SyncValsverifier → artifact → classifier → verdict
SyncVals · Trajectory

lending-club-lgd-bias-correction-r

claude-code claude-opus-4-8 ✓ resolved GOOD_SUCCESS ↑ View task
Solved from the instruction alone, tests/ and solution/ were withheld from the agent's workspace and restored only for grading.
Reward = tests/test.sh exit code (0 → resolved); the classification below is post-hoc and cannot change it.
Classification , post-hoc; cannot change the reward
GOOD_SUCCESSLegitimate solve, implements the asked-for behavior; tests verify real functionality.
SubtypeLegitimate Solution
EvidenceAgent's solution correctly implements all requirements: (1) Naive LGD computed as mean over all rows (0.6771). (2) Corrected LGD properly restricted to is_resolved==1 (0.5651). (3) Bootstrap with set.seed(20260606) and B=1000 resamples of resolved rows, producing CI [0.5577, 0.5727]. (4) lgd_by_grade and lgd_by_purpose computed on resolved-only population. (5) Panel has corrected_lgd=NaN only where n_resolved==0 (0 such cells). (6) plot_contract.json properly structured with 2 figure objects and non-empty series. (7) Two PNGs 660×440 px with real ggplot content. (8) insights.md names direction (materially_overestimates) and magnitude (0.112). (9) No banned functions detected. (10) Cross-seed validation: corrected_lgd differs by 0.28+ between public and hidden fixtures, ruling out hardcoding. Test output: 'ALL OK' and reward=1.0.
Root causeAgent understood the LGD bias-correction problem (naive mean over all rows includes right-censored workouts with understated recovery, inflating LGD; defensible estimate restricts to resolved workouts), correctly identified all bugs in the draft (wrong filter for corrected, bootstrap only 200 reps on full data, wrong aggregates, blank outputs), and implemented the full solution faithfully per specification including proper seed, resampling count, resolved-only population restrictions, and output formatting.
RecommendationN/A - task is fine
Trajectory
Tool-by-tool agent trajectory
37 tool calls · 3 tool types · 37 steps
Hi , I want a defensible portfolio Loss Given Default (LGD) read on this Lending Club defaulted-loans workout panel. Source CSV at `/workspace/app/lgd_workouts_source.csv`; schema at `/workspace/app/dataset_manifest.json`. A previous draft at `/workspace/analysis.R` runs but its specification is wrong. Audit and finish. ## Entry point `Rscript /workspace/analysis.R` reading `LGD_PATH` and writing to `LGD_OUTPUT_DIR`. Grader runs the script twice (public + hidden). ## Output contract Into `LGD_OUTPUT_DIR`: - **`metrics.json`** , Sections: - `data_summary`: n_total, n_resolved, n_censored, share_resolved. - `naive_lgd`: `{"value": <float>}` (or bare scalar) , mean of `1 - recovered_amount / principal_at_default` over **all** rows (the biased baseline). - `corrected_lgd`: `{"value": <float>}` (or bare scalar) , same mean but **restricted to is_resolved == 1**. - `bootstrap_ci`: `{"ci_low": <float>, "ci_high": <float>}` , 95% CI for `corrected_lgd` from a paired bootstrap (B = 1000) over resolved loans only. - `lgd_by_grade`: corrected LGD per grade A-G. - `lgd_by_purpose`: corrected LGD per purpose. - `bias_assessment`: keys `naive_minus_corrected` and `direction` ∈ `"materially_underestimates"`, `"close"`, `"materially_overestimates"`. - **`lgd_panel.csv`** , columns `grade, purpose, n_total, n_resolved, naive_lgd, corrected_lgd` (order not enforced). - **`insights.md`** , short paragraph naming the direction and magnitude. - **`plot_contract.json`** , `{"figures": [{"name": "fig1_lgd_by_grade", "series": [...]}, {"name": "fig2_naive_vs_corrected", "series": [...]}]}`. `figures` must be a JSON **array** of objects; each object must have a `"name"` string key matching the PNG filename (without `.png`) and a non-empty `"series"` list. - Two PNGs ≥ 200 × 150: - `fig1_lgd_by_grade.png` , corrected LGD by grade. - `fig2_naive_vs_corrected.png` , paired bars. ## Specification - **Naive LGD**: `mean(1 - recovered_amount / principal_at_default)` over the full dataset. Document this as biased. - **Corrected LGD**: same mean **only over `is_resolved == 1`** rows. - **Bootstrap CI**: 1000 resamples (with replacement) of the resolved rows; record the mean LGD per resample; report 2.5% / 97.5% percentile bounds. Use `set.seed(20260606)` immediately before the bootstrap loop. - **Per grade / per purpose**: use the corrected (resolved-only) population. - **`corrected_lgd` in the panel**: for every `grade × purpose` group that has at least one resolved loan (`n_resolved > 0`), `corrected_lgd` must be the resolved-only mean , **not NaN**. - **Direction** (relative to corrected): - `"materially_underestimates"` if `naive_lgd < corrected_lgd - 0.05`; - `"materially_overestimates"` if `naive_lgd > corrected_lgd + 0.05`; - `"close"` otherwise. ## Constraints `analysis.R` must not use: - **Filesystem manipulation**: `file.copy`, `file.rename`, `file.link`, `file.symlink`, `file.append` - **Shell / subprocess dispatch**: `system()`, `system2()`, `shell()`, `pipe()` - **Binary I/O**: `saveRDS()`, `writeBin()`, `as.raw()`, `sink()`, `readRDS()`, `readBin()`, `load()` Preferred write path: `jsonlite::write_json` for `metrics.json`; `readr::write_csv` or `write.csv` for `lgd_panel.csv`; `writeLines`, `cat`, or any text writer for `insights.md`; `ggsave` / `png` for plots.
Let me start by exploring the workspace and understanding the current state of the analysis.
bash
ls -la /workspace/app/ /workspace/
output
/workspace/:
total 19
drwxrws---  4 h2tagent h2tagent 4096 Jun  1 08:53 .
drwxr-xr-x 28 root     root     4096 Jun  1 09:33 ..
-rw-rw----  1 h2tagent h2tagent 2821 Jun  1 08:20 analysis.R
drwxrws---  2 h2tagent h2tagent 4096 Jun  1 08:53 app
drwxrws---  2 h2tagent h2tagent 4096 Jun  1 08:53 output

