implement

An implementation step that follows an approved software specification in a fresh working context.

In plain words
What is it for?
Use it to build a planned feature, run its checks after each step, and verify the finished work end to end, including boundary and error cases.
Why use it?
It keeps coding tied to defined behavior and requires each change to be checked as it is made. It also exposes and revises an incorrect plan instead of silently changing the scope.

Command

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 commands/ashkaan/contextium/implement
Clone the repo
git clone --depth 1 https://github.com/Ashkaan/contextium
Per session 16 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 177 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 $0.00016 $0.00177
Opus 5 $0.00008 $0.00088
Sonnet 5 $0.00003 $0.00035
Haiku 4.5 $0.00002 $0.00018

Measured yesterday against content hash 424ad8dabb4e, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

implement 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.

templates/commands/implement.md · 13 lines

What it actually says

Run the Do move of the Contextium Loop. Start from a fresh context and load the SPEC.

  1. Implement task by task, in the order the SPEC lays out.
  2. Validate after each change — run the command that proves that step works before moving on.
  3. When the build is done, run it end to end against the SPEC's success criteria, including the edge cases (0 / 1 / empty / max / error).
  4. Match the weight of the solution to the problem: an inline script beats a service that does the same thing. Land the full scope; do not defer in-scope work to "later".

If something in the SPEC turns out wrong, surface it and revise the SPEC — do not silently build something else.

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 · 13 lines · 16 tokens per session scan A 424ad8dabb4e

Subscribe to this mod's changes

implement is a command published in the GitHub repository Ashkaan/contextium (32 stars, last pushed 4d ago), licensed MIT. It adds 16 tokens to every session and 177 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.