PPL Free Ground School
REMOTE · PPLFREE.COM · SCANNED SEP 27
Free FAA private-pilot ground school: source-cited answers, lessons and practice questions.
Available components
How this component scores in each security and reliability category. Every signal is checked automatically against the live server, and we only credit what we can confirm. How we score → Why this is hard to score →
Endpoint Security80
- The endpoint's TLS certificate is valid, in date, and uses a strong key. View diagnostics → Pass
- No authorisation is required to call this server. Every tool declares its destructiveHint and none is destructive, so open access doesn't expose one. See how to fix → View diagnostics → Partial
- HTTPS is enforced; there's no plaintext access path. View diagnostics → Pass
- The HSTS (Strict-Transport-Security) header is present. View diagnostics → Pass
- DNSSEC check failed: this domain isn't protected by DNSSEC. See how to fix → View diagnostics → Fail
Transport & Reachability100
- Verified streamable-http transport via a live MCP handshake. View diagnostics → Pass
Schema Quality & AI Usability71
- AI-judged instruction clarity (excellent).Pass
- Context-footprint check failed: tool/resource definitions use about 1037 tokens (~207/item across 5 items; 5 tools + 0 resources), over budget; trim descriptions and params. See how to fix → Fail
- Usage-examples check failed: none of the tools include examples. See how to fix → Fail
Stability & Change Management3
- Stability observed for 1 of 30 days with no destabilising changes; credit accrues until the full window elapses.Partial
Tool Coverage100
- 100% of tools have a non-trivial description (not blank, and not just the tool's name).Pass
- 100% of tool parameters carry a description.Pass
Tool Safety100
- No prompt-injection markers were found in the server instructions, tool names or descriptions we captured.Pass
- We read all 5 captured tool definition(s), and no name or description among them implies an irreversible operation.Pass
- An AI judge read all 6 captured unit(s) of tool text and found none that tries to manipulate the model reading it.Pass
Capabilities60
- Spec-recency check failed: implements MCP spec 2025-06-18; the latest is 2026-07-28. See how to fix → Fail
How do I install the PPL Free Ground School MCP server?
PPL Free Ground School is a hosted endpoint at https://pplfree.com/mcp, so there is nothing to install locally. Ready-made configuration for Claude, Cursor, VS Code, Codex and 5 more is on this page, copied from each client's own documentation.
remote · pplfree.com
claude mcp add --transport http com-pplfree-ground-school 'https://pplfree.com/mcp'
{
"mcpServers": {
"com-pplfree-ground-school": {
"url": "https://pplfree.com/mcp"
}
}
} {
"servers": {
"com-pplfree-ground-school": {
"type": "http",
"url": "https://pplfree.com/mcp"
}
}
} [mcp_servers.com-pplfree-ground-school] url = "https://pplfree.com/mcp"
{
"$schema": "https://opencode.ai/config.json",
"mcp": {
"com-pplfree-ground-school": {
"type": "remote",
"url": "https://pplfree.com/mcp",
"enabled": true
}
}
} openclaw mcp add com-pplfree-ground-school --url 'https://pplfree.com/mcp' --transport streamable-http
mcp_servers:
com-pplfree-ground-school:
url: "https://pplfree.com/mcp" {
"McpServers": {
"com-pplfree-ground-school": {
"Transport": "http",
"Url": "https://pplfree.com/mcp"
}
}
} assistant mcp add com-pplfree-ground-school -t streamable-http -u 'https://pplfree.com/mcp'
{
"mcpServers": {
"com-pplfree-ground-school": {
"type": "http",
"url": "https://pplfree.com/mcp"
}
}
} The mcpServers block is a cross-client convention. Remote transports vary, so check your client's docs.
Every change we have recorded for this component, newest first. Security-relevant changes are always shown. ▲ marks a change for the better, ▼ a change for the worse; unmarked changes are neutral.
- 27 Sept 26 0
- The server rewrote its instructions, which are the text every model session reads security
- Tool “get_practice_question” rewrote its description, which is the text the model reads security
- Schema quality: 185 → 207 ▼ functional
- Stability: unverified → 0.03 ▲ functional
- Server version: 1.0.0 → 1.1.0 functional
- New tool “check_answer” functional
- 26 Sept 26 72
First indexed and scored.
Diagnostic detail from the automated scan of this channel: what the scanner observed at each step, so you can see exactly where a check passed or failed. It is informational only and never changes the trust score.