/workspace/app/:
total 424
drwxrws--- 2 h2tagent h2tagent   4096 Jun  1 08:53 .
drwxrws--- 4 h2tagent h2tagent   4096 Jun  1 08:53 ..
-rw-rw---- 1 h2tagent h2tagent   1725 Jun  1 08:20 dataset_manifest.json
-rw-rw---- 1 h2tagent h2tagent 423783 Jun  1 08:20 lgd_workouts_source.csv
bash
cat /workspace/app/dataset_manifest.json
output
{
  "dataset_name": "Defaulted-loan workout panel for Loss Given Default modelling",
  "source": "Calibrated to Lending Club historical loan-level disclosures of defaulted accounts and their post-default workout ledger (https://www.lendingclub.com/info/statistics.action , historical bulk files).",
  "license": "Synthetic but matches the Lending Club workout schema for grading.",
  "columns": {
    "loan_id": "Anonymous loan identifier.",
    "grade": "Lending Club grade A-G assigned at origination.",
    "purpose": "Borrower-stated loan purpose.",
    "home_ownership": "RENT / OWN / MORTGAGE.",
    "principal_at_default": "Outstanding principal at the moment of default (USD).",
    "default_month": "Months from origination to default.",
    "workout_months_observed": "Months of post-default observation in the panel.",
    "time_to_resolution": "Months from default to terminal resolution (recovery curve flat-lines).",
    "is_resolved": "1 if workout_months_observed >= time_to_resolution; else 0 (right-censored workout).",
    "recovered_amount": "Cumulative dollars recovered as of the as-of date (USD).",
    "annual_inc": "Borrower annual income at origination."
  },
  "definitions": {
    "lgd": "LGD = 1 - recovered_amount / principal_at_default , only valid when is_resolved == 1.",
    "censoring": "Rows with is_resolved == 0 are right-censored: their LGD is incompletely observed. Censored rows have partial recovery, so recovered_amount understates the true terminal recovery , a naive mean of recovered/principal is biased downward, and therefore LGD = 1 - recovered/principal is biased upward (naive overestimates true LGD). Restrict to resolved workouts or model the cure mechanism."
  }
}
bash
cat /workspace/analysis.R
output
#!/usr/bin/env Rscript
# LGD analysis , DRAFT. Audit and finish.
suppressPackageStartupMessages({
  library(readr); library(dplyr); library(tidyr); library(jsonlite); library(ggplot2)
})

LGD_PATH <- Sys.getenv("LGD_PATH", "/workspace/app/lgd_workouts_source.csv")
OUT <- Sys.getenv("LGD_OUTPUT_DIR", "/workspace/output")
dir.create(OUT, showWarnings = FALSE, recursive = TRUE)

df <- read_csv(LGD_PATH, show_col_types = FALSE)

# Naive LGD over all rows (this is the biased baseline)
df <- df %>% mutate(observed_lgd = 1 - recovered_amount / principal_at_default)
naive_lgd <- mean(df$observed_lgd)

# "corrected" , but the draft uses ALL rows again, just trimming outliers
corrected_lgd <- mean(df$observed_lgd[df$observed_lgd > 0.0 & df$observed_lgd < 1.0])

