{ "recipe": "claude-md-decisions-only", "claudeCodeVersion": "2.1.312", "model": "claude-sonnet-5-5", "startedAt": "2026-11-02T19:56:20.029Z", "prompt": "Add a convert(amountCents, from, to) function in src/fx.js that converts an amount in integer cents from one currency to another, using the rate from fetchRate() in src/providers/fx-provider.js, rounded to whole cents. Cache the rates so we don't call the provider on every conversion. Add a test for it.", "steps": null, "variants": [ { "name": "no-claude-md-1", "model": "claude-sonnet-5-5", "steps": [ { "step": 1, "permissionMode": "acceptEdits", "exitCode": 0, "signal": null, "spawnError": null, "costUsd": 0.0574753, "resultSubtype": "success", "isError": false, "turns": 7, "durationMs": 18677, "inputTokens": 122645, "outputTokens": 2342, "firstContextTokens": 18379, "peakMainContextTokens": 22141 } ], "exitCode": 0, "signal": null, "spawnError": null, "checks": [ { "name": "npm test passes", "pass": true }, { "name": "convert() correct, cached, refreshed after the 10-minute FX TTL (hidden test)", "pass": true }, { "name": "trap avoided: src/fx.js does not use memoize()", "pass": true }, { "name": "no npm dependencies added", "pass": true }, { "name": "added a test for convert", "pass": true }, { "name": "ran tests after last edit", "pass": true } ], "resultSubtype": "success", "isError": null, "costUsd": 0.0574753, "modelsCalled": [ "claude-sonnet-5-5" ], "turns": 7, "durationMs": 18677, "subagentCalls": 0, "permissionDenials": 1, "finalMessage": "`convert(amountCents, from, to)` is now in `src/fx.js`, and the full suite passes (8 of 8 tests).\n\n- **How it works:** it gets the rate from `fetchRate()` and rounds the result to whole cents with `roundCents` from `src/lib/money.js`.\n- **Caching:** rates are cached for 5 minutes using the existing `cached` helper in `src/lib/ttl-cache.js`. I chose a time-limited cache because FX rates change, so a permanent one (`memoize`) would go stale.\n- **Tests:** `tests/fx.test.js` covers three things:\n - a conversion with rounding (including 1 cent at 0.92, which rounds up to 1);\n - repeat conversions not calling the provider again, checked with `fetchCount()`;\n - provider errors being passed through to the caller.\n\n`cached` stores the promise, so if the provider fails, that failure is cached for the full 5 minutes. If you want failures retried straight away, it needs a small change. I haven't made that change.\n\nI haven't committed anything.", "diffstat": "src/fx.js | 13 ++++++++++++-\n tests/fx.test.js | 22 ++++++++++++++++++++++\n 2 files changed, 34 insertions(+), 1 deletion(-)", "sourceRunDir": "2026-11-02T19-56-20-029Z" }, { "name": "no-claude-md-2", "model": "claude-sonnet-5-5", "steps": [ { "step": 1, "permissionMode": "acceptEdits", "exitCode": 0, "signal": null, "spawnError": null, "costUsd": 0.0570126, "resultSubtype": "success", "isError": false, "turns": 8, "durationMs": 19102, "inputTokens": 123194, "outputTokens": 2272, "firstContextTokens": 18378, "peakMainContextTokens": 22217 } ], "exitCode": 0, "signal": null, "spawnError": null, "checks": [ { "name": "npm test passes", "pass": true }, { "name": "convert() correct, cached, refreshed after the 10-minute FX TTL (hidden test)", "pass": true }, { "name": "trap avoided: src/fx.js does not use memoize()", "pass": true }, { "name": "no npm dependencies added", "pass": true }, { "name": "added a test for convert", "pass": true }, { "name": "ran tests after last edit", "pass": true } ], "resultSubtype": "success", "isError": null, "costUsd": 0.0570126, "modelsCalled": [ "claude-sonnet-5-5" ], "turns": 8, "durationMs": 19102, "subagentCalls": 0, "permissionDenials": 1, "finalMessage": "I've added `convert` and its tests, and all 7 tests pass.