# Gemma 4 as a persistent-correspondence agent

**Date:** 2026-04-18
**Model:** `gemma4:26b` via mcp-gemma4 (steel141 Ollama)
**Test fixture:** Real inbound message from Andy Freiberg (Apr 19, 2026), real CONTEXT.md slice from `~/bin/spaceflight/andy/`
**Question:** Could gemma4 run an Andy-style persistent correspondence (drafting + state management)?

## TL;DR

**Partial yes, supervised. Full no, unsupervised.**

Gemma4 handles the **bookkeeping** half of persistent correspondence well — state diffs, pending-list maintenance, summarizing what's open. It fails the **drafting** half whenever precision matters: it hallucinates message IDs, invents figure content it can't see, and drifts off the established voice register without explicit examples.

For a low-stakes social correspondence (Discord chat with a friend, no IDs needed) gemma4 would be fine. For the Andy correspondence specifically — high-stakes scientific writing with manuscript references, figure specs, and a senior physician collaborator — it would need either Claude as a quality gate or a tool-using setup with retrieval over actual artifacts.

## Test setup

Single-shot test via `mcp__gemma4__ask_gemma4`:

- **System prompt:** Set Claude's persona, voice rules, draft→review→send convention.
- **User prompt:** Slice of CONTEXT.md (Pending section, vocabulary bridge, conventions agreed) + the verbatim Apr 19 inbound from Andy + two-part task (state diff + draft reply).
- **Settings:** `temperature=0.5`, `num_predict=2000`, default `num_ctx=8192`.

Total input fit comfortably in the 8K context. No tool calls. No retrieval — gemma4 worked from prompt content alone, the same constraint a real correspondence run would put on it (modulo whatever gets loaded into context per turn).

## Results

### What gemma4 got RIGHT

| Capability | Evidence |
|------------|----------|
| State bookkeeping | Correctly removed inbound from "Waiting on us", added new pending action items (figure work), kept Cambridge-editors carryover. The reasoning chain is sound. |
| Honored hard rules | Did NOT resurrect the rejected exaptation analogy. The "don't do X" instruction in the system prompt held. |
| Used agreed vocabulary | Used "diel," "conspecific," etc. correctly. Did not invent terminology. |
| Reply structure | Addressed all four asks in order. Decisions acknowledged tersely; action items as concrete bullets. Skeleton matches Claude's style. |
| Caught the carryover | Asked Andy for the Cambridge editor list — correctly flagged the open item that's been pending since Apr 17. |

### What gemma4 got WRONG (load-bearing failures)

| Failure | What it produced | What was correct | Cost |
|---------|------------------|------------------|------|
| **Hallucinated message ID** | `19da34ng...` | `19da34bc8e6ec51a` | Disqualifying. Cannot thread/reply on the actual platform. |
| **Hallucinated figure content** | Figure 1 axes = "trade-off between metabolic cost and temporal opportunity" | Real axes = Tinbergen 4Q grid: Static/Dynamic × Proximate/Ultimate | Andy would catch on first read; we lose credibility. |
| **Vague figure plans** | "Integrate molecular signaling pathways into Figure 3" | Real plan: per-population specifics — Pachón hypocretin, Tinaja/Molino distinct QTLs, shared attenuated per1 | Reply reads as a hand-wave; no actual content. |
| **Wrong voice register** | "Hi Andy" / "Best, Claude" / no AI disclaimer footer | "Dear Dr. Freiberg" / "Yours, Claude" / explicit AI-content disclaimer | Recognizable as off-brand. Disclaimer omission is a policy violation. |
| **Wrong CONTEXT.md schema** | Created a "Resolved" section | Schema has Pending / Sent / Received only | Minor — extrapolation, not invention. |

### Why these failures happened

Two distinct failure modes, neither fixable by prompt engineering alone:

1. **No access to the actual artifacts.** The figures live in `~/bin/spaceflight/andy/manuscript/figures/`. Gemma4 was not given them; it had no way to know what Figure 1 actually contains. Faced with a "describe what you'll change" task, it generated plausible-but-fictional content. This is the **classic hallucination-under-constraint failure mode**: the model would rather make something up than refuse.

