code-doc-lockstep

A rule that requires code changes and their matching documentation to be updated together. The documentation may describe architecture, user features, APIs, operations, or project specifications.

In plain words
What is it for?
Use it whenever a code change affects system design, user behavior, API contracts, deployment procedures, or documented project requirements.
Why use it?
It prevents the code and the instructions describing it from drifting out of agreement.

Cursor rule for Cursor

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add rules/alphabitcore/nexus-gateway/code-doc-lockstep
Clone the repo
git clone --depth 1 https://github.com/AlphaBitCore/nexus-gateway

Made for: Cursor.

Per session 1,054 This file is loaded in full into every session.
When invoked 1,054 The same file — it is already loaded in full.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.01054 $0.01054
Opus 5 $0.00527 $0.00527
Sonnet 5 $0.00211 $0.00211
Haiku 4.5 $0.00105 $0.00105

Measured yesterday against content hash a1f2aa85cd5e, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

code-doc-lockstep scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured yesterday.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

.cursor/rules/code-doc-lockstep.mdc · 69 lines

How it starts

The opening of the file, as written. The whole thing — 69 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Code / Doc Lockstep (BINDING)

Docs are the single source of truth. If code drifts from a doc, the code is wrong — fix the doc to match reality if needed, but never ship code that contradicts its doc.

The rule

When a PR touches code in a region covered by a doc, every matching doc MUST be updated in the same commit. The doc isn't a follow-up; it's part of the change. This applies to every doc tree:

Doc tree What changes here trigger an update
docs/developers/architecture/** internal mechanics, data flow, contracts between services
docs/users/features/** user-visible UI surface, admin features, agent UX
docs/users/api/openapi/** request/response schemas, new/renamed/removed endpoints
docs/operators/ops/runbooks/** deployment steps, recompute scripts, operational procedures
docs/developers/specs/** Epic / Story acceptance criteria as scope evolves

A single code change typically touches multiple doc trees. Examples:

  • New admin endpoint → OpenAPI spec + architecture doc + feature doc (if UI surface) + runbook (if ops procedure).
  • Cost-stamping change → cost-estimation-architecture.md + prod-deploy-data-changes.md (if historical recompute) + feature doc for the Traffic drawer (if visible breakdown changes).
  • Provider adapter codec change → provider-adapter-architecture.md + feature doc if visible to admins.
  • Schema migration → cost-estimation-architecture.md (if cost columns) OR thing-config-sync-architecture.md (if shadow) + runbook if any historical data fix is part of the PR.

How it's enforced

scripts/check-doc-lockstep.mjs runs on the PR diff against origin/main. If any code file matches a configured glob and none of the mapped docs are in the diff, the check fails with the file list + which docs were expected.

The mapping lives at scripts/doc-lockstep.config.mjs. Each entry is one or more code globs plus one or more required docs. Adding a new entry is easy — edit the config and open the PR.

Read the full file on GitHub · 69 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. yesterday First seen · 69 lines · 1,054 tokens per session scan A a1f2aa85cd5e

Subscribe to this mod's changes

code-doc-lockstep is a cursor rule published in the GitHub repository AlphaBitCore/nexus-gateway (22 stars, last pushed 6d ago), licensed Apache-2.0. It adds 1,054 tokens to every session, about $0.0053 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.