Decision infrastructure for coding agents
Decision infrastructure gives coding agents a durable, reviewable and enforceable record of what a software team has already decided.
Decision infrastructure
Practical, evidence-led notes on giving AI coding agents durable project context, reproducible decisions and constraints that mean what they claim.
Maintained by Tom Ballard · Initial library published 3 August 2026 · Read the decision-governance pillar
Canonical collection answer
AsDecided Notes are evidence-led explanations of the decisions that let software teams work with AI coding agents without losing project authority. The collection covers architecture decision records, persistent context, deterministic retrieval, decision provenance, exceptions and enforcement in CI. Each note gives a focused answer, identifies the boundary of the claim and links to the canonical product documentation or source material. Five canonical guides are the collection’s durable answers; shorter notes support them with comparisons, worked examples and implementation questions. Notes are editorial guidance rather than product guarantees, so the current specification, documentation and changelog remain the source of truth for released behaviour.
Decision infrastructure
Decision infrastructure is the repository-level system that records an engineering decision, makes the relevant decision retrievable by coding agents, and verifies any machine-checkable constraint against the code. It turns project memory from optional prose into maintained engineering infrastructure.
Read the field notePILLAR INDEX
These five records define the main topics in the collection. The supporting notes link back to them so a reader or answer system can move from a specific question to the broader source of authority.
01
Decision infrastructure gives coding agents a durable, reviewable and enforceable record of what a software team has already decided.
Decision drift happens when later code changes gradually stop reflecting an engineering decision that the team still considers valid.
Coding agents often reverse valid architectural decisions because the rationale and rejected alternatives are missing from the task context.
Negative decisions document approaches a team deliberately rejected so people and coding agents do not repeatedly reintroduce them.
Repository-local decisions travel with the code, inherit review and remain available across agent vendors and execution environments.
Record rejected approaches with scope, evidence and reconsideration conditions so coding agents do not rediscover the same failure.
An agent-ready ADR adds explicit scope, lifecycle, rejected alternatives, retrieval terms and machine-checkable consequences.
Migrate decisions by preserving identifiers and provenance, then deliberately rescoping, accepting or rejecting them in the destination repository.
An architectural decision control plane connects reviewed decisions, agent context, code changes and deterministic verification without replacing Git or CI.
Monitor whether accepted decisions remain owned, retrievable, enforced where claimed and aligned with the code they govern.
Combine local repository authority with explicit organisation-level decisions, versioned distribution and deterministic precedence.
02
Use layered instructions, repository decision records and deterministic retrieval to give coding agents persistent context without one enormous prompt.
AGENTS.md and CLAUDE.md guide particular coding agents; ADRs preserve durable decisions. They solve related but different problems.
Agent instruction files shape model behaviour, but they do not prove that a patch complies with an engineering decision.
Coding agents remember architectural decisions reliably only when the repository can retrieve a current, cited record for each task.
Keep decisions in one vendor-neutral repository record and use each agent's instruction file only as a route into that shared authority.
A practical AGENTS.md should teach Codex how to work in a repository while routing durable engineering decisions to their authoritative records.
Use CLAUDE.md to route Claude Code toward current architecture decisions, not to duplicate an entire decision history.
Multiple agents stay consistent when they share authority, retrieval and verification—not when prompts happen to resemble one another.
Decision citations should identify the exact reviewed record, its repository revision, applicability and the files or claims it influenced.
Make applicable decisions, conflicts, required checks and citations visible in an agent plan before implementation begins.
03
ADRs become more useful to coding agents when they are validated, discoverable by task language, lifecycle-aware and connected to checks.
Requirements as code makes important product constraints versioned, validated, discoverable and testable alongside the implementation.
04
RAG is flexible for broad knowledge discovery; deterministic retrieval is useful when engineering decisions need reproducible results and citations.
A read-only MCP boundary lets coding agents discover and cite accepted decisions without silently changing the authority they depend on.
05
Enforce an architectural decision in CI by translating one objective consequence into a deterministic check linked to the accepted record.
Deterministic checks make agent governance reproducible by evaluating explicit constraints without asking another model for a compliance opinion.
06
A worked example showing how to record, retrieve and enforce a 30-day account-restoration decision for coding agents.
Use this checklist to assess whether a repository gives coding agents durable decisions, reproducible retrieval and honest enforcement.
Instruction files, ADRs, MCP servers, RAG and CI policy engines govern different stages; dependable systems combine them without confusing guidance with proof.
A reproducible benchmark can measure whether instructions improve agent behaviour and whether deterministic checks catch the violations that remain.
Add stable identity, lifecycle, scope, agent instructions and enforcement references to human-readable decision records.
07
Record the database convention, expose its rationale before planning, and enforce only the structural consequences that CI can prove.
Test observable outcomes—decision retrieval, citations, commands, policy results and patch behaviour—rather than asking the agent whether it complied.
Decision provenance links an AI-assisted change to the reviewed records, repository state and evidence that governed it.
Treat architectural exceptions as scoped, approved and expiring records instead of disabled checks or permanent temporary workarounds.
Preserve repository state, retrieved decisions, citations, check results, approvals and exceptions as an inspectable evidence chain.
Connect each deterministic policy rule to the reviewed architectural decision that explains its purpose, scope and remediation.
08
Repository-native context is the safer authority layer for engineering decisions; RAG remains useful for broader discovery across large, mixed corpora.
Resolve applicable decisions with deterministic repository and path signals first, then use semantic signals only to improve discovery.