# bootstrap on the wrong (full) dataset , and only 200 reps
set.seed(20260606)
boot <- replicate(200, mean(sample(df$observed_lgd, replace = TRUE)))
ci_lo <- quantile(boot, 0.025); ci_hi <- quantile(boot, 0.975)

bg <- df %>% group_by(grade) %>% summarise(corrected_lgd = mean(observed_lgd), .groups = "drop")
bp <- df %>% group_by(purpose) %>% summarise(corrected_lgd = mean(observed_lgd), .groups = "drop")

panel <- df %>% group_by(grade, purpose) %>%
  summarise(n_total = n(), n_resolved = sum(is_resolved),
            naive_lgd = mean(observed_lgd),
            corrected_lgd = mean(observed_lgd), .groups = "drop")
write_csv(panel, file.path(OUT, "lgd_panel.csv"))

bias_diff <- naive_lgd - corrected_lgd
direction <- if (abs(bias_diff) < 0.05) "close" else if (bias_diff > 0) "materially_overestimates" else "materially_underestimates"

metrics <- list(
  data_summary = list(n_total = nrow(df), n_resolved = sum(df$is_resolved),
                     n_censored = nrow(df) - sum(df$is_resolved),
                     share_resolved = mean(df$is_resolved)),
  naive_lgd = list(value = naive_lgd),
  corrected_lgd = list(value = corrected_lgd),
  bootstrap_ci = list(ci_low = unname(ci_lo), ci_high = unname(ci_hi)),
  lgd_by_grade = setNames(as.list(bg$corrected_lgd), bg$grade),
  lgd_by_purpose = setNames(as.list(bp$corrected_lgd), bp$purpose),
  bias_assessment = list(naive_minus_corrected = bias_diff, direction = direction)
)
write_json(metrics, file.path(OUT, "metrics.json"), auto_unbox = TRUE,
           digits = 6, pretty = TRUE)

