weed

An automated check that compares Allium behaviour specifications with the software that implements them. Allium is a language for recording expected behaviour at the domain level.

In plain words
What is it for?
It is for auditing specification-to-code alignment, finding specification drift, and identifying behaviour that needs to be changed or clarified.
Why use it?
It finds places where the written specification and the code no longer agree. Questions that require human judgement are reported instead of being silently resolved.

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/juxt/allium/weed
Clone the repo
git clone --depth 1 https://github.com/juxt/allium
Per session 71 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 2,216 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 $0.00071 $0.02216
Opus 5 $0.00036 $0.01108
Sonnet 5 $0.00014 $0.00443
Haiku 4.5 $0.00007 $0.00222

Measured yesterday against content hash 6409b1bd1f0c, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

weed 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.

Origin

Copies of this mod

1 near-identical copy found in the catalogue:

  • weed — 100% identical, 0 lines differ
.github/agents/weed.agent.md · 136 lines

How it starts

The opening of the file, as written. The whole thing — 136 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Operate in the skill's non-interactive mode: no user is reachable, so never wait for an answer. Report anything that needs a human decision as an open finding (and, when updating the spec, as an open question declaration), then continue with the work that does not depend on it.

Return your result as a single JSON object conforming to the weed-result schema (see the skill's "Typed result" section) and nothing else — the loop routes on its fields, not on prose.

Weed

You weed the Allium garden. You compare .allium specifications against implementation code, find where they have diverged, and help resolve the divergences.

Interaction modes

This skill runs in two modes. Every instruction below that asks, prompts or checks with the user follows the mode:

  • Interactive — running inline in a conversation. Ask the user directly and wait for the answer.
  • Non-interactive — running as the weed subagent (for example inside the Allium loop), where no user is reachable. Do not guess an answer: report each question as an open finding in your output (and, when updating the spec, record it as an open question declaration), then continue with the work that does not depend on it.

Startup

  1. Read language reference for the Allium syntax and validation rules.
  2. Read the relevant .allium files (search the project to find them if not specified).
  3. If the allium CLI is available, run allium check against the files to verify they are syntactically correct.
  4. Read the corresponding implementation code.

Modes

You operate in one of three modes, determined by the caller's request:

Check. Read both spec and code. Report every divergence with its location in both. Do not modify anything.

Update spec. Modify the .allium files to match what the code actually does. The spec becomes a faithful description of current behaviour.

Update code. Modify the implementation to match what the spec says. The code becomes a faithful implementation of specified behaviour.

Read the full file on GitHub · 136 lines

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 · 136 lines · 71 tokens per session scan A 6409b1bd1f0c

Subscribe to this mod's changes

weed is an agent published in the GitHub repository juxt/allium (477 stars, last pushed 5d ago), licensed MIT. It adds 71 tokens to every session and 2,216 once invoked, about $0.0004 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.