codeburn/docs/providers/gemini.md

Gemini

Google Gemini CLI.

• Source: src/providers/gemini.ts
• Loading: eager (src/providers/index.ts)
• Test: tests/providers/gemini.test.ts

Where it reads from

~/.gemini/tmp/<project>/chats/session-*.json and session-*.jsonl (gemini.ts:218-252).

Storage format

Either a single JSON document per session or JSONL, depending on Gemini CLI version. The parser tries JSON.parse on the whole file first (single-JSON, Gemini CLI <=0.38); if that throws or the result doesn't look like a session, it falls back to parsing the file line by line as JSONL (gemini.ts:194-204).

Caching

None.

Deduplication

Per session and message: the key is gemini:<sessionId>:<messageId>, where messageId falls back to a per-message ordinal when the message has no id (gemini.ts:97).

Quirks

• Cached tokens are a subset of input. Gemini reports cached tokens included inside promptTokenCount. The parser subtracts them so callers see Anthropic semantics (cached are separate).
• Thoughts are billed at output rate (gemini.ts:125).
• One call per assistant message that carries usage. parseSession walks every gemini-type message with tokens and model set and emits one ParsedProviderCall per message, not one per session.

When fixing a bug here

1. Add a fixture-based regression test alongside any parsing change; tests/providers/gemini.test.ts is the place for it.
2. If the bug involves a new Gemini version's schema, keep the same try-JSON-then-JSONL fallback; do not assume one format based on a byte sniff.
3. If the bug is "Gemini sessions report less than expected", check whether the cached-token subtraction is over-correcting.