30-posttask

A mandatory final validation rule for coding tasks. It requires each required check to be reported as passed, failed, or not applicable.

In plain words
What is it for?
Running post-task checks, recording command results, explaining any not-applicable checks, and identifying the scope and evidence of failures.
Why use it?
It prevents unfinished work or failed checks from being hidden inside a summary before completion is declared.

Cursor rule

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 rules/joaonic/agentkit/30-posttask
Clone the repo
git clone --depth 1 https://github.com/Joaonic/agentkit
Per session 119 This file is loaded in full into every session.
When invoked 119 The same file — it is already loaded in full.
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 $0.00119 $0.00119
Opus 5 $0.00060 $0.00060
Sonnet 5 $0.00024 $0.00024
Haiku 4.5 $0.00012 $0.00012

Measured yesterday against content hash 29ab434656bb, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

30-posttask 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.

src/core/rules/30-posttask.mdc · 22 lines

What it actually says

Posttask Gate

Mandatory:

  • execute posttask before declaring completion
  • report each mandatory command as pass, fail, or n/a
  • include failure evidence and impacted scope when fail
  • never hide failed checks in aggregated summary

Blocker policy:

  • any failed mandatory check blocks completion
  • missing required tooling/binaries must be explicit in report

Evidence:

  • include validation table in final report
  • include explicit reason for each n/a
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 · 22 lines · 119 tokens per session scan A 29ab434656bb

Subscribe to this mod's changes

30-posttask is a cursor rule published in the GitHub repository Joaonic/agentkit (2 stars, last pushed 3mo ago), licensed MIT. It adds 119 tokens to every session, about $0.0006 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 2026-08-31.