Agent rule pattern
Rules for approaching the work, not facts about the repository.
State tradeoffs, do not over-build, and touch only what the request needs. Two projects say these rules came from mistakes agents kept making.
Turn a recurring mistake into a decision the agent can act on: what to check before editing, when to stop expanding scope, or when a request should remain read-only.
Four general sections come first: Think Before Coding, Simplicity First, Surgical Changes, and Goal-Driven Execution. They cover assumptions, scope, adjacent code, and completion criteria.
Source excerpt starting at line 3.**Don't assume. Don't hide confusion. Surface tradeoffs.**
Reproduction is the start of triage. The file requires evidence from documented behavior, types, or established runtime semantics before treating the result as a bug.
Source excerpt starting at line 56.- A reproducible error is not automatically a bug. First prove the behavior violates Better Auth's documented contract, TypeScript contract, or established runtime semantics.
A question about the codebase does not imply permission to change it. The default is stated in one line at the top of the working style section.
Source excerpt starting at line 23.- Treat questions about the codebase as read-only unless the user asks for changes.
AnarlogScale command architecture to its state
AstroFour framing sections before any repository detail
Better AuthProve the contract violation
BiomeRequire evidence for claims about the codebase
Cal.diyState the local exception to a repository-wide import rule
cmuxIsolate the complete development identity
Codexopenai/codex
Deep AgentsReject tests that only freeze implementation shape
DiffusersExplain how old skill symlinks can alter the source
ElectronUse the result CI has already produced
FirecrawlDefine both success and failure
GitButlerQuestions treated as read-only
GradioAssign review responsibility to the submitting human
GrafanaDerive change boundaries from deployment boundaries
Hermes AgentProvide an ordered decision process for new capability
LanceDBRebuild stale extensions before giving up
LogfirePreserve intentional warnings in production
marimoExpand the audience beyond the immediate requester
NxSelect a work mode from the request
OpenAI Agents SDK for PythonDefine a concrete trigger for reconsidering complexity
OpenAI Agents SDK for TypeScriptMake a runtime finding prove a supported consequence
opencodeA rule against extracting helpers
OxcExplain an empty search result before it misleads
PayloadPut database lifecycle in the shared fixture
pnpmSeparate version policy from bug parity
Pydantic AIKeep general design philosophy from widening a bug fix
PyTorchExpose the cost hidden behind a documentation edit
RailpackChoose defaults that users can override
RolldownExplain an internal compatibility exception
RuffExplain the hidden configuration behind a reproduction
RustFSPermit a review with no findings
SGLangRead neighboring pages before choosing a structure
StorybookPrinciples labelled as observed failure modes
StrapiDistinguish an absent optional tool from a broken one
StreamlitKeep concurrent debugging evidence tied to a session
T3 CodeCheck the reverse operation
TanStack DBTurn review bugs into missing test dimensions
TanStack QueryPair narrow scope with responsibility for generated code
TemporalA stated persona and background
TursoA named debugging shortcut, ruled out
TwentyGive surrounding code precedence over written defaults
vLLMDesign the test before writing its setup
ZedUse timers that the test scheduler can see
Astro 
Better Auth 
GitButler