# Agent identity profile's `agent_model` is frozen at first-ever provisioning, never updates

## Background

Noticed a real discrepancy: [https://staging.musehub.ai/gabriel/mists/4dB2qCpPV5vG's](https://staging.musehub.ai/gabriel/mists/4dB2qCpPV5vG)
provenance correctly shows `model_id: "claude-sonnet-5"` (accurate, per-object,
live), but the linked `claude-code` agent profile
([https://staging.musehub.ai/claude-code](https://staging.musehub.ai/claude-code)) shows `model claude-sonnet-4-6` — an
older model, from before this session's convention shifted to `claude-sonnet-5`.

## Root cause, traced precisely — not assumed

Two contributing bugs:

1. **`ensure_agent_identity`** (`musehub/services/derived_agent_provisioner.py:40-45`)
   is a pure upsert:
   ```python
   existing = (await session.execute(
       select(MusehubIdentity).where(MusehubIdentity.handle == handle)
   )).scalar_one_or_none()
   if existing is not None:
       return existing
   ```
   Once an agent's `musehub_identities` row exists, `agent_model` is **never
   updated again** — regardless of how many later commits use a different
   model. Every subsequent profile view returns the same frozen row.

2. **The seed value itself came from the wrong commit.** The fallback lookup
   that seeds `agent_model` when first auto-provisioning a derived agent
   (`musehub/api/routes/musehub/ui_user_profile.py:122-130`) orders by
   `MusehubCommit.timestamp` **ascending**, `.limit(1)` — the *oldest* commit
   by that `agent_id`, not the most recent:
   ```python
   select(MusehubCommit.agent_id, MusehubCommit.model_id, MusehubCommit.timestamp)
   .where(MusehubCommit.agent_id == handle)
   .order_by(MusehubCommit.timestamp)   # ascending — oldest first
   .limit(1)
   ```
   So `claude-code`'s identity got permanently seeded with whatever model was
   used in its very first-ever commit, and has been frozen there since.

Worth noting: `musehub/api/routes/musehub/ui_agents.py:278-297` (a *different*
agent-profile-adjacent route, repo-scoped) does this correctly — orders by
`MusehubCommit.timestamp.desc()` and re-derives `model_id` on every request
rather than caching it. That's the pattern to converge on.

## Goal (to be decided when picked up — this is a placeholder with real findings, not a full plan yet)

Decide deliberately: should `agent_model` mean "the model this identity was
first seen using" (a genesis/historical marker, in which case the bug is only
#1 — the oldest-first ordering was actually intentional and just needs the
value to stay frozen, which it already does) or "the model this identity is
*currently* using" (in which case both bugs need fixing: reseed from the
newest commit, and refresh on every new commit rather than caching forever)?
Given the profile page reads as a live status indicator (no "since" or
"first seen" qualifier next to it), current behavior is almost certainly the
wrong interpretation for how it's displayed today.

## Out of Scope (for now)

- Any broader redesign of derived-agent auto-provisioning beyond this one
  field.
- Retroactively backfilling `agent_model` for already-provisioned identities
  — decide whether that's needed once the live-vs-genesis question is
  resolved.