doubleo7/spike/NOTES.md
Austin Schaefer c5c25c8b49 spike: try ai-agents crate for declarative YAML agent config
Adds a standalone binary (src/bin/ai_agents_spike.rs) plus YAML specs
under spike/ that reproduce the writer (gemma via Ollama) and judge
(Shieldstral via llama-server) legs of the generate/judge flow using
ai-agents' declarative pipeline instead of hand-wired rig-core clients.

Both legs verified working individually against real local models.
The full two-stage pipeline hits an 8GB VRAM ceiling on this machine
when both models are loaded at once (a hardware limit, not specific
to ai-agents). ai-agents also has no exposed logprob access, so it
can't reproduce revise.rs's actual scoring mechanism as-is. See
spike/NOTES.md for the full writeup and verdict.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
2026-08-06 09:38:49 +02:00

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# Spike: `ai-agents` (declarative YAML) vs. hand-wired `rig-core`
## What this proves
- `ai-agents` (crates.io `ai-agents` v1.0.0, Rust-native, no Python) can load an
agent purely from YAML and talk to both of this project's real backends:
- `spike/agents/writer.yaml` -> Ollama (`gemma4-e4b:latest`), matches `wire_gemma_client`
in `src/main.rs`.
- `spike/agents/judge.yaml` -> `provider: openai-compatible` against the local
`llama-server` (Shieldstral), matches `wire_shieldstral`.
- Both worked verbatim against this machine's real models/config, no mocking.
- `spike/pipeline.yaml` expresses the two-stage generate -> judge flow (this
project's `revise::generate_below_threshold` shape) as one declarative
`pipeline:` block with `spawner.auto_spawn` and `{{ stages.<id> }}`
templating, no manual Rust orchestration code.
## What it doesn't prove (real limitations found)
1. **VRAM ceiling, not a framework bug.** Running the full pipeline in one
process needs Ollama's gemma model and Shieldstral's llama-server (32k
ctx, ~5.6GB) resident at once. On this 8GB card that overflows CUDA
("out of memory" from Ollama's own `/api/chat`, not from `ai-agents`).
The writer and judge legs each work fine in isolation. This constraint is
identical for the existing rig-core code — nothing here is
`ai-agents`-specific — but it means an actual migration would need to
confirm the current app doesn't already skirt this same ceiling.
2. **No logprob-based scoring.** `revise.rs`'s real `score()` function reads
token logprobs off Shieldstral's response (see `models::ChatLogprobs`) to
get a continuous 0.0-1.0 score, not a yes/no string. `ai-agents`'
`Agent::chat()` returns plain text content; there's no exposed hook for
raw logprobs in the YAML/builder API surface I found. Reproducing the
current scoring behavior would mean dropping to `ai-agents`' lower-level
provider access (if any) or keeping rig-core for the judge call and only
using `ai-agents` for orchestration/prompt config — a hybrid, not a
clean swap.
3. Multi-turn revision loop (`MAX_REVISION_ITERATIONS`, feeding the previous
score back into the next prompt) isn't attempted here — the pipeline
stage in this spike is a single writer -> judge pass, not the full
generate/score/revise loop with a threshold-driven exit condition. The
`pipeline:` construct is one-shot; the retry/threshold loop would likely
need `states:`/`transitions:` (state machine) rather than `pipeline:`.
## Verdict
The declarative-YAML story checks out for *provider wiring and prompt
config* — that part is genuinely config, not code, and matches the
CrewAI-style ergonomics from the earlier conversation. It does **not**
cleanly cover this project's actual judge mechanism (logprob scoring), so
adopting it wholesale would be a partial rewrite of `revise.rs`'s scoring
logic, not a drop-in replacement. Worth revisiting if a future judge model
switches to yes/no-only verdicts, or if `ai-agents` grows raw-logprob
access.
## Reproducing
```
ollama serve # writer leg
# and/or
/home/austin/.local/share/llama.cpp/build/bin/llama-server \
-m /home/austin/ai/Shieldstral-1.0-3B-BF16.gguf --jinja -c 32768 \
--host 127.0.0.1 --port 8000 # judge leg
cargo run --bin ai_agents_spike
```