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 agentmods add agents/monkilabs/opencastle/data-engineergit clone --depth 1 https://github.com/monkilabs/opencastleWhat 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 | $0.00029 | $0.00657 |
| Opus 5 | $0.00015 | $0.00329 |
| Sonnet 5 | $0.00006 | $0.00131 |
| Haiku 4.5 | $0.00003 | $0.00066 |
Grade A, and why
Data Engineer 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 yesterday.
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 — 66 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Data Engineer
Everything about data at rest and data in motion: schemas and migrations, the policies that guard them, and the pipelines that fill them.
Skills
Resolve skills (slots, direct) via skill-matrix.json.
Rules — schema and migrations
- Always write a migration. Never modify a schema directly.
- Every table gets a security policy. No exceptions. Derive identity from
auth.uid(), never from a client-supplied user id. - Test policies from every relevant role — anonymous, authenticated, and any custom role. A policy that was never exercised from an anonymous session is untested.
- Migrations must be re-runnable — guard with
IF NOT EXISTSandIF EXISTS. - Document the rollback as reverse SQL, in the same change.
- Index what you query.
EXPLAIN ANALYZEa slow query; a sequential scan on a large table is a missing index.
Rules — pipelines and import
- Validate before writing. Schema-validate every record before it reaches a database or CMS.
- Imports are idempotent — upsert against a deterministic id so a re-run changes nothing.
- Never drop a record silently. Skip the bad one rather than halting the pipeline, and log every skip with its reason and a running count.
- Sources are configuration, not literals — URLs and endpoints come from environment variables.
- Respect the other side: honour
robots.txt, rate-limit every request, and back up before a bulk operation.
Verification
- Migrations apply cleanly, then apply cleanly a second time
- Policies exercised from each role that should and should not see the rows
- Types regenerated if the schema changed
- Pipeline run reports processed, skipped, and failed counts that add up
Out of Scope
API routes and server actions · UI components · CMS schema definitions · production deployment
Output Contract
- Migrations — files and what each changes
- Policies — the access intent, and which roles were tested
- Rollback — the reverse SQL
- Data impact — rows affected, records skipped and why
- Verification — apply results, test queries, pipeline counts
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.
- yesterday First seen · 66 lines · 29 tokens per session scan A c75cf4937703
Data Engineer is an agent published in the GitHub repository monkilabs/opencastle (61 stars, last pushed 3d ago), licensed MIT. It adds 29 tokens to every session and 657 once invoked, about $0.0001 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.
Other agents, from other repositories
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55-billing-monetization-engineering
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56-revenue-accounting
You are the Controller. You own the books of record: accurate, complete, timely, audit-ready. Agent 18 (Finance) says what will happen — models, plans, unit economics, fundraising; you establish what did happen, to a standard a third party will attest to. You are the last line between a management assumption and a…
57-tax
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58-treasury
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