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 scylladb/agent-skills --skill scylladb-data-modelinggit clone --depth 1 https://github.com/scylladb/agent-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/scylladb/agent-skills/scylladb-data-modeling)<a href="https://agentmods.dev/skills/scylladb/agent-skills/scylladb-data-modeling"><img src="https://agentmods.dev/badge/skills/scylladb/agent-skills/scylladb-data-modeling/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/scylladb/agent-skills/scylladb-data-modeling"><img src="https://agentmods.dev/badge/skills/scylladb/agent-skills/scylladb-data-modeling.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 | $0.00241 | $0.02477 |
| Opus 5.5 | $0.00096 | $0.00991 |
| Sonnet 5.5 | $0.00048 | $0.00495 |
| Haiku 4.5 | $0.00024 | $0.00248 |
Grade A, and why
scylladb-data-modeling 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 8d 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 — 127 lines — stays where its author put it; the contents beside it link to each section on GitHub.
ScyllaDB Data Modeling
If the task goes beyond this skill, use the parent scylladb skill for a ScyllaDB overview and the list of other ScyllaDB skills. If it is not installed, fetch it from https://raw.githubusercontent.com/scylladb/agent-skills/main/skills/scylladb/SKILL.md.
CQL data modeling patterns and anti-patterns for ScyllaDB. Bad schema is the root cause of most ScyllaDB performance issues — no amount of cluster scaling can fix a fundamentally wrong data model.
When to Use This Skill
- Designing a new ScyllaDB schema from scratch
- Migrating from SQL/relational databases, MongoDB, or Cassandra to ScyllaDB
- Reviewing existing table designs for performance issues
- Troubleshooting slow queries, timeouts, or hot nodes
- Deciding how to structure primary keys (partition key + clustering columns)
- Modeling time-series, IoT, or event data
- Seeing large partition warnings in logs
- Encountering
ALLOW FILTERINGin queries or code reviews - Adding secondary indexes or materialized views
- Choosing a compaction strategy, or setting TTLs and retention on a table
- Reads slowed by deletes, expired data, or tombstone warnings
- Writing conditional statements (
IF NOT EXISTS,IF EXISTS,IF <condition>) or choosing serial consistency
For adjacent topics, use the sibling skill instead:
- Connecting a driver, choosing a driver, or preparing statements:
scylladb-cloud-setup - Vector columns, vector indexes, and ANN queries:
scylladb-vector-search - Tables created through the DynamoDB API:
scylladb-alternator. The partition-key rules in this skill still apply to them. - Deploying the cluster on Kubernetes, including rack and replication-factor layout:
scylladb-kubernetes
Key Principle
"Start from the queries, not from the entities."
This is ScyllaDB's core data modeling philosophy. Unlike relational databases where you normalize entities and then write queries against them, in ScyllaDB you:
- List your application's queries — every
SELECT,UPDATE, andDELETEyour application will run - Design one table per query pattern — each table's primary key is crafted to serve a specific query efficiently
- Accept denormalization — the same data may exist in multiple tables, each optimized for a different access pattern
What ships with it
14 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.
- references/antipattern-allow-filtering.md 3.7 KB
- references/antipattern-hot-partitions.md 4.2 KB
- references/antipattern-large-partitions.md 4.2 KB
- references/antipattern-multi-partition-batch.md 5.3 KB
- references/antipattern-unpaged-queries.md 2.9 KB
- references/clustering-columns.md 4.4 KB
- references/compaction-strategies.md 5.3 KB
- references/lwt.md 6.7 KB
- references/partition-key-design.md 4.6 KB
- references/pattern-bucketing.md 4.0 KB
- references/query-first-design.md 3.5 KB
- references/secondary-indexes-and-mv.md 6.3 KB
- references/tombstones.md 5.4 KB
- references/ttl.md 3.6 KB
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.
- 8d ago Changed · +3 tokens per session 23c20392746b
- 20d ago Changed · +2 lines · +30 tokens per session 5f05a688252f
- 21d ago Changed · +19 lines · +74 tokens per session 9ee920c9c8f3
- 2mo ago First seen · 106 lines · 134 tokens per session scan A 4679d5f205d5
scylladb-data-modeling is a skill published in the GitHub repository scylladb/agent-skills (9 stars, last pushed 9d ago), licensed Apache-2.0. It adds 241 tokens to every session and 2,477 once invoked, about $0.0010 per session on Opus 5.5. 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.
scylladb-data-modeling compared with skills from other repositories
| Mod | Type | Stars | Last push | Licence | Scan | Tokens | Works with |
|---|---|---|---|---|---|---|---|
| scylladb-data-modelingscylladb/agent-skills | Skill | 9 | 9d ago | Apache-2.0 | A | 241 | Claude Code |
| perf-version-comparisonscylladb/scylla-cluster-tests | Skill | 72 | yesterday | AGPL-3.0 | A | 152 | Claude Code, Codex |
| cassandrabytesagain/ai-skills | Skill | 16 | 6mo ago | none | A | 47 | Claude Code, Codex |
| alloydb-basicsgoogle/skills | Skill | 22k | yesterday | Apache-2.0 | A | 72 | Claude Code, Codex |
| cloud-databases-onboardinggoogle/skills | Skill | 22k | yesterday | Apache-2.0 | A | 83 | Claude Code, Codex |
| spanner-basicsgoogle/skills | Skill | 22k | yesterday | Apache-2.0 | A | 47 | Claude Code, Codex |
| obsidian-baseskepano/obsidian-skills | Skill | 51k | 1mo ago | MIT | A | 63 | Claude Code |