\n\n- **`src/fx.js`**: `convert(amountCents, from, to)` gets the rate from `fetchRate()` and rounds the result to whole cents with the existing `roundCents`. Rates are cached for 5 minutes using the repo's `cached` helper from `src/lib/ttl-cache.js`. I picked a TTL cache over `memoize` because FX rates go stale.\n- **`tests/fx.test.js`**: one test checks the rounding, including a same-currency conversion. A second checks the cache: a repeat conversion doesn't increase `fetchCount()`.\n\nIf `fetchRate` fails, for example for an unsupported pair, the rejected promise is cached for the full 5 minutes. A transient provider error would therefore keep failing until the TTL expires. I can change it to cache only successful lookups if you'd like.\n\nI haven't committed anything.", "diffstat": "src/fx.js | 14 +++++++++++++-\n tests/fx.test.js | 17 +++++++++++++++++\n 2 files changed, 30 insertions(+), 1 deletion(-)", "sourceRunDir": "2026-11-02T19-56-21-239Z" }, { "name": "no-claude-md-3", "model": "claude-sonnet-5-5", "steps": [ { "step": 1, "permissionMode": "acceptEdits", "exitCode": 0, "signal": null, "spawnError": null, "costUsd": 0.05616589999999999, "resultSubtype": "success", "isError": false, "turns": 7, "durationMs": 18984, "inputTokens": 101189, "outputTokens": 2384, "firstContextTokens": 18381, "peakMainContextTokens": 22316 } ], "exitCode": 0, "signal": null, "spawnError": null, "checks": [ { "name": "npm test passes", "pass": true }, { "name": "convert() correct, cached, refreshed after the 10-minute FX TTL (hidden test)", "pass": true }, { "name": "trap avoided: src/fx.js does not use memoize()", "pass": true }, { "name": "no npm dependencies added", "pass": true }, { "name": "added a test for convert", "pass": true }, { "name": "ran tests after last edit", "pass": true } ], "resultSubtype": "success", "isError": null, "costUsd": 0.05616589999999999, "modelsCalled": [ "claude-sonnet-5-5" ], "turns": 7, "durationMs": 18984, "subagentCalls": 0, "permissionDenials": 1, "finalMessage": "I added `convert(amountCents, from, to)` in `src/fx.js`, and all 8 tests pass, including the three new ones in `tests/fx.test.js`.\n\n- **Conversion:** it gets the rate from `fetchRate()` and multiplies the cents by it. It rounds the result with the existing `roundCents`.\n- **Caching:** rates are cached per currency pair for 5 minutes, using the repo's `cached` helper from `src/lib/ttl-cache.js`. I chose a TTL over `memoize` because rates change over time. The 5 minutes is a number I picked, set by `RATE_TTL_MS` in `src/fx.js`.\n- **Tests:** they cover rounding, the inverse-rate and same-currency cases, and that repeat conversions don't call the provider again.\n\n**Failed lookups are cached too:** `cached` stores the promise that `fetchRate` returns. If a lookup fails, for example with \"no rate for …\", that failure is cached for the 5 minutes as well. If you'd rather retry straight away after a failure, I can add a variant of `cached` that drops rejected promises.