Build: Records, Vignettes, the File Contract

Maps to: Task 3. Kind: Build.

Objective

Create vignette.rs and record.rs in panoptes-core. Define Vignette, the deterministic vignette_id function, Usage, and ResponseRecord — the struct that becomes one line in responses.jsonl, the dataset of record. These types are the file contract: the interface every later stage and the Python analysis tail depend on.

Scaffold

Create: crates/panoptes-core/src/vignette.rs and crates/panoptes-core/src/record.rs. Modify: crates/panoptes-core/src/lib.rs (re-export both).

Dependencies: no manifest changes — chrono (with its serde feature, for DateTime<Utc>) is already declared.

Expected result: cargo test -p panoptes-core → 7 tests pass across the crate (2 params + 3 codes + 1 vignette + 1 record). The shared data model is complete.

The spec (givens)

• Vignette fields: id: String, family: String, params: Params, prompt: String, prompt_sha256: String.
• vignette_id(family: &str, p: &Params) -> String produces family-<conf:03>-<H|D>-<REV|IRREV>-<INFO|NOINFO> — e.g. ca_geo-030-H-REV-INFO (confidence zero-padded to 3 digits).
• Usage fields: input_tokens: u32, output_tokens: u32.
• ResponseRecord fields, in order: response_id: String, vignette_id: String, model: String, epoch: u32, params: Params, prompt: String, response: String, usage: Usage, run_at: chrono::DateTime<Utc>.

Full code: Answer Key, Task 3.

Concepts exercised

• chrono::DateTime<Utc> with serde support for timestamps.
• Deterministic ID construction from typed fields (no stringly-typed field access).
• Why the JSONL schema is the contract that makes the underlying tool fungible.

The build loop (you drive)

1. Write failing tests: vignette_id produces the exact formatted string (ca_geo-030-H-REV-INFO); ResponseRecord round-trips through a JSON line.
2. Predict what vignette_id returns for a given Params, character by character, before running.
3. Run, check.
4. Implement.
5. Run green, commit.

Done when

All of cargo test -p panoptes-core passes (params + codes + vignette + record). You now have the complete shared data model — every type the other three crates will import.