Add Prime Agent as an ACP provider

apps/app/src/components/icons/PrimeAgentIcon.tsx

@@ -0,0 +1,14 @@
+export function PrimeAgentIcon({ className }: { className?: string }) {
+  return (
+    <svg
+      fill="currentColor"
+      viewBox="0 0 178 178"
+      xmlns="http://www.w3.org/2000/svg"
+      className={className}
+    >
+      <title>Prime Agent</title>
+      <path d="m 123.322,84.092671 c -0.192,0.0065 -0.43,0.0147 -0.74,0.0147 l -0.018,-0.0247 c -0.873,0.1977 -1.958,0.1266 -3.067,0.0537 -3.29,-0.216 -6.799,-0.4465 -5.635,6.2824 0.259,1.4822 -1.538,1.8465 -2.73,1.9082 -3.384,0.1853 -6.78,0.2594 -10.171,0.1915 -0.641,-0.0106 -1.2979,-0.5506 -1.8904,-1.0388 -0.1022,-0.0844 -0.2034,-0.1673 -0.3016,-0.2457 -0.1052,-0.0865 0.2898,-1.2042 0.4942,-1.2166 3.3078,-0.1931 4.5068,-2.4361 5.7028,-4.6724 0.603,-1.1253 1.204,-2.2488 2.072,-3.1088 7.856,-7.7874 15.878,-15.4265 25.054,-21.7008 0.895,-0.6114 1.989,-1.1733 2.73,-0.1111 0.571,0.8205 0.036,1.2854 -0.512,1.7627 -0.24,0.2088 -0.482,0.4199 -0.637,0.6642 -0.554,0.8792 -1.538,1.5273 -2.514,2.1717 -1.92,1.2655 -3.82,2.5172 -2.408,5.4798 1.225,2.5651 0.129,3.0202 -1.555,3.7198 l -0.069,0.0287 c -0.72,0.3021 -1.458,0.5764 -2.194,0.8506 -1.568,0.5835 -3.134,1.1662 -4.537,2.0149 -1.408,0.8522 -2.081,2.5134 0.222,3.4954 5.033,2.1428 18.064,-1.2784 20.608,-5.9965 2.377,-4.4147 5.931,-7.6891 9.481,-10.9611 1.992,-1.836 3.984,-3.6712 5.767,-5.7067 3.844,-4.3849 8.344,-8.1939 12.846,-12.005 2.239,-1.8944 4.478,-3.78938 6.637,-5.75588 1.624,-1.48207 2.297,-3.43353 1.026,-5.56412 -1.267,-2.118215 -3.416,-2.402287 -5.435,-1.926802 -13.309,3.130982 -26.166,7.355122 -37.585,15.241302 -18.23,12.5919 -36.4911,25.1406 -54.9002,37.4669 -6.2743,4.2056 -10.0723,2.1491 -12.1657,-5.1318 -4.6502,-16.1676 -11.4681,-30.2664 -31.0569,-32.4587 -7.1574,-0.8028 -12.4066,3.6807 -11.3692,10.7949 0.5249,3.6065 0.0495,7.003 -1.6858,10.3872 -0.3827,0.7472 -0.7689,1.4947 -1.1556,2.243 -2.672,5.1706 -5.3671,10.3857 -7.0394,15.8885 -0.1399,0.4602 -0.3002,0.9444 -0.4654,1.4437 -1.4909,4.5052 -3.3862,10.2323 5.659,10.5492 0.3705,0.0123 1.0808,0.944799 0.9943,1.290699 -0.1976,0.8213 -0.5991,1.797 -1.2413,2.2725 -8.6705,6.3917 -15.79706,14.1294 -18.860151,24.5971 -1.550066,5.2865 -0.524909,10.7765 3.989391,14.8705 3.22984,2.928 7.35516,4.625 10.97396,2.162 3.3009,-2.247 6.9232,-3.754 10.538,-5.259 3.1819,-1.324 6.358,-2.646 9.3041,-4.468 0.7101,-0.439 1.5727,-0.841 2.4456,-1.248 2.4138,-1.1228 4.9063,-2.2843 4.4709,-4.3841 -0.6854,-3.2908 -4.1623,-6.3418 -7.0586,-8.7384 -2.8716,-2.3769 -10.1897,-18.3411 -9.3189,-22.176099 1.2193,-5.3704 3.9645,-10.0201 6.7125,-14.6744 2.3458,-3.9731 4.6935,-7.9497 6.0956,-12.3806 0.5804,-1.828 2.8037,-2.8284 4.9466,-2.0997 1.4543,0.4928 1.2068,1.8278 0.9762,3.0715 -0.0063,0.0344 -0.0127,0.0685 -0.019,0.1027 -0.8688,4.7802 -1.721,9.566 -2.5733,14.3517 -0.4261,2.3924 -0.8521,4.7847 -1.2803,7.1762 -0.2717,1.5316 0.2038,2.7544 1.7909,3.0631 3.0569,0.599 2.989,1.9762 1.6119,4.341499 -1.4636,2.5072 -1.6674,5.5703 -0.0309,7.8861 1.6427,2.3282 4.3908,2.8161 7.1821,1.4204 1.7415,-0.8646 3.094,-0.0927 3.0755,1.6612 -0.1112,9.3688 3.8103,7.2561 8.584,3.1681 0.439,-0.3763 1.0373,-0.5846 1.6152,-0.7857 0.1048,-0.0366 0.2091,-0.0728 0.3116,-0.1098 0.4529,-0.1616 0.9062,-0.3224 1.3595,-0.4833 8.986,-3.1884 17.9603,-6.3725 23.0334,-15.573099 0.392,-0.7187 1.6783,-1.0669 2.6795,-1.3377 0.057,-0.0154 0.113,-0.0307 0.1681,-0.0456 5.8013,-1.5766 11.7248,-1.6001 17.6438,-1.6237 4.445,-0.0176 8.888,-0.0352 13.277,-0.7107 4.329,-0.667 9.047,-3.1928 9.084,-7.3736 0.035,-3.3707 -2.546,-3.1612 -5.123,-2.9519 -1.115,0.0906 -2.231,0.1811 -3.134,-0.0185 -0.182,-0.0381 -0.375,-0.0316 -0.686,-0.0209 z" />
+      <path d="m 55.1325,131.29447 c -1.0745,7.1515 1.6551,13.2715 12.8266,13.1915 h -0.0062 c 9.5413,-0.389 20.3365,-6.164 30.8838,-13.5492 6.9653,-4.8787 12.9873,-10.0236 16.8903,-17.6253 2.872,-5.5889 1.395,-10.0723 -2.933,-13.993799 -1.908,-1.7291 -3.73,-1.9205 -5.867,0.1667 -7.5842,7.423099 -17.0261,11.474299 -26.7218,15.550099 -2.4706,1.0393 -5.2847,1.5582 -8.1187,2.0809 -7.5511,1.3924 -15.2431,2.8103 -16.954,14.1791 z" />
+    </svg>
+  );
+}

apps/app/src/lib/provider-icon.ts

@@ -13,6 +13,7 @@ import { OpenAiIcon } from "@/components/icons/OpenAiIcon";
 import { OpencodeIcon } from "@/components/icons/OpencodeIcon";
 import { OmpIcon } from "@/components/icons/OmpIcon";
 import { PiIcon } from "@/components/icons/PiIcon";
+import { PrimeAgentIcon } from "@/components/icons/PrimeAgentIcon";
 import { Icon } from "@bb/shared-ui/icon";
 
 const ACP_ID_PREFIX = "acp-";
@@ -36,6 +37,7 @@ const KNOWN_ACP_BRAND_ICONS: Record<
   "hermes-agent": HermesAgentIcon,
   opencode: OpencodeIcon,
   omp: OmpIcon,
+  "prime-agent": PrimeAgentIcon,
 };
 
 const configuredProviderLogoIcons = new Map<
@@ -151,5 +153,8 @@ export function getProviderIconColorClass(providerId: string): string {
   if (providerId === "acp-omp") {
     return "text-[#9333EA]";
   }
+  if (providerId === "acp-prime-agent") {
+    return "text-[#9333EA]";
+  }
   return "text-foreground";
 }

apps/server/src/services/system/known-acp-agents.ts

@@ -13,6 +13,33 @@ export interface KnownAcpAgentExecutableQuery {
 }
 
 export const KNOWN_ACP_AGENTS: readonly KnownAcpAgent[] = [
+  {
+    // bb owns transcript persistence, so Prime must not reuse saved sessions.
+    id: "acp-prime-agent",
+    displayName: "Prime Agent",
+    command: "prime-agent",
+    args: ["--mode", "acp", "--no-session"],
+    env: {},
+    executableName: "prime-agent",
+    modelCli: {
+      listArgs: ["model", "list"],
+      selectFlag: "--model",
+      primaryModels: [
+        "openai-codex/gpt-5.6-luna",
+        "openai-codex/gpt-5.6-sol",
+        "openai-codex/gpt-5.6-terra",
+        "anthropic/claude-opus-5",
+        "anthropic/claude-sonnet-5",
+        "anthropic/claude-fable-5",
+      ],
+    },
+    reasoningCli: {
+      flag: "--thinking",
+      supportedLevels: ["low", "medium", "high", "xhigh", "max"],
+      levelValues: { low: "minimal" },
+      defaultLevel: "medium",
+    },
+  },
   {
     id: "acp-opencode",
     displayName: "opencode",

apps/server/test/public/public-thread-data.test.ts

@@ -3212,6 +3212,7 @@ describe("public thread data routes", () => {
         {
           type: "known_acp_agents.status",
           agents: [
+            { id: "acp-prime-agent", executableName: "prime-agent" },
             { id: "acp-opencode", executableName: "opencode" },
             { id: "acp-omp", executableName: "omp" },
             { id: "acp-grok", executableName: "grok" },

packages/agent-runtime/src/acp/bridge/bridge.test.ts

@@ -97,6 +97,7 @@ interface StartThreadArgs {
         selectFlag: string;
         model: string;
         reasoningLevel?: ReasoningLevel;
+        serviceTier?: "default" | "fast";
       }
     | { modelId: string; reasoningLevel?: ReasoningLevel };
   launchReasoningLevel?: ReasoningLevel;
@@ -870,6 +871,35 @@ describe("acp bridge", () => {
     ).toBe(true);
   });
 
+  it("passes a provider-qualified fast model through the model flag", async () => {
+    chmodSync(FAKE_AGENT_PATH, 0o755);
+
+    const { providerThreadId } = await startThread({
+      agent: { command: FAKE_AGENT_PATH, args: [] },
+      modelSelection: {
+        listCommand: {
+          command: process.execPath,
+          args: [
+            "-e",
+            'console.error("provider  model  context\\nanthropic  claude-opus-5  1M\\nanthropic  claude-opus-5-fast  1M")',
+          ],
+        },
+        selectFlag: "--model",
+        model: "anthropic/claude-opus-5",
+        serviceTier: "fast",
+      },
+    });
+    sendRequest("turn/start", {
+      threadId: providerThreadId,
+      input: [{ type: "text", text: "echo-argv", mentions: [] }],
+    });
+    await waitForTurnCompleted();
+
+    expect(agentMessageTexts()).toContain(
+      "argv:--model anthropic/claude-opus-5-fast",
+    );
+  });
+
   it("selects ACP-native models with session/set_config_option before the first prompt", async () => {
     const { providerThreadId } = await startThread({
       envVars: { FAKE_ACP_MODEL_CONFIG: "1" },

packages/agent-runtime/src/acp/bridge/bridge.ts

@@ -665,7 +665,8 @@ async function loadAgentModelCatalog(
       },
       (error, out, stderr) => {
         if (!error) {
-          resolveExec(out);
+          // Prime Agent writes its model table to stderr.
+          resolveExec(out.trim().length > 0 ? out : stderr);
           return;
         }
         if (isMissingExecutableError(error)) {

packages/agent-runtime/src/acp/bridge/model-catalog.test.ts

@@ -62,6 +62,27 @@ describe("acp model catalog", () => {
     ]);
   });
 
+  it("parses Prime Agent's provider/model table", () => {
+    expect(
+      parseAgentModelLines(
+        [
+          "provider      model                context  max-out  thinking  images",
+          "openai        gpt-5.6-sol          1.1M     128K     yes       yes",
+          "openai-codex  gpt-5.6-terra        272K     128K     yes       yes",
+        ].join("\n"),
+      ),
+    ).toEqual([
+      {
+        id: "openai/gpt-5.6-sol",
+        displayName: "gpt-5.6-sol",
+      },
+      {
+        id: "openai-codex/gpt-5.6-terra",
+        displayName: "gpt-5.6-terra",
+      },
+    ]);
+  });
+
   it("parses Grok's bulleted model list", () => {
     expect(
       parseAgentModelLines(

packages/agent-runtime/src/acp/bridge/model-catalog.ts

@@ -66,6 +66,8 @@ interface AgentModelVariant extends RawAgentModel {
 const MODEL_LINE_PATTERN = /^(\S+) - (.+)$/;
 const BARE_PROVIDER_MODEL_LINE_PATTERN = /^\S+\/\S+$/;
 const BULLETED_MODEL_LINE_PATTERN = /^[*-]\s+(\S+)(?:\s+\([^)]*\))?$/u;
+// Prime prints provider and model as the first two fixed-width columns.
+const PRIME_MODEL_TABLE_ROW_PATTERN = /^(\S+)\s{2,}(\S+)\s{2,}\S+/;
 
 // Trailing id tokens that mark a reasoning-effort variant, longest first so
 // `extra-high` wins over `high`. `none` maps onto bb's "none" (thinking-off)
@@ -118,6 +120,13 @@ export function parseAgentModelLines(stdout: string): RawAgentModel[] {
       if (BARE_PROVIDER_MODEL_LINE_PATTERN.test(trimmed)) {
         models.push({ id: trimmed, displayName: trimmed });
       }
+      const primeTableRow = PRIME_MODEL_TABLE_ROW_PATTERN.exec(trimmed);
+      if (primeTableRow) {
+        const [, provider, model] = primeTableRow;
+        if (provider !== "provider" && model !== "model") {
+          models.push({ id: `${provider}/${model}`, displayName: model });
+        }
+      }
       continue;
     }
     const [, id, displayName] = match;