Zed

Zed's built-in AI agent.

Source: src/providers/zed.ts
Loading: lazy (src/providers/index.ts:177)
Test: tests/providers/zed.test.ts

Where it reads from

One SQLite database with one row per agent thread (zed.ts:19):

macOS: ~/Library/Application Support/Zed/threads/threads.db
Linux: ~/.local/share/zed/threads/threads.db
Windows: %LOCALAPPDATA%\Zed\threads\threads.db

Storage format

The threads table stores each thread's data BLOB as zstd-compressed JSON (data_type = "zstd"; legacy rows may be uncompressed "json", both are read, zed.ts:117-127). Decompression uses Node's built-in zlib.zstdDecompressSync (zed.ts:17), no extra dependency.

The decompressed thread JSON carries:

model: { "provider": ..., "model": ... }
request_token_usage: map of user-message id to { input_tokens, output_tokens, cache_creation_input_tokens, cache_read_input_tokens } (zero-valued fields are omitted)
cumulative_token_usage: same shape, whole-thread totals

Token semantics match Anthropic's (separate cache-creation and cache-read fields), so pricing maps directly onto the LiteLLM engine. Shapes verified against Zed's serialization source (crates/agent/src/db.rs: DbThread, TokenUsage, SerializedLanguageModel, DataType) and a real store.

Caching

None.

Deduplication

Per zed:<threadId>:<requestKey> (zed.ts:96), where requestKey is the user-message id from request_token_usage or the synthetic cumulative-remainder.

Quirks

request_token_usage is keyed by user message and does not cover every request a thread made (verified on a real thread: cumulative was ~3x the map sum). One remainder entry per thread tops usage up to the exact cumulative_token_usage (zed.ts:133-153), so totals always match the store.
The per-request map carries no timestamps, so every call in a thread uses the thread's updated_at; day-level attribution inside long-running threads is approximate.
Node's zlib gained zstd in 22.15. On older Nodes the provider skips with a notice instead of failing (zed.ts:14-17).
All Zed usage currently lands under a single zed project; folder_paths is not yet mapped to per-project attribution.

When fixing a bug here

If discovery returns no sessions, confirm threads.db exists at the platform path and the threads table still has id, summary, updated_at, data_type, data.
If threads are skipped, check data_type values on disk; only zstd and json are read.
If totals disagree with the store, compare against cumulative_token_usage per thread; the remainder logic must bring each thread exactly to it.
If model names stop pricing, inspect model.model strings in a real thread and add aliases if Zed introduces new hosted-model ids.

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Zed