EphemeralAgent::get_patterns() returns an empty list because of a stub-shaped internal call

[shaal]

What's happening

EphemeralAgent::get_patterns() is supposed to return the list of patterns the agent has learned so far. In practice it returns an empty Vec — every time, regardless of how much the agent has learned.

The line at fault

In crates/sona/src/training/federated.rs, around line 232:

pub fn get_patterns(&self) -> Vec<LearnedPattern> {
    self.engine.find_patterns(&[], 0)
}

The call is asking the engine two things at once:

• "Give me the patterns most similar to this query embedding: &[]" (an empty vector)
• "Return the top k = 0 of them"

Both halves are degenerate. k = 0 means "return zero results." The engine complies and hands back Vec::new(). So get_patterns() answers its "please give me everything the agent learned" contract with "nothing, ever" — silently.

The shape of the call (passing &[] and 0 as literals, rather than forwarding real arguments) strongly suggests this was scaffolding that compiled and was never revisited.

Why this is easy to miss

A consumer calling agent.get_patterns() gets vec![] back. No error, no panic, no log line. If the downstream UI then renders "no patterns yet" or simply hides an empty panel, the agent appears to be doing its job — it just appears to be a very quiet learner. Stats surfaces that read from get_stats() instead (which works fine) continue to report the correct pattern counts, so any "how many patterns do you have?" check gives the impression that everything is wired up.

I found this while building a consumer that tried to visualise the learned-pattern list and was confused why it was always empty despite get_stats().patterns growing.

What's actually available in the engine

The underlying engine.find_patterns(query, k) works — it does a proper cosine-similarity top-k lookup. And there's a get_all_patterns() method on the engine that returns the full accumulated list. Neither is exposed through EphemeralAgent:

• get_patterns() should almost certainly delegate to engine.get_all_patterns() (the literal "everything you've learned" contract).
• There's no public find_patterns(query, k) on EphemeralAgent at all — so consumers who want a query-ranked top-k have no way to ask for one, even though the engine can do it.

The WASM binding inherits the same gap: WasmEphemeralAgent::getPatterns returns empty, and there's no findPatterns JS method on the WASM wrapper at all.

Suggested fix (sketch)

A narrow, two-file change:

1. federated.rs: make get_patterns() call self.engine.get_all_patterns(), and add a public fn find_patterns(&self, query: &[f32], k: usize) that forwards to the engine.
2. wasm.rs: add a #[wasm_bindgen(js_name = findPatterns)] binding on WasmEphemeralAgent that accepts a Vec<f32> + usize and returns the serialized pattern list.

I have a ready-to-review PR with exactly this change — linking it shortly.

Version / context

Found against main (upstream head at time of reporting: 6964dfdc). Reproducible by constructing an EphemeralAgent, calling agent.observe(...) / the equivalent pattern-accumulation path enough times that get_stats().patterns > 0, then calling get_patterns() — which will still return vec![].

Happy to adjust the fix shape (e.g. rename, deprecate get_patterns in favour of find_patterns(query, k), or anything else) based on what you'd prefer for the public API.