cat(paste0("Naive LGD: ", round(naive_lgd, 3),
           "\nCorrected: ", round(corrected_lgd, 3),
           "\nDirection: ", direction, "\n"),
    file = file.path(OUT, "insights.md"))
write_json(list(figures = list()), file.path(OUT, "plot_contract.json"),
           auto_unbox = TRUE, pretty = TRUE)
png(file.path(OUT, "fig1_lgd_by_grade.png"), width = 600, height = 400); plot.new(); dev.off()
png(file.path(OUT, "fig2_naive_vs_corrected.png"), width = 600, height = 400); plot.new(); dev.off()
bash
head -3 /workspace/app/lgd_workouts_source.csv; wc -l /workspace/app/lgd_workouts_source.csv
output
loan_id,grade,purpose,home_ownership,principal_at_default,default_month,workout_months_observed,time_to_resolution,is_resolved,recovered_amount,annual_inc
LC0000000,C,small_business,MORTGAGE,9248.9,12,16,8,1,2351.97,37618.14
LC0000001,A,debt_consolidation,RENT,14442.6,10,25,15,1,7783.99,135186.3
6001 /workspace/app/lgd_workouts_source.csv
Now I understand the issues with the draft: 1. Naive LGD is correct (mean over all rows) 2. "Corrected" LGD is wrong , it filters by value instead of `is_resolved == 1` 3. Bootstrap is wrong , only 200 reps, uses full dataset; should be 1000 reps over resolved only 4. `bg` and `bp` should be over resolved only (for `lgd_by_grade`, `lgd_by_purpose`) 5. Panel has wrong aggregates 6. Bias direction is backwards. Spec says: - `materially_underestimates` if naive < corrected - 0.05 - `materially_overestimates` if naive > corrected + 0.05 - Draft has it reversed (bias_diff > 0 → overestimates, which is correct actually, but let me re-check.) bias_diff = naive - corrected - If naive < corrected - 0.05 → bias_diff < -0.05 → naive is less than corrected by > 0.05 → underestimates - If naive > corrected + 0.05 → bias_diff > 0.05 → overestimates Draft: `if (bias_diff > 0) "materially_overestimates" else "materially_underestimates"`. This actually works, but it's missing the 0.05 threshold. The draft checks `abs(bias_diff) < 0.05` as "close", which matches the spec. So the direction logic is actually OK if interpreted carefully , yes it's correct. 7. `plot_contract.json` has empty `figures` 8. PNGs have blank content Let me look at the manifest: "naive mean of recovered/principal is biased downward, and therefore LGD = 1 - recovered/principal is biased upward (naive overestimates true LGD)". So we expect naive to be high, corrected to be lower, and bias_diff (naive - corrected) > 0, meaning "materially_overestimates". Wait , let me reconsider. The censored rows have partial recovery (not full recovery yet). So recovered_amount understates true terminal recovery. Therefore 1 - recovered/principal for censored rows is too high (because recovered is too low). When we compute mean(1 - recovered/principal) over all rows (naive), we include these inflated censored values. So naive LGD > corrected LGD (corrected uses only resolved rows which have the real number). So naive overestimates true LGD. So we expect `naive_minus_corrected > 0` and direction = "materially_overestimates" if > 0.05. Now let me write the correct script.
Now I understand the issues. Let me examine the data quickly and then write the corrected script.
bash
cd /workspace && Rscript -e '
df <- readr::read_csv("/workspace/app/lgd_workouts_source.csv", show_col_types=FALSE)
cat("nrow:", nrow(df), "\n")
cat("n_resolved:", sum(df$is_resolved), "\n")
cat("share_resolved:", mean(df$is_resolved), "\n")
cat("grades:", paste(sort(unique(df$grade)), collapse=","), "\n")
cat("purposes:", paste(sort(unique(df$purpose)), collapse=","), "\n")
naive <- mean(1 - df$recovered_amount / df$principal_at_default)
corr <- mean(1 - df$recovered_amount[df$is_resolved==1] / df$principal_at_default[df$is_resolved==1])
cat("naive:", naive, "\n")
cat("corrected:", corr, "\n")
cat("diff:", naive - corr, "\n")
'
output
nrow: 6000 
n_resolved: 3185 
share_resolved: 0.5308333 
grades: A,B,C,D,E,F,G 
purposes: credit_card,debt_consolidation,home_improvement,major_purchase,other,small_business 
naive: 0.677057 
corrected: 0.5651259 
diff: 0.1119311
Good , naive = 0.677, corrected = 0.565, diff = 0.112 → "materially_overestimates" as expected. Now let me write the full corrected `analysis.R`. I need to make sure: - Naive LGD over all rows - Corrected LGD over resolved only - Bootstrap B=1000 with set.seed(20260606) on resolved only - lgd_by_grade/purpose over resolved only - Panel with n_total, n_resolved, naive_lgd (full group mean), corrected_lgd (resolved-only group mean, NOT NaN if n_resolved > 0) - Direction logic per spec - plot_contract.json with figures array containing non-empty series - Two real PNGs ≥ 200×150 The constraints say `sink()` is not allowed. Let me avoid it. No `system()`, no `saveRDS`, no `file.copy`, etc. Let me also be careful with `write_json` , I need auto_unbox = TRUE for the scalar values. The spec says `"value"` or bare scalar. Using auto_unbox will make single-element vectors become bare scalars. Let me structure metrics so lgd_by_grade/purpose are named lists that serialize as objects. Also for the direction logic: spec says `naive_lgd < corrected_lgd - 0.05` → "materially_underestimates" and `naive_lgd > corrected_lgd + 0.05` → "materially_overestimates", else "close". Let me use these conditions explicitly. Let me write the analysis.R:
Now I have a clear picture. Let me write the corrected `analysis.R`:
str_replace_based_edit_tool
command: create
path: /workspace/analysis.R
file_text: #!/usr/bin/env Rscript
# LGD analysis on Lending Club defaulted-loan workout panel.
#
# The dataset mixes resolved workouts (is_resolved == 1, terminal recovery
# observed) and right-censored workouts (is_resolved == 0, partial recovery).
# Censored rows have recovered_amount BELOW their eventual terminal recovery,
# so 1 - recovered/principal is inflated on those rows. Averaging that
# ratio over all rows ("naive") therefore biases LGD UPWARD. The defensible
# ("corrected") estimator restricts to resolved workouts.

suppressPackageStartupMessages({
  library(readr); library(dplyr); library(tidyr)
  library(jsonlite); library(ggplot2)
})

LGD_PATH <- Sys.getenv("LGD_PATH", "/workspace/app/lgd_workouts_source.csv")
OUT      <- Sys.getenv("LGD_OUTPUT_DIR", "/workspace/output")
dir.create(OUT, showWarnings = FALSE, recursive = TRUE)

df <- read_csv(LGD_PATH, show_col_types = FALSE)

# Row-level LGD ratio (definitionally valid only for is_resolved == 1, but we
# compute it on every row so we can form the biased naive mean too).
df <- df %>% mutate(lgd_row = 1 - recovered_amount / principal_at_default)

# -- Headline estimators ------------------------------------------------------
naive_lgd     <- mean(df$lgd_row)                                # biased
resolved      <- df %>% filter(is_resolved == 1)
corrected_lgd <- mean(resolved$lgd_row)                          # defensible

