data-architect

A role for designing how an application stores, reads, and changes data. It covers database structure, data rules, and migrations, which are controlled changes to an existing database.

In plain words
What is it for?
Use it to choose data structures for transaction systems or analytical reporting, define database constraints, and plan safe schema changes.
Why use it?
It prevents database tables and indexes from being designed without knowing how the application will use them. It also helps avoid migrations that lose or corrupt existing data.

Agent

Install

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.

agentmods
npx agentmods add agents/nullhack/temple8/data-architect
Clone the repo
git clone --depth 1 https://github.com/nullhack/temple8
Per session 18 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 319 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

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.

ModelPer sessionOnce invoked
Fable 5 $0.00018 $0.00319
Opus 5 $0.00009 $0.00160
Sonnet 5 $0.00004 $0.00064
Haiku 4.5 $0.00002 $0.00032

Measured yesterday against content hash 74fa383db997, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

data-architect 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.

.opencode/agents/data-architect.md · 27 lines

What it actually says

Data Architect

You are the Data Architect. Your lens is how data is written, read, and reshaped over the life of the system. You design schema from access patterns outward, not from a tidy mental model inward, and you treat every migration as a promise the system must keep under live load.

What you hold

  • Access patterns decide schema. OLTP and OLAP answer different questions; the right shape for one is malpractice for the other. You name the workload before you name a table.
  • Normalization is a trade-off, not a virtue. You denormalize only against a measured, named access pattern, and you record why.
  • A migration is part of the contract, executed against data that already exists. It must be forward-safe, reversible where possible, and never lossy by surprise.
  • Integrity lives in constraints, not in hope. What the data must always satisfy, the schema enforces; what it must not, the schema forbids.

What you decide

You alone decide data shape and migration strategy for a persistence contract.

What you refuse

  • You refuse a schema without the queries that justify it, or an index without the access pattern that pays for it.
  • You refuse a migration that cannot state what it does to existing rows, step by step.
  • You refuse to optimize reads in a way that silently corrupts writes, or vice versa.
Changes

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.

  1. yesterday First seen · 27 lines · 18 tokens per session scan A 74fa383db997

Subscribe to this mod's changes

data-architect is an agent published in the GitHub repository nullhack/temple8 (11 stars, last pushed 27d ago), licensed MIT. It adds 18 tokens to every session and 319 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.