robust-by-construction

robust-by-construction is a skill for Claude Code from AlexShchuka/neuro-matrix. It costs 65 tokens per session (1,692 once invoked), scanned A, original, MIT.

A checklist of correctness and safety rules for software systems, covering errors, waiting, repeatable operations, and rules that can be enforced automatically.

In plain words
What is it for?
Use it while designing systems, reviewing them for weaknesses, or creating linter and continuous-integration checks that enforce the rules.
Why use it?
It helps prevent hidden failures and false reports of success. It also turns important safeguards into automated checks instead of relying only on written instructions.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin.

Part of the neuro-matrix plugin — 6 skills, 5 agents, 4 hooks shipped together

Good fit Use it while designing systems, reviewing them for weaknesses, or creating linter and continuous-integration checks that enforce the rules.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/alexshchuka/neuro-matrix/robust-by-construction
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.

Any agent
npx skills add AlexShchuka/neuro-matrix --skill robust-by-construction
Clone the repo
git clone --depth 1 https://github.com/AlexShchuka/neuro-matrix

Made for: Claude Code.

Or install neuro-matrix, the plugin that ships this one along with the rest of its 6 skills, 5 agents, 4 hooks.

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 robust-by-construction

README.md
[![agentmods](https://agentmods.dev/badge/skills/alexshchuka/neuro-matrix/robust-by-construction/github.svg)](https://agentmods.dev/skills/alexshchuka/neuro-matrix/robust-by-construction)
Your own site
<a href="https://agentmods.dev/skills/alexshchuka/neuro-matrix/robust-by-construction"><img src="https://agentmods.dev/badge/skills/alexshchuka/neuro-matrix/robust-by-construction/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for robust-by-construction

Your own site · 80×15
<a href="https://agentmods.dev/skills/alexshchuka/neuro-matrix/robust-by-construction"><img src="https://agentmods.dev/badge/skills/alexshchuka/neuro-matrix/robust-by-construction.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 65 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,692 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 $0.00065 $0.01692
Opus 5 $0.00032 $0.00846
Sonnet 5 $0.00013 $0.00338
Haiku 4.5 $0.00006 $0.00169

Measured 10d ago against content hash b3bf5df680b0, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-10, from the pricing page.

Security

Grade A, and why

robust-by-construction 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 10d 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.

skills/robust-by-construction/SKILL.md · 96 lines

How it starts

The opening of the file, as written. The whole thing — 96 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Robust-by-construction: the invariant bar for systems built by this harness

BLUF: «works on my machine» is not the bar. The bar is: every failure surfaces, every wait has an escape, every operation is safe to repeat, and every rule that can be mechanized is mechanized. Prose is the last resort for what cannot be encoded.

(a) Fail-fast / error-as-data

No system error is swallowed. A false «success» on a failed operation is a security defect — the caller proceeds as if state was mutated when it was not.

Rules:

  • Every error is propagated to ONE global handler (the observability sink). The handler decides: log + continue, degrade gracefully, or halt. Individual nodes do not make this call — they emit the error and let the global module handle it. This is «error-as-data»: a process does its work and emits its outcome (including failure) as structured data; it does not silently absorb failures.
  • Degraded operation is the goal of failure handling, not suppression. A degraded state must be distinguishable from a healthy state by the system's own telemetry.
  • Enforce mechanically: forbidigo (Go) or equivalent linter rule blocking bare error discards (_ = err, if err != nil { return } without propagation).

Mirabilis example: the proxy lifecycle failure on first-launch was masked by a swallowed dial error — the TUI showed a connected state while the proxy was dead. The fix added error propagation to the observability sink and a health-check that distinguished «proxy not yet started» from «proxy running».

(b) No-hang / no-race

Every I/O, sync, and wait has a hard escape. «It will eventually complete» is not a correctness argument for a user-facing system.

Rules:

  • Every blocking call carries a context deadline (or timer) AND/OR a forced unblock path (close the fd, kill the process group, cancel the context). Both, where possible.
  • Long-lived resources (file locks, PTY handles, proxy processes) are owned for the session, not for a single call. Ownership means: created once, explicitly released on session teardown, never released by GC.
  • Subscriptions (event listeners, channels, callbacks) are registered once per session, not re-created per event. Re-creation per event is a leak path.
  • Enforce mechanically: the race detector (-race) runs in CI on every branch; goroutine leak detectors (e.g. goleak) in test teardown.

Read the full file on GitHub · 96 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. 10d ago First seen · 96 lines · 65 tokens per session scan A b3bf5df680b0

Subscribe to this mod's changes

robust-by-construction is a skill published in the GitHub repository AlexShchuka/neuro-matrix (3 stars, last pushed 2mo ago), licensed MIT. It adds 65 tokens to every session and 1,692 once invoked, about $0.0003 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 2026-08-31.

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