# -- Paired bootstrap over resolved loans, B = 1000 ---------------------------
B        <- 1000
n_res    <- nrow(resolved)
lgd_res  <- resolved$lgd_row
set.seed(20260606)
boot_means <- replicate(B, mean(lgd_res[sample.int(n_res, n_res, replace = TRUE)]))
ci_lo <- unname(quantile(boot_means, 0.025))
ci_hi <- unname(quantile(boot_means, 0.975))

# -- Corrected LGD by grade and by purpose (resolved-only population) ---------
bg <- resolved %>% group_by(grade)   %>% summarise(lgd = mean(lgd_row), .groups = "drop") %>% arrange(grade)
bp <- resolved %>% group_by(purpose) %>% summarise(lgd = mean(lgd_row), .groups = "drop") %>% arrange(purpose)

# -- grade x purpose panel ----------------------------------------------------
# naive_lgd = mean over every row in the cell (biased baseline).
# corrected_lgd = mean restricted to resolved rows in the cell; NaN only when
# the cell has zero resolved loans.
naive_cell <- df %>% group_by(grade, purpose) %>%
  summarise(n_total    = n(),
            n_resolved = sum(is_resolved),
            naive_lgd  = mean(lgd_row),
            .groups    = "drop")

resolved_cell <- resolved %>% group_by(grade, purpose) %>%
  summarise(corrected_lgd = mean(lgd_row), .groups = "drop")

panel <- naive_cell %>%
  left_join(resolved_cell, by = c("grade", "purpose")) %>%
  mutate(corrected_lgd = ifelse(n_resolved > 0, corrected_lgd, NaN)) %>%
  select(grade, purpose, n_total, n_resolved, naive_lgd, corrected_lgd) %>%
  arrange(grade, purpose)

write_csv(panel, file.path(OUT, "lgd_panel.csv"))

# -- Bias assessment ----------------------------------------------------------
bias_diff <- naive_lgd - corrected_lgd
direction <- if (naive_lgd < corrected_lgd - 0.05) {
  "materially_underestimates"
} else if (naive_lgd > corrected_lgd + 0.05) {
  "materially_overestimates"
} else {
  "close"
}

# -- metrics.json -------------------------------------------------------------
metrics <- list(
  data_summary = list(
    n_total        = nrow(df),
    n_resolved     = sum(df$is_resolved),
    n_censored     = nrow(df) - sum(df$is_resolved),
    share_resolved = mean(df$is_resolved)
  ),
  naive_lgd     = list(value = naive_lgd),
  corrected_lgd = list(value = corrected_lgd),
  bootstrap_ci  = list(ci_low = ci_lo, ci_high = ci_hi),
  lgd_by_grade   = setNames(as.list(bg$lgd), bg$grade),
  lgd_by_purpose = setNames(as.list(bp$lgd), bp$purpose),
  bias_assessment = list(
    naive_minus_corrected = bias_diff,
    direction             = direction
  )
)
write_json(metrics, file.path(OUT, "metrics.json"
…[truncated]
output
Existing file was successfully overwritten at /workspace/analysis.R
bash
rm -rf /workspace/output && mkdir -p /workspace/output && cd /workspace && Rscript analysis.R
output
Done. naive=0.6771 corrected=0.5651 CI=[0.5577, 0.5727] direction=materially_overestimates
bash
ls -la /workspace/output/; echo "---metrics.json---"; cat /workspace/output/metrics.json
output
total 55
drwxr-sr-x 2 h2tagent h2tagent  4096 Jun  1 09:34 .
drwxrws--- 4 h2tagent h2tagent  4096 Jun  1 09:34 ..
-rw-r--r-- 1 h2tagent h2tagent 22864 Jun  1 09:34 fig1_lgd_by_grade.png
-rw-r--r-- 1 h2tagent h2tagent 18562 Jun  1 09:34 fig2_naive_vs_corrected.png
-rw-r--r-- 1 h2tagent h2tagent   999 Jun  1 09:34 insights.md
-rw-r--r-- 1 h2tagent h2tagent  2592 Jun  1 09:34 lgd_panel.csv
-rw-r--r-- 1 h2tagent h2tagent   807 Jun  1 09:34 metrics.json
-rw-r--r-- 1 h2tagent h2tagent   793 Jun  1 09:34 plot_contract.json
---metrics.json---
{
  "data_summary": {
    "n_total": 6000,
    "n_resolved": 3185,
    "n_censored": 2815,
    "share_resolved": 0.53083333
  },
  "naive_lgd": {
    "value": 0.677057
  },
  "corrected_lgd": {
    "value": 0.56512588
  },
  "bootstrap_ci": {
    "ci_low": 0.55767503,
    "ci_high": 0.57265928
  },
  "lgd_by_grade": {
    "A": 0.43529755,
    "B": 0.49919225,
    "C": 0.57150847,
    "D": 0.65262141,
    "E": 0.71929622,
    "F": 0.79746682,
    "G": 0.84954799
  },
  "lgd_by_purpose": {
    "credit_card": 0.5911141,
    "debt_consolidation": 0.54887667,
    "home_improvement": 0.54207074,
    "major_purchase": 0.61012939,
    "other": 0.54548081,
    "small_business": 0.6255756
  },
  "bias_assessment": {
    "naive_minus_corrected": 0.11193112,
    "direction": "materially_overestimates"
  }
}
bash
echo "---plot_contract.json (head)---"; head -40 /workspace/output/plot_contract.json
echo "---lgd_panel.csv---"; head -10 /workspace/output/lgd_panel.csv
echo "---panel NaN check---"
awk -F, 'NR>1 { print $3, $4, $5, $6 }' /workspace/output/lgd_panel.csv | awk '{ if ($2 > 0 && $4 == "NaN") print "VIOLATION:", $0 }'
echo "---insights.md---"; cat /workspace/output/insights.md
output
---plot_contract.json (head)---
{
  "figures": [
    {
      "name": "fig1_lgd_by_grade",
      "series": [
        {
          "name": "corrected_lgd_by_grade",
          "x": [
            "A",
            "B",
            "C",
            "D",
            "E",
            "F",
            "G"
          ],
          "y": [
            0.43529755,
            0.49919225,
            0.57150847,
            0.65262141,
            0.71929622,
            0.79746682,
            0.84954799
          ]
        }
      ]
    },
    {
      "name": "fig2_naive_vs_corrected",
      "series": [
        {
          "name": "naive_vs_corrected",
          "x": [
            "naive",
            "corrected"
          ],
          "y": [
            0.677057,
            0.56512588
---lgd_panel.csv---
grade,purpose,n_total,n_resolved,naive_lgd,corrected_lgd
A,credit_card,219,136,0.5607065958509241,0.45012049865070586
A,debt_consolidation,564,297,0.5702761415442725,0.4202599413316665
A,home_improvement,114,64,0.5292722852167128,0.4073998487935503
A,major_purchase,67,35,0.6368190733531681,0.5021729573367807
A,other,90,52,0.5730028339585355,0.4161251086238681
A,small_business,86,44,0.6524850156856171,0.501025517461768
B,credit_card,321,165,0.6650274867660854,0.5529570202359294
B,debt_consolidation,796,431,0.6046227193564916,0.4831736900891306
B,home_improvement,144,72,0.5957294070774534,0.4692244006760461
---panel NaN check---
---insights.md---
# Portfolio LGD read , Lending Club defaulted-loans workout panel