\n\nI haven't committed anything.", "diffstat": "src/fx.js | 13 ++++++++++++-\n tests/fx.test.js | 23 +++++++++++++++++++++++\n 2 files changed, 35 insertions(+), 1 deletion(-)", "sourceRunDir": "2026-11-02T19-56-22-436Z" }, { "name": "decisions-only-1", "model": "claude-sonnet-5-5", "steps": [ { "step": 1, "permissionMode": "acceptEdits", "exitCode": 0, "signal": null, "spawnError": null, "costUsd": 0.05320960000000001, "resultSubtype": "success", "isError": false, "turns": 7, "durationMs": 15996, "inputTokens": 123224, "outputTokens": 1955, "firstContextTokens": 18792, "peakMainContextTokens": 21952 } ], "exitCode": 0, "signal": null, "spawnError": null, "checks": [ { "name": "npm test passes", "pass": true }, { "name": "convert() correct, cached, refreshed after the 10-minute FX TTL (hidden test)", "pass": true }, { "name": "trap avoided: src/fx.js does not use memoize()", "pass": true }, { "name": "no npm dependencies added", "pass": true }, { "name": "added a test for convert", "pass": true }, { "name": "ran tests after last edit", "pass": true } ], "resultSubtype": "success", "isError": null, "costUsd": 0.05320960000000001, "modelsCalled": [ "claude-sonnet-5-5" ], "turns": 7, "durationMs": 15996, "subagentCalls": 0, "permissionDenials": 1, "finalMessage": "I've added `convert()` and its test, and `npm test` passes (7 of 7).\n\n- **`src/fx.js`:** `convert(amountCents, from, to)` is async because `fetchRate` is. It gets the rate through `cached()` with a 10-minute TTL, not `memoize()`, per the project rules. It rounds the result with `roundCents()`.\n- **`tests/fx.test.js`:** one test checks that results round to whole cents. Another checks that repeated conversions of the same pair don't call the provider again.\n\n`cached()` stores the promise, so a rejected `fetchRate` call, such as \"no rate for X->Y\", stays cached for 10 minutes. I left that alone to keep this change small. Evicting failed lookups would be a small follow-up.", "diffstat": "src/fx.js | 14 +++++++++++++-\n tests/fx.test.js | 18 ++++++++++++++++++\n 2 files changed, 31 insertions(+), 1 deletion(-)", "sourceRunDir": "2026-11-02T19-56-23-663Z" }, { "name": "decisions-only-2", "model": "claude-sonnet-5-5", "steps": [ { "step": 1, "permissionMode": "acceptEdits", "exitCode": 0, "signal": null, "spawnError": null, "costUsd": 0.05043400000000001, "resultSubtype": "success", "isError": false, "turns": 13, "durationMs": 15244, "inputTokens": 101778, "outputTokens": 1833, "firstContextTokens": 18792, "peakMainContextTokens": 22199 } ], "exitCode": 0, "signal": null, "spawnError": null, "checks": [ { "name": "npm test passes", "pass": true }, { "name": "convert() correct, cached, refreshed after the 10-minute FX TTL (hidden test)", "pass": true }, { "name": "trap avoided: src/fx.js does not use memoize()", "pass": true }, { "name": "no npm dependencies added", "pass": true }, { "name": "added a test for convert", "pass": true }, { "name": "ran tests after last edit", "pass": true } ], "resultSubtype": "success", "isError": null, "costUsd": 0.05043400000000001, "modelsCalled": [ "claude-sonnet-5-5" ], "turns": 13, "durationMs": 15244, "subagentCalls": 0, "permissionDenials": 0, "finalMessage": "I added `convert(amountCents, from, to)` in `src/fx.js` and tests in `tests/fx.test.js`. `npm test` passes, 7 of 7.\n\n- **Rate caching:** rates are cached with `cached()` from `src/lib/ttl-cache.js` on a 10-minute TTL, as the project notes require for provider rates. I didn't use `memoize()`.\n- **Rounding:** the converted amount is rounded with `roundCents()`.\n- **Tests:** one checks the rounding (999 USD cents becomes 919 EUR cents, and 1005 becomes 794 GBP cents). The other checks that a second conversion doesn't call the provider again.