separate event for providing tool details

OpenAI and Anthropic have tool details (id, name) converge on different
timelines. In all cases they are available in `onBlockComplete` which
comes with the full block, and previously we had an optional `BlockMeta`
argument to `onBlockStart` - the anthropic timeline.

We removed the `BlockMeta` from `onBlockStart` since it was always going
to be unreliable, and now have an explicit `onToolDetails` instead. This
allows us to provide the tool id and name as early as possible from the
openai provider (could be in the middle of content deltas), and provide
a reliable signal across providers.

Also, fix test output.

1 files changed, 11 insertions, 1 deletions

diff --git a/libpanto/src/root.zig b/libpanto/src/root.zig
index 5dacfef..ff02d4d 100644
--- a/libpanto/src/root.zig
+++ b/libpanto/src/root.zig
@@ -1,3 +1,5 @@
+const std = @import("std");
+
 pub const conversation = @import("conversation.zig");
 pub const provider = @import("provider.zig");
 pub const agent = @import("agent.zig");
@@ -25,7 +27,15 @@ const anthropic_messages_json = @import("anthropic_messages_json.zig");
 const provider_anthropic_messages = @import("provider_anthropic_messages.zig");
 
 test {
-    const std = @import("std");
+    // Test contract: deliberate error-path tests should not produce visible
+    // log output. Library code logs at `.err` for genuine production failures
+    // and `.warn` for expected-failure paths exercised by tests; the test
+    // runner's logger gates on `std.testing.log_level`, which defaults to
+    // `.warn`. Raising it to `.err` silences expected warnings without
+    // changing production behavior. Anything that *should* be visible in a
+    // passing test must use `std.debug.print` or assert via the testing API.
+    std.testing.log_level = .err;
+
     std.testing.refAllDecls(@This());
     std.testing.refAllDecls(openai_chat_json);
     std.testing.refAllDecls(provider_openai_chat);