Getting it into your agent
It runs from inside its repository, so the clone comes first — what it calls does not travel with the file alone.
git clone --depth 1 https://github.com/selvarajmurugesan90/ops-engineering-skillsnpx agentmods add skills/selvarajmurugesan90/ops-engineering-skills/cassandra-wide-column-database-operationsWrote 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/selvarajmurugesan90/ops-engineering-skills/cassandra-wide-column-database-operations)<a href="https://agentmods.dev/skills/selvarajmurugesan90/ops-engineering-skills/cassandra-wide-column-database-operations"><img src="https://agentmods.dev/badge/skills/selvarajmurugesan90/ops-engineering-skills/cassandra-wide-column-database-operations/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/selvarajmurugesan90/ops-engineering-skills/cassandra-wide-column-database-operations"><img src="https://agentmods.dev/badge/skills/selvarajmurugesan90/ops-engineering-skills/cassandra-wide-column-database-operations.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector pass
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 | $0.00119 | $0.04169 |
| Opus 5 | $0.00060 | $0.02084 |
| Sonnet 5 | $0.00024 | $0.00834 |
| Haiku 4.5 | $0.00012 | $0.00417 |
Grade A, and why
cassandra-wide-column-database-operations 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 11d 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 — 346 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Cassandra Wide-Column Database Operations
Purpose
Cassandra's defining architectural choice — a masterless ring where every node is structurally equal, data is distributed by consistent hashing of the partition key, and consistency is tunable per query rather than fixed by the engine — trades the strong consistency guarantees of a single-primary database for horizontal write scalability and no single point of failure. That trade only pays off operationally if the partition key is chosen well (a bad choice creates a hot partition the ring can't help with), the consistency level matches the actual durability/availability requirement per query, and compaction strategy matches the write pattern. This skill covers ring topology and token design, consistency-level selection, and compaction/ tombstone management — the recurring operational decisions that determine whether a Cassandra cluster stays healthy as it scales.
When to use
- Designing a new table's partition key and clustering columns, or diagnosing an existing "hot partition" causing uneven node load.
- Choosing a consistency level for a specific read/write path (balancing latency/availability against consistency guarantees).
- Selecting or changing a table's compaction strategy (SizeTieredCompactionStrategy, LeveledCompactionStrategy, TimeWindowCompactionStrategy) to match its write/delete pattern.
- Tombstone-related warnings in logs (
ReadTimeoutExceptionmentioning tombstones, or a "tombstone_warn_threshold" log message) or overall read performance degrading over time on a table with regular deletes/ TTLs. - Adding, removing, or replacing a node in the ring, or diagnosing an uneven token/data distribution across nodes.
- Deciding on and validating a replication factor and rack/datacenter topology for a new keyspace.
Prerequisites & environment
- Apache Cassandra 4.x assumed for the syntax below (the
nodetoolcommand surface and virtual tables referenced here are stable across most of the 3.x/4.x line, but note that vnodes — virtual nodes, multiple token ranges per physical node — have been the default since Cassandra 2.x, and choosingnum_tokensdeliberately still matters for cluster balance at small node counts). nodetoolaccess on each node (local or via JMX) for ring, repair, and compaction administration — this typically requires host access or JMX credentials, not just CQL client access.- A replication factor and
NetworkTopologyStrategykeyspace configuration appropriate to the deployment's rack/datacenter layout —SimpleStrategy(rack/DC-unaware) is only appropriate for a single-datacenter test/dev cluster, never production. - Familiarity with the actual query patterns a table will serve before creating it — unlike a relational schema, a Cassandra table design is driven by "what queries will read this data," since Cassandra has no general-purpose secondary-index-driven ad hoc query capability comparable to a relational engine's optimizer.
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.
- 11d ago First seen · 346 lines · 119 tokens per session scan A f12bd5054ad2
cassandra-wide-column-database-operations is a skill published in the GitHub repository selvarajmurugesan90/ops-engineering-skills (38 stars, last pushed 1mo ago), licensed Apache-2.0. It adds 119 tokens to every session and 4,169 once invoked, about $0.0006 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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