Sources
Every source the notes cite, in full. The notes cite by key ([Study: METR 2025]); this file is where the key resolves.
Each entry carries enough to find the work again if the link dies: who produced it, when, its stable identifier where one exists, and the sample it rests on. Each also declares how this repo checked it - primary means the source itself was read, secondary means the figure comes from a summary and has not been confirmed at the source. A secondary figure is not wrong; it is unconfirmed, and a note leaning on one says so.
The key's prefix is the evidence class, so a reader sees what kind of support a sentence has without leaving the sentence: Study (controlled or systematic), Data (large-scale measurement), Survey (self-report at scale), Vendor (the tool maker's own statement), Incident (a public, consequential event), Field (practitioner testimony).
Studies
Study: METR 2025
Becker, J., Rush, N., Barnes, E., Rein, D. Measuring the Impact of Early-2025 AI on Experienced Open-Source Developer Productivity. METR, 12 July 2025 (revised 25 July 2025). arXiv:2507.09089.
- Method - randomized controlled trial. 16 experienced open-source developers, 246 real tasks in repositories they already maintain, with the AI tooling available February to June 2025.
- Used for - measured completion time 19% longer when AI use was allowed; the same developers forecast 24% faster beforehand and reported 20% faster afterwards. Economics and ML experts predicted 38-39% faster.
- Caveat - the authors treat the result as historical and have since changed the experiment design. It is evidence that the perception gap exists, not a constant to plan with.
- Verified - primary (abstract and figures read). arxiv.org/abs/2507.09089 / metr.org, accessed 2026-08-01.
Study: Chroma 2025
Hong, K., Troynikov, A., Huber, J. Context Rot: How Increasing Input Tokens Impacts LLM Performance. Chroma Research, 14 July 2025.
- Method - 18 models across four families (Claude Opus/Sonnet/Haiku, GPT-4.1 family, o3, GPT-4o, Gemini 2.5/2.0, Qwen3 at three sizes), over five controlled experiments: needle-question similarity, distractor impact, needle-haystack similarity, haystack structure, and repeated words, plus LongMemEval conversational QA.
- Used for - performance degrades non-uniformly as input length grows, on tasks simple enough that length should not matter; lower question-answer semantic similarity accelerates the decline; distractors hurt more at length; a shuffled haystack is retrieved from more reliably than a logically coherent one; on LongMemEval, a focused ~300-token prompt beats the full ~113k-token one across every family.
- Verified - primary (methodology and findings read). trychroma.com/research/context-rot, accessed 2026-08-01.
Study: Veracode 2025
Veracode. 2025 GenAI Code Security Report: Assessing the Security of Using LLMs for Coding. Veracode, October 2025 update.
- Method - 80 code-completion tasks: four CWEs (SQL injection CWE-89, cross-site scripting CWE-80, log injection CWE-117, broken cryptography CWE-327) x four languages (Java, JavaScript, C#, Python) x five task instances, given to over 100 LLMs, with the output checked by a SAST engine. Each task can be completed securely or insecurely, and the prompt contains no security guidance - the point is to observe the default choice.
- Used for - overall security pass rate ~55%, so in 45% of tasks the model introduces a detectable OWASP Top 10 flaw. By language (pass rate): Python 61.69%, JavaScript 57.34%, C# 55.27%, Java 28.50%. By CWE (pass rate): broken crypto 85.61%, SQL injection 80.44%, cross-site scripting 13.53%, log injection 12.03%. Model size barely matters (50.87 / 51.10 / 50.65% for large / medium / small). Syntactic pass rates rose steeply over the period while the security pass rate stayed flat.
- Caveat - this measures the default choice on isolated function-completion tasks without security prompting. It is not a claim about the rate of vulnerabilities in shipped AI-assisted code.
- Verified - primary (report PDF read: methodology p5-8, results p10-13). veracode.com, accessed 2026-08-01.
Study: ImpossibleBench 2025
Zhong, Z., Raghunathan, A., Carlini, N. ImpossibleBench: Measuring LLMs' Propensity of Exploiting Test Cases. 30 October 2025. arXiv:2510.20270.
- Method - impossible tasks built by mutating the tests of established benchmarks (LiveCodeBench, SWE-bench) so they contradict the natural-language specification, in two variants (one-off and conflicting mutations). Models are explicitly told to prioritize the specification over the tests.
- Used for - on the one-off variant of impossible-SWEbench, GPT-5 exploits the test cases 76% of the time rather than reporting the task impossible; stronger models generally show higher cheating rates, so capability gains do not resolve the behavior.
- Verified - primary (paper details and figures read via the authors' write-up). arxiv.org/abs/2510.20270, accessed 2026-08-01.
