feat(models): add gpt-5.4-mini to Codex and OpenCode selection (and openai/gpt-5.5 to OpenCode) (#4357)

## Thinking Path

> - Paperclip is the open source app people use to manage AI agents for
work
> - Agent runtimes are selected through adapters, and each adapter
exposes the model IDs an operator can pick in the UI
> - The `codex_local` and `opencode_local` adapters hardcode those
lists, so a newly released model stays unreachable until it is added
> - `gpt-5.4-mini` is available via both the Codex CLI and the OpenCode
CLI, but neither adapter lists it; `openai/gpt-5.5` is likewise missing
from `opencode_local`
> - This pull request adds those entries, and deliberately keeps
`gpt-5.4-mini` out of the Codex Fast mode allowlist because the model
does not support Fast mode
> - The benefit is that operators can select these models from the UI
instead of falling back to a manual model ID, and Fast mode fails closed
rather than sending unsupported overrides to the CLI

## Linked Issues or Issue Description

No existing issue covers this. Describing it inline, following the
feature request template:

### Problem or motivation

`gpt-5.4-mini` is absent from the `models` list of both the
`codex_local` and `opencode_local` adapters, and `openai/gpt-5.5` is
absent from `opencode_local`. (`codex_local` already ships `gpt-5.5` —
it is the default model on master.) Operators who want these models must
type a manual model ID.

For `codex_local` that has a real side effect.
`isCodexLocalFastModeSupported` treats any *unknown* model as
Fast-mode-capable and passes `service_tier="fast"` and
`features.fast_mode=true` through to the CLI. Because `gpt-5.4-mini`
does not support Codex Fast mode, an agent configured with a manual
`gpt-5.4-mini` model ID and `fastMode` enabled silently sends overrides
the CLI cannot honor.

### Proposed solution

Add the three missing entries to the two `models` lists, and leave
`CODEX_LOCAL_FAST_MODE_SUPPORTED_MODELS` untouched. Listing
`gpt-5.4-mini` in `models` is precisely what makes it a *known* model,
so `isCodexLocalFastModeSupported` returns `false`, `buildCodexExecArgs`
omits the Fast mode overrides, and `fastModeIgnoredReason` is surfaced
to the operator.

### Alternatives considered

Adding `gpt-5.4-mini` to `CODEX_LOCAL_FAST_MODE_SUPPORTED_MODELS` as
well — rejected, because the model does not support Fast mode and the
overrides would be rejected at run time. Leaving the models unlisted so
operators keep using manual IDs — rejected, because that is the path
that silently enables Fast mode for a model that cannot use it.

### Roadmap alignment

Not core roadmap work. `ROADMAP.md` does not plan adapter model-list
maintenance; this is routine upkeep as upstream CLIs ship new models.

## What Changed

- Add `gpt-5.4-mini` to the `codex_local` adapter's `models` list,
positioned after `gpt-5.4` (newest-first ordering).
- Add `openai/gpt-5.5` and `openai/gpt-5.4-mini` to the `opencode_local`
adapter's `models` list.
- Add a `buildCodexExecArgs` test asserting Fast mode is ignored for
`gpt-5.4-mini`.

`CODEX_LOCAL_FAST_MODE_SUPPORTED_MODELS` is intentionally unchanged. No
behavior changes to existing models or adapter logic.

## Verification

```
pnpm --filter @paperclipai/adapter-codex-local --filter @paperclipai/adapter-opencode-local typecheck
npx vitest run packages/adapters/codex-local packages/adapters/opencode-local
```

Both pass: typecheck clean on both packages, and 22 test files / 133
tests green, including the new `ignores fast mode for gpt-5.4-mini`
case.

## Risks

Low risk. The change is additive: three entries appended to two
model-selection lists, plus one test. No default model changes, no
adapter logic changes, no migrations.

One behavioral shift is intended. An operator who had `gpt-5.4-mini`
configured as a *manual* model ID with `fastMode` enabled was getting
Fast mode overrides passed through to the Codex CLI. After this change
`gpt-5.4-mini` is a known model, so those overrides are dropped and
`fastModeIgnoredReason` explains why.

