fix(agents): explain why Create/Save is disabled and fix Codex/Claude gate

[atishpatel]

Problem

Two related defects surfaced in the New/Edit Agent dialog:

1. Ian — Save permanently disabled when editing a Codex/Claude agent. agentAiConfigurationModeSatisfied always required a provider for a Customize pair, but Codex/Claude intentionally hide the provider picker (they drive their own provider). Save was gated on a value the user could never set.
2. Mat — Create disabled with no explanation. Selecting Use AI defaults while the global defaults have no provider/model leaves Create greyed out with nothing telling the user why.

Both share a root UX gap: the dialog exposed only a grey button, never the reason.

Fix

• Provider-aware agentAiConfigurationModeSatisfied (agentAiConfigurationPolicy.ts): new needsProviderSelection param (defaults true, so existing callers are unchanged). The call site passes runtimeSupportsLlmProviderSelection(runtime) — Buzz Agent/Goose still require provider+model; Codex/Claude need only a model.
• Inline disabled reason (personaSubmitBlock.ts, new pure module): maps the existing canSubmit gate outputs to one deterministic, human-readable reason rendered next to Create/Save. Precedence mirrors the canSubmit term order, so the reason is null exactly when the form can submit (transient Saving/Uploading aside) and advances/disappears as each input is fixed. Incomplete AI defaults name the actual missing pieces (provider/model/credential env keys) and point to Settings → AI defaults — never a generic "configuration incomplete".

No policy logic is duplicated in presentation code: the dialog passes the same gate results it already computes for canSubmit.

Validation

• desktop unit tests (node --test): 18 pass, 0 fail across personaSubmitBlock.test.mjs (new) and agentAiConfigurationPolicy.test.mjs (extended). Coverage includes: Buzz Agent + defaults missing provider/model shows the reason; Codex custom with model + empty provider is submittable; a valid form has no reason; the reason disappears once the blocking input is corrected; and reason precedence.
• tsc --noEmit: clean.
• biome check: clean.

Rust pre-push hooks were skipped on push (change is JS-only); CI runs the full gate.

Remaining UX note

The reason is a single line derived by strict canSubmit-order precedence — it names the first blocking input, not all of them at once. This is intentional (actionable + deterministic) and matches the acceptance criteria, but is worth a look during review.

[wesbillman]

The Codex/Claude correction is sound, but the new gate regresses the existing runtime-less legacy-definition path. Please use the already-derived provider-field capability (runtimeCanChooseLlmProvider, which includes blankRuntimeModelProviderEditable) rather than raw runtime support, and add coverage for a runtime-less edit before merge. The branch also needs rebasing onto current main and fresh CI after the fix.

[wesbillman]

Blocking: this conflates "runtime drives its own provider" with "runtime is blank." Existing legacy/builtin definitions can intentionally edit model/provider with no runtime (blankRuntimeModelProviderEditable), and this dialog already exposes the provider field for that case via runtimeCanChooseLlmProvider. Passing raw runtimeSupportsLlmProviderSelection("") === false now makes Customize require only a model, so after choosing No preference (or editing a runtime-less definition) Save can persist provider: undefined despite the visible provider picker. Pass the actual field capability (runtimeCanChooseLlmProvider) here and to the reason input, and add a runtime-less edit regression test.

[atishpatel]

🤖 (posted by Atish's AI agent) Fixed in 0b30d07. The three "provider is required" expressions — providerIsRequired, customAiPairSatisfied, and the submit-block reason input — now key off runtimeCanChooseLlmProvider (the same capability that governs whether the picker is shown) instead of the raw runtimeSupportsLlmProviderSelection(runtime). So a runtime-less legacy/builtin definition (blank runtime + saved model/provider, exposed via blankRuntimeModelProviderEditable) keeps requiring the visible provider, while Codex/Claude stay exempt (picker hidden). Added a runtime-less edit regression e2e (case 11 in global-agent-config-screenshots.spec.ts) that seeds no available runtime so the dialog does not auto-seed a runtime — verified it fails (Save enabled) without the change and passes with it — plus a policy unit test.

[wesbillman]

Code blocker resolved; merge gate still blocked on freshness. The new head correctly uses runtimeCanChooseLlmProvider for all three gates, and the runtime-less edit regression covers the failure mode while preserving Codex/Claude behavior. Current-head CI is green. However, this head is now 5 commits behind current main (79598bd), with overlapping changes in desktop/src/testing/e2eBridge.ts and desktop/tests/helpers/bridge.ts. Please rebase onto current main and rerun CI; I will clear the change request once that rebased head is green.