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 Altinity/altinity-skills --skill altinity-expert-clickhouse-mutationsgit clone --depth 1 https://github.com/Altinity/altinity-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/altinity/altinity-skills/altinity-expert-clickhouse-mutations)<a href="https://agentmods.dev/skills/altinity/altinity-skills/altinity-expert-clickhouse-mutations"><img src="https://agentmods.dev/badge/skills/altinity/altinity-skills/altinity-expert-clickhouse-mutations/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/altinity/altinity-skills/altinity-expert-clickhouse-mutations"><img src="https://agentmods.dev/badge/skills/altinity/altinity-skills/altinity-expert-clickhouse-mutations.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 | $0.00034 | $0.00685 |
| Opus 5 | $0.00017 | $0.00342 |
| Sonnet 5 | $0.00007 | $0.00137 |
| Haiku 4.5 | $0.00003 | $0.00068 |
Grade A, and why
altinity-expert-clickhouse-mutations 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.
How it starts
The opening of the file, as written. The whole thing — 123 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Mutation Tracking and Analysis
Track and diagnose ALTER UPDATE, ALTER DELETE, and other mutation operations.
Diagnostics
Run all queries from checks.sql in this skill's directory and analyze the results.
Problem Investigation
Why Is Mutation Stuck?
Check for competing operations using these ad-hoc queries:
-- Active merges on same table
select
database,
table,
is_mutation,
elapsed,
progress,
num_parts
from system.merges
where database = '{database}' and table = '{table}'
-- Replication queue for same table
select
type,
create_time,
is_currently_executing,
num_tries,
last_exception
from system.replication_queue
where database = '{database}' and table = '{table}'
order by create_time
limit 20
-- Part mutations status
select
name,
active,
mutation_version,
modification_time
from system.parts
where database = '{database}' and table = '{table}'
order by mutation_version desc
limit 30
Canceling Mutations
To kill a stuck mutation:
-- Find mutation_id first
select mutation_id, command from system.mutations
where database = '{database}' and table = '{table}' and not is_done;
-- Then kill it
-- KILL MUTATION WHERE database = '{database}' AND table = '{table}' AND mutation_id = '{mutation_id}';
Warning: Killed mutations leave table in partially-mutated state.
Best Practices
Mutation Anti-Patterns
| Anti-Pattern | Problem | Solution |
|---|---|---|
| Frequent small UPDATEs | Creates many mutations | Batch updates together |
| DELETE without WHERE | Full table rewrite | Use TTL instead |
| UPDATE on high-cardinality column | Slow, lots of IO | Restructure data model |
| Many concurrent mutations | Queue builds up | Serialize mutations |
Monitoring Mutations
Set alerts for:
- Mutations pending > 10
- Mutation age > 1 hour
latest_fail_reasonnot empty
Cross-Module Triggers
What ships with it
1 file 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.
- 10d ago First seen · 123 lines · 34 tokens per session scan A 860b9006dba0
altinity-expert-clickhouse-mutations is a skill published in the GitHub repository Altinity/altinity-skills (16 stars, last pushed yesterday), licensed Apache-2.0. It adds 34 tokens to every session and 685 once invoked, about $0.0002 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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