Captured 27 Sept 2026 · Probed https://pplfree.com/mcp
TLS valid
Negotiated TLS 1.3 with TLS_AES_128_GCM_SHA256 .
| Subject | Issuer | Valid from | Valid until | Key | Signature | Serial |
|---|---|---|---|---|---|---|
| CN=pplfree.com | CN=WE1,O=Google Trust Services,C=US | 6 Sept 2026 | 5 Dec 2026 | ECDSA 256 | ECDSA-SHA256 | f5fe0551f13af0240ea7de63ed092a90 |
| SANs: pplfree.com, *.pplfree.com | ||||||
| CN=WE1,O=Google Trust Services,C=US (CA) | CN=GTS Root R4,O=Google Trust Services LLC,C=US | 13 Dec 2023 | 20 Feb 2029 | ECDSA 256 | ECDSA-SHA384 | 7ff31977972c224a76155d13b6d685e3 |
| CN=GTS Root R4,O=Google Trust Services LLC,C=US (CA) | CN=GlobalSign Root CA,OU=Root CA,O=GlobalSign nv-sa,C=BE | 15 Nov 2023 | 28 Jan 2028 | ECDSA 384 | SHA256-RSA | 7fe530bf331343bedd821610493d8a1b |
Background: What to check on a remote MCP endpoint →
DNSSEC insecure
Validation of pplfree.com. — Not signed
| Zone | DS | Keys | Algorithms | Outcome |
|---|---|---|---|---|
| . | trust_anchor | 20326, 38696 | 8, 8 | Verified |
| com. | present | 19718 | 13 | Verified |
| pplfree.com. | absent | Unsigned (proven) parent-signed NSEC/NSEC3 proves an unsigned delegation |
Authentication No authorisation required
The endpoint answered without asking for a token. Anyone who knows the URL can reach it.
| Result | No authorisation required |
|---|---|
| HTTP status | 200 |
| Header | Value |
|---|---|
| strict-transport-security | max-age=31536000; includeSubDomains; preload |
| content-security-policy | default-src 'self'; script-src 'self' 'nonce-MDgyNWU2ODItYWZkOC00MzZlLWE1OTYtOTY3NWFjNjQxNTRi' 'strict-dynamic' https://www.youtube.com; style-src 'self' 'unsafe-inline'; img-src 'self' data: https://*.google-analytics.com https://www.googletagmanager.com https://i.ytimg.com; font-src 'self'; connect-src 'self' https://*.google-analytics.com https://*.analytics.google.com https://analytics.google.com https://stats.g.doubleclick.net https://www.googletagmanager.com https://www.google.com; frame-src 'self' https://www.youtube-nocookie.com; frame-ancestors 'none'; object-src 'none'; base-uri 'self'; form-action 'self'; upgrade-insecure-requests |
| x-content-type-options | nosniff |
| x-frame-options | DENY |
| referrer-policy | strict-origin-when-cross-origin |
| permissions-policy | camera=(), microphone=(self), geolocation=() |
Background: How OAuth 2.1 works in the 2026 MCP spec →
Transports 2 probes
| Transport | URL | Outcome | Status | Location |
|---|---|---|---|---|
| streamable-http | https://pplfree.com/mcp | Verified | 200 | |
| http (plaintext) | http://pplfree.com/mcp | HTTPS enforced | 301 | https://pplfree.com/mcp |
The tools this component advertises to a client, with an estimated token cost for each. Expand a tool to see its parameters and schema. The per-tool counts are indicative and are not scored directly; the schema's total context footprint is one signal in Schema Quality & AI Usability. A tool's description is untrusted text the model reads on every call, which is what makes this list a security surface and not just an inventory: how tool poisoning works →
check_answer Check a practice answer ~234
Grade the user's answer to a practice question from get_practice_question. Use this when the user replies with their choice (for example "B" or "I think it is C"): pass the question_id and their choice. Returns whether the answer is correct, the correct choice, why each choice is right or wrong, and the FAA citations. It also returns save_progress_url, a pplfree.com link where the user can save the answers from this chat to their study progress on that site, and save_token: pass it back as previous_token on the next check_answer call so one link collects every answer in the chat (up to 20, valid for 7 days). Nothing is stored unless the user opens the link.
| Name | Type | Req | Description |
|---|---|---|---|
| choice | string | yes | The choice the user picked: its label (e.g. "b" or "B"). |
| previous_token | string | – | The save_token from the previous check_answer call in this chat, if any, so the save link keeps every answer. Omit on the first answer. |
| question_id | string | yes | The questionId returned by get_practice_question. |
No output schema declared.