Study: Code comprehension 2025
How Accurately Do Large Language Models Understand Code? 2025. arXiv:2504.04372.
- Method - 9 LLMs, ~575,000 debugging tasks over 637 Python and 670 Java programs; semantic-preserving mutations are injected and fault-localization accuracy is compared before and after.
- Used for - injecting misleading comments degrades fault localization more than misleading variable names does (24.55% vs 28.7% accuracy on the mutated phase). Models extract meaning from comments even though comments do not execute.
- Verified - primary (methodology and the comparison figures read). arxiv.org/abs/2504.04372, accessed 2026-08-01.
Study: Comment internalization 2025
Inside Out: Uncovering How Comment Internalization Steers LLMs for Better or Worse. 2025. arXiv:2512.16790.
- Method - representation-level analysis using concept activation vectors: the comment concept is activated and deactivated inside the model across code completion, translation and refinement, plus a controlled comparison over 10 software-engineering tasks with identical code inputs.
- Used for - manipulating the comment concept shifts task performance across a range of -90% to +67%; the effect is strongest on summarization and weakest on completion. Comments are a large lever whose sign depends on the task.
- Verified - primary (abstract read). arxiv.org/abs/2512.16790, accessed 2026-08-01.
Study: Agent cheating 2026
Do Coding Agents Deceive Us? Detecting and Preventing Cheating via Capped Evaluation with Randomized Tests. 2026. arXiv:2606.07379.
- Used for - the catalogue of cheating strategies: reverse-engineering test cases, modifying or deleting failing tests, editing evaluation code, hardcoding outputs for known inputs; and read-only test sandboxing as the countermeasure.
- Verified - secondary (identified through search summaries; the paper itself has not been read in full here). The claims it supports are corroborated by
Study: ImpossibleBench 2025. - arxiv.org/abs/2606.07379, accessed 2026-08-01.
Data: Benchmark cheating audit
Finding Widespread Cheating on Popular Agent Benchmarks. DebugML.
- Used for - harness-level cheating found across top submissions on multiple public agent leaderboards, plus confirmed reward-hacking cases across several benchmarks.
- Verified - secondary (search summary only). debugml.github.io/cheating-agents, accessed 2026-08-01.
Large-scale measurement
Data: GitClear 2025
GitClear. AI Copilot Code Quality: 2025 Data Suggests 4x Growth in Code Clones.
- Method - 211 million changed lines of code, January 2020 to December 2024, from repositories including those owned by Google, Microsoft and Meta plus enterprise corporations.
- Used for - cloned code rose from 8.3% of changed lines in 2021 to 12.3% in 2024; moved (refactored) lines fell from 25% in 2021 to under 10% in 2024; copy/paste exceeded moved code for the first time on record.
- Verified - primary (report page read). gitclear.com, accessed 2026-08-01.
Data: GitClear 2026
GitClear. The Maintainability Gap: AI Code Quality in 2026. January 2026.
- Method - 623 million analyzed changes, 2023 to 2026.
- Used for - copy/paste rose from 9.4% of changed lines (2022) to 15.7% in the first half of 2026; moved code fell 21% (2022) -> 13% (2023) -> 3.8% (2026 to date); block duplication rose from 40.3 to 73.0 duplicated lines per million changed (+81%); and long-term maintenance of older code fell from 1.7% to 0.46%, a 74% decline.
- Verified - primary (report page read). gitclear.com, accessed 2026-08-01.
Data: Repo mining 2026
An Exploratory Study on LLM-Generated Code and Comments in Code Repositories. 2026. arXiv:2607.01867.
- Method - eight long-lived repositories (four company-maintained: Google, Meta, Uber, Shopify; four community), October 2021 to October 2025, across Java, Python, Go, Ruby, JavaScript and PHP, with detector-based attribution of LLM-written code and comments.
- Used for - comments attributed to models concentrate in the meta / explanation categories, 63-74% of them in the company repositories; file-level intra-repository clones in suspected LLM code run 45-100% depending on repository.
- Caveat - attribution is by detector, not by disclosure; treat the categories as indicative rather than exact.
- Verified - primary (paper read). arxiv.org/abs/2607.01867, accessed 2026-08-01.
Surveys
Survey: DORA 2025
DORA / Google Cloud. 2025 DORA Report: State of AI-Assisted Software Development. 23 September 2025.
- Method - nearly 5,000 technology professionals surveyed, plus over 100 hours of qualitative data.
- Used for - 90% report using AI at work and more than 80% believe it increased their productivity; AI adoption shows a positive relationship with software delivery throughput and product performance (a reversal from the previous year) and a negative relationship with delivery stability; 30% report little or no trust in AI-generated code. The report's framing: without strong automated testing, mature version control and fast feedback, more change volume produces instability.
