[diogenxs]

Fixes #593.

Problem

On Postgres, ai_messages.content_json is a text column. Bun SQL binds a plain array to a text parameter via String(), so every AI message is stored as the literal '[object Object]'. On replay the row fails schema validation, history comes back with empty content, and the provider call fails (Anthropic: 400 user messages must have non-empty content).

Fix

JSON.stringify(input.content) at the single insert in server/ai/conversations/store.ts.

• Postgres: the text column now holds real JSON; normalizePostgresRow already JSON.parses string-valued *_json columns on read.
• SQLite: toBindable passes strings through unchanged, so what gets stored is byte-for-byte the same as before.

Why narrow (revised)

The first version of this PR serialized every object param in the Postgres adapter. As @qu4ntom pointed out, that breaks jsonb columns: Bun binds objects to jsonb correctly today, and a pre-stringified value would be stored as a JSON string scalar, so jsonField() queries (data-row filters, plugins) would stop matching new rows. content_json is the only text JSON column in migrations-pg.ts, so the fix belongs at that call site.

Not included

• Rows already stored as '[object Object]' aren't recoverable. They read back as empty blocks, which the read path already handles. Migrating the column to jsonb could be a follow-up if you'd prefer that over the call-site fix.

Verification

• bun test src/__tests__/ai/ (conversation / tool-result / image round-trip tests): green
• typecheck and eslint clean

🤖 Generated with Claude Code

[diogenxs]

Filed the underlying report as #593. Rebased onto current main (the adapter gained ownsPool/close() — conflict resolved, serializer untouched) and the full test suite runs green locally; the only failures I see are the canvas/DOM tests that also fail on pristine main in my environment, nothing related to this change.

[qu4ntom]

Root cause confirmed. We hit this on 0.0.21 (Postgres, Bun 1.4.2): AI chat messages are stored as [object Object], and Anthropic answers with 400 user messages must have non-empty content.

One caveat with this approach: stringifying all object params breaks jsonb columns. Bun binds objects to jsonb correctly today, but a pre-stringified value is stored as a JSON string scalar:

${{ theme: 'dark' }}                 // jsonb_typeof = object, ->>'theme' = 'dark'
${JSON.stringify({ theme: 'dark' })} // jsonb_typeof = string, ->>'theme' = NULL

Reads still work (normalizePostgresRow re-parses strings), but jsonField() queries, e.g. data-row filters and plugins, stop matching for newly written rows.

ai_messages.content_json is the only text JSON column on Postgres, so a narrower fix seems safer, either:

• JSON.stringify(input.content) in server/ai/conversations/store.ts (verified), or
• migrating that column to jsonb (after cleaning up existing [object Object] rows).

[diogenxs]

Thanks @qu4ntom, good catch on jsonb. Pre-stringifying in the adapter would have turned objects bound to jsonb columns into string scalars and broken jsonField() matching. I've reworked the PR to the narrow fix you suggested: JSON.stringify(input.content) at the ai_messages insert in server/ai/conversations/store.ts, rebased on current main, and the adapter is left untouched. SQLite stores exactly the same thing as before (strings pass through toBindable). Existing [object Object] rows are left alone, since they read back as empty blocks. Happy to follow up with a jsonb migration for that column if the maintainers prefer it.