## Model Used

- OpenAI Codex CLI with GPT-5 / GPT-5.5-assisted code editing (the
original commits on this branch).
- Anthropic Claude Opus 4.8 (`claude-opus-4-8`, 1M context, extended
thinking, tool use) for the master merge, conflict resolution, and the
scope reduction in the latest commit.

## Checklist

- [x] I have included a thinking path that traces from project context
to this change
- [x] I have specified the model used (with version and capability
details)
- [x] I have checked ROADMAP.md and confirmed this PR does not duplicate
planned core work
- [x] I have searched the GitHub PR list for similar or duplicate PRs
and confirmed this one is not a duplicate
- [x] I have either (a) linked existing issues with `Fixes: #` / `Closes
#` / `Refs #` OR (b) described the issue in-PR following the relevant
issue template
- [x] I have not referenced internal/instance-local Paperclip issues or
links (only public GitHub `#NNN` / `github.com/paperclipai/paperclip`
URLs)
- [x] My branch name describes the change (e.g. `docs/...`, `fix/...`)
and contains no internal Paperclip ticket id or instance-derived details
- [x] I have run tests locally and they pass
- [x] I have added or updated tests where applicable
- [x] I have updated relevant documentation to reflect my changes (N/A;
the adapter docs describe Fast mode support, which is unchanged)
- [x] I have considered and documented any risks above
- [ ] All Paperclip CI gates are green
- [ ] Greptile is 5/5 with no open P2s, recommendations, or follow-ups
- [x] I will address all Greptile and reviewer comments before
requesting merge

---------

Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>
Co-authored-by: Andrew Aymeloglu <aaymeloglu@gmail.com>

packages/adapters/codex-local/src/index.ts

@@ -40,6 +40,7 @@ export function isCodexLocalFastModeSupported(model: string | null | undefined):
 export const models = [
   { id: DEFAULT_CODEX_LOCAL_MODEL, label: DEFAULT_CODEX_LOCAL_MODEL },
   { id: "gpt-5.4", label: "gpt-5.4" },
+  { id: "gpt-5.4-mini", label: "gpt-5.4-mini" },
   { id: "gpt-5.3-codex-spark", label: "gpt-5.3-codex-spark" },
   { id: "gpt-5", label: "gpt-5" },
   { id: "o3", label: "o3" },

packages/adapters/codex-local/src/server/codex-args.test.ts

@@ -109,6 +109,23 @@ describe("buildCodexExecArgs", () => {
     ]);
   });
 
+  it("ignores fast mode for gpt-5.4-mini", () => {
+    const result = buildCodexExecArgs({
+      model: "gpt-5.4-mini",
+      fastMode: true,
+    });
+
+    expect(result.fastModeRequested).toBe(true);
+    expect(result.fastModeApplied).toBe(false);
+    expect(result.args).toEqual([
+      "exec",
+      "--json",
+      "--model",
+      "gpt-5.4-mini",
+      "-",
+    ]);
+  });
+
   it("adds --skip-git-repo-check when requested", () => {
     const result = buildCodexExecArgs(
       {

packages/adapters/opencode-local/src/index.ts

@@ -55,7 +55,9 @@ export function isValidOpenCodeModelId(value: unknown): value is string {
 
 export const models: Array<{ id: string; label: string }> = [
   { id: DEFAULT_OPENCODE_LOCAL_MODEL, label: DEFAULT_OPENCODE_LOCAL_MODEL },
+  { id: "openai/gpt-5.5", label: "openai/gpt-5.5" },
   { id: "openai/gpt-5.4", label: "openai/gpt-5.4" },
+  { id: "openai/gpt-5.4-mini", label: "openai/gpt-5.4-mini" },
   { id: "openai/gpt-5.2", label: "openai/gpt-5.2" },
   { id: "openai/gpt-5.1-codex-max", label: "openai/gpt-5.1-codex-max" },
   { id: "openai/gpt-5.1-codex-mini", label: "openai/gpt-5.1-codex-mini" },