No examples provided.
get_lesson Get a lesson ~113
Fetch one full ground-school lesson: its summary, why it matters in flight, the learning objectives it covers, and a link to read it. Use this after search_faa_knowledge when the user wants the whole topic rather than a single answer, or when they ask to study or learn a subject properly. Call list_curriculum first if you do not already have a lesson key.
| Name | Type | Req | Description |
|---|---|---|---|
| lessonKey | string | yes | Lesson key, e.g. "as.lesson.vfr-minimums". From list_curriculum. |
No output schema declared.
No examples provided.
get_practice_question Get a practice question ~293
Return private-pilot practice questions written for this course in the style of the FAA knowledge test (not actual FAA test questions), each with its answer choices, its topic, a question_id and a link to try it on pplfree.com. The correct answer is withheld by default so the user can attempt the question first. Once the user has answered, call check_answer with that question_id and their choice to grade it (or call this tool again with the question_id and reveal_answer: true to show the answer without grading). Use this when the user wants to be quizzed, asks for practice or test questions, wants to check their understanding of a topic, or is preparing for the FAA private-pilot knowledge test. Optionally scope it to a topic.
| Name | Type | Req | Description |
|---|---|---|---|
| count | integer | – | How many questions to return (1-5, default 1). |
| question_id | string | – | A question_id from an earlier call, to return that exact question (typically with reveal_answer: true). Overrides topic and count. |
| reveal_answer | boolean | – | Include the correct choice and the explanation. Default false: leave it off until the user has attempted the question. |
| topic | string | – | Optional topic to draw from, e.g. "airspace", "weather", "aerodynamics", "regulations", "navigation", "weight-balance", "systems". Omit for any topic. |
No output schema declared.
No examples provided.
list_curriculum List the curriculum ~83
List the ground-school curriculum: modules and the published lessons in each, with their keys. Use this to orient yourself before get_lesson, to answer "what does the course cover", or to help a user plan what to study next.
| Name | Type | Req | Description |
|---|---|---|---|
| module | string | – | Optional module key to expand, e.g. "MOD-08". Omit for all modules. |
No output schema declared.
No examples provided.
search_faa_knowledge Search FAA ground-school knowledge ~155
Answer a US private-pilot (FAA) ground-school question from a source-cited curriculum. Use this whenever the user asks about FAA regulations, airspace, VFR weather minimums, weight and balance, aerodynamics, aircraft systems, navigation, weather theory, human factors, or private-pilot certification requirements. Returns short passages, each with the FAA citation it came from (e.g. "14 CFR 91.155", "PHAK Ch. 15") and a link to the lesson. Cite those labels in your answer.
| Name | Type | Req | Description |
|---|---|---|---|
| limit | integer | – | How many passages to return (1-8, default 4). |
| query | string | yes | The user's question, in their own words. |
No output schema declared.
No examples provided.
What is the PPL Free Ground School MCP server?
PPL Free Ground School is an MCP server listed in the public MCP registry as com.pplfree/ground-school. Free FAA private-pilot ground school: source-cited answers, lessons and practice questions. This page covers its hosted endpoint (https://pplfree.com/mcp).
Is the PPL Free Ground School MCP server safe to use?
PPL Free Ground School scores 72 out of 100 on VerifyMCP. That is a record of what we were able to check automatically, not an endorsement. The category breakdown on this page shows every signal behind the number, including the ones we could not confirm.
What tools does the PPL Free Ground School MCP server expose?
PPL Free Ground School exposes 5 tools: search_faa_knowledge, get_practice_question, check_answer, get_lesson, list_curriculum. Their descriptions and schemas cost roughly 878 tokens of context every time the server is loaded.
Does the PPL Free Ground School MCP server require authentication?
No. We connected to PPL Free Ground School without credentials and it answered, so anything it exposes is reachable by anyone who knows the address.
Is the PPL Free Ground School MCP server still maintained?
PPL Free Ground School is still listed as active in the MCP registry. We last reached this channel on 27 September 2026. Those dates come from our own scans of the registry and the channel itself, not from anything the publisher announced.