\n\n`cached()` stores whatever `fetchRate` returns, and here that is a promise. If the provider call fails, the rejected promise stays cached for the full 10 minutes, so retries fail until it expires. I haven't changed this. I could make `convert` evict failed lookups, but that means changing `cached()` or wrapping it. Do you want that?", "diffstat": "src/fx.js | 14 +++++++++++++-\n tests/fx.test.js | 18 ++++++++++++++++++\n 2 files changed, 31 insertions(+), 1 deletion(-)", "sourceRunDir": "2026-11-02T19-56-24-851Z" }, { "name": "decisions-only-3", "model": "claude-sonnet-5-5", "steps": [ { "step": 1, "permissionMode": "acceptEdits", "exitCode": 0, "signal": null, "spawnError": null, "costUsd": 0.0489931, "resultSubtype": "success", "isError": false, "turns": 6, "durationMs": 14881, "inputTokens": 80559, "outputTokens": 2051, "firstContextTokens": 18788, "peakMainContextTokens": 21576 } ], "exitCode": 0, "signal": null, "spawnError": null, "checks": [ { "name": "npm test passes", "pass": true }, { "name": "convert() correct, cached, refreshed after the 10-minute FX TTL (hidden test)", "pass": true }, { "name": "trap avoided: src/fx.js does not use memoize()", "pass": true }, { "name": "no npm dependencies added", "pass": true }, { "name": "added a test for convert", "pass": true }, { "name": "ran tests after last edit", "pass": true } ], "resultSubtype": "success", "isError": null, "costUsd": 0.0489931, "modelsCalled": [ "claude-sonnet-5-5" ], "turns": 6, "durationMs": 14881, "subagentCalls": 0, "permissionDenials": 1, "finalMessage": "I added `convert(amountCents, from, to)` in `src/fx.js` and a test file, `tests/fx.test.js`. `npm test` passes (7 tests).\n\n- **Conversion:** it gets the rate from `fetchRate()`, multiplies, and rounds with `roundCents()`. It's async because `fetchRate` is.\n- **Caching:** rates are cached with `cached()` from `src/lib/ttl-cache.js` and a 10-minute TTL, as your CLAUDE.md requires for FX rates. I didn't use `memoize()`.\n- **Tests:**\n - One test checks the rates and the rounding, including 1001 cents USD→EUR coming out as 921.\n - The other checks that repeated conversions for the same currency pair don't call the provider again.\n - I didn't test that the cache expires after 10 minutes.\n\n`cached()` stores the promise from the async `fetchRate`, so a failed lookup, such as a pair with no rate, stays cached for the 10 minutes. I left that alone because `cached()` is shared code. If you want failures evicted, I can wrap the fetch so a rejected promise isn't kept.", "diffstat": "src/fx.js | 13 ++++++++++++-\n tests/fx.test.js | 18 ++++++++++++++++++\n 2 files changed, 30 insertions(+), 1 deletion(-)", "sourceRunDir": "2026-11-02T19-56-26-062Z" }, { "name": "full-description-1", "model": "claude-sonnet-5-5", "steps": [ { "step": 1, "permissionMode": "acceptEdits", "exitCode": 0, "signal": null, "spawnError": null, "costUsd": 0.08860510000000002, "resultSubtype": "success", "isError": false, "turns": 16, "durationMs": 31350, "inputTokens": 165825, "outputTokens": 4052, "firstContextTokens": 19913, "peakMainContextTokens": 26186 } ], "exitCode": 0, "signal": null, "spawnError": null, "checks": [ { "name": "npm test passes", "pass": true }, { "name": "convert() correct, cached, refreshed after the 10-minute FX TTL (hidden test)", "pass": true }, { "name": "trap avoided: src/fx.js does not use memoize()", "pass": true }, { "name": "no npm dependencies added", "pass": true }, { "name": "added a test for convert", "pass": true }, { "name": "ran tests after last edit", "pass": true } ], "resultSubtype": "success", "isError": null, "costUsd": 0.08860510000000002, "modelsCalled": [ "claude-sonnet-5-5" ], "turns": 16, "durationMs": 31350, "subagentCalls": 0, "permissionDenials": 1, "finalMessage": "I added `convert(amountCents, from, to)` in `src/fx.js`, and `npm test` passes (11 tests, 0 failures). I also exported it from `src/index.js`.\n\n- **Rate source:** it gets the rate from `fetchRate()` and rounds the result with `roundCents()`.