.trim().replace(/\/+$/u, "");
+  return /\/chat\/completions$/u.test(trimmed)
+    ? trimmed
+    : `${trimmed}/chat/completions`;
 }
 
 export async function requestSummary(