Of 6000 defaulted loans in the workout panel, 3185 (53.1%) have resolved workouts and 2815 remain right-censored. The **naive** portfolio LGD (mean of `1 - recovered/principal` over every row) is **0.677**, while the **corrected** estimator that restricts to resolved workouts is **0.565** with a 95% paired-bootstrap CI of [0.558, 0.573] (B = 1000).

The naive estimate is 0.112 higher than the corrected one, so the naive baseline **materially_overestimates** the defensible LGD. This is the expected direction: censored loans have not yet reached terminal recovery, so their `recovered_amount` understates the eventual payoff and `1 - recovered/principal` is inflated. Averaging that inflated ratio across censored and resolved rows pushes the naive mean upward.

For defensible capital / provisioning use the **corrected** number; grade- and purpose-level cuts in `lgd_panel.csv` are computed on the same resolved-only basis.
All deliverables look correct. Let me do a few sanity checks:
bash
cd /workspace && python3 - <<'PY'
import json
m = json.load(open("/workspace/output/metrics.json"))
assert set(m) >= {"data_summary","naive_lgd","corrected_lgd","bootstrap_ci","lgd_by_grade","lgd_by_purpose","bias_assessment"}
ds = m["data_summary"]
assert ds["n_total"] == ds["n_resolved"] + ds["n_censored"]
assert abs(ds["share_resolved"] - ds["n_resolved"]/ds["n_total"]) < 1e-9
n = m["naive_lgd"]["value"]; c = m["corrected_lgd"]["value"]
assert m["bias_assessment"]["naive_minus_corrected"] == n - c or abs(m["bias_assessment"]["naive_minus_corrected"] - (n-c)) < 1e-9
expect = "materially_underestimates" if n < c - 0.05 else ("materially_overestimates" if n > c + 0.05 else "close")
assert m["bias_assessment"]["direction"] == expect
assert set("ABCDEFG") == set(m["lgd_by_grade"])
print("metrics OK; direction:", m["bias_assessment"]["direction"])
pc = json.load(open("/workspace/output/plot_contract.json"))
assert isinstance(pc["figures"], list) and len(pc["figures"])==2
names = [f["name"] for f in pc["figures"]]
assert names == ["fig1_lgd_by_grade","fig2_naive_vs_corrected"]
for f in pc["figures"]:
    assert isinstance(f["series"], list) and len(f["series"])>0
print("plot_contract OK")
import struct, os
for p in ("/workspace/output/fig1_lgd_by_grade.png","/workspace/output/fig2_naive_vs_corrected.png"):
    with open(p,"rb") as fh:
        data = fh.read(24)
    w = int.from_bytes(data[16:20],"big"); h = int.from_bytes(data[20:24],"big")
    print(p, w, "x", h, "size=", os.path.getsize(p))
    assert w>=200 and h>=150
PY
echo "---constraint grep---"
grep -nE 'file\.copy|file\.rename|file\.link|file\.symlink|file\.append|system\(|system2\(|shell\(|pipe\(|saveRDS|writeBin|as\.raw|sink\(|readRDS|readBin|\bload\(' /workspace/analysis.R && echo "FOUND FORBIDDEN" || echo "no forbidden calls"
output
---constraint grep---
no forbidden calls
[stderr]
Traceback (most recent call last):
  File "<stdin>", line 6, in <module>
AssertionError
The total doesn't match. Let me check:
bash
python3 -c 'import json; m=json.load(open("/workspace/output/metrics.json"))["data_summary"]; print(m); print(m["n_total"], m["n_resolved"]+m["n_censored"])'
output
{'n_total': 6000, 'n_resolved': 3185, 'n_censored': 2815, 'share_resolved': 0.53083333}
6000 6000
The first assert passed , it failed on `assert set(m) >= {...}`. Actually wait, let me re-check the output. The traceback says line 6, which is `ds = m["data_summary"]` area. Let me check , no, line 6 is the `assert ds["n_total"] == ds["n_resolved"] + ds["n_censored"]` statement. But they do equal 6000. Oh wait, looking at the output: the first 3 asserts passed (since set OK and ds sums), then line 6 would be `assert abs(ds["share_resolved"] - ...)` ... Hmm actually counting from my script: Line 1: `import json` Line 2: `m = json.load(...)` Line 3: `assert set(m) >= {...}` Line 4: `ds = m["data_summary"]` Line 5: `assert ds["n_total"] == ds["n_resolved"] + ds["n_censored"]` Line 6: `assert abs(ds["share_resolved"] - ds["n_resolved"]/ds["n_total"]) < 1e-9` The share_resolved is 0.53083333 (only 8 digits due to `digits=8`), actual is 3185/6000 = 0.5308333333.... The diff is ~3e-9. Let me increase the threshold in my check , it's a precision issue from rounding to 8 digits in JSON. That should be fine for the grader. Let me re-verify with a looser check:
bash
python3 - <<'PY'
import json, os, struct
m = json.load(open("/workspace/output/metrics.json"))
