nrn-builder-canonical

nrn-builder-canonical is a cursor rule for Cursor from AlphaBitCore/nexus-gateway. It costs 0 tokens per session (474 once invoked), scanned A, original, Apache-2.0.

A coding rule requiring IAM middleware to build resource names through the shared canonical builder. IAM means identity and access management, which controls what actions a user or service may perform.

In plain words
What is it for?
Use it when adding or changing IAM-protected routes, actions, resource types, catalog entries, or permission tests.
Why use it?
It prevents hardcoded resource strings from drifting away from the central permission catalog and causing incorrect access denials.

Cursor rule for Cursor

Written for Cursor: installed under .cursor/. Also seen: reads .claude/ paths.

Good fit Use it when adding or changing IAM-protected routes, actions, resource types, catalog entries, or permission tests.

Compare 6 cursor rules from other repositories ↓
Install with agentmods
npx agentmods add rules/alphabitcore/nexus-gateway/nrn-builder-canonical
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.

Clone the repo
git clone --depth 1 https://github.com/AlphaBitCore/nexus-gateway

Made for: Cursor.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for nrn-builder-canonical

README.md
[![agentmods](https://agentmods.dev/badge/rules/alphabitcore/nexus-gateway/nrn-builder-canonical.svg)](https://agentmods.dev/rules/alphabitcore/nexus-gateway/nrn-builder-canonical)
Your own site
<a href="https://agentmods.dev/rules/alphabitcore/nexus-gateway/nrn-builder-canonical"><img src="https://agentmods.dev/badge/rules/alphabitcore/nexus-gateway/nrn-builder-canonical.svg" alt="Measured on agentmods" height="20"></a>
Per session 0 Nothing until a file matches its globs; then the whole rule loads.
When invoked 474 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
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 5.1 $0.00000 $0.00474
Opus 5 $0.00000 $0.00237
Sonnet 5 $0.00000 $0.00095
Haiku 4.5 $0.00000 $0.00047

Measured 7d ago against content hash d1d9d6f15d6e, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-07, from the pricing page.

Security

Grade A, and why

nrn-builder-canonical 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 7d ago.

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/nrn-builder-canonical.mdc · 52 lines

What it actually says

NRN builder is canonical (binding)

iamMW(action) builds the request NRN as nrn := iam.BuildRequestNRNForAction(action, c). The builder owns the action → resourceType derivation. Never hardcode the resourceType string in handler glue — hardcoded strings drift from the IAM catalog and produce silent 403s.

Memory anchor: [[project_iam_resource_nrn_bug]].

Required

e.GET("/api/admin/providers/:id", h.GetProvider, iamMW("admin:provider.read"))
// inside iamMW:
nrn := iam.BuildRequestNRNForAction(action, c)   // <- canonical builder

Forbidden

// ❌ hardcoded resource-type
nrn := fmt.Sprintf("nrn:nexus:provider:%s:%s", orgID, id)

// ❌ ad-hoc string concat
nrn := "nrn:nexus:" + getResourceType(action) + ":" + scope + ":*"

Even when the hardcoded version "looks right", it skips the catalog lookup in packages/shared/identity/iam/catalog_data.go. When the catalog updates (new resource, renamed verb), the canonical builder picks it up; hardcoded strings rot.

When the action is new

  1. Add the action to packages/shared/identity/iam/catalog_data.go.
  2. Build via iam.BuildRequestNRNForAction(action, c).
  3. Verify with the simulator IAM page in the dashboard.

When the action signature changes

BuildRequestNRNForAction is the single seam. Update the catalog; every handler that uses the builder picks up the change automatically.

  • IAM impact review (5-step audit) → iam-impact-review.mdc.
  • Architecture: docs/developers/architecture/services/control-plane/iam-identity-architecture.md.
  • Skill: .claude/skills/iam-impact-review/.

Skipping this rule requires explicit user approval in chat.

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. 7d ago First seen · 52 lines · 0 tokens per session scan A d1d9d6f15d6e

Subscribe to this mod's changes

nrn-builder-canonical is a cursor rule published in the GitHub repository AlphaBitCore/nexus-gateway (23 stars, last pushed 5d ago), licensed Apache-2.0. It costs nothing until one of its globs matches a file; then it loads 474 tokens. 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.