- Verified - primary (announcement and findings read). cloud.google.com, accessed 2026-08-01.
Survey: Stack Overflow 2025
Stack Overflow. 2025 Developer Survey - AI section.
- Method - annual developer survey; individual AI questions answered by roughly half to two thirds of a respondent pool on the order of 49,000.
- Used for - 84% use or plan to use AI tools (up from 76%); trust in accuracy 32.7% (3.1% highly trust + 29.6% somewhat trust) against 45.7% distrust (26.1% somewhat + 19.6% highly); the top frustration is solutions that are almost right but not quite at 66%; 45.2% say debugging AI-generated code is more time-consuming.
- Caveat - press coverage widely reported trust as "29%", which is the somewhat trust band alone. The full trust figure is 32.7%.
- Verified - primary (survey AI section read). survey.stackoverflow.co/2025/ai, accessed 2026-08-01.
Vendor statements
Vendor: Claude Code docs
Anthropic. Best practices for Claude Code. Product documentation, living page.
- Used for - context as the primary constraint and performance degrading as it fills; give the agent a check it can run and demand evidence rather than assertions; stop hooks and fresh-context reviewer subagents; the over-eager-reviewer caveat; the deletion test for instruction files and the warning that a bloated one causes rules to be ignored; hooks as deterministic where instructions are advisory; permission modes, allow lists and sandboxing; checkpoints not covering shell-made changes.
- Caveat - a living page. It states intent and the maker's view of what counts as a defect; it is not evidence of outcomes, and it can change without notice.
- Verified - primary (page read). code.claude.com/docs/en/best-practices, accessed 2026-08-01.
Vendor: Anthropic context engineering 2025
Anthropic. Effective context engineering for AI agents. Engineering blog.
- Used for - the attention-budget argument (n tokens imply n^2 pairwise relations, so every token spends a finite budget); performance as a gradient rather than a cliff; just-in-time retrieval, compaction, structured note-taking and sub-agent architectures as the countermeasures.
- Verified - primary (post read). anthropic.com/engineering, accessed 2026-08-01.
Vendor: Claude Code system prompts
Piebald AI. claude-code-system-prompts - a public mirror of Claude Code's shipped system prompts and tool descriptions, updated per release.
- Used for - the agent is instructed to comment only where the reason is non-obvious and useful to a future reader, and to match the comment density of the file it is editing.
- Caveat - a third-party mirror, not an official publication; it tracks a specific release and the shipped text changes between versions.
- Verified - primary (repository searched for the relevant instruction text). github.com/Piebald-AI/claude-code-system-prompts, accessed 2026-08-01.
Incidents
Incident: curl 2025-2026
Stenberg, D. Death by a Thousand Slops. Personal blog, 14 July 2025. Plus the programme's closure, reported January 2026.
- Who - the maintainer of curl, writing under his own name about his own project's security process; the security team numbers seven people.
- Used for - by July 2025 roughly 20% of submissions were AI-generated slop while the valid-report rate had fallen to about 5%; a typical report engages three or four people for thirty minutes to a few hours each. The bug bounty programme was ended in January 2026. Separately, the same maintainer publicly praised AI-assisted findings from a researcher who verified them before reporting - the tool was never the problem, unverified volume was.
- Verified - primary for the blog figures (post read); secondary for the closure date and the praised findings (trade press). daniel.haxx.se / theregister.com / cybernews.com, accessed 2026-08-01.
Incident: Replit 2025
An AI-powered coding tool wiped out a software company's database in a "catastrophic failure". Fortune, 23 July 2025. Catalogued as incident 1152 in the AI Incident Database.
- Used for - an agent executed destructive commands against live infrastructure during an explicit code-and-action freeze, deleting records for over 1,200 executives and more than 1,190 companies; it then reported that recovery was not possible, which was false - the data was restored. Replit's CEO acknowledged it publicly and shipped separated development and production databases, improved rollback, and a planning-only mode.
- Verified - primary (article read); the incident-database entry corroborates. fortune.com / incidentdatabase.ai/cite/1152, accessed 2026-08-01.
Field reports
Practitioner testimony. Cited by artifact, never by author: the identifier is the thread or issue id, which is stable, and engagement figures are the state at the access date. See the citation rules for why pseudonymous posters are not named.
Field: review refusal 2026
Today I announced that I won't be reviewing AI generated PRs at company meeting. r/ExperiencedDevs, thread 1towli9, posted 2026-05-27. 1,908 points (0.89 upvote ratio), 442 comments at access.
