Gemini 3.8 Flash on Fix three bugs in a Python repo so its tests pass

GGemini 3.8 Flash · Gemini CLI 0.64.0 (headless -p --yolo) · cloud · 2026-10-17 · by @bobsiopener

Trust 80%Fully autonomoussuccess · first tryCompare

Estimated cost: $0.10
Wall time: 2m
Human step-ins: 0
Outcome: Pass

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Exact prompt

You are working on the repository in ./repo. Fix the three bugs described in repo/ISSUES.md in textstats.py. Run the existing tests (python3 -m unittest in repo) and make sure they pass. Do not change function names or signatures.

Task prompt given to the agent (headless, offline, synthetic fixture inputs): You are working on the repository in ./repo. Fix the three bugs described in repo/ISSUES.md in textstats.py. Run the existing tests (python3 -m unittest in repo) and make sure they pass. Do not change function names or signatures. Inspired by https://x.com/bnjmn_marie/status/2089775546943312076 (unverified; not checked with the author). This is an independent re-run on a reproducible synthetic task; it does not report or reproduce the original post's numbers. Cost is a list-price estimate (run on the AI Studio free tier, $0 billed).

Success criteria: All automated rubric checks pass: hidden test test_avg; hidden test test_mc; hidden test test_wc.

Setup notes: Harness: Gemini CLI (headless -p, --yolo, json output) v0.64.0, Google AI Studio API key (free tier, $0 billed). cost_is_estimate=true: cost = tokens x list price. Price source: Gemini 3.8 Flash $0.75 in / $3.75 out / $0.075 cached per 1M (introductory, per 9io.ai Oct 8 2026 https://9io.ai/blog/llm-api-pricing-benchmarks-comparison and artificialwatch.com/llm-pricing). Output includes thinking tokens. Actually billed $0 (free tier). Output tokens include thinking tokens. input_tokens includes cached reads; cached_tokens = cache reads; cache_write_tokens = 0 (not reported by Gemini CLI). Single run, no retries; scored automatically (3/3 checks). Runner notes: Adapted: full DeepSWE (45h) scaled to a 3-bug mini-repo with hidden unit tests. Single run, no retries, 600s timeout. Web tools excluded via work/.gemini/settings.json. Same rubric/score.py as other runs.

Estimated cost List-price estimate; not actually billed.

Metrics

Estimated cost: $0.10
Wall time: 2m
Human step-ins: 0
Turns: 11

Model usage
Model	Input tok	Output tok	Cost
GGemini 3.8 Flashgoogle/gemini-3.8-flash	186,332	8,133	$0.10

Reproduce this run

Use the use case prompt on the use case page.
Same setup: Gemini 3.8 Flash (google/gemini-3.8-flash) via Gemini CLI 0.64.0 (headless -p --yolo), cloud.
It counts as a success only if it meets every success criterion: All automated rubric checks pass: hidden test test_avg; hidden test test_mc; hidden test test_wc.
Log model, tokens, wall time, human step-ins and the evidence log, then submit it as a reproduction. A different model? Submit a head-to-head rerun.

How runs are scored: Methodology.

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Automated checks

Trust 80% comes from these checks (how Trust % works).

Run date is not in the future : passed
Model is in the dated pricing table : passed
Cost recomputed from tokens matches : passed
Cached tokens are consistent : passed
Output throughput is plausible : passed
Autonomy matches step-ins : passed
Step-ins do not exceed turns : passed
Retries agree with first-try result : passed
Evidence log SHA-256 matches : passed
Evidence log is substantial : passed

Evidence log

{
 "session_id": "[REDACTED]",
 "response": "The three bugs reported in `repo/ISSUES.md` have been resolved in `repo/textstats.py`:\n\n1. **`word_count`**: Updated `text.split(\" \")` to `text.split()` to correctly handle consecutive spaces, newlines, and tabs without counting empty tokens.\n2. **`avg_word_length`**: Added a check for empty word lists to return `0.0` instead of raising `ZeroDivisionError`.\n3. **`most_common`**: Case-folded tokens using `text.lower()`, handled empty inputs by returning `None`, and implemented alphabetical tie-breaking via `min(counts, key=lambda wd: (-counts[wd], wd))`.\n\nAll tests pass cleanly when running `python3 -m unittest` in `repo`.",
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