The pipeline was only writer->judge, missing the format quality-check gemma does on its own output before scoring (is_usable() in revise.rs). Added spike/agents/critic.yaml with the [critic] prompts from prompts.toml, wired as a middle pipeline stage. Confirmed the full three-stage pipeline runs end to end. Note in NOTES.md that the stage runs but doesn't gate/retry -- pipeline: is linear, real retry-on-unusable behavior would need states:/transitions:.
83 lines
4.7 KiB
Markdown
83 lines
4.7 KiB
Markdown
# Spike: `ai-agents` (declarative YAML) vs. hand-wired `rig-core`
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## What this proves
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- `ai-agents` (crates.io `ai-agents` v1.0.0, Rust-native, no Python) can load an
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agent purely from YAML and talk to both of this project's real backends:
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- `spike/agents/writer.yaml` -> Ollama (`gemma4-e4b:latest`), matches `wire_gemma_client`
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in `src/main.rs`.
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- `spike/agents/critic.yaml` -> Ollama (`gemma4-e4b:latest`), matches the
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self-review/quality-guard call in `revise.rs`'s `is_usable()` — same
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provider as the writer, but its own system prompt and prompt template
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lifted verbatim from `prompts.toml`'s `[critic]` section.
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- `spike/agents/judge.yaml` -> `provider: openai-compatible` against the local
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`llama-server` (Shieldstral), matches `wire_shieldstral`.
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- All three worked verbatim against this machine's real models/config, no mocking.
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- `spike/pipeline.yaml` expresses the three-stage generate -> critic -> judge
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flow (this project's `revise::generate_below_threshold` shape, including
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the format quality-guard before scoring) as one declarative `pipeline:`
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block with `spawner.auto_spawn` and `{{ stages.<id> }}` templating, no
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manual Rust orchestration code. Confirmed working end to end: writer runs,
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critic judges its format (`yes`/`no`), judge scores it independently — all
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three stages complete in a single `agent.chat()` call.
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## What it doesn't prove (real limitations found)
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1. ~~VRAM ceiling~~ **Resolved — not a framework limitation at all.** The
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initial failure (`cudaMalloc failed: out of memory` from Ollama's
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`/api/chat`) was from running Shieldstral's `llama-server` at its
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default `-ngl 999` (full GPU offload) alongside Ollama's own gemma
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load — both fighting for the same 8GB card. Restarting `llama-server`
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with `-ngl 0` (CPU-only, same flag this project already documents
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using for Shieldstral) puts it entirely on CPU, and the full
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three-stage `pipeline:` (writer -> critic -> judge) then runs cleanly
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end to end in one process — GPU usage stayed flat at ~6GB (all Ollama)
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throughout. This
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is a `llama-server` launch flag, not anything `ai-agents`-specific;
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`ai-agents` never touches GPU/CPU placement itself, it only talks HTTP
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to whatever backend is configured. `src/server.rs`'s `ensure_running()`
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doesn't currently pass `-ngl`, so it would need an `-ngl 0` addition
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(mirroring `server.toml`) to get the same behavior in the real app.
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2. **No logprob-based scoring.** `revise.rs`'s real `score()` function reads
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token logprobs off Shieldstral's response (see `models::ChatLogprobs`) to
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get a continuous 0.0-1.0 score, not a yes/no string. `ai-agents`'
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`Agent::chat()` returns plain text content; there's no exposed hook for
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raw logprobs in the YAML/builder API surface I found. Reproducing the
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current scoring behavior would mean dropping to `ai-agents`' lower-level
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provider access (if any) or keeping rig-core for the judge call and only
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using `ai-agents` for orchestration/prompt config — a hybrid, not a
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clean swap.
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3. **Critic stage runs but doesn't gate anything.** `spike/agents/critic.yaml`
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reproduces the self-review prompt from `is_usable()`, and the pipeline
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calls it after the writer — but `pipeline:` stages are linear/fire-and-
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forget, so its `yes`/`no` verdict is just an extra text output; it never
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branches back to re-run the writer the way `MAX_GENERATION_RETRIES`
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does in `revise.rs`. Getting real retry-on-unusable behavior (or the
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separate `MAX_REVISION_ITERATIONS` score-feedback loop) would need
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`states:`/`transitions:` (a state machine keyed off the critic's/judge's
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output) instead of the one-shot `pipeline:` construct used here.
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## Verdict
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The declarative-YAML story checks out for *provider wiring and prompt
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config* — that part is genuinely config, not code, and matches the
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CrewAI-style ergonomics from the earlier conversation, and the full
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two-stage pipeline now runs end to end against this project's real local
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models (see reproducing steps below). It does **not** cleanly cover this
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project's actual judge mechanism (logprob scoring), so adopting it
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wholesale would be a partial rewrite of `revise.rs`'s scoring logic, not a
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drop-in replacement. Worth revisiting if a future judge model switches to
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yes/no-only verdicts, or if `ai-agents` grows raw-logprob access.
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## Reproducing
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```
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ollama serve # writer leg (gemma)
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/home/austin/.local/share/llama.cpp/build/bin/llama-server \
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-m /home/austin/ai/Shieldstral-1.0-3B-BF16.gguf --jinja -c 32768 \
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--host 127.0.0.1 --port 8000 -ngl 0 # judge leg, CPU-only so it
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# doesn't fight gemma for VRAM
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cargo run --bin ai_agents_spike
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```
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