- Who - a web developer receiving Rails/Vue pull requests generated with an agent by data scientists on the same company's staff.
- Used for - the refusal itself, and the poster's own two stated conclusions: the problem is code nobody owns or understands, and the cost ratio between generation and review has collapsed onto the reviewer.
- Verified - primary (thread and both updates read). reddit.com/r/ExperiencedDevs/comments/1towli9, accessed 2026-08-01.
Field: slop cleanup 2025
The era of AI slop cleanup has begun. r/ExperiencedDevs, thread 1mg2r6y, posted 2025-08-02. 4,272 points (0.97 upvote ratio), 473 comments at access.
- Who - a freelance software engineer of about eight years, mainly early-stage startups.
- Used for - inbound work shifting from building systems to repairing AI-built ones.
- Verified - primary (thread read). reddit.com/r/ExperiencedDevs/comments/1mg2r6y, accessed 2026-08-01.
Field: repair calls 2026
Getting more calls to fix ai generated codebases than actual new builds lately. r/ExperiencedDevs, thread 1sskw4r, posted 2026-04-22. 402 points (0.93 upvote ratio), 102 comments at access.
- Who - a consultant of about ten years, smaller companies and early-stage startups.
- Used for - the same shift, described independently and roughly eight months later.
- Verified - primary (thread read). reddit.com/r/ExperiencedDevs/comments/1sskw4r, accessed 2026-08-01.
Field: parallel projects 2026
AI code vs human code: a small anecdotal case study. r/ExperiencedDevs, thread 1qjbipc, posted 2026-01-21. 205 points (0.95 upvote ratio), 66 comments at access.
- Who - an engineer of about five years, comparing their own project against a colleague's near-identical one (Python, ML, greenfield, same period), the colleague's being roughly 90% AI-generated.
- Used for - about 80% of input models carrying nullability and shape mistakes; many tests, mostly trivial validation, of which roughly a tenth were judged worth keeping, with a share asserting the wrong behavior; comment density inverted (heavy on simple CRUD, near-absent in the dense mathematical parts); a common utility reimplemented where a library existed; defensive checks the control flow made unnecessary; no structural narrative.
- Caveat - explicitly anecdotal, one observer, self-described as such. It is the most concrete public side-by-side available, not a controlled study.
- Verified - primary (post read in full). reddit.com/r/ExperiencedDevs/comments/1qjbipc, accessed 2026-08-01.
Field: six-month setup 2025
Claude Code is a Beast - Tips from 6 Months of Hardcore Use. r/ClaudeAI, thread 1oivjvm, posted October 2025, about 2,331 points at access; companion repository post 1ojqxbg (2025-10-30) publishes the configuration.
- Who - an engineer running an agent daily against an internal work project of 300k+ lines.
- Used for - documented rules being ignored until the "how to write code" guidance moved out of the always-loaded instruction file into skills loaded on demand, leaving the instruction file with project mechanics only; hooks used for enforcement (a prompt-submit hook injecting the relevant skill, a stop hook checking what was edited); a plan/context/task file pattern kept explicitly because it survives context resets; re-prompting from an earlier branch instead of stacking corrections.
- Verified - primary (post and companion post read). reddit.com/r/ClaudeAI/comments/1oivjvm, accessed 2026-08-01.
Field: CC issue 3382
Claude says "You're absolutely right!" about everything. anthropics/claude-code issue 3382, closed, ~1,375 reactions at access.
- Used for - reflexive agreement as a recognized, widely-experienced behavior rather than an anecdote; self-assessment is therefore not verification.
- Verified - primary (issue metadata read via the GitHub API). github.com/anthropics/claude-code/issues/3382, accessed 2026-08-01.
Field: CC issue 6235
Feature Request: Support AGENTS.md. anthropics/claude-code issue 6235, open, ~5,802 reactions at access - the most-reacted issue in that tracker.
- Used for - teams maintaining duplicate instruction files per tool, and drift between them as the reported pain.
- Verified - primary (issue metadata read via the GitHub API; confirmed as the highest-reaction issue by a sorted query). github.com/anthropics/claude-code/issues/6235, accessed 2026-08-01.
Field: HN agent workflows
Hacker News comment threads on agent workflows, retrieved through the Algolia search API.
- Used for - independent convergence on lean instruction files, sub-agent delegation, fresh context per stage, spec documents before execution, and reports of agents running destructive git commands despite explicit instruction.
- Caveat - an aggregate of many comments rather than one citable artifact; the weakest form of evidence used here, and used only where a study or vendor statement says the same thing.
- Verified - primary (comment corpus retrieved and read). hn.algolia.com, accessed 2026-08-01.
