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.
npx skills add proyecto26/system-design-skills --skill consistency-coordinationgit clone --depth 1 https://github.com/proyecto26/system-design-skillsWrote 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.
[](https://agentmods.dev/skills/proyecto26/system-design-skills/consistency-coordination)<a href="https://agentmods.dev/skills/proyecto26/system-design-skills/consistency-coordination"><img src="https://agentmods.dev/badge/skills/proyecto26/system-design-skills/consistency-coordination/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.
<a href="https://agentmods.dev/skills/proyecto26/system-design-skills/consistency-coordination"><img src="https://agentmods.dev/badge/skills/proyecto26/system-design-skills/consistency-coordination.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00141 | $0.03223 |
| Opus 5 | $0.00071 | $0.01612 |
| Sonnet 5 | $0.00028 | $0.00645 |
| Haiku 4.5 | $0.00014 | $0.00322 |
Grade A, and why
consistency-coordination 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 9d 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.
How it starts
The opening of the file, as written. The whole thing — 201 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Consistency & Coordination
Decide what a reader is guaranteed to see when data lives on more than one node, and how independent nodes agree on a single answer. Get this wrong and the system either serves stale or conflicting data silently, or stalls the moment a network link drops — the most common and most punishing distributed-systems failure.
When to reach for this
Any time state is replicated, sharded, or coordinated across nodes: choosing a replication or quorum scheme, picking a consistency level, electing a leader, spreading keys across an elastic fleet (consistent hashing), or committing a change that spans services. Reach here the instant someone asks "what does a read see right after a write?" or "what happens during a partition?"
When NOT to
A single node with no replicas has nothing to coordinate — don't invoke quorums or consensus for it (YAGNI). Most apps tolerate seconds of staleness; reaching for strong consistency or distributed transactions when eventual consistency would do buys latency and operational pain for a guarantee no requirement asked for. The cheapest model that satisfies the invariant wins. Naming Raft or 2PC before a correctness requirement forces it is a red flag.
Clarify first
- What breaks if a read is stale? A wrong balance vs a slightly old like count
are different systems. (→
requirements-scoping.) - Must a user see their own writes immediately? Read-your-writes is far cheaper than global strong consistency.
- What is the blast radius of a partition or lost region? Drives the CAP/PACELC choice. (GUIDE failure mode #1.)
- Write contention and conflict shape — single-writer per key, or concurrent writers needing conflict resolution?
- Latency budget — synchronous coordination adds a round trip (or a
cross-region one); confirm the budget allows it. (→
back-of-the-envelope.)
The options
Pick a consistency model (the guarantee a read gets):
- Strong / linearizable — every read sees the latest committed write. Use when an invariant must hold globally (balances, inventory, uniqueness).
- Read-your-writes / monotonic — a session sees its own writes and never goes backward. Use for profile edits, "post then see your post".
- Causal — reads respect cause→effect order (a reply never precedes its parent). Use for comments, chat, collaborative edits.
- Eventual — replicas converge "soon"; reads may lag. Use for like counts, feeds, caches — anything where staleness is cheap.
What ships with it
4 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
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.
- 9d ago First seen · 201 lines · 141 tokens per session scan A 065b4076e0e6
consistency-coordination is a skill published in the GitHub repository proyecto26/system-design-skills (69 stars, last pushed 3mo ago), licensed MIT. It adds 141 tokens to every session and 3,223 once invoked, about $0.0007 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.
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