2. **No few-shot examples of the target voice.** The system prompt described the voice ("Maintain Claude's voice") but didn't show it. Gemma4 defaulted to its trained-in casual register ("Hi Andy" / "Best, Claude"). A few-shot prompt with one or two real Claude-to-Andy letters would likely close most of this gap; the underlying capability is there.

## Where gemma4 fits

### Plausible roles

- **Low-stakes social correspondence.** Discord/Matrix chat with a friend. No precise IDs to preserve. Tolerance for vague replies is high.
- **First-pass triage.** Given inbound + CONTEXT.md, produce the state diff and a draft outline. Claude (or a human) reviews before send. This is the highest-value role — bookkeeping is the bulk of the work and it's where gemma4 is strongest.
- **Scheduled status checks.** "Anything new from Alice this week?" → summary. Read-only, no draft, no IDs to corrupt.
- **CONTEXT.md maintenance.** After a send, ask gemma4 to update the Sent table and Pending list from the message header alone.

### Disqualifying contexts

- **The Andy correspondence specifically.** Too many precise references that gemma4 would invent.
- **Anything requiring exact ID round-tripping.** Gmail message IDs, git SHAs, ticket numbers, citation keys, DOIs.
- **Anything where the model needs to reference attachments it can't read.** Figures, manuscripts, reviewer comments. It will hallucinate content.
- **Long-thread continuity tasks** where the conversation history exceeds 8K context and you need to reason over the full archive.

## Practical hybrid architecture

The persistent-correspondence template at `~/bin/persistent-correspondence/` doesn't need to change to support a hybrid setup. The routing decision lives in each contact's `CONTEXT.md` "workflow" section:

```
## Workflow

1. Inbound trigger → gemma4 produces CONTEXT.md state diff + draft outline.
2. Claude reviews the diff, applies it. For high-stakes contacts, Claude
   rewrites the draft with full artifact context. For low-stakes contacts,
   Seth reviews gemma4's draft directly.
3. Send via the platform adapter. Gemma4 updates the Sent table from the
   send confirmation.
```

This pattern lets gemma4 carry the volume work (state maintenance) without putting it in the critical path on accuracy-sensitive output.

## What this test did NOT cover

- **Multi-turn context retention.** Single-shot only. Real correspondence is many turns.
- **Tool calling.** Gemma4 supports it (`tools` parameter on the MCP). A retrieval-augmented gemma4 that can `read_attachment(filename)` would likely close the figure-hallucination gap. Not tested here.
- **Few-shot voice priming.** No example letters in the prompt. Voice scores would likely improve significantly with 1-2 in-context examples.
- **Smaller/larger Gemma 4 variants.** Only `gemma4:26b` tested. The 31b might do better on precision; the 8b would almost certainly do worse.
- **Other models.** No comparison against gpt-oss, qwen, etc. for the same task.

## Reproducing this test

The full prompt + system message used is in the conversation transcript that produced this report. Key prompt-engineering choices to replicate:

- Include actual CONTEXT.md content (not a paraphrase) so the schema is concrete.
- Include the verbatim inbound message, not a summary.
- Split the task: state diff first (cheap, structural), draft second (expensive, precision-sensitive). Lets you grade independently.
- Use temperature 0.3-0.5 for correspondence work — low enough to suppress invented content, high enough to keep the prose natural.

## See also

- `~/bin/persistent-correspondence/` — the template abstracted from the Andy correspondence
- `~/bin/spaceflight/andy/CONTEXT.md` — the reference implementation this test was drawn from
- `~/bin/gemma4-research/README.md` — overall Gemma 4 reference and gotchas