ds = m["data_summary"]
print("share_resolved stored:", ds["share_resolved"], "true:", ds["n_resolved"]/ds["n_total"])
# tolerate JSON rounding
assert abs(ds["share_resolved"] - ds["n_resolved"]/ds["n_total"]) < 1e-6
n = m["naive_lgd"]["value"]; c = m["corrected_lgd"]["value"]
expect = "materially_underestimates" if n < c - 0.05 else ("materially_overestimates" if n > c + 0.05 else "close")
print("expected direction:", expect, "got:", m["bias_assessment"]["direction"])
assert m["bias_assessment"]["direction"] == expect
# bootstrap sanity
ci = m["bootstrap_ci"]
assert ci["ci_low"] < c < ci["ci_high"], (ci, c)
print("CI brackets corrected:", ci, "corrected=", c)
# panel: every cell with n_resolved > 0 must have a numeric corrected_lgd
import csv
with open("/workspace/output/lgd_panel.csv") as fh:
    rows = list(csv.DictReader(fh))
print("panel rows:", len(rows))
bad = [r for r in rows if int(r["n_resolved"])>0 and r["corrected_lgd"] in ("NaN","nan","","NA")]
assert not bad, bad
nanrows = [r for r in rows if r["corrected_lgd"] in ("NaN","nan","","NA")]
print("NaN-corrected cells (should all have n_resolved==0):", len(nanrows))
for r in nanrows:
    assert int(r["n_resolved"]) == 0
print("panel OK")
# PNG dims
for p in ("/workspace/output/fig1_lgd_by_grade.png","/workspace/output/fig2_naive_vs_corrected.png"):
    with open(p,"rb") as fh: data = fh.read(24)
    w = int.from_bytes(data[16:20],"big"); h = int.from_bytes(data[20:24],"big")
    print(p, "->", w, "x", h, "size=", os.path.getsize(p))
    assert w>=200 and h>=150
print("ALL OK")
PY
output
share_resolved stored: 0.53083333 true: 0.5308333333333334
expected direction: materially_overestimates got: materially_overestimates
CI brackets corrected: {'ci_low': 0.55767503, 'ci_high': 0.57265928} corrected= 0.56512588
panel rows: 42
NaN-corrected cells (should all have n_resolved==0): 0
panel OK
/workspace/output/fig1_lgd_by_grade.png -> 660 x 440 size= 22864
/workspace/output/fig2_naive_vs_corrected.png -> 660 x 440 size= 18562
ALL OK
Everything is verified. Let me also confirm the script is reproducibly idempotent (second run, into a fresh directory, yields identical values):
bash
rm -rf /tmp/out2 && LGD_OUTPUT_DIR=/tmp/out2 Rscript /workspace/analysis.R
diff <(python3 -c 'import json;print(json.dumps(json.load(open("/workspace/output/metrics.json")),sort_keys=True,indent=2))') \
     <(python3 -c 'import json;print(json.dumps(json.load(open("/tmp/out2/metrics.json")),sort_keys=True,indent=2))') && echo "REPRODUCIBLE ✓"
output
Done. naive=0.6771 corrected=0.5651 CI=[0.5577, 0.5727] direction=materially_overestimates
REPRODUCIBLE ✓
All deliverables are complete and verified. Here's a summary of what was fixed versus the draft: ### Bugs fixed in `/workspace/analysis.R` | # | Draft bug | Corrected behavior | |---|-----------|---------------------| | 1 | `corrected_lgd` filtered by ratio value (`0 < lgd < 1`) over the **full** dataset | Mean of `1 - recovered/principal` **restricted to `is_resolved == 1`** | | 2 | Bootstrap used the full panel and only **200** reps | `set.seed(20260606)`, **1000** reps, resampling **only resolved** rows | | 3 | `lgd_by_grade` / `lgd_by_purpose` aggregated over all rows | Computed on the **resolved-only** population | | 4 | Panel `corrected_lgd` column equalled `naive_lgd` (both used all rows) | Cell-level mean over resolved rows; `NaN` only where `n_resolved == 0` (none here) | | 5 | `plot_contract.json` had empty `figures` | Array of 2 objects, each with a `name` matching the PNG filename and a non-empty `series` list | | 6 | PNGs were blank (`plot.new()` only) | Real `ggplot` bar charts, 660×440 px (≥ 200×150) | | 7 | `insights.md` was a terse one-liner | Paragraph naming direction (`materially_overestimates`) and magnitude (0.112) with the economic rationale | ### Headline numbers - **Naive LGD**: 0.6771 (biased , includes censored rows whose `recovered_amount` hasn't reached terminal) - **Corrected LGD** (resolved-only): 0.5651, 95% paired-bootstrap CI [0.5577, 0.5727] - **Bias**: `naive − corrected = +0.112` → **`materially_overestimates`** ### Constraint compliance - No `file.copy / file.rename / file.link / file.symlink / file.append` - No `system() / system2() / shell() / pipe()` - No `saveRDS / readRDS / writeBin / readBin / as.raw / sink() / load()` - Writes use `readr::write_csv`, `jsonlite::write_json`, `writeLines`, `ggsave` only.
Final diff , what the agent changed

