What is implement-from-stub?

An implementation helper that fills in a Python module from its type stub, a file describing the module's functions and classes, until its tests pass.

Implement or re-implement Python modules, create database migrations for database models, and reproduce recorded requests for external-service adapters.

It gives an incomplete module a concrete implementation while keeping its code consistent with the declared interface and the tests.

implement-from-stub — Skill by nullhack

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 skills/nullhack/temple8/implement-from-stub

Any agent

npx skills add nullhack/temple8 --skill implement-from-stub

Clone the repo

git clone --depth 1 https://github.com/nullhack/temple8

Made for: Claude Code, Codex.

Per session 29 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 460 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.

Model	Per session	Once invoked
Fable 5	$0.00029	$0.00460
Opus 5	$0.00015	$0.00230
Sonnet 5	$0.00006	$0.00092
Haiku 4.5	$0.00003	$0.00046

Measured 2d ago against content hash 7aa65238d79d, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

implement-from-stub 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 2d 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.

.opencode/skills/implement-from-stub/SKILL.md · 14 lines

What it actually says

Implement From Stub

Load [[software-craft/source-stubs]], [[software-craft/tdd]], [[software-craft/design-patterns]] — stub sync, the cycle, and implementation patterns.
Implement — or, for rework, re-implement — the .py from its .pyi. The .pyi signature is the spec; fill or correct the body to satisfy it and pass the tests. Keep the .py consistent with its sibling .pyi.
Emit the structural artifacts the module requires, keyed on what it is: IF an ORM model THEN emit an Alembic migration (the migration is the schema spec); IF an external adapter THEN reproduce the recorded request shape exactly (method, path, query parameters, headers from external-contracts.md) — vcr matches the request strictly, so the implementation conforms to the cassette, not the other way around. Config follows 12-factor per [[software-craft/secrets-and-config]]: non-secret config via load_dotenv() from the workspace .env; secrets via dotenv_values() from ~/.secrets/<project>.env — read once into a frozen typed Settings, never into os.environ. IF an auth-dependent test fails on credentials THEN stop and ask the user with suggestions — do not investigate the secret.
IF the body cannot satisfy the .pyi without changing it THEN that is a contract gap — do not edit the stub; escalate at review.
Run stubtest scoped to the modules built this cycle — the source module(s) and the test module(s) whose pending marks were removed. The whole-suite stubtest waits until every source .py exists, because unbuilt sibling stubs would false-fail per [[software-craft/source-stubs]], [[software-craft/tdd]].
Stubtest imports the runtime module, so every transitive runtime dependency must be installed in the project venv. IF an import is used only for types THEN prefer if typing.TYPE_CHECKING: so stubtest does not pull heavy runtime deps for type-only references.

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.

2d ago First seen · 14 lines · 29 tokens per session scan A 7aa65238d79d

Subscribe to this mod's changes

implement-from-stub is a skill published in the GitHub repository nullhack/temple8 (11 stars, last pushed 27d ago), licensed MIT. It adds 29 tokens to every session and 460 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.

Databases Languages Testing project-template pytest python python-project-template python3 uv

load-github-action-thread

Download retained Codex GitHub Action thread artifacts and load their rollout history into the local Codex app. Use when asked to open, load, import, resume, or inspect a Codex automation thread from a GitHub Actions run or a related GitHub issue or pull request.

astral-sh/uv · 62 tokens

implement-from-stub

Getting it into your agent

What it costs to keep this loaded

Grade A, and why

Nothing flagged

What it actually says

Implement From Stub

What this file has done since we first saw it

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