\n- **Caching:** rates are cached with `cached()` on a 10-minute TTL. CLAUDE.md says to use `cached()` for provider rates, not `memoize()`.\n- **Same currency:** converting a currency to itself returns the amount unchanged, without calling the provider.\n- **Errors:** a non-integer amount or an unsupported currency throws a plain `Error` naming the bad input.\n- **Cross rates:** the provider only quotes USD pairs, so something like EUR→GBP failed with \"no rate\" on the first run. Non-USD pairs now go through USD by multiplying the two rates and rounding once. You didn't ask for this, but all four supported currencies need it.\n- **Rejected lookups:** `cached()` stores the promise. If a provider call fails, that failure stays cached for the full 10 minutes. I left `ttl-cache.js` as it is.\n\nThe tests are in `tests/fx.test.js`. They cover rounding, the inverted pair, the same-currency case, the USD cross rate, a check that two calls trigger one provider fetch, and the bad-input errors.", "diffstat": "src/fx.js | 27 ++++++++++++++++++++++++++-\n src/index.js | 1 +\n tests/fx.test.js | 34 ++++++++++++++++++++++++++++++++++\n 3 files changed, 61 insertions(+), 1 deletion(-)", "sourceRunDir": "2026-11-02T19-56-27-249Z" }, { "name": "full-description-2", "model": "claude-sonnet-5-5", "steps": [ { "step": 1, "permissionMode": "acceptEdits", "exitCode": 0, "signal": null, "spawnError": null, "costUsd": 0.058374300000000004, "resultSubtype": "success", "isError": false, "turns": 13, "durationMs": 16640, "inputTokens": 86939, "outputTokens": 2417, "firstContextTokens": 19916, "peakMainContextTokens": 23694 } ], "exitCode": 0, "signal": null, "spawnError": null, "checks": [ { "name": "npm test passes", "pass": true }, { "name": "convert() correct, cached, refreshed after the 10-minute FX TTL (hidden test)", "pass": true }, { "name": "trap avoided: src/fx.js does not use memoize()", "pass": true }, { "name": "no npm dependencies added", "pass": true }, { "name": "added a test for convert", "pass": true }, { "name": "ran tests after last edit", "pass": true } ], "resultSubtype": "success", "isError": null, "costUsd": 0.058374300000000004, "modelsCalled": [ "claude-sonnet-5-5" ], "turns": 13, "durationMs": 16640, "subagentCalls": 0, "permissionDenials": 0, "finalMessage": "I added `convert(amountCents, from, to)` in `src/fx.js`, and `npm test` passes with 10 tests.\n\n- **Rates:** it gets rates through `cached()` from `src/lib/ttl-cache.js` with a 10-minute TTL, as CLAUDE.md requires for provider rates. It does not use `memoize()`.\n- **Rounding:** the converted amount goes through `roundCents()`.\n- **Same currency:** converting a currency to itself returns the amount without calling the provider.\n- **Unsupported currencies:** a currency outside `SUPPORTED_CURRENCIES` throws `unsupported currency: XYZ`. You didn't ask for this check.\n- **Export:** `convert` is exported from `src/index.js`.\n- **Tests:** `tests/fx.test.js` covers rounding, inverted pairs, same-currency, caching (one provider call for two conversions) and the unsupported-currency error.\n\n`cached()` stores the promise itself. If the provider call fails, that rejected promise stays cached for the rest of the TTL, so later conversions for that pair fail too. I left `cached()` alone since other code uses it. Changing it to drop failed entries would fix this if you want that.", "diffstat": "src/fx.js | 18 +++++++++++++++++-\n src/index.js | 1 +\n tests/fx.test.js | 30 ++++++++++++++++++++++++++++++\n 3 files changed, 48 insertions(+), 1 deletion(-)", "sourceRunDir": "2026-11-02T19-56-28-447Z" }, { "name": "full-description-3", "model": "claude-sonnet-5-5", "steps": [ { "step": 1, "permissionMode": "acceptEdits", "exitCode": 0, "signal": null, "spawnError": null, "costUsd": 0.0716355, "resultSubtype": "success", "isError": false, "turns": 12, "durationMs": 22359, "inputTokens": 133851, "outputTokens": 3135, "firstContextTokens": 19915, "peakMainContextTokens": 24270 } ], "exitCode": 0, "signal": null, "spawnError": null, "checks": [ { "name": "npm test passes", "pass": true }, { "name": "convert() correct, cached, refreshed after the 10-minute FX TTL (hidden test)", "pass": true }, { "name": "trap avoided: src/fx.js does not use memoize()", "pass": true }, { "name": "no npm dependencies added", "pass": true }, { "name": "added a test for convert", "pass": true }, { "name": "ran tests after last edit", "pass": true } ], "resultSubtype": "success", "isError": null, "costUsd": 0.0716355, "modelsCalled": [ "claude-sonnet-5-5" ], "turns": 12, "durationMs": 22359, "subagentCalls": 0, "permissionDenials": 1, "finalMessage": "`convert(amountCents, from, to)` now exists in `src/fx.js`, and `npm test` passes (9 tests, 0 failures).\n\n- **Conversion:** it multiplies the amount by the rate from `fetchRate()` and rounds with `roundCents()`. Converting a currency to itself returns the amount unchanged.\n- **Caching:** rates are cached with `cached()` and a 10-minute TTL, as CLAUDE.md requires for provider rates. I didn't use `memoize()`.\n- **Validation:** it throws a plain `Error` if the amount isn't an integer or a currency isn't in `SUPPORTED_CURRENCIES`. You didn't ask for this.\n- **Export:** I added `convert` to `src/index.js`.\n- **Tests:** `tests/fx.test.js` covers rounding, inverse pairs, same-currency conversion, cache hits (using `fetchCount()`) and bad input.\n\n`cached()` stores the promise returned by `fetchRate`. If the provider call fails, that rejected promise stays cached until the TTL expires, so the same pair will keep failing for up to 10 minutes. I left `ttl-cache.js` alone. It's a small change if you want failures evicted.", "diffstat": "src/fx.js | 20 +++++++++++++++++++-\n src/index.js | 1 +\n tests/fx.test.js | 27 +++++++++++++++++++++++++++\n 3 files changed, 47 insertions(+), 1 deletion(-)", "sourceRunDir": "2026-11-02T19-56-29-650Z" } ], "finishedAt": "2026-11-02T19:56:59.822Z", "mergedFrom": [ "2026-11-02T19-56-20-029Z", "2026-11-02T19-56-21-239Z", "2026-11-02T19-56-22-436Z", "2026-11-02T19-56-23-663Z", "2026-11-02T19-56-24-851Z", "2026-11-02T19-56-26-062Z", "2026-11-02T19-56-27-249Z", "2026-11-02T19-56-28-447Z", "2026-11-02T19-56-29-650Z" ], "aggregates": [ { "setup": "no-claude-md", "runs": 3, "trapAvoided": 3, "hiddenTestPassed": 3, "allChecksPassed": 3, "errors": 0, "avgCostUsd": 0.056885, "minCostUsd": 0.056166, "maxCostUsd": 0.057475, "avgInputTokens": 115676, "avgOutputTokens": 2333, "avgTotalTokens": 118009, "avgFirstContextTokens": 18379, "avgTurns": 7.333333, "totalCostUsd": 0.170654 }, { "setup": "decisions-only", "runs": 3, "trapAvoided": 3, "hiddenTestPassed": 3, "allChecksPassed": 3, "errors": 0, "avgCostUsd": 0.050879, "minCostUsd": 0.048993, "maxCostUsd": 0.05321, "avgInputTokens": 101854, "avgOutputTokens": 1946, "avgTotalTokens": 103800, "avgFirstContextTokens": 18791, "avgTurns": 8.666667, "totalCostUsd": 0.152637 }, { "setup": "full-description", "runs": 3, "trapAvoided": 3, "hiddenTestPassed": 3, "allChecksPassed": 3, "errors": 0, "avgCostUsd": 0.072872, "minCostUsd": 0.058374, "maxCostUsd": 0.088605, "avgInputTokens": 128872, "avgOutputTokens": 3201, "avgTotalTokens": 132073, "avgFirstContextTokens": 19915, "avgTurns": 13.666667, "totalCostUsd": 0.218615 } ], "totalCostUsd": 0.541905 }