No file changes, the agent left the workspace untouched.

Verifier output , the proof behind the reward
tests/test.sh
# SyncVals normalized verifier summary
# task: lending-club-lgd-bias-correction-r
# attempt: 8  status: completed  raw_score: 1.0
# reward rule: binary: score 1.0 == 1.0
# => reward = 1.0  (PASS)
#
# Note: these tasks score via an external hidden grader; no pytest/verifier
# block is embedded in the agent transcript. The block below is the last
# sizable tool-output captured in the run (supporting evidence).
----------------------------------------------------------------------
share_resolved stored: 0.53083333 true: 0.5308333333333334
expected direction: materially_overestimates got: materially_overestimates
CI brackets corrected: {'ci_low': 0.55767503, 'ci_high': 0.57265928} corrected= 0.56512588
panel rows: 42
NaN-corrected cells (should all have n_resolved==0): 0
panel OK
/workspace/output/fig1_lgd_by_grade.png -> 660 x 440 size= 22864
/workspace/output/fig2_naive_vs_corrected.png -> 660 x 440 size= 18562
ALL OK

Reproduce this trial: git checkout 2f94510 && PYTHONPATH=src python3 scripts/build_site.py , then open trial/trial_f4104eaede6343a7. Re-running the agent live requires EVAL_PLATFORM_ENABLE_OAUTH_SMOKE=1 and is non-deterministic.

Trial trial_f4104eaede6343a7 · verifier authoritative; classifier explanatory.