What is threading-patterns?

A set of Delphi rules for running work in background threads while keeping user-interface access safe.

It guides the use of TThread, TTask, parallel loops, futures, cancellation, and thread-safe updates through Synchronize or Queue.

It prevents secondary threads from directly changing visual components, which can cause unsafe or broken applications.

threading-patterns — Cursor rule for Cursor by SecondLifes

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.

Clone the repo

git clone --depth 1 https://github.com/SecondLifes/delphi-expert

Made for: Cursor.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

README.md

[![agentmods](https://agentmods.dev/badge/rules/secondlifes/delphi-expert/threading-patterns/github.svg)](https://agentmods.dev/rules/secondlifes/delphi-expert/threading-patterns)

Your own site

<a href="https://agentmods.dev/rules/secondlifes/delphi-expert/threading-patterns"><img src="https://agentmods.dev/badge/rules/secondlifes/delphi-expert/threading-patterns/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

Your own site · 80×15

<a href="https://agentmods.dev/rules/secondlifes/delphi-expert/threading-patterns"><img src="https://agentmods.dev/badge/rules/secondlifes/delphi-expert/threading-patterns.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 0 Nothing until a file matches its globs; then the whole rule loads.

When invoked 732 The whole file, excluding the scripts and references it only reads on demand.

Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.

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 5.1	$0.00000	$0.00732
Opus 5.5	$0.00000	$0.00293
Sonnet 5.5	$0.00000	$0.00146
Haiku 4.5	$0.00000	$0.00073

Measured 1mo ago against content hash fa311cc64830, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

threading-patterns 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 1mo 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.

.cursor/rules/threading-patterns.mdc · 117 lines

How it starts

The opening of the file, as written. The whole thing — 117 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Threading & Multi-Threading — Rules

Use these rules when working with threads and asynchronous tasks in Delphi.

Golden Rule

NEVER access visual components (VCL/FMX) from a secondary thread. Use TThread.Synchronize (blocking) or TThread.Queue (non-blocking).

Approaches

Approach	When to Use
`TThread.CreateAnonymousThread`	Simple, one-shot tasks
`TTask.Run` (PPL)	Modern way, managed pool
`TParallel.For`	Parallel loop in collections
`TFuture<T>`	Asynchronous result with value
`TThread` (inheritance)	Permanent workers, queues, servers

Update UI from Thread

{ Queue: não-bloqueante (PREFERIR) }
TThread.Queue(nil,
  procedure
  begin
    lblStatus.Caption := 'Processando...';
  end);

{ Synchronize: bloqueante (quando precisa do resultado) }
TThread.Synchronize(nil,
  procedure
  begin
    lblStatus.Caption := 'Processando...';
  end);

TTask.Run — Modern Way

uses System.Threading;

TTask.Run(
  procedure
  begin
    { Código pesado em background }
    PerformWork;
    TThread.Queue(nil,
      procedure
      begin
        lblResult.Caption := 'Concluído';
      end);
  end);

Thread-Safety

Mechanism	When to Use
`TCriticalSection`	Classic critical section (Enter/Leave)
`TMonitor`	Object native lock (Enter/Exit)
`TInterlocked`	Atomic operations on Integer/Int64
`TThreadList<T>`	Thread-safe list with LockList/UnlockList
`TMultiReadExclusiveWriteSynchronizer`	Cache: many reads, few writes
`TThreadedQueue<T>`	Thread-safe queue (Producer-Consumer)

{ TCriticalSection — SEMPRE Leave no finally }
FLock.Enter;
try
  Inc(FSharedCounter);
finally
  FLock.Leave;
end;

{ TInterlocked — Operações atômicas simples }
TInterlocked.Increment(FProcessed);

Cancelamento

{ Via Terminated em TThread }
while not Terminated do
begin
  DoWork;
end;

{ Via token customizado em TTask }
if AToken.IsCancelled then
  Exit;

Read the full file on GitHub · 117 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.

1mo ago First seen · 117 lines · 0 tokens per session scan A fa311cc64830

Subscribe to this mod's changes

threading-patterns is a cursor rule published in the GitHub repository SecondLifes/delphi-expert (3 stars, last pushed 1mo ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 732 tokens. 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 2026-09-03.

Debugging

error-handling-and-validation

A code-quality guide for handling errors, invalid inputs, edge cases, preconditions, logging, and user-friendly error messages.

holtwood/awesome-cursorrules-zh · 185 tokens

css-render-blocking-diagnosis

Cursor rule "css-render-blocking-diagnosis" from adobecom/da-express-milo, covering css render-blocking diagnosis & resolution, critical learning from 98 pagespeed achievement, primary diagnostic protocol, step 1: css blocking symptom recognition and step 2: css loading sequence audit.

adobecom/da-express-milo · 1,102 tokens

threading-patterns