agent: add --list-models flag

build.zig.zon

@@ -39,8 +39,8 @@
             .hash = "N-V-__8AAJ4HAgCX79UDBfNwhqAqUVoGC44ib6UYa18q6oa_",
         },
         .zenai = .{
-            .url = "git+https://github.com/lightpanda-io/zenai.git#37cad37184736fafea8afcff9d1593b7009a71eb",
-            .hash = "zenai-0.0.0-iOY_VGRyAwCRQnr-DCFhnQBC-eM2JVHjS1mUKWBHTWmm",
+            .url = "git+https://github.com/lightpanda-io/zenai.git#580f172579e211b07ecaff311149543e6a47a1f3",
+            .hash = "zenai-0.0.0-iOY_VASPAwAYCAzeFaDegm0F227A-I-hYNFnZpV1yw3A",
         },
         .libidn2 = .{
             .url = "https://ftp.gnu.org/gnu/libidn/libidn2-2.3.8.tar.gz",

src/Config.zig

@@ -200,6 +200,7 @@ const Commands = cli.Builder(.{
             .{ .name = "task", .type = ?[]const u8 },
             .{ .name = "task_attachments", .type = []const u8, .multiple = true },
             .{ .name = "verbosity", .type = AgentVerbosity, .default = AgentVerbosity.low },
+            .{ .name = "list_models", .type = bool },
         },
         .shared_options = CommonOptions,
     },
@@ -783,6 +784,10 @@ pub fn printUsageAndExit(self: *const Config, success: bool) void {
         \\                a positional script is present, any new commands
         \\                entered in the REPL are appended to that file.
         \\
+        \\--list-models   Print the model IDs usable with `agent` for
+        \\                --provider, one per line, sorted, and exit.
+        \\                Requires --provider; the API key must be set.
+        \\
         \\--verbosity     Stderr chatter level: low, medium, high.
         \\                Default: low. In a TTY REPL, low shows a single-
         \\                line agent indicator and a per-turn summary;

src/agent.zig

@@ -6,6 +6,7 @@ pub const CommandExecutor = @import("agent/CommandExecutor.zig");
 pub const Recorder = @import("agent/Recorder.zig");
 pub const Verifier = @import("agent/Verifier.zig");
 pub const SlashCommand = @import("agent/SlashCommand.zig");
+pub const listModels = @import("agent/list_models.zig").run;
 
 test {
     _ = Agent;

src/agent/list_models.zig

@@ -0,0 +1,96 @@
+const std = @import("std");
+const zenai = @import("zenai");
+const log = @import("../log.zig");
+
+const Allocator = std.mem.Allocator;
+const ProviderKind = zenai.provider.ProviderKind;
+
+/// List the models usable with the lightpanda agent for `provider` and print
+/// their IDs to stdout, one per line, sorted alphabetically. Returns
+/// `error.MissingApiKey` when the provider's env var isn't set; other errors
+/// propagate from the underlying HTTP call.
+///
+/// Filtering uses each provider's `isChatModel` predicate from zenai.
+/// Ollama is unfiltered — local catalogs don't follow a naming convention
+/// the heuristic could rely on.
+pub fn run(allocator: Allocator, provider: ProviderKind, base_url_override: ?[:0]const u8) !void {
+    const api_key = zenai.provider.envApiKey(provider) orelse {
+        log.fatal(.app, "missing API key", .{
+            .provider = @tagName(provider),
+            .env = switch (provider) {
+                .anthropic => "ANTHROPIC_API_KEY",
+                .openai => "OPENAI_API_KEY",
+                .gemini => "GOOGLE_API_KEY or GEMINI_API_KEY",
+                .ollama => "(none)",
+            },
+        });
+        return error.MissingApiKey;
+    };
+
+    var arena_state = std.heap.ArenaAllocator.init(allocator);
+    defer arena_state.deinit();
+    const arena = arena_state.allocator();
+
+    var ids: std.ArrayList([]const u8) = .empty;
+
+    switch (provider) {
+        .anthropic => {
+            var client = zenai.anthropic.Client.init(allocator, api_key, .{});
+            defer client.deinit();
+            var resp = try client.listModels();
+            defer resp.deinit();
+            for (resp.value.data orelse &.{}) |m| {
+                if (!zenai.anthropic.Client.isChatModel(m)) continue;
+                if (m.id) |id| try ids.append(arena, try arena.dupe(u8, id));
+            }
+        },
+        .openai => {
+            var client = zenai.openai.Client.init(allocator, api_key, if (base_url_override) |u| .{ .base_url = u } else .{});
+            defer client.deinit();
+            var resp = try client.listModels();
+            defer resp.deinit();
+            for (resp.value.data orelse &.{}) |m| {
+                if (!zenai.openai.Client.isChatModel(m)) continue;
+                if (m.id) |id| try ids.append(arena, try arena.dupe(u8, id));
+            }
+        },
+        .ollama => {
+            const opts: zenai.openai.Client.InitOptions = if (base_url_override) |u|
+                .{ .base_url = u }
+            else
+                .{ .base_url = "http://localhost:11434/v1" };
+            var client = zenai.openai.Client.init(allocator, api_key, opts);
+            defer client.deinit();
+            var resp = try client.listModels();
+            defer resp.deinit();
+            for (resp.value.data orelse &.{}) |m| {
+                if (m.id) |id| try ids.append(arena, try arena.dupe(u8, id));
+            }
+        },
+        .gemini => {
+            var client = zenai.gemini.Client.init(allocator, api_key, .{});
+            defer client.deinit();
+            var resp = try client.listModels(.{});
+            defer resp.deinit();
+            for (resp.value.models orelse &.{}) |m| {
+                if (!zenai.gemini.Client.isChatModel(m)) continue;
+                const name = m.name orelse continue;
+                // Gemini returns "models/<id>"; strip the prefix so the
+                // output is pipe-ready into `--model`.
+                const stripped = if (std.mem.startsWith(u8, name, "models/")) name["models/".len..] else name;
+                try ids.append(arena, try arena.dupe(u8, stripped));
+            }
+        },
+    }
+
+    std.mem.sort([]const u8, ids.items, {}, lessThan);
+
+    var stdout_file = std.fs.File.stdout().writer(&.{});
+    const w = &stdout_file.interface;
+    for (ids.items) |id| try w.print("{s}\n", .{id});
+    try w.flush();
+}
+
+fn lessThan(_: void, a: []const u8, b: []const u8) bool {
+    return std.mem.lessThan(u8, a, b);
+}

src/main.zig

@@ -63,6 +63,14 @@ fn run(allocator: Allocator, main_arena: Allocator) !void {
             try stdout.interface.print("{s}\n", .{lp.build_config.version});
             return std.process.cleanExit();
         },
+        .agent => |opts| if (opts.list_models) {
+            const provider = opts.provider orelse {
+                log.fatal(.app, "missing --provider", .{ .flag = "--list-models" });
+                return args.printUsageAndExit(false);
+            };
+            try lp.agent.listModels(allocator, provider, opts.base_url);
+            return std.process.cleanExit();
+        },
         else => {},
     }