QGroundControl is a cross-platform ground control station for unmanned aircraft, allowing operators to control MAVLink-enabled drones and plan their missions. Drone users work with it to monitor flights, configure vehicles, tune parameters, stream video, and manage autonomous missions, while the catalogue contains skills and instructions for using the application.
Borrowing it
Nothing to install: this file belongs to mavlink/qgroundcontrol. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/mavlink/qgroundcontrol/master/.github/instructions/forward-declarations.instructions.mdgit clone --depth 1 https://github.com/mavlink/qgroundcontrolWrote 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.
[](https://agentmods.dev/instructions/mavlink/qgroundcontrol/forward-declarations)<a href="https://agentmods.dev/instructions/mavlink/qgroundcontrol/forward-declarations"><img src="https://agentmods.dev/badge/instructions/mavlink/qgroundcontrol/forward-declarations/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.
<a href="https://agentmods.dev/instructions/mavlink/qgroundcontrol/forward-declarations"><img src="https://agentmods.dev/badge/instructions/mavlink/qgroundcontrol/forward-declarations.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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 | $0.00246 | $0.00246 |
| Opus 5.5 | $0.00098 | $0.00098 |
| Sonnet 5.5 | $0.00049 | $0.00049 |
| Haiku 4.5 | $0.00025 | $0.00025 |
Grade A, and why
qgroundcontrol forward-declarations.instructions.md 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 2mo 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.
What it actually says
Forward Declaration Rules for Headers
Prefer forward declarations and lightweight type headers over including full class definitions.
Vehicle.h
Vehicle.h is one of the heaviest headers in the codebase. Most headers that reference Vehicle only need:
- A pointer/reference to Vehicle →
class Vehicle;forward declaration - Vehicle type aliases →
#include "VehicleTypes.h"
Only include Vehicle.h if the header calls Vehicle methods, accesses Vehicle members, or inherits from Vehicle.
QGCMAVLink.h
QGCMAVLink.h combines MAVLink enums, message types, and QGC-specific type aliases. Most headers only need one of these. Use the specific lightweight header instead:
MAVLinkEnums.hfor enum constantsMAVLinkMessageType.hformavlink_message_tQGCMAVLinkTypes.hforFirmwareClass_t,VehicleClass_t
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.
- 2mo ago First seen · 24 lines · 246 tokens per session scan A 3a75729a7a0c
qgroundcontrol forward-declarations.instructions.md is an instructions file published in the GitHub repository mavlink/qgroundcontrol (5,076 stars, last pushed today), licensed Apache-2.0. It adds 246 tokens to every session, about $0.0010 per